CN111366263B

CN111366263B - High-temperature calibration equipment and method for TDLAS temperature measurement based on shock tube

Info

Publication number: CN111366263B
Application number: CN202010070139.9A
Authority: CN
Inventors: 李飞; 林鑫; 汪球; 余西龙
Original assignee: Institute of Mechanics of CAS
Current assignee: Institute of Mechanics of CAS
Priority date: 2020-01-21
Filing date: 2020-01-21
Publication date: 2021-03-02
Anticipated expiration: 2040-01-21
Also published as: CN111366263A

Abstract

The embodiment of the invention relates to high-temperature calibration equipment for TDLAS temperature measurement based on a shock tube, which comprises: the high-pressure inflating device, the low-pressure inflating device, the air extracting device, the collecting device and the TDLAS device are arranged on the shock tube; the device utilizes a high-temperature shock tube with strong driving capability to realize the high-temperature gas simulation capability of 1200-3000K. In addition, the embodiment of the application also provides a high-temperature calibration method for TDLAS temperature measurement based on the shock tube, on one hand, the method can provide high-temperature gas with the known temperature which is uniform along the optical path, on the other hand, the method can achieve the temperature range of 1200K-3000K, and the calibrated temperature error is about +/-0.75%.

Description

High-temperature calibration equipment and method for TDLAS temperature measurement based on shock tube

Technical Field

The embodiment of the invention relates to the technical field of non-contact spectrum test research of gas temperature in a combustor and an engine, in particular to high-temperature calibration equipment and method for TDLAS temperature measurement based on a shock tube.

Background

When the spectrum of sunlight on the earth is used, the absorption spectrum has been studied. Subject to light source devices, absorption spectroscopy technology has not rapidly developed until the end of the sixties of the last century after laser discovery, with advances in lasers ranging from lead salt lasers, to eighties 'tunable dye lasers, to ninety's single-mode InGaAsP lasers. Due to the strong push of communication technology, in the nineties, the development of semiconductor materials and laser technology is rapid, the size is small, and a narrow linewidth semiconductor laser operated at room temperature becomes the main force, and a tunable diode absorption spectroscopy Technology (TDLAS) which takes a narrow linewidth tunable diode laser as a light source, modulates the output of the laser through high-frequency scanning, scans an absorbed fine spectral line, and determines the temperature by utilizing the light ray absorption rate or a modulation signal is developed.

At the end of 90 years in the last century abroad, the TDLAS technology is widely applied to the aspects of aircraft engines, plasma diagnosis, microgravity combustion diagnosis, combustion control, automobile engines, industrial boilers and the like. In the domestic aspect, in this century, many units have developed studies on methods for detecting environmental pollution and measuring gas concentration based on TDLAS, and since 2006, the society of science and technology, leifei, et al, applied TDLAS technology to combustion measurement at domestic rates (leifei, sisilong, chenghong, zhangxinyu, TDLAS system design for measuring the temperature of a scramjet combustion chamber, seventh national experimental hydromechanics academic conference, beidaihe, 2007 month 8), and used TDLAS technology to internationally obtain the temperature and speed of an air flow in an supersonic combustion chamber for the first time, so as to obtain key data of combustion efficiency. At present, domestic research in the technical field of TDLAS is abundant, and application occasions are numerous.

The TDLAS has the key difficulty of calibrating temperature measurement accuracy for aviation and aerospace engines, and the TDLAS is also the key difficulty of the technology in the aspect of basic research. For the temperature measurement calibration of the TDLAS, many attempts have been made at home and abroad, for example, in the temperature calibration system of the TDLAS of patent 201310048162.8, the temperature in a thermostatic bath is used to calibrate the temperature measurement accuracy of the TDLAS, but the calibration temperature is only below hundreds of K; hanson's group, Stanford university, USA, has published a series of TDLAS techniques and applications, which in TDLAS calibration, use a high temperature tube furnace and a self-made calibration chamber to calibrate TDLAS temperature measurement accuracy, with a maximum temperature measurement of about 1200K (Liu X, Zhou X, Jeffries J B and Hanson R K. Experimental study of H2O spectroscopic parameters in the near-IR (6940-. The team also tried to measure the post-wave gas temperature in the shock tube using TDLAS equipment for verifying the TDLAS test capability, with the highest reported gas temperature in the experiment being about 1700K. However, the solution of using a shock tube to calibrate the TDLAS device is not proposed, and no more effort is made to achieve the temperature accuracy of TDLAS above 1700K. In China, Li Fei et al (Yu X L, Li F, Chen L H, Chang X Y. Acompact sensor based on near in front of diode laser absorption spectroscopy for flow diagnostic in a low-concentration hydrogen and oxygen diagnostic in a drive-type shock tube, 23(1-2) pp1-17,2012.) applies LASTDS to a hydrogen and oxygen combustion drive-type shock tube with stronger driving capability, and measures the gas temperature and concentration in the shock tube. In these operations, the shock tube is the only object under test, not the tool used to calibrate the TDLAS temperature measurement accuracy.

Disclosure of Invention

The embodiment of the invention provides high-temperature calibration equipment and method for TDLAS temperature measurement based on a shock tube, and can solve the problem that the existing scheme cannot meet higher temperature calibration.

In a first aspect, a high temperature calibration device for TDLAS temperature measurement based on a shock tube is provided, which includes: the high-pressure inflating device, the low-pressure inflating device, the air extracting device, the collecting device and the TDLAS device are arranged on the shock tube;

the high-pressure inflating device is connected with the driving section of the shock tube and used for filling gas into the driving section, the low-pressure inflating device and the vacuumizing device are arranged on one side of the driven section and connected with the driven section through a first metal pipeline, and the collecting device is arranged on the other side of the driven section and used for collecting initial parameters in the shock tube;

the acquisition device is also connected with the TDLAS device and used for sending a trigger signal to the TDLAS device;

the TDLAS device is arranged at the tail end of the driven section of the shock tube and used for testing the temperature and the gas component concentration in the shock tube.

In one possible embodiment, the low pressure inflator includes: the system comprises a standard gas cylinder, a first valve, a water tank, a high-purity nitrogen cylinder, an atomizer, a second valve, an electric heating belt, a first vacuum gauge and a third valve;

the standard gas bottle is connected with the first metal pipeline, the first valve is arranged on a pipeline between the standard gas bottle and the first metal pipeline, one end of the atomizer is respectively connected with the water tank and the high-purity nitrogen gas bottle, the other end of the atomizer is connected with the first metal pipeline, the second valve is arranged at the outlet of the atomizer, and the electric heating belt is arranged on one side of the first metal pipeline and used for heating the first metal pipeline;

the vacuum gauge and the third valve are arranged on the first metal pipe.

In one possible embodiment, the suction device comprises: the vacuum pump, the fourth valve and the second vacuum gauge;

the vacuum pump is connected with the second vacuum gauge, the first metal pipeline is connected with a pipeline between the vacuum pump and the second vacuum gauge, and the fourth valve is arranged on the first metal pipeline.

In one possible embodiment, a diaphragm for isolating gas is arranged between the driving section and the driven section of the shock tube, and the diaphragm comprises any one of the following components: dacron diaphragm, aluminium membrane piece and stainless steel diaphragm.

In one possible embodiment, the collecting device comprises: a speed measuring device and an initial parameter measuring device;

the speed measuring device comprises a sensor transmitter and a plurality of high-frequency pressure sensors arranged on the wall surface of the driven section of the shock tube, and the shock wave speed is determined by recording the lifting moment of each high-frequency pressure sensor;

the initial parameter measuring device is connected with the driven section through a second metal pipeline and is used for measuring the gas flow temperature, the gas pressure and the gas composition in the driven section.

In one possible embodiment, the initial parameter measuring device includes: the gas temperature measuring device comprises a temperature detector for measuring the temperature of the gas flow in the driven section, a pressure sensor for measuring the gas pressure in the driven section, and an analyzer for measuring the components and the concentration of the gas in the driven section.

In one possible embodiment, the collecting device further comprises: and the time schedule controller is connected with the speed measuring device and the TDLAS device through cables respectively, and when the time schedule controller receives the voltage signal sent by the speed measuring device, the time schedule controller sends a trigger signal to the TDLAS device.

In one possible embodiment, the TDLAS apparatus includes: a transmitting end and a receiving end, wherein the transmitting end and the receiving end are oppositely arranged on two sides of the driven section.

In a second aspect, an embodiment of the present application further provides a high temperature calibration method for TDLAS temperature measurement based on a shock tube, where the high temperature calibration apparatus for TDLAS temperature measurement based on a shock tube is adopted, and the method includes:

adopting an air extractor to extract air from the driven section in the shock tube until the driven section is in a vacuum state, and adopting a low-pressure air charging device to charge test air into the driven section;

measuring the temperature, the pressure and the gas components of the gas flow of the driven section in the shock tube by adopting an initial parameter measuring device;

changing gas pressure in a driving section in a shock tube by using a high-pressure inflating device, so that an initial shock wave is formed in the driven section by pressure difference at the moment of rupture of a diaphragm between the driving section and the driven section;

measuring the initial shock wave by using a speed measuring device to obtain a pressure signal, and sending the pressure signal to the time sequence controller;

the time sequence controller sends a trigger signal to the TDLAS device according to the pressure signal, the TDLAS device determines the gas temperature of the position to be measured, and the gas temperature is used as the temperature to be evaluated;

acquiring the shock wave velocity measured by the velocity measuring device and the airflow temperature, the gas pressure and the gas components measured by the initial parameter measuring device by using an acquisition device;

calculating gas flow parameters according to the shock wave velocity, the gas flow temperature, the gas pressure and the gas components, wherein the gas flow parameters comprise: theoretical temperature, which is the gas temperature in the driven section after the shock wave flows;

and determining the temperature measurement error of the TDLAS device according to the theoretical temperature and the temperature to be evaluated.

In one possible embodiment, the calculating the gas flow parameter according to the shock wave speed, the gas flow temperature, the gas pressure and the gas composition comprises:

and substituting the shock wave velocity, the gas flow temperature, the gas pressure and the gas components into the following formula to obtain the gas flow parameters, wherein the gas flow parameters comprise: theoretical temperature and theoretical pressure, the formula being as follows:

v is the velocity of the shock wave, a and gamma are the local sound velocity and the specific heat ratio of the gas in the low-pressure section respectively, T1 is the initial temperature, P1 is the initial pressure, M is the shock wave Mach number, T2 is the theoretical temperature, and P2 is the theoretical pressure.

The high-temperature calibration equipment for TDLAS temperature measurement based on the shock tube provided by the embodiment of the invention utilizes the high-temperature shock tube with strong driving capability to realize the high-temperature gas simulation capability of 1200-3000K temperature in the second zone or the fifth zone. The TDLAS device is calibrated with a uniform gas flow of several milliseconds (ms) after the wave. In addition, the embodiment of the application also provides a simple, stable and traceable TDLAS high-temperature calibration method based on the shock wave tube wave-wave transient high-temperature gas. The method can provide high temperature gas with known temperature along the optical path, and can change the temperature, pressure and composition of the calibration gas by changing the gas pressure and composition of the driving section and the driven section.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

Fig. 1 is a schematic diagram of a high-temperature calibration apparatus for TDLAS temperature measurement based on a shock tube according to an embodiment of the present disclosure;

FIG. 2 is a schematic illustration of a low pressure inflator provided in accordance with an embodiment of the present disclosure;

FIG. 3 is a schematic view of a gas evacuation device provided in accordance with an embodiment of the present application;

FIG. 4 is a schematic diagram of a speed measurement device provided in an embodiment of the present application;

fig. 5 is a schematic diagram of a TDLAS apparatus according to an embodiment of the present disclosure;

fig. 6 is a flowchart of a high-temperature calibration method for TDLAS temperature measurement based on a shock tube according to an embodiment of the present disclosure;

FIG. 7 is a schematic diagram of initial shock wave motion and acquisition during operation according to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of the variation of theoretical temperature in a shock tube with initial pressure of a driven section according to an embodiment of the present application.

Detailed Description

To make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the present invention will be combined with

The accompanying drawings in the embodiments of the present invention clearly and completely describe the technical method in the embodiments of the present invention, and obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without any creative effort, shall fall within the scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, back, etc.) are involved in the embodiment of the present invention, the directional indications are only used for explaining the relative positional relationship between the components in a certain posture, the motion situation, etc., and if the certain posture is changed, the directional indications are changed accordingly.

At present, no special measurement standard for a shock tube exists internationally, and in order to realize the calibration capability of measuring the temperature of the TDLAS, the theoretical temperature precision after the shock tube is traced to the source and is required to be converted into the precision measurement of each sensor component used in the operation of the high-temperature calibration equipment based on the shock tube. Therefore, the embodiment of the application utilizes the high-temperature shock tube with strong driving capability to realize the high-temperature gas simulation capability of 1200-3000K. The TDLAS device is calibrated with a uniform gas flow of several milliseconds (ms) after the wave.

Fig. 1 is a schematic diagram of a high-temperature calibration apparatus for TDLAS temperature measurement based on a shock tube according to an embodiment of the present application, as shown in fig. 1, the shock tube includes: the high-temperature calibration device comprises a driving section 1 and a driven section 2, and comprises: the high-pressure inflating device 3, the low-pressure inflating device 4, the air extracting device 5, the collecting device 10 and the TDLAS device 9 are arranged on the shock tube. A diaphragm used for isolating gas is arranged between the driving section and the driven section of the shock tube, and the diaphragm comprises any one of the following components: dacron diaphragm, aluminium membrane piece and stainless steel diaphragm.

Specifically, the high-pressure inflating device 3 is connected with the driving section 1 of the shock tube and used for filling gas into the driving section, the low-pressure inflating device 4 and the vacuumizing device 5 are arranged on one side of the driven section 2 and connected with the driven section 2 through the first metal pipeline 11, and the collecting device 10 is arranged on the other side of the driven section 2 and used for collecting initial parameters in the shock tube.

In addition, the collection device 10 is connected with the TDLAS device 9 for sending a trigger signal to the TDLAS device 9, and the TDLAS device 9 is arranged at the tail end of the driven section 2 of the shock tube for testing the temperature and the gas component concentration in the shock tube.

The high-pressure inflator 3 in this embodiment may fill the driving section 1 of the shock tube with a gas such as hydrogen, oxygen, nitrogen, argon, helium, acetylene, or a mixture of a plurality of gases.

It should be noted that the shock tube is a transient operation device, the air flow uniformity is good, and the main non-uniformity is caused by the boundary layer influence of the wall surface. According to aerodynamic knowledge, the boundary layer should be less than 2% of the absorption length to be considered negligible, and therefore the diameter of the shock tube should be large enough, typically greater than 120 mm.

In addition, for high-temperature calibration, the shock tube needs to operate stably, and the post-wave temperature is high. This requires a high operating state and a high driving ability of the shock tube. The driving capacity of the driving section is strong, and the high-pressure air driving of the most conventional shock tube can only generate the shock wave speed of about Mach 2, so that the requirement can not be met. In order to improve the driving capability, there are several ways, one is to use small molecule gas driving, such as hydrogen and helium, and the other is to increase the driving gas pressure, and combustion and detonation driving can be used, wherein the detonation-driven shock tube technology can realize the shock wave Mach number of 10-20, and the technology is the original technology of Chinese academy mechanics and has a leading position in the whole world.

Fig. 2 is a schematic view of a low pressure inflator according to an embodiment of the present application, and as shown in fig. 2, the low pressure inflator 4 includes: a standard gas bottle 41, a first valve 42, a water tank 43, a high purity nitrogen gas bottle 44, an atomizer 45, a second valve 46, an electric heating belt 47, a first vacuum gauge 48, and a third valve 49;

the target gas bottle 41 is connected with the first metal pipeline 11, the first valve 42 is arranged on a pipeline between the target gas bottle 41 and the first metal pipeline 11, one end of the atomizer 45 is respectively connected with the water tank 43 and the high-purity nitrogen gas bottle 44, the other end of the atomizer 45 is connected with the first metal pipeline 11, the second valve 46 is arranged at the outlet of the atomizer 45, and the electric heating belt 47 is arranged at one side of the first metal pipeline 11 and used for heating the first metal pipeline 11; the first vacuum gauge 48 and the third valve are disposed on the first metal pipe 11.

The low pressure inflator 4 in this embodiment may fill the driven segment 1 of the shock tube with a gas such as oxygen, nitrogen, air, carbon monoxide, carbon dioxide, nitric oxide, water vapor, or a mixture of a plurality of gases.

The specific working process is as follows, when TDLAS calibration with H2O as the absorption component is performed, the standard gas bottle 41 and the first valve 42 are closed, the water tank 43, the high purity nitrogen gas bottle 44, the atomizer 45, the second valve 46 and the electric heating belt 47 are opened, water vapor is atomized by high purity nitrogen gas, the water vapor is filled into the driven section through the third valve 49, and finally the air charging balance pressure is read by the first vacuum gauge 48. The electric heating belt 47 heats the first metal pipeline to keep the temperature above 110 ℃ so as to ensure that the high-concentration water vapor in the first metal pipeline is not condensed. When the TDLAS temperature measurement calibration taking non-H2O as the absorption component is performed, for example, CO2, NO and other gases, the high-temperature valve and the electric heating belt are closed, the corresponding standard gas is filled in the standard gas bottle 41, the first valve 42 is opened, and the standard gas is filled in the driven section 2.

FIG. 3 is a schematic view of a gas extraction device provided in an embodiment of the present application, and as shown in FIG. 3, the gas extraction device 5 includes: a vacuum pump 51, a fourth valve 53, and a second vacuum gauge 52; the vacuum pump 51 is connected to the second vacuum gauge 52, the first metal pipe 11 is connected to a pipe between the vacuum pump 51 and the second vacuum gauge 52, and the fourth valve 53 is disposed in the first metal pipe.

The collecting device 10 in this embodiment includes: a speed measuring device 6 and an initial parameter measuring device 7. Fig. 4 is a schematic diagram of a speed measuring device provided in an embodiment of the present application, and as shown in fig. 4, the speed measuring device includes a sensor transmitter 61 and a plurality of high-frequency pressure sensors 62 disposed on a wall surface of a driven section of a shock tube, and determines a shock wave speed by recording a lifting time of each high-frequency pressure sensor.

The initial parameter measuring device 7 is connected with the driven section through a second metal pipeline and is used for measuring the gas flow temperature, the gas pressure and the gas composition in the driven section. Wherein, initial parameter measurement device includes: the gas temperature measuring device comprises a temperature detector for measuring the temperature of the gas flow in the driven section, a pressure sensor for measuring the gas pressure in the driven section and an analyzer for measuring the components and the concentration of the gas in the driven section.

The collection system in this embodiment further comprises: and the time sequence controller 8 is connected with the speed measuring device 6 and the TDLAS device 9 through cables, and sends a trigger signal to the TDLAS device 9 when receiving a voltage signal sent by the speed measuring device 6.

The TDLAS apparatus 9 in this embodiment includes: a transmitting end and a receiving end, wherein the transmitting end and the receiving end are oppositely arranged on two sides of the driven section.

The TDLAS system 9 uses a tunable diode as a laser source, and the wavelength band of the tunable diode can be any wavelength of visible light, near infrared and middle infrared bands, and the TDLAS system 9 uses a double absorption wavelength of a component for temperature measurement, wherein the component includes any one of water vapor (H2O), carbon monoxide (CO), carbon dioxide (CO2) and Nitric Oxide (NO), and the temperature measurement component is not limited to H2O, CO2 and NO in the examples.

In a second aspect, this embodiment further provides a high temperature calibration method for TDLAS temperature measurement based on a shock tube, where the method employs the above high temperature calibration apparatus for TDLAS temperature measurement based on a shock tube, and fig. 6 is a flowchart of the high temperature calibration method for TDLAS temperature measurement based on a shock tube provided in this embodiment of the present application, and as shown in fig. 6, the method includes:

step S11, using an air extractor to extract air from the driven section in the shock tube, and using a low-pressure air-filling device to fill test gas into the driven section until the driven section is in a vacuum state;

step S12, measuring the temperature, pressure and gas composition of the gas flow of the driven section in the shock tube by using an initial parameter measuring device;

step S13, changing the gas pressure in the driving section of the shock tube by using a high-pressure inflating device, so that the initial shock wave is formed in the driven section by the pressure difference at the moment of rupture of the membrane between the driving section and the driven section;

the shock tube in this embodiment is a shock tube filled with high-pressure gas as driving gas, the high-pressure gas includes hydrogen, helium, argon, air or a mixture of multiple gases, or a combustion driving shock tube using hydrogen and oxygen or doped gas as fuel gas, or a shock tube driven by detonation, the detonation gas includes a mixture of hydrogen and oxygen, a mixture of hydrogen/oxygen/nitrogen, an acetylene/oxygen/mixture, an acetylene/oxygen/nitrogen mixture, and the like, and the initial shock wave moving at high speed is generated at a passive section of the shock tube by a high-pressure european impulse membrane.

Step S14, measuring the initial shock wave by using a speed measuring device to obtain a pressure signal, and sending the pressure signal to a time schedule controller;

specifically, the initial shock wave passes through the first of n (n ≧ 3) sensors of the velocity measurement system 6, causing those sensors to output a step-shaped pressure transition signal, which activates the timing controller 8 as shown in FIG. 7.

Step S15, the time schedule controller sends a trigger signal to the TDLAS device according to the pressure signal, the TDLAS device determines the gas temperature of the position to be measured, and the gas temperature is used as the temperature to be evaluated;

the TDLAS device 9 measures the gas parameters after the initial shock wave has passed. The initial shock wave is then reflected at the end of the driven section of the shock tube 1, moving towards the location of the diaphragm. After the gas is compressed by two shock waves of an initial shock wave and a reflected shock wave, the temperature, the pressure and the density of the gas are greatly improved, and a uniform high-temperature high-pressure gas flow lasting for milliseconds (ms) is formed.

The TDLAS device 9 measures the data over the time period as raw data of a spectrum, using the raw data of the spectrum. The TDLAS device may calculate the gas temperature measured by its device and use the gas temperature as the temperature to be assessed.

Step S16, acquiring the shock wave velocity measured by the velocity measuring device and the measured gas flow temperature, gas pressure and gas components of the initial parameter measuring device by using the acquisition device;

step S17, calculating gas flow parameters according to the shock wave velocity, the gas flow temperature, the gas pressure and the gas components, wherein the gas flow parameters comprise: theoretical temperature, which is the gas temperature in the driven section after the shock wave flows;

specifically, the gas flow parameters are calculated according to the shock wave velocity, the gas flow temperature, the gas pressure and the gas components, and the method comprises the following steps:

the shock wave velocity, the gas flow temperature, the gas pressure and the gas components are substituted into the following formula to obtain gas flow parameters, wherein the gas flow parameters comprise: theoretical temperature and theoretical pressure, the formula is as follows:

in the above formula, V is the velocity of the shock wave, a and γ are the local sonic velocity and specific heat ratio of the gas in the low-pressure stage, T1 is the initial temperature, P1 is the initial pressure, M is the shock wave mach number, T2 is the theoretical temperature, and P2 is the theoretical pressure, respectively.

And step S18, determining the temperature measurement error of the TDLAS device according to the theoretical temperature and the temperature to be evaluated.

The temperature calculated using the above formula is referred to as the theoretical temperature. And the difference between the temperature to be evaluated and the theoretical temperature is the temperature measurement error of the TDLAS system.

In addition, the thickness of the diaphragm can be changed, the filling gas pressure of the driven section of the shock tube can be changed, and the pressure difference between the driving section and the driven section of the shock tube at the membrane rupture time can be changed, so that the wave speed of the initial shock wave can be changed, and the gas temperature and pressure after the wave and the reflected wave can be further changed. Therefore, the calibration equipment can change the calibration temperature to form a temperature calibration curve of 1200-3000K, and the wide temperature calibration requirement of the TDLAS equipment is met.

For example, in the case of a driving hydrogen pressure of 3atm, when the initial pressure of the driven section is reduced from 5kPa to 1.0kPa, the gas temperature of the five zones after the reflection laser is raised from 1200K to 3000K. As shown in fig. 8.

At present, no special measurement standard for a shock tube exists internationally, and in order to realize the calibration capability of temperature measurement of the TDLAS, the present embodiment needs to convert the theoretical temperature precision after the shock tube into precision measurement of each sensor component used in the operation of the high-temperature calibