CN212674463U - Visual test device for accurately testing unsteady detonation flame arrester effect of combustible gas - Google Patents

Visual test device for accurately testing unsteady detonation flame arrester effect of combustible gas Download PDF

Info

Publication number
CN212674463U
CN212674463U CN202022000550.7U CN202022000550U CN212674463U CN 212674463 U CN212674463 U CN 212674463U CN 202022000550 U CN202022000550 U CN 202022000550U CN 212674463 U CN212674463 U CN 212674463U
Authority
CN
China
Prior art keywords
pipeline
detonation
flame
unsteady
ignition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202022000550.7U
Other languages
Chinese (zh)
Inventor
肖华华
李晓曦
孙金华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Science and Technology of China USTC
Original Assignee
University of Science and Technology of China USTC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Science and Technology of China USTC filed Critical University of Science and Technology of China USTC
Priority to CN202022000550.7U priority Critical patent/CN212674463U/en
Application granted granted Critical
Publication of CN212674463U publication Critical patent/CN212674463U/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Investigating Or Analyzing Materials Using Thermal Means (AREA)

Abstract

The utility model discloses a visual test device of accurate test combustible gas unsteady state detonation spark arrester effect, including vacuum system, automatic gas distribution system, schlieren camera system, unsteady state detonation block experimental combustion pipeline, test and data acquisition system, high pressure ignition and synchronous control system. The utility model discloses a deflagration changes detonation process and spark arrester back-fire relief process in the recording pipeline is shot to the method that high-speed camera shooting technique and schlieren optical technology combined together, realizes that non-stable state detonation generates and blocks the visualization of overall process, accurately presents the shape including flame and detonation wave and the dynamic change law of position along with time directly perceivedly. The dynamic rising characteristic of the pressure in the pipeline is measured by using the pressure sensor, and the correlation between the pressure in the pipeline and the characteristics of flame and detonation waves can be analyzed by combining a high-speed schlieren image. The position changes of the initial flame and the later detonation wave are obtained by detecting the light intensity changes in the pipeline through the photodiode, and the propagation speeds of the flame and the detonation wave at all times can be obtained by combining high-speed schlieren image analysis and calculation.

Description

Visual test device for accurately testing unsteady detonation flame arrester effect of combustible gas
Technical Field
The utility model belongs to the technical field of the safety, concretely relates to visual test device of accurate test combustible gas and air or oxygen premix gas unsteady state detonation spark arrester effect.
Background
Combustible gases (such as hydrogen, methane, ethylene and the like) are widely applied to the fields of petroleum, electric power, mining, metallurgy, transportation, chemical industry, fuel gas supply and the like due to the advantages of cleanness, high efficiency, wide sources and the like. On the other hand, however, safety concerns during production, transportation, storage and use of combustible gases are of particular concern due to the hazardous nature of combustible gases which are inherently flammable, explosive, susceptible to leakage and low ignition energy. If the combustible gas is improperly controlled or used, the combustion-supporting gas such as air or oxygen enters the limited space containing the combustible gas, premixed gas is formed, and accidents such as fire and explosion are easily caused. The industrial pipeline is a common limited space, and the general industrial pipeline has various process flows, various production and manufacturing environment states, various types of conveyed media and harsh conditions, so that the inducement and evolution process of fire and explosion accidents in the industrial pipeline are more complicated. In the event of a premixed gas explosion in an industrial pipeline, the combustion mechanism of the flame generally undergoes a laminar-flow turbulent flow, and the combustion wave also progresses from slow combustion to deflagration, and even finally, extremely destructive detonation can be formed. Detonation is a combustion reaction form which is propagated in a shock wave compression mode at an ultrasonic speed relative to a front medium, the formation and propagation mechanism of the detonation is very complex, and the detonation comprises various contents such as chemical reaction kinetics, shock wave kinetics, hydromechanics and the like, and is one of the problems which are not completely solved in the field of combustion and industrial safety. The formation of detonation waves can be achieved by two basic processes of direct detonation and deflagration to detonation respectively. The direct detonation requires a strong ignition source, and forms a strong shock wave through instantaneous energy release, so that the shock wave is developed into a detonation wave; the detonation energy required in the process of converting detonation into detonation is small, the detonation wave gradually develops into the detonation wave under a certain condition, and the detonation wave is influenced by various factors such as turbulence, shock wave action, shear layer instability, boundary layer and the like. The ignition process in engineering practice usually uses lower ignition energy, so that detonation formation generally changes from deflagration to detonation. In the test, a combustion pipeline with obstacles is generally adopted to simulate the process of converting the deflagration of combustible premixed gas into the detonation in the industrial pipeline, and at the moment, the process of converting the deflagration into the detonation substantially comprises two stages of a gradual acceleration process of deflagration waves and sudden formation of the detonation waves. Firstly, the low-speed flame can be continuously accelerated to be high-speed turbulent flame under the action of the barrier under a certain condition; then local initiation centers, i.e. initiation hot spots, can be generated in the vicinity of the boundary layer instability regions or turbulent flame surfaces. Stronger compression waves generated by hot point initiation induce stronger chemical reaction in the outward propagation process to form detonation waves, and then form unsteady over-drive detonation waves which continuously grow and catch up with leading shock waves. The overdrive detonation wave is accelerated, and is attenuated to a Chapman-Jouguet (C-J) steady-state detonation wave after being propagated for a certain distance. Later steady-state C-J detonation can be qualitatively and quantitatively analyzed by using classical C-J theory and ZND (Zeldovich, von Neumann, Doring) model, however, initial unsteady detonation is unpredictable. Although qualitative explanation theory has been provided for the hot spot formation and initiation mechanism of deflagration to detonation, the critical initiation conditions, time and position of hot spot formation are not clear, and the result of quantitative prediction is lacked. The process of detonation wave acceleration to form detonation waves is essentially controlled by the interaction of the combustion reaction zone with nonlinear pressure waves, and also depends on the formation of critical detonation conditions. Even for a detonatable mixture given initial and boundary conditions, it is still difficult to predict whether or when and where the deflagration to detonation event occurs. Therefore, it is often difficult to control deflagration to detonation formation during testing, which presents difficulties for engineering applications, such as the design of detonation flame arresters. And because of the high cost and danger of gas combustion and explosion tests, numerical simulation research is carried out on the process of converting deflagration to detonation by using high-performance computers at home and abroad at present, and a test technology platform test capable of accurately controlling the formation of deflagration to detonation is lacked.
Meanwhile, the existing explosion test platform is difficult to realize accurate measurement and control of unstable states such as over-drive detonation at the initial stage of explosion. The movement speed and pressure of the early-stage over-drive detonation wave are both greater than those of the later-stage C-J steady-state detonation, the pressure of the wave surface of the over-drive detonation wave can reach nearly twice that of the C-J steady-state detonation wave surface, and the over-drive detonation wave has greater destructive power. The related researches such as prevention of the formation of the over-drive detonation wave, or blocking of the formed over-drive detonation wave to reduce the destructive capacity thereof, are of great significance to the prevention and treatment of the explosion accident. Flame arrestors are often used in industrial processes to provide protection for storage, transportation, and chemical processing equipment of combustible gases. Flame arrestors, which are devices that allow gas flow but prevent the propagation of deflagration or detonation flames in gas pipelines and related equipment, are effective devices for quenching flames and assisting the free flow of gases in systems, and especially those of the detonation-resistant type are most complex in structure, and are required to quench the detonation front moving at supersonic velocity and withstand the great pressure generated by detonation waves. Compared with the steady-state detonation-resistant flame arrester, the unsteady-state detonation wave passing through the unsteady-state detonation-resistant flame arrester mainly relates to the over-drive detonation formed by the detonation-to-detonation transition, the propagation speed is higher, and the wave surface pressure of the detonation wave is higher, so that the requirement on the detonation-resistant effect of the unsteady-state detonation-resistant flame arrester is higher. At present, few devices for testing the fire-retardant effect of the unsteady-state detonation-resistant type fire arrester at home and abroad exist, the existing devices have great uncertainty, and the detonation wave entering the fire arrester can be a steady-state detonation wave with small wave surface pressure instead of an unsteady-state over-drive detonation wave. Therefore, the flame arrester cannot ensure the blocking effect on the powerful over-drive detonation waves, and the conventional testing device with high uncertainty can cause great safety risk when applied to an industrial process.
Visual research is carried out to combustible premixed gas deflagration to detonation transition process, the required pipeline length of quantitative deflagration to detonation process, and then development unsteady state detonation spark arrester back-fire relief's accurate test technique, not only can reveal the mechanism that deflagration changes the detonation, still can provide theoretical foundation for developing the unsteady state detonation spark arrester of more efficient. Meanwhile, reliable test basis and technical guidance are provided for preventing and controlling explosion accidents and realizing safe utilization of the gas fuel.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to prior art not enough, provide one kind and can survey the visual test device that combustible gas and air or oxygen premixed gas deflagration changes detonation process and can accurate test unsteady state detonation spark arrester effect. The apparatus may be used to: (1) the characteristics and the rules of the process of converting the deflagration to the detonation of the premixed gas under the influence of factors such as different combustible gas components, premixed gas with different equivalent ratios, different ignition positions, different ignition energies, obstacles with different heights (namely different blocking rates) and the like are researched, and the mechanism of converting the deflagration to the detonation is further perfected; (2) accurately testing the blocking effect of the unsteady state detonation flame arrester on the unsteady state detonation wave; (3) the visualization of the deflagration to detonation process and the visualization of the fire-retarding effect of the unsteady detonation flame arrester are realized.
The utility model adopts the technical scheme as follows: the utility model provides a visual test device of accurate survey combustible gas test unsteady state detonation spark arrester effect, whole test device includes vacuum system, automatic gas distribution system, schlieren camera system, unsteady state detonation block experimental burning pipeline, test and data acquisition system, high pressure ignition and synchronous control system.
The vacuum system comprises a vacuum pump and a vacuum pressure gauge, wherein the vacuum pump device is used for extracting air in the combustion pipeline. During the test, the air inlet at the left end of the pipeline is closed, the vacuum pump is connected to the pressure relief opening at the right end of the downstream pipeline to begin to pump air, when the reading in the vacuum pressure gauge connected to the upper wall surface of the upstream pipeline is equal to zero (or less than zero and related to the local atmospheric pressure) and is kept stable within a period of time, the vacuum state is achieved, and the vacuum pump is closed at the moment.
The automatic gas distribution system is used for configuring combustible gas with target concentration. The concentration of combustible gas is controlled by a high-precision mass flow Meter (MFC) in the shell, and all the flow meters are directly controlled by a computer of the control platform through electromagnetic valves. During gas distribution, concentration parameters in computer matched software are set, combustible gas and combustion-supporting gas (air or oxygen) in a raw material gas cylinder are conveyed into a gas mixing chamber in a target equivalence ratio to be uniformly mixed, and then the gas mixing chamber is connected with a combustion pipeline gas inlet valve through a pipeline.
The schlieren camera system includes a schlieren instrument and a high speed camera and is arranged in a standard "Z" pattern with the combustion conduit in the central path of the optical path. The schlieren instrument includes schlieren light source, focusing lens, slit, a pair of reflecting concave mirrors and schlieren edge, and is a general optical display instrument for observing the refractive index change of transparent medium density and temperature distribution in the medium. When premixed flame or detonation waves propagate in the pipeline, obvious density difference exists near the flame or the front of the reaction area, and when light passes through the flow field, the direction, the position and the optical path of the light are changed, so that the density discontinuities can be captured by using an optical measurement method, and the internal flow field cannot be interfered. After light emitted by the schlieren point light source passes through the focusing lens, the filament is imaged on the slit. And adjusting the slit to generate divergent beams, transmitting the divergent beams to the corresponding reflecting concave mirror, receiving the generated parallel beams by the reflecting concave mirror on the other side after passing through the combustion pipeline to generate convergent beams, and then entering the high-speed camera through the schlieren edge and the focusing lens. The high-speed camera visually presents the process of flame evolution and detonation-to-detonation in the pipeline by recording the first-order derivative distribution image of the density of the flow field, and the propagation speed of flame and detonation wave can be calculated by pictures shot by the high-speed camera.
The unsteady detonation blocking test combustion pipeline is mainly used for observing and determining the forming mode and the forming position of unsteady detonation in the combustion pipeline, ensuring that deflagration-to-detonation transition is quickly formed within a certain distance from the ignition position, and testing the blocking effect of the unsteady detonation flame arrester on unsteady detonation waves. The characteristic that premixed gas with different components or the same components but different equivalent ratios can be subjected to deflagration to detonation conversion can also be researched through an unsteady state detonation blocking test combustion pipeline, a schlieren photo is obtained through the combination of a schlieren technology and a high-speed camera, the distance from a detonation generating position to a ignition position is further calculated, and multiple tests are repeated under the same test working condition to obtain the run-up distance (run-up distance) required by deflagration to detonation conversion under the condition.
The unsteady state detonation blocking test combustion pipeline is a straight pipeline with a horizontal rectangular section, and comprises six combustion pipelines, namely: the device comprises an upstream pretest pipeline, an upstream segmented combined pipeline, a telescopic joint, an intermediate pipeline, an unsteady detonation flame-retardant segment and a downstream pipeline. The high-speed schlieren camera system can shoot schlieren images in the pipeline conveniently, visualization of a flame propagation process, a deflagration-to-detonation process and a detonation-resistant process is achieved, and accordingly the forming position of unsteady detonation is determined and the fire-retardant effect of a fire-retardant section is observed. The upper wall surface and the lower wall surface of all pipelines are made of stainless steel plates, and the foremost end, the last end (tail end) and the end wall surfaces are also made of stainless steel plates. Except the fire retardant section, the upper wall surface and the lower wall surface in the other part of the pipeline are respectively symmetrically provided with continuous triangular barriers made of stainless steel, and the disturbance acceleration effect of the continuous triangular barriers on flame can enable deflagration to detonation to be formed in a short distance. The unsteady state detonation flame-retardant section comprises a flame-retardant core and a stainless steel shell. The fire retardant core that the multiple detonation type of hindering that the fire retardant core can choose for use corresponds, like buckled plate, foam metal and packing gravel etc. for the test different materials hinder the inhibitory action of section to unsteady state detonation. Optical glass is arranged on the left side and the right side of the fire retardant section and used for observing the blocking process of the unsteady detonation in the fire retardant section. The stainless steel shell of the pipeline is used for fixing the inner fire retardant core and butting with the outer pipeline.
For guaranteeing that the set of test device is effective really in the actual industrial process, on the basis of laboratory small-size test, the size of the test device can be increased integrally, and then the larger unsteady state detonation flame arrester of connecting dimension is connected, thereby accurately testing the fire-arresting effect of the unsteady state detonation flame arresters of various sizes and meeting the industrial application requirement. Besides different fire retardant core materials, the flame retardant device can replace industrial flame retardants with different structures, and the accurate measurement of the flame retardant effect of various different types of detonation-resistant flame retardants is realized.
An exhaust pipeline is arranged on the lower side wall surface of the downstream pipeline close to the rightmost end, an insulating valve is arranged, the exhaust pipeline is opened when the pipeline is inflated, the smooth air flow in the pipeline is ensured, and the phenomenon that air is blocked in the pipeline to cause overpressure in the pipeline is avoided. A pressure relief opening is arranged on the end wall of the downstream pipeline, an insulating valve is arranged, and the pressure relief opening is opened during vacuum pumping so as to meet the requirement of vacuum pumping from the pressure relief opening; sealing during inflation, and discharging replaced air and redundant mixed gas from a lower wall surface exhaust pipeline; and the test device is opened during the test, and combustion products are discharged to realize pressure relief, so that the safety of the deflagration to detonation test in the pipeline is ensured. The upstream pretest duct and the upstream segmented modular duct are each provided with an insulated valve at the left end wall for controlling the start and end of the inflation process.
The accurate determination of the occurrence position of detonation to detonation is a key point for testing the effect of an unsteady detonation flame arrester, and is also one of difficulties. Therefore, a pre-test is required before formally starting a detection test of the flame arrester effect, the purpose is to preliminarily determine the length of a pipeline required to be propagated by flame before the occurrence of the unsteady detonation, namely, the run-up distance from the detonation to the detonation, and further ensure that the length of the fire-arresting section from the ignition position is the run-up distance when the test of the flame arrester effect is carried out, so that the detonation to the detonation is generated right ahead of the fire-arresting section, the unsteady detonation wave at the initial stage of the detonation is ensured to smoothly enter the fire-arresting section, and finally the accurate test of the unsteady detonation-arresting effect of the fire-arresting section is realized. When in pretest, the upstream pretest pipeline, the unsteady detonation flame-retardant section and the downstream pipeline are connected, the occurrence position of deflagration to detonation is observed through a schlieren picture shot at a high speed, and the run-up distance is calculated. In addition, when the pre-test is carried out, other parameters are set to be the same, but the characteristics of the process of converting the premixed gas from deflagration to detonation under the influence of different blockage rates can be researched by the obstacle pipelines with different heights. The blockage ratio is defined herein as the ratio of twice the height of the pipe (two pairs of obstacles symmetrically disposed on the upper and lower walls) to the height of the pipe. After the run-up distance is obtained through testing, the run-up distance is used for testing the fire-retardant effect of the unsteady detonation flame arrester. Usually, the length of the upstream pretest pipeline deviates from the run-up distance, at this time, if the upstream pipeline is reprocessed, the project progress is delayed, the influence on the flow field is difficult to effectively adjust after the length of the pipeline is increased, the length of the upstream pipeline needs to be continuously adjusted to keep consistent with the run-up distance, the process is complicated, the consumed time is long, and therefore after the run-up distance is determined, the pipeline length needs to be quickly adjusted through the adjustable pipeline. If the length of the upstream pretest pipeline is greater than or less than the run-up distance measured in the pretest, the upstream pretest pipeline needs to be replaced by an adjustable pipeline structure formed by combining an upstream segmented combined pipeline, an expansion joint and a middle pipeline, and then the fire blocking section and the downstream pipeline are connected. The upstream sectional combined pipeline consists of a plurality of sections of pipe sections which are uniformly divided and have the same structure, is used for increasing or reducing the pipe sections according to the result of the pretest, and is matched with the telescopic joint and the middle pipeline, so that the sum of the three sections of the upstream sectional combined pipeline, the telescopic joint and the middle pipeline is the run-up distance, and the unstable detonation is ensured to be generated right in front of the fire retardant section.
The expansion joint is a special small section of pipeline with adjustable length within the expansion range, and is mainly used for compensating the change of the length of the pipeline and the change of the position of unsteady detonation caused by the influence of the expansion joint on a flow field. After the upstream pretest pipeline is replaced by a combined structure of three parts, namely an upstream segmented combined pipeline, a telescopic joint and a middle pipeline, the position of deflagration to detonation (namely the position of unsteady detonation) can be slightly advanced or delayed relative to the pretest. Therefore, an expansion joint needs to be connected into the pipeline, and if the detonation-to-detonation position is advanced, the small expansion joint is contracted; if the detonation-to-detonation position is delayed, the small-section telescopic joint is extended, so that the position where the unsteady detonation occurs is controlled at the run-up distance on the basis of ensuring that the pipeline at other parts is not changed, and the unsteady detonation wave entering the fire-blocking section is ensured. The wall adopts stainless steel material about the telescopic joint, and the junction with upper reaches pipeline and back-fire relief section adopts the spacing expansion joint of two flanges to make both sides all with flange joint, adjusts the length of being connected of telescopic joint both ends and flange during the installation, and the gland bolt is evenly screwed up in proper order to the diagonal angle, and spacing nut has been adjusted again, just so can let the telescopic joint extend or shorten in flexible volume within range, and the flexible volume of locking ensures the safe operation of pipeline. Because the wall is also stainless steel about the telescopic joint, can't guarantee in this subsection visual, consequently need connect one section visual intermediate pipe behind it (also before the section of putting into a fire stopping promptly) to confirm the concrete position before unsteady state detonation wave gets into the back-fire stopping section.
The structure, the material and the like of the intermediate pipeline are completely the same as those of the upstream pretest pipeline and the downstream pipeline, only the length of the intermediate pipeline is short, and the length of the intermediate pipeline can be properly increased or shortened in the pipeline processing before the test according to the difference of unsteady detonation run-up distances caused by the difference of initial working conditions such as test gas components or gas equivalent ratio. Finally, before a fire retardant effect test of the fire retardant section is carried out, the sum of the lengths of the three parts of the upstream sectional combined type pipeline, the expansion joint in the initial state and the middle pipeline is equal to the run-up distance obtained by the pre-test, and the expansion joint is finely adjusted according to the actual condition in the process of the fire retardant effect test so as to ensure that the unsteady detonation occurs right in front of the fire retardant section.
The test and data acquisition system comprises a high-frequency dynamic pressure sensor, a photodiode and a data acquisition instrument; a group of high-frequency dynamic pressure sensors and photodiodes are arranged on the central lines of the upper wall surface and the lower wall surface of the upstream pretest pipeline and the upstream segmented combined pipeline at intervals according to the length of the pipelines, and the pressure sensors are used for recording pressure changes in the pipelines and monitoring the formation and development of detonation waves. The sensing part of the pressure sensor converts the pressure signal into weak electric charge with very high output impedance, and the weak electric charge is converted into voltage in direct proportion with the voltage through the adaptive charge amplifier and the high output impedance is converted into low output impedance. The charge amplifier is connected with a dynamic data acquisition system, and the selected data acquisition system has higher sampling frequency and a plurality of input units and is used for capturing deflagration flame and detonation waves with extremely high propagation speed and synchronously acquiring a plurality of signals. The photodiode is a semiconductor device composed of a PN junction, has a one-way conductive characteristic, and can convert an optical signal into an electric signal to form a photoelectric sensing device when the current of the photodiode is changed due to the change of light, and the larger the intensity of the light is, the larger the reverse current is. The photodiode is directly connected with the data acquisition instrument, and the positions of flame and detonation wave propagation and arrival in the pipeline can be detected through signal intensity change. And a group of pressure sensors and photodiodes are arranged on the upper wall surface and the lower wall surface of the middle pipeline close to the fire retardant section, so as to detect the pressure and the light intensity when the over-drive detonation waves are formed. Meanwhile, a group of pressure sensors and photodiodes are also installed on the upper wall surface and the lower wall surface of the downstream pipeline close to the middle fire-retardant section, and are used for detecting pressure and light signals in the pipeline behind the fire-retardant section, and combining with the streak images in the fire-retardant section and the downstream pipeline which are shot by the high-speed streak image shooting system, the visualization of detonation blocking and the subsequent process is realized, so that whether unsteady detonation waves are completely blocked by the fire-retardant section or not is judged, and if the pressure and light signal curves obtained by the data acquisition instrument in the downstream pipeline have no abrupt change and no flame is observed in the downstream pipeline in the streak images, the unsteady detonation waves are completely blocked by the fire-retardant section. If the pressure and optical signal curves have no abrupt change in the results of the test times (13) continuous tests and GB/T13347-2010) repeated tests according to the national standard and no obvious detonation reaction front or flame is observed in the schlieren image, the fire-retardant section has excellent performance and can effectively block the unsteady detonation; if obvious detonation reaction front or flame is observed in a primary curve with abrupt change or a schlieren image in 13 continuous tests, which indicates that unstable detonation is not effectively blocked by the fire retardant section, the fire retardant performance of the fire retardant section is considered to be unqualified, and the performance of the fire retardant section can be optimized by changing the structure of a fire retardant core material or the fire retardant section, so that a feasible scheme is provided for further developing a high-performance unstable detonation flame arrester.
The high-voltage ignition and synchronous control system mainly comprises a high-voltage igniter, an ignition electrode, an ignition energy oscilloscope, a high-voltage probe and a current probe which are adaptive, a synchronous controller and an ignition switch. The high-voltage igniter is a high-voltage pulse generator for realizing ignition through capacitor energy storage discharge, and the high voltage range is 5000-. Ignition electrodes are arranged on the left end wall face of the first section of the upstream pretest pipeline and the upstream segmented combined pipeline in pairs, the ignition position of each ignition electrode is located on the center line of the upstream pipeline and the center line of the downstream pipeline, and the ignition position can be changed along the center line according to test requirements, so that the characteristic and the law of the process of converting the premixed gas from deflagration to detonation under the influence of different ignition positions are researched. The ignition electrode discharge triggering is realized by a synchronous controller, and the premixed gas is ignited by high-voltage electric sparks generated by the point instantaneous discharge. In the instantaneous ignition process, the applicable high-voltage probe and the current probe are connected to the ignition electrode end heads exposed on the outer sides of the upper wall surface and the lower wall surface of the pipeline, voltage and current data of ignition sparks of the ignition device are captured in real time and fed back to the oscilloscope, and the energy value of the ignition sparks of the ignition device is obtained through mathematical calculation in the oscilloscope. Different ignition energies can be generated by setting different capacitors and voltage values in the high-voltage igniter, so that different ignition capacities of the premixed combustible gas are determined. In the test process, the synchronous control and synchronous triggering of the high-voltage ignition system, the high-speed camera and the data acquisition system are realized through the programmable synchronous controller.
The synchronous controller mainly comprises a CPU and a control panel. The high-voltage igniter, the high-speed camera and the data acquisition instrument are connected to the synchronous controller at the same time, and the core component CPU precisely controls the triggering time of each terminal by setting and storing the triggering sequence and time interval of each component. In addition, it is necessary to separately configure a power supply and set a different operating voltage for each terminal. The ignition switch is connected with the synchronous controller and is used as a final trigger device of each system.
Wherein, the working process of the test device is as follows:
(ii) Pre-test procedure
(1) Adjusting the temperature of the laboratory to the initial temperature required by the test;
(2) installing and debugging a test device, connecting an upstream pretest pipeline, an unsteady state detonation fire-blocking section and a downstream pipeline which are required by a pretest, and simultaneously ensuring that test systems (an automatic gas distribution system, a test and data acquisition system, a schlieren camera system and a high-pressure ignition and synchronous control system) of each part have good states and work normally;
(3) opening each test device, and preheating for 30 minutes;
(4) meanwhile, a vacuum pump device is utilized to vacuumize the combustion pipeline, and then the air tightness of the pipeline is checked to ensure that the air tightness of the pipeline is good;
(5) an intake valve of the combustion pipe and an exhaust pipe of the rightmost lower wall surface are opened. Combustible premixed gas with target concentration configured by the automatic gas distribution system is conveyed into a combustion pipeline through an air inlet pipeline, and other gas or impurities in the pipeline are discharged from an exhaust pipeline by adopting a replacement method. When the gas distribution system software displays that the gas concentration reaches the target concentration and the concentration value is stable, stopping gas distribution and finishing gas distribution and inflation work;
(6) closing the air inlet valve and the air outlet valve of the combustion pipeline, and standing for about 30 seconds to ensure that the combustible gas mixture is in a stable and uniform mixing state;
(7) opening the high-voltage ignition system, and setting the ignition voltage of the high-voltage ignition system to a target value;
(8) starting and adjusting a high-voltage probe, a current probe, an ignition energy oscilloscope, a data acquisition instrument, a high-speed camera and a synchronous controller to a state to be triggered;
(9) after the preparation is finished, an ignition switch connected with the synchronous controller is pressed, a high-voltage ignition system is started, the ignition in the tube is realized through the point discharge of an ignition electrode, the energy value of instantaneous discharge is obtained through each probe and an ignition energy oscilloscope, meanwhile, a high-speed camera and a data acquisition instrument are sequentially triggered according to preset time, the process of flame acceleration and detonation-to-detonation conversion is shot, and the dynamic changes of the pressure and the light intensity in the tube are measured;
(10) after the primary flame acceleration and detonation-to-detonation test is finished, storing image data of the high-speed camera and pressure and optical signal data recorded by the data acquisition instrument into a target memory card to prepare for subsequent data processing and analysis;
(11) cleaning the combustion pipeline, resetting each test device, and preparing to start the next group of repeated tests;
(12) carrying out at least 13 repeated tests under the same test working conditions including the same combustible premixed gas components, equivalent ratio and the like, researching the characteristics of the process of converting detonation into detonation, obtaining the run-up distance of converting detonation into detonation of each group by analyzing the image data of the high-speed camera and the pressure and optical signal data recorded by the data acquisition instrument, and finally obtaining the fixed run-up distance of converting detonation into detonation under the test working conditions by taking the average value to reduce the error;
(13) besides the application of obtaining the run-up distance, the working condition can be changed after the repeated test under the same working condition of the step (12), such as changing the components of the combustible gas by connecting different gas inlet cylinders, changing the equivalence ratio of the combustible gas by setting the parameters of gas distribution system software, changing the ignition position by setting different punching installation positions of the ignition electrode, changing the ignition energy output by the ignition electrode by setting the ignition voltage of the high-voltage igniter, changing the blockage rate of the pipeline (namely the ratio of the height of the obstacle to the height of the pipeline on the same longitudinal section) by setting triangular obstacles with different heights, and carrying out repeated tests in each group, and further researching the characteristics and the law of the process of converting the premixed gas from deflagration to detonation under the influence of factors such as different combustible gas components, premixed gases with different equivalence ratios, different ignition positions, different ignition energies, different pipeline blockage rates and the like.
(II) testing process for fire-retardant effect of unsteady detonation fire-retardant section
(A) Selecting the number of sections of the upstream segmented combined pipeline according to the run-up distance obtained in the pre-test process step (12), enabling the sum of the lengths of the upstream segmented combined pipeline, the telescopic joint and the middle pipeline to be the length of the run-up distance, connecting the starting end of the fire-retardant section to the rear of the middle pipeline and connecting the tail end of the fire-retardant section to the front of the downstream pipeline, then repeating the steps (3) - (11) in the pre-test, observing and judging whether the occurrence position of the unsteady detonation is right in front of the fire-retardant section or not through a schlieren image shot by a high-speed camera, pressure obtained by a pressure sensor and a photodiode and judging whether the occurrence position of the unsteady detonation is right in front of the fire-retardant section or not through the pressure; if the occurrence position of the unstable detonation is delayed, the length of the telescopic joint is prolonged, and the unstable detonation is ensured to occur right in front of the fire retardant section;
(B) after a testing experiment of the fire retardant effect of the unsteady detonation fire retardant section is completed, storing image data of a high-speed camera and pressure signals and optical signal data recorded by a data acquisition instrument, researching the process of blocking unsteady detonation waves of the fire retardant section through schlieren images shot by the high-speed camera, simultaneously, observing whether obvious flames exist in a downstream pipeline or not by the schlieren images, and judging the blocking effect of the fire retardant section on the unsteady detonation waves by combining a group of pressure sensors, photodiodes and high-speed schlieren images of the upper wall surface and the lower wall surface of the downstream pipeline, which are close to the fire retardant section. If the pressure sensor and the photodiode do not detect a sudden change signal and no obvious detonation reaction front or flame is observed in a schlieren image according to the test times (13) of continuous tests specified by the national standard and GB/T13347-2010) repeated test results, the performance of a fire retardant section is excellent and unsteady state detonation can be effectively blocked; if obvious detonation reaction front or flame is observed in a primary curve with abrupt change or a schlieren image in 13 continuous tests, which indicates that unstable detonation is not effectively blocked by the fire retardant section, the fire retardant performance of the fire retardant section is considered to be unqualified, and the performance of the fire retardant section can be optimized by changing the structure of a fire retardant core material or the fire retardant section, so that a feasible scheme is provided for further developing a high-performance unstable detonation flame arrester.
Compared with the prior art, the utility model the advantage lie in:
1. the utility model provides a technique and device that can accurate test combustible gas astable state detonation spark arrester effect have overcome the difficult point of hindering detonation type spark arrester to astable state detonation back-fire relief effect in the test. The device can study the test device of deflagration to detonation process characteristics and unsteady state detonation flame arrester back-fire relief effect under the conditions such as different combustible gas components, the premixed gas of different equivalence ratio, different ignition position, different ignition energy, the barrier of co-altitude not (different blockage rates) to can record the important characteristic parameter of unsteady state detonation formation in-process, and can artificially control test environment and test condition.
2. The utility model discloses a deflagration changes detonation process and spark arrester back-fire relief process in the recording pipeline is shot to the method that high-speed camera shooting technique and schlieren optical technology combined together, realizes that non-stable state detonation generates and blocks the visualization of overall process, accurately presents the shape including flame and detonation wave and the dynamic change law of position along with time directly perceivedly.
3. The utility model discloses utilize pressure sensor to measure the interior pressure dynamic rising characteristic of pipeline, can combine the interrelationship between high-speed schlieren image analysis intraductal pressure and flame, the detonation wave characteristic. The position changes of the initial flame and the later detonation wave are obtained by detecting the light intensity changes in the pipeline through the photodiode, and the propagation speeds of the flame and the detonation wave at all times can be obtained by combining high-speed schlieren image analysis and calculation. The device can be used for realizing a plurality of researches on the process from detonation to detonation, for example, the researches are carried out according to the speed change and the pressure rising characteristic rules in the processes of premixed flame acceleration and detonation to detonation of different types of test gases, and the influences of mixed gases with different equivalence ratios, different ignition positions, different ignition energies, obstacles with different heights and the like on the characteristics of flame acceleration and detonation to detonation can be respectively researched.
4. The utility model discloses an adjustable pipeline structure that upper reaches segmentation combination formula pipeline, telescopic joint and middle pipeline triplex combination formed. The expansion joint is a special small section of pipeline with adjustable length within the expansion range, and is mainly used for compensating the change of the length of the pipeline and the change of the position of unsteady detonation caused by the influence of the expansion joint on a flow field. After the upstream pretest pipeline is replaced by a combined structure of three parts, namely an upstream segmented combined pipeline, a telescopic joint and a middle pipeline, the position of deflagration to detonation (namely the position of unsteady detonation) can be slightly advanced or delayed relative to the pretest. Therefore, an expansion joint needs to be connected into the pipeline, and if the detonation-to-detonation position is advanced, the small expansion joint is contracted; if the detonation-to-detonation position is delayed, the small-section telescopic joint is extended, so that the position where the unsteady detonation occurs is controlled at the run-up distance on the basis of ensuring that the pipeline at other parts is not changed, and the unsteady detonation wave entering the fire-blocking section is ensured.
5. The utility model adds fire retardant cores of different kinds of fire retardants in the middle of the upper and lower pipelines of the combustion pipeline of the unsteady detonation blocking test and then fixes the fire retardant cores as different fire retardant sections through the stainless steel shell, and researches the change conditions of the characteristics of the unsteady detonation wave, such as the propagation speed, the light intensity change, the pressure rise and the like under the action of the fire retardant sections; the blocking effect of various fire retardant cores such as corrugated plates, foamed metal, gravel filling and the like on unsteady state detonation is revealed. Except changing the material of the fire retardant core, the structure of the fire retardant section can be changed, and the blocking effect of the fire retardant sections with different structures on the unsteady detonation can be accurately tested. On the experimental basis of laboratory small-size, can wholly increase testing arrangement's size, and then connect the bigger industry spark arrester of size to the back-fire relief effect of the unsteady state detonation spark arrester of using in the accurate test industry.
Drawings
FIG. 1 is a schematic view of a visual testing apparatus for accurately testing the effect of an unsteady detonation flame arrester of combustible gas according to the present invention;
fig. 2 is a schematic diagram of the internal structure of the high-precision automatic air distribution system of the present invention; in the figure, the MFC is a high-precision mass flow meter.
FIG. 3 is a schematic view of a combustion pipe used in a test for testing the fire retarding effect of the unsteady detonation flame-retarding segment;
FIG. 4 is a schematic view of an industrial unsteady state detonation flame arrestor.
Description of reference numerals: taking the pipeline connection situation in the pretest test as an example, in the figure, 1-a high-pressure igniter, 2-an ignition energy oscilloscope, 3-a current probe, 4-a high-pressure probe, 5-an ignition electrode, 6-a vacuum pressure gauge, 7-an upstream pretest pipeline, 8-a pressure sensor, 9-an unsteady detonation flame-resistant section, 10-a downstream pipeline, 11-a vacuum pump, 12-a first schlieren reflection concave mirror, 13-a slit, 14-a focusing lens, 15-a schlieren light source, 16-an automatic gas distribution system, 17-an insulating valve, 18-a photodiode, 19-an exhaust pipeline, 20-a pressure relief port, 21-a synchronous controller, 22-a high-speed camera, 23-a schlieren knife edge and 24-a second schlieren reflection concave mirror, 25-data collector, 26-charge amplifier. It is particularly noted that the diameter of the first and second concave schlieren mirrors 12, 24 may be increased or decreased in practical application depending on the length of the pipe, and the figure is merely schematic, 27-upstream sectional combined pipe, 28-expansion joint, 29-intermediate pipe, 30-fire retardant core; 31-industrial unsteady state detonation flame arrestors.
Detailed Description
Embodiments of the present invention will be described below with reference to the drawings. The hydrogen and oxygen premixed gas is common industrial pipeline transportation gas, and the detonation wave velocity, the pressure and the like generated when the premixed gas is detonated are higher than those generated when the premixed gas is detonated by other components, so that the requirement on the unstable detonation flame arrester of the hydrogen and oxygen premixed gas is higher. In the following, parameters such as the size of each part are designed by taking a deflagration-to-detonation test of hydrogen-oxygen premixed gas with an equivalent ratio of 1 in a triangular barrier pipeline with a height of 3mm in a laboratory as an example.
The utility model relates to a visual test device of accurate test unsteady state detonation spark arrester effect, mainly include high pressure ignition ware 1, ignition energy oscilloscope 2, current probe 3, high pressure probe 4, ignition electrode 5, vacuum pressure gauge 6, upper reaches pretest pipeline 7, pressure sensor 8, unsteady state detonation flame retardant section 9, low reaches pipeline 10, vacuum pump 11, first schlieren reflection concave mirror 12, second schlieren reflection concave mirror 24, slit 13, focusing lens 14, schlieren light source 15, automatic gas distribution system 16, insulated valve 17, photodiode 18, exhaust pipe 19, pressure release mouth 20, synchronous control ware 21, high-speed camera 22, schlieren edge of a knife 23, data acquisition instrument 25, charge amplifier 26, upper reaches segmentation combination formula pipeline 27, telescopic joint 28, middle pipeline 29, back-fire relief core 30 and industry unsteady state detonation spark arrester 31.
The embodiment of the present invention provides the following definitions regarding the direction: in the longitudinal length direction of the whole device, one end close to the insulating valve 17 is defined as a front end, and one end close to the pressure relief opening 20 is defined as a rear end or a tail end; the left hand direction is the left side, and the right hand direction is the right side when the front end direction is seen from the rear end;
the vacuum pump 11 is a 2XZ rotary vane vacuum pump, i.e. a rotary vane vacuum pump with a two-stage high-speed direct connection structure, and is connected with a pressure relief port 20 at the right end of the downstream pipeline 10 through a connecting pipeline, and the combustion pipeline is pumped to a vacuum state before a test to prepare for charging combustible premixed gas. The vacuum pressure gauge 6 is an OMEGA DPG4000-30A type ultrahigh precision digital pressure gauge, has the range of 0-30psi, the withstand pressure of 60psi, the rupture pressure of 500psi and the precision of the full range +/-0.05% (positive pressure), is connected to the upper wall surface of an upstream combustion pipeline and is used for synchronously monitoring the vacuum degree in the pipe, and when the reading of the vacuum pressure gauge is equal to zero (or about zero and is related to the local atmospheric pressure) and is kept stable and unchanged for a period of time, the vacuum pressure gauge indicates that the vacuum state in the pipe is achieved.
The automatic gas distribution system 16 is controlled by a computer of the control platform, the computer is opened and gas distribution system software is operated during test, combustible gas and combustion-supporting gas in a raw material gas cylinder with a certain equivalence ratio are conveyed into a gas distribution box through inputting target concentration parameters, the gas distribution box comprises a high-precision mass flow Meter (MFC), a gas mixing chamber, an electromagnetic stop valve, a connecting circuit and the like, and the flow of component gas is controlled through monitoring the MFC in real time, so that dynamic gas distribution automation is realized. The automatic gas distribution system 16 is connected with a gas inlet insulating valve 17 at the front end of an upstream pipeline of the combustion pipeline through a main gas transmission pipeline output by a gas mixing chamber in the box body, and is used for filling premixed gas with a certain equivalence ratio into the combustion pipeline until the internal pressure of the pipeline is stabilized to be atmospheric pressure, and closing the gas inlet valve.
The schlieren camera system comprises a pair of schlieren reflection concave mirrors, namely a first schlieren reflection concave mirror 12 and a second schlieren reflection concave mirror 24 (the first schlieren reflection concave mirror 12 and the second schlieren reflection concave mirror 24 are actually positioned in the same horizontal direction and are respectively arranged on the left side and the right side relative to a combustion pipeline), a high-speed camera 22, a schlieren edge 23, a slit 13, a focusing lens 14 and a schlieren light source 15. The schlieren instrument optical system adopts a standard Z-shaped optical path arrangement, two reflecting concave mirrors, namely a first schlieren reflecting concave mirror 12, a second schlieren reflecting concave mirror 24 and a focusing lens 14 are adjusted to be consistent with the center height of a schlieren knife edge 23 and a slit 13, and a combustion pipeline is placed in the center of the optical path. The schlieren light source 15 is a iodine tungsten lamp; the mirror surfaces of the two reflecting concave mirrors 12 and 24 have the diameter of 300mm and the focal length of 2000 mm; the adjusting range of the schlieren knife edge 23 is 0-10 mm, the minimum reading value is 0.01mm, and the adjusting angle is 360 degrees; the adjustment range of the slit 13 is 0-3 mm, the minimum reading value is 0.01mm, and the adjustment angle is 360 degrees; the high-speed camera 22 is a high-performance high-speed camera (such as photon FASTCAM SAZ 2100K), the shooting speed is set to 200000-500000fps, and the high-speed camera 22 is triggered and started by the synchronous controller 21. During the test, light from the schlieren light source 15 passed through the focusing lens 14, causing the filament to be imaged onto the slit 13. The slit 13 position forms the pointolite, and the light of pointolite forms a bunch of parallel light after reflection concave mirror 12 through the first schlieren, and the light beam passes through the quartz glass lateral wall of burning pipe, reflects through second schlieren reflection concave mirror 24 again, and is cut by schlieren edge 23, through focusing lens, finally gets into high-speed camera 22. In the test, the schlieren and the high-speed camera are combined for researching the dynamic characteristics of flame at the initial stage and detonation wave at the later stage of propagation of combustion waves. The schlieren picture shot by the high-speed camera visually shows the dynamic change process of the shapes of the flame and the detonation waves and the change relation of the positions of the flame and the detonation wave fronts along with the time, and has very important significance for analyzing the blocking process of the non-stable detonation waves by the fire retardant core 30 in the non-stable detonation flame retardant section 9. In addition, the schlieren picture can also be used for calculating the propagation speed of flame and detonation waves. And reading the schlieren picture through software such as Matlab and the like to obtain a binary drawing of flame or detonation wave, and further reading a pixel x coordinate sequence of a corresponding front so as to calculate the number of pixels of the flame or detonation wave front moving in a certain time. Then, obtaining the actual length corresponding to the pixel value of the schlieren picture according to the actual measurement result, for example, a pixels in the schlieren picture correspond to the actual length of b meters, and then the flame or detonation wave front velocity can be calculated according to the following formula:
Figure BDA0002680701080000121
in the formula, v is the flame front velocity (m/s), x is the pixel difference value of the flame or detonation wave front positions in two adjacent schlieren pictures, and f is the shooting velocity (fps) set by the high-speed camera.
During the pre-test in the test, the adopted combustion pipeline is a straight pipeline with a rectangular cross section, the pipeline is horizontally placed, the external dimension of the pipeline is 70mm multiplied by 340mm, and the internal dimension of the cavity is 20mm multiplied by 300 mm. The pipeline consists of three parts: the length of the upstream pretest pipeline 7, the unstable detonation flame-retardant section 9 and the downstream pipeline 10 in the pretest test is 166mm, 40mm and 94mm respectively, and the upper wall surface, the lower wall surface, the front wall surface and the rear wall surface of the three pipelines are made of 304 stainless steel with the thickness of 25 mm. Continuous isosceles triangle barriers are symmetrically arranged on the upper and lower stainless steel wall surfaces inside the upstream pretest pipeline 7 and the downstream pipeline 10 respectively, the length of the bottom edge of each barrier is 5.8mm, the height of each barrier is 3mm, the barriers are solid barriers made of 304 stainless steel, and the barriers and the pipeline wall surfaces are machined into a whole. Optical glass is arranged on the left side and the right side of the three-part pipeline, the glass material is optical quartz glass, the thickness is 25mm, the optical performance is good, and the three-part pipeline is suitable for shooting clear schlieren images. A pair of ignition electrodes 5 are mounted on the upper and lower wall surfaces of the combustion pipe at a distance of 26mm from the outer wall surface of the front end, namely at a position 6mm from the inner wall surface, and premixed gas filled in the pipe is ignited by electric sparks at the tips of the electrodes. According to the relevant requirements in the national oil and gas pipeline flame arrester standard GB/T13347-2010, a pair of pressure sensors 8 and photodiodes 18 are arranged on the upper wall surface and the lower wall surface of an upstream pretest pipeline 7 at intervals of 80mm and used for detecting real-time pressure and optical signals in the pipeline at intervals of the same distance, and the distance between the pressure sensors is set to be 80mm, so that the requirement that the pair of pressure sensors 8 and photodiodes 18 are arranged on the upper wall surface and the lower wall surface of the tail end of the upstream pretest pipeline can be met, and the pressure and optical signals of a combustion wave before entering an unsteady detonation flame-resistant section 9 can be accurately measured. The length of the unsteady detonation flame-retardant section 9 is 40mm, and the unsteady detonation flame-retardant section consists of a flame retardant core 30, optical quartz glass and a stainless steel shell. Fire retardant core 30 chooses the buckled plate fire retardant core that common buckled plate explosion-proof type flame arrester corresponds for use, and then studies its back-fire relief effect, and follow-up also can be changed into the back-fire relief core that other common explosion-proof type flame arrester corresponds, like foam metal flame arrester, fill gravel etc. and then contrast the back-fire relief effect of studying other back-fire relief cores. Optical quartz glass is installed to the back-fire relief section left and right sides, observes inside back-fire relief section and shoots the process of blocking of unsteady state detonation in back-fire relief section through the quartz glass visual window, and the stainless steel shell is used for the fixed of inside back-fire relief core and the butt joint with outside pipeline. Except changing the material of the fire retardant core, the existing fire retardant section can be replaced by the fire retardant devices with other different structures, so that the blocking effect of the fire retardant devices with different structures on the unsteady detonation can be accurately tested. In order to ensure that the set of test device is effective really in the actual industrial process, the size of the test device can be integrally increased on the basis of the laboratory small-size test, and then the industrial unstable detonation flame arrester 31 with larger size is connected, so that the flame arresting effect of the unstable detonation flame arrester applied to the industry can be accurately tested. The downstream pipeline 10 is a protective side pipe section and is used for discharging pressure and exhaust gas, the length of the downstream pipeline 10 is 94mm, and the requirements related to the national oil gas pipeline flame arrester standard GB/T13347-2010 are met. A pair of pressure sensors 8 and photodiodes 18 are arranged on the upper wall surface and the lower wall surface of the starting end of the downstream pipeline 10 adjacent to the fire-retardant section, and are used for detecting the pressure and the light intensity of airflow in the pipeline behind the fire-retardant section and taking the images of the schlieren shot by a high-speed camera as an important basis for judging the detonation-resistant effect of the fire-retardant section. A20 mm pressure relief opening 20 is arranged at the tail end of the downstream pipeline 10 and used as a sealing cover for installing a valve, the valve is opened instantly during the test, and after combustion products pass through the valve, exhaust gas is exhausted outdoors through a smoke foil pipe connected to the outdoors, so that no gas is accumulated indoors. An exhaust pipeline 19 is arranged on the lower side wall surface close to the tail end, and when the automatic gas distribution system 16 is used for filling the gas into the pipe, a valve of the exhaust pipeline is opened to ensure that gas flows smoothly, so that the safety of the test is ensured. Under the test working condition, the run-up distance of the unsteady detonation is 145mm by repeating the pre-test for more than three times.
In the experiment, when the testing of the fire-retardant effect of the unsteady detonation fire-retardant section is carried out, the adopted combustion pipeline consists of five parts, namely an upstream segmented combined pipeline 27, an expansion joint 28, a middle pipeline 29, the unsteady detonation fire-retardant section 9 and a downstream pipeline 10, and the fire-retardant section 9 also comprises fire-retardant cores 30 of different types. The upstream sectional combined pipeline 27 is formed by splicing multiple sections of pipelines and is used for selecting different sections to connect according to a pretest test result, so that the length of the upstream pipeline can be flexibly changed. The structure and the material of each section of the upstream sectional combined pipeline are similar to those of the upstream pretest pipeline, the upper wall surface, the lower wall surface, the front end wall surface and the rear end wall surface are also made of 304 stainless steel with the thickness of 25mm, the upper wall surface and the lower wall surface inside the upstream sectional combined pipeline are respectively and symmetrically provided with continuous isosceles triangle barriers, the bottom side length of a single barrier is 5.8mm, the height of the single barrier is 3mm, the barrier is a solid barrier made of 304 stainless steel and is processed into a whole with the pipeline wall surface, the front side and the rear side of the pipeline are also provided with optical quartz glass with the thickness of 25mm, the upper wall surface and the lower wall surface at the position of 6mm away from the front end outer wall surface at the first section are also provided with. The length of the expansion joint 28 in an initial state (when the expansion joint is not extended or shortened) is 20mm, the adjustable length range of the rotary nut is +/-10 mm, the structure and the material of the expansion joint are slightly different from those of an upstream pipeline and a downstream pipeline, in order to realize effective expansion and guarantee the compressive strength of the structure, the left wall surface and the right wall surface of the expansion joint do not adopt optical quartz glass, but a stainless steel shell is arranged, and the whole expansion joint is made of a full stainless steel material. The material and the internal structure of the middle pipeline are the same as those of each section of the upstream section combined pipeline, and the length of the middle pipeline is 40 mm. The upstream segmented combined pipeline is composed of multiple segments, the upstream segmented combined pipeline is machined in advance, the specific number of the segments can be selected according to actual needs, generally, 6-7 segments are machined in advance, and the length of the first segment is 20mm except that the length of the first segment is 26mm because the ignition electrode is required to be arranged at a distance of 6mm from the inner wall surface of the front end. In a deflagration-to-detonation test of oxyhydrogen premixed gas with an equivalent ratio of 1 in a triangular barrier pipeline with the height of 3mm in a laboratory, the run-up distance of unsteady detonation is 145mm according to a pre-test result, so that only 4 sections of upstream segmented combined pipelines are needed, namely, the total length of the upstream segmented combined pipeline is 86mm plus each 20mm of the rear three sections, and in addition, the length of the expansion joint in an initial state is 20mm and the length of the middle pipeline is 40mm, so that the length of the pipeline before the fire retardant section is 146mm, the run-up distance is close to 145mm, the length of the expansion joint is shortened by 1mm, and finally, the length of the pipeline before the fire retardant section is the run-up distance. It should be noted that the structure of the expansion joint is slightly different from the upstream and downstream pipelines, in order to achieve effective expansion and guarantee the compressive strength of the structure, the left and right wall surfaces of the expansion joint are made of stainless steel instead of optical quartz glass, the difference of the structure and the material may have a weak influence on the flow field in the pipeline, the run-up distance may be slightly increased or decreased above 145mm, the length of the expansion joint can be finely adjusted according to the unstable detonation occurrence position observed by an actual schlieren picture in a test, so as to achieve the sum of the lengths of the three parts of the upstream segmented combined pipeline, the expansion joint and the intermediate pipeline as the run-up distance length, ensure that the unstable detonation occurs right ahead of the flame retardant section, and accurately test the detonation resistance effect of the unstable detonation flame retardant section or the flame arrester for industrial application.
Pressure sensor 8 is adopted in the measurement of pressure in this test device, considers that premixed flame and detonation wave propagation are very rapid process, simultaneously along with instantaneous high temperature high pressure, pressure sensor 8 needs to select the high frequency dynamic pressure sensor who possesses extremely fast response speed and higher instantaneous high temperature endurance ability. The device selects a PCB 112A05 type piezoelectric quartz pressure sensor, the maximum measuring range is 34475kPa, the response frequency is more than or equal to 200kHz, the charge sensitivity is 151.0pC/MPa, and the maximum instantaneous temperature is 1649 ℃. The pressure sensor is followed by a charge amplifier 26 for converting the weak charge output by the pressure sensor into a voltage proportional thereto and changing the high output impedance into a low output impedance. The device selects YE5852B type charge amplifier, has dual channels, and maximum input charge amount of + -106Pc, sensitivity of 0.01-1000mV/Pc, low noise less than 5 μ V. The charge amplifier required 30 minutes of warm-up before testing. The photodiode 18 was an SM05PD2A type packaged silicon photodiode with a measured spectral range of 200-1100 nm. The charge amplifier and the photodiode are connected with the data acquisition instrument 25, so that the dynamic change rule of the pressure and the light intensity in the pipeline along with the time in the combustion process is recorded. The occurrence time and position of detonation-to-detonation can also be determined through the changes of pressure and light intensity, that is, the formation time and position of unsteady detonation, and the pressure and light intensity curves of the whole combustion process output by the data acquisition instrument can all generate sharp leaps when detonation is to be converted into detonation. The data acquisition instrument is a HIOKI 8826 type dynamic data acquisition instrument, provides a plurality of input units, has 32 channels in total, can simultaneously acquire various types of signals, and has the highest waveform sampling rate of 1Ms/s in each channel.
The high-pressure igniter 1 is respectively connected with the synchronous controller 21 and two ignition electrodes 5 which are arranged on the upper wall surface and the lower wall surface of the first section of the upstream pretest pipeline 7 or the upstream segmented combined pipeline 27 close to the left end through leads. A2002-1 type synchronous high-voltage pulse generator is selected in the testing device, and alternating current is adopted to complete capacitor charging in the testing process. The ignition electrode is installed at the position 6mm away from the wall surface of the left end of the pipeline, the ignition position of the ignition electrode is located on the central line of the pipeline, and the position of the ignition electrode can be changed according to test requirements, so that the characteristics and the law of the process of converting the deflagration premixed gas into the detonation gas under the influence of different ignition positions are researched. Ignition electrode discharge triggering is achieved by the synchronous controller 21, during which the transformer will transform the voltage between 1: the proportion of 50 is increased, instantaneous discharge is realized through the ignition electrode, and high-voltage electric sparks are generated at the tip of the ignition electrode to ignite the premixed combustible gas. Different capacitances and different voltages produce different ignition energies, which in turn determine different ignition capabilities of the spark for the premixed gas. The ignition energy generally accounts for a certain proportion of the total reserve energy, which can be calculated as follows:
Figure BDA0002680701080000151
wherein E is total reserve energy (J), C is capacitance (mu F), V is voltage (V), and the voltage can be adjusted according to requirements. In the test, C was 200. mu.F, and when V was 100V, the total reserve energy of the ignition electrode was 1J as calculated from the formula (2). In order to realize accurate measurement of the ignition energy of the high-voltage igniter, the ignition energy oscilloscope 2 can be utilized to cooperate with the applicable current probe 3 and the high-voltage probe 4, so that the data of the voltage and current values of the ignition spark of the ignition device are fed back to the oscilloscope, and the ignition spark energy value of the ignition device is obtained through internal calculation of the oscilloscope. In the test device, a Keysight InfiniVision DSOX3024T type oscilloscope with a bandwidth of 200MHz is selected, the rising time obtained by calculation is less than or equal to 1.75ns, 4 channels are used in total, the maximum sampling rate of all the channels is 5GSa/s, the maximum storage depth is 4Mpts, and the waveform capture rate is more than 100 ten thousand waveforms/second. The current probe is an adaptive Keysight CP8500A type current probe, the bandwidth is 12MHz at most, the rise time is less than or equal to 29ns, the maximum value of continuous current is 150Arms, and the peak current is 300A. The high-voltage probe is a Keysight DP6700A type high-voltage differential probe, the bandwidth is 100MHz at most, the rise time is less than or equal to 3.5ns, the precision is +/-2%, and the range selection (attenuation ratio) can be 100X/1000X. The horizontal scale unit of the oscilloscope is set to be 1 mu s, so that the oscilloscope is ensured to capture a single electric spark. The high-voltage probe and the current probe are respectively connected to channels 1 and 2 of the oscilloscope, a channel 1 test voltage value is set, a channel 2 test current value is set, and decay ratios of the voltage probe and the current probe are adjusted to be multiplied by 1000. Before testing, the positive electrode and the negative electrode of the testing end of the high-voltage probe are respectively connected with the discharging positive electrode of the ignition electrode and the shell (grounded) and used for collecting discharging voltage of the ignition device during discharging. Then the ignition cable is disconnected from the ignition electrode needle, and two wires are prepared, wherein the first wire is connected with the ignition cable and the inner core of the electrode, and the second wire is connected with the metal shell of the ignition cable and the metal shell of the electrode. And loading the current probe to the first wire according to the test method of the current probe, and collecting the output current of the ignition device. During testing, the oscilloscope is adjusted, the measurement channels 1, 2 and M (M is the waveform of the oscilloscope calculated by mathematics) are added, the maximum value is selected for the test types of the measurement channels 1 and 2, and the area is selected for the test type of M. In the mathematical function of the oscilloscope, a mathematical expression (1 channel and 2 channels) is set, and the mathematical waveform displays a single spark energy value. If the corresponding value is A and the corresponding value is B, the value of A multiplied by B is the ignition energy value.
During the test, the high-speed camera 22, the high-voltage electric fire device 1 and the data acquisition instrument 25 are synchronously controlled and simultaneously triggered by the synchronous controller 21. The device selects an OMRON SK20 type programmable synchronous controller (PLC), which mainly comprises a CPU and a control panel, and can be connected with a plurality of terminals at the same time, and the CPU can accurately control the triggering time of each terminal by inputting and storing the triggering sequence and time interval of each terminal. Usually, each terminal needs to be individually configured with a power supply and set with different working voltages, in this test, the high-speed camera 22, the high-voltage electric fire device 1 and the data acquisition instrument 25 need 3.3V, 5V and 3.3V dc voltages respectively, and the synchronous controller 21 itself needs 24V dc voltage.
The pressure resistance, the flow resistance and other designs in the test all meet the relevant requirements in the national standard GB/T13347-2010 of the petroleum gas pipeline flame arrester.
The details of the present invention not disclosed in detail belong to the known art in the field.
Although illustrative embodiments of the invention have been described above to facilitate the understanding of the invention by those skilled in the art, it should be understood that the invention is not limited to the scope of the embodiments, and that various changes may be apparent to those skilled in the art without departing from the spirit and scope of the invention as defined and defined in the appended claims.

Claims (8)

1. The utility model provides a visual test device of accurate test combustible gas unsteady state detonation spark arrester effect which characterized in that: the system comprises a vacuum system, an automatic gas distribution system, a schlieren camera system, an unsteady state detonation blocking test combustion pipeline, a test and data acquisition system and a high-pressure ignition and synchronous control system;
the vacuum system comprises a vacuum pump and a vacuum pressure gauge, wherein the vacuum pump is used for extracting air in the combustion pipeline to enable the combustion pipeline to reach a vacuum state;
the automatic gas distribution system is used for configuring combustible gas with target concentration, a plurality of raw material gas cylinders are connected to the mass flow meter through electromagnetic stop valves, the electromagnetic stop valves are connected to a computer of the control platform to be directly controlled, and gas in the raw material gas cylinders is introduced into the gas mixing chamber through the electromagnetic stop valves and the mass flow meter and then is connected with the combustion pipeline gas inlet valve through a pipeline;
the schlieren camera system comprises a schlieren instrument and a high-speed camera, and is arranged according to a standard Z shape, the combustion pipeline is positioned in the central path of the optical channel, the schlieren instrument comprises a schlieren point light source, a focusing lens, a slit, a pair of reflecting concave mirrors and a schlieren edge, the pair of reflecting concave mirrors are arranged at the left side and the right side of the combustion pipeline, the schlieren instrument is used for observing the refractive index change of the density and the temperature distribution of a transparent medium in the medium, when premixed flame or detonation waves are transmitted in the combustion pipeline, the density difference exists near the front of a flame or a reaction area, when light passes through the flow field, the direction, the position and the optical path of the light can be changed, therefore, the schlieren instrument is used for capturing the density discontinuity of the flow field, the interior cannot be interfered, and after the light emitted by the point light source of the schlieren instrument passes; adjusting the slit to generate divergent beams, transmitting the divergent beams to the corresponding first reflecting concave mirror, receiving the generated parallel beams by the second reflecting concave mirror on the other side after passing through the combustion pipeline to generate convergent beams, and then entering the high-speed camera through the schlieren edge and the focusing lens; the high-speed camera visually presents the process of flame evolution and detonation-to-detonation in the pipeline by recording the first-order derivative distribution image of the density of the flow field, and calculates the propagation speed of flame and detonation wave by pictures shot by the high-speed camera;
the unsteady detonation blocking test combustion pipeline is used for observing and determining the forming mode and the forming position of unsteady detonation in the combustion pipeline, and the unsteady detonation blocking test combustion pipeline is a horizontal rectangular section straight pipeline and comprises six combustion pipelines, namely: the system comprises an upstream pretest pipeline, an upstream segmented combined pipeline, an expansion joint, a middle pipeline, an unsteady detonation flame-retardant section and a downstream pipeline, wherein the left and right side wall surfaces of all the combustion pipelines except the expansion joint are made of quartz glass, so that a high-speed schlieren camera system can shoot schlieren images in the pipelines conveniently, and the visualization of a flame propagation process, a deflagration to detonation process and a detonation flame-retardant process is realized, so that the forming position of the unsteady detonation is determined and the flame-retardant effect of the flame-retardant section is observed, all the upper and lower wall surfaces are made of stainless steel plates, and the wall surfaces at the forefront end and the rearmost end are also made of stainless steel plates; except for the unsteady detonation flame-retardant section, the upper wall surface and the lower wall surface in the other part of the combustion pipeline are respectively and symmetrically provided with a continuous triangular barrier made of stainless steel, the unsteady detonation flame-retardant section comprises a flame-retardant core and a stainless steel shell, optical glass is arranged on the left side and the right side of the unsteady detonation flame-retardant section and used for observing the blocking process of unsteady detonation in the flame-retardant section, the stainless steel shell is used for fixing the internal flame-retardant core and butting with an external pipeline, the lower side wall surface of a downstream pipeline close to the tail end is provided with an exhaust pipeline and an insulating valve, and is opened when the combustion pipeline is inflated to ensure that the airflow in the combustion pipeline is smooth and prevent the gas from being blocked in the combustion pipeline to cause overpressure in the pipeline, the tail end wall of the downstream pipeline is provided with a pressure relief port and the insulating valve is arranged and opened when the combustion pipeline is vacuumized, so; sealing during inflation, and discharging replaced air and redundant mixed gas from a lower wall surface exhaust pipeline; the pipeline is opened during the test, combustion products are discharged, and pressure relief is realized, so that the safety of a deflagration-to-detonation test in the pipeline is ensured, and the front end wall surfaces of the upstream pretest pipeline and the upstream segmented combined pipeline are provided with an insulating valve for controlling the start and the end of an inflation process;
the high-voltage ignition and synchronous control system comprises a high-voltage igniter, an ignition electrode, an ignition energy oscilloscope, a high-voltage probe and a current probe which are adaptive, a synchronous controller and an ignition switch; the high-voltage igniter is a high-voltage pulse generator for realizing ignition through capacitance energy storage and discharge, ignition electrodes are arranged at the positions close to the front end wall surface of the first section of the upstream pretest pipeline or the upstream segmented combined pipeline in pairs, the ignition positions of the ignition electrodes are positioned on the central lines of the upstream pipeline and the downstream pipeline, and the positions can be adjusted along the central lines, so that the characteristics and the rules of the conversion process of the premixed gas from deflagration to detonation under the influence of different ignition positions are researched; the synchronous controller comprises a CPU and a control panel, three terminals of the high-voltage igniter, the high-speed camera and the data acquisition instrument are simultaneously connected to the synchronous controller, and the core component CPU precisely controls the triggering time of each terminal by setting and storing the triggering sequence and time interval of each component;
the test and data acquisition system comprises a pressure sensor, a photodiode and a data acquisition instrument; a group of high-frequency dynamic pressure sensors and photodiodes are arranged on the central lines of the upper wall surface and the lower wall surface of the upstream pretest pipeline and the upstream segmented combined pipeline at intervals according to the length of the pipelines, and the pressure sensors are used for recording pressure changes in the pipelines and monitoring the formation and development of detonation waves.
2. The visual test device for accurately testing the effect of the unsteady-state detonation flame arrester of the combustible gas as claimed in claim 1, characterized in that:
during the test, seal burning pipeline front end air inlet, connect vacuum pump in pipeline right-hand member pressure release mouth of low reaches and begin to bleed, and the reading equals zero or is less than zero in the vacuum pressure gauge of wall connection on the pipeline of upper reaches when stable, reaches vacuum state promptly, closes the vacuum pump this moment.
3. The visual test device for accurately testing the effect of the unsteady-state detonation flame arrester of the combustible gas as claimed in claim 1, characterized in that:
the target concentration of the combustible gas is controlled by a mass flow meter MFC in the automatic gas distribution box, all the mass flow meters are directly controlled by a computer of the control platform through an electromagnetic stop valve, concentration parameters in computer matched software are set during gas distribution, the combustible gas and combustion-supporting gas in the raw material gas cylinder are conveyed into a gas mixing chamber in a target equivalence ratio to be uniformly mixed, and then the combustible gas and the combustion-supporting gas are connected with a combustion pipeline gas inlet valve through a pipeline.
4. The visual test device for accurately testing the effect of the unsteady-state detonation flame arrester of the combustible gas as claimed in claim 1, characterized in that:
the unsteady detonation blocking test combustion pipeline is used for ensuring that deflagration-to-detonation is formed at a certain distance from the ignition position and testing the blocking effect of the unsteady detonation flame arrester on unsteady detonation waves; the characteristic that premixed gas with different components or the same components but different equivalent ratios can be subjected to deflagration to detonation conversion through an unsteady detonation blocking test combustion pipeline can be researched, a schlieren photo is obtained through the combination of a schlieren technology and a high-speed camera, the distance from a detonation generating position to an ignition position is further calculated, and the running-up distance required by deflagration to detonation conversion under the condition is obtained through repeated tests under the same test working condition.
5. The visual test device for accurately testing the effect of the unsteady-state detonation flame arrester of the combustible gas as claimed in claim 1, characterized in that:
the fire retardant core that multiple anti-detonation type flame arrester corresponds is selected for use to the fire retardant core for the testing different materials hinder the inhibitory action of section to unsteady state detonation.
6. The visual test device for accurately testing the effect of the unsteady-state detonation flame arrester of the combustible gas as claimed in claim 1, characterized in that:
the telescopic joint is a section of pipeline with adjustable length in a telescopic quantity range and is used for compensating the change of the length of the combustion pipeline and the change of the position of the unsteady detonation caused by the influence of the telescopic joint on the flow field; after the upstream pretest pipeline is replaced by a combined structure of three parts of an upstream segmented combined pipeline, a telescopic joint and a middle pipeline, the position of deflagration to detonation conversion is possibly advanced or delayed relative to the pretest, the telescopic joint is connected into the pipeline, and if the position of deflagration to detonation conversion is advanced, the telescopic joint is contracted; if the detonation-to-detonation position is delayed, the section of telescopic joint is extended, so that the position of the non-stable detonation is controlled at the run-up distance on the basis of ensuring that the combustion pipeline of other parts is unchanged, and the non-stable detonation wave entering the fire-blocking section is ensured.
7. The visual test device for accurately testing the effect of the unsteady-state detonation flame arrester of the combustible gas as claimed in claim 1, characterized in that:
the ignition electrode discharge triggering is realized by a synchronous controller, the premixed gas is ignited by high-voltage electric sparks generated by the point instantaneous discharge, in the instantaneous ignition process, the applicable high-voltage probe and the current probe are connected to the ignition electrode end heads exposed on the outer sides of the upper wall surface and the lower wall surface of the pipeline, the voltage and current data of the ignition sparks of the ignition device are captured in real time and fed back to the oscilloscope, and the energy value of the ignition sparks of the ignition device is obtained through the internal mathematical calculation of the oscilloscope; different ignition energies are generated by setting different capacitors and voltage values in the high-voltage igniter, so that different ignition capacities of premixed combustible gas are determined, and synchronous control and synchronous triggering of a high-voltage ignition system, a high-speed camera and a test and data acquisition system are realized through a programmable synchronous controller in the test process; the high pressure range is 5000-.
8. The visual test device for accurately testing the effect of the unsteady-state detonation flame arrester of the combustible gas as claimed in claim 1, characterized in that:
the induction part of the pressure sensor converts the pressure signal into electric charge, and then the electric charge is converted into voltage in direct proportion to the electric charge through an adaptive charge amplifier, and the charge amplifier is connected with a dynamic data acquisition system to capture deflagration flame and detonation wave with extremely high propagation speed and simultaneously realize the synchronous acquisition of various signals; the photodiode is directly connected with a data acquisition instrument and detects the positions of flame and detonation wave propagation in the pipeline through signal intensity change; ensuring that a group of pressure sensors and photodiodes are arranged on the upper wall surface and the lower wall surface of the middle pipeline close to the fire retardant section to detect the pressure and the light intensity when the over-drive detonation waves are formed; meanwhile, a group of pressure sensors and photodiodes are also installed on the upper wall surface and the lower wall surface of the downstream pipeline close to the middle fire retardant section and used for detecting pressure and light signals in the pipeline behind the fire retardant section.
CN202022000550.7U 2020-09-14 2020-09-14 Visual test device for accurately testing unsteady detonation flame arrester effect of combustible gas Active CN212674463U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202022000550.7U CN212674463U (en) 2020-09-14 2020-09-14 Visual test device for accurately testing unsteady detonation flame arrester effect of combustible gas

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202022000550.7U CN212674463U (en) 2020-09-14 2020-09-14 Visual test device for accurately testing unsteady detonation flame arrester effect of combustible gas

Publications (1)

Publication Number Publication Date
CN212674463U true CN212674463U (en) 2021-03-09

Family

ID=74824452

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202022000550.7U Active CN212674463U (en) 2020-09-14 2020-09-14 Visual test device for accurately testing unsteady detonation flame arrester effect of combustible gas

Country Status (1)

Country Link
CN (1) CN212674463U (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113777213A (en) * 2021-07-28 2021-12-10 上海交通大学 Measuring device and method for visualizing propagation state and characteristics of high-speed detonation wave
CN115825060A (en) * 2022-11-17 2023-03-21 中国农业大学 Screw extrusion equipment for visually monitoring and sampling in whole extrusion process
CN117092470A (en) * 2023-10-16 2023-11-21 江苏创大电气有限公司 Electric spark detection method and system applied to distribution box

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113777213A (en) * 2021-07-28 2021-12-10 上海交通大学 Measuring device and method for visualizing propagation state and characteristics of high-speed detonation wave
CN115825060A (en) * 2022-11-17 2023-03-21 中国农业大学 Screw extrusion equipment for visually monitoring and sampling in whole extrusion process
CN115825060B (en) * 2022-11-17 2024-05-24 中国农业大学 Screw extrusion equipment for visually monitoring and sampling in whole extrusion process
CN117092470A (en) * 2023-10-16 2023-11-21 江苏创大电气有限公司 Electric spark detection method and system applied to distribution box
CN117092470B (en) * 2023-10-16 2024-01-19 江苏创大电气有限公司 Electric spark detection method and system applied to distribution box

Similar Documents

Publication Publication Date Title
CN112082798A (en) Visual test device for accurately testing unsteady detonation flame arrester effect of combustible gas
CN212674463U (en) Visual test device for accurately testing unsteady detonation flame arrester effect of combustible gas
CN103454308B (en) A kind of combustible gas and air pre-mixing gas explosion process Flame Propagation and the experimental rig of suppression
CN203465230U (en) Test device for flame propagation and inhibition in explosion process of combustible gas and air premixed gas
Kobayashi et al. Flame instability effects on the smallest wrinkling scale and burning velocity of high-pressure turbulent premixed flames
Li et al. Large eddy simulation and experimental study on vented gasoline-air mixture explosions in a semi-confined obstructed pipe
Blanchard et al. Effect of ignition position on the run-up distance to DDT for hydrogen–air explosions
Li et al. Experimental and computational fluid dynamics study of separation gap effect on gas explosion mitigation for methane storage tanks
CN202870016U (en) Test system for size effect of gas explosion characteristics
CN102879429A (en) Testing system for gas explosion characteristic size effect
Wang et al. Experimental study of detonation propagation in a square tube filled with orifice plates
CN107870180A (en) The test system of gas burst feature structure effect
Cordier et al. Experimental and numerical analysis of an ignition sequence in a multiple-injectors burner
CN103018397A (en) Secondary pulsating pressure coupling response measuring method
CN207779944U (en) The test system of gas burst feature structure effect
Cooper et al. Effect of deflagration-to-detonation transition on pulse detonation engine impulse
US10286241B2 (en) Combustion arrester quantification systems and methods
Craven et al. The development of detonation over-pressures in pipelines
Frolov et al. Deflagration-to-detonation transition in the gas–liquid-fuel film system
CN101776529A (en) Equipment for small scale booster test
EP3381520B1 (en) Combustion arrester test systems and methods
Moffett et al. Investigation of statistical nature of spark ignition
Krivosheev et al. Reducing the critical pressure of detonation initiation in transmission to a semiconfined volume
Jingde et al. Study on the development of the medium-scale gas explosion integrated testing system
CN218629690U (en) Combustion-supporting testing arrangement of low concentration combustible gas

Legal Events

Date Code Title Description
GR01 Patent grant
GR01 Patent grant
CP02 Change in the address of a patent holder
CP02 Change in the address of a patent holder

Address after: No.443 Huangshan Road, Shushan District, Hefei City, Anhui Province 230022

Patentee after: University of Science and Technology of China

Address before: 230026 Jinzhai Road, Baohe District, Hefei, Anhui Province, No. 96

Patentee before: University of Science and Technology of China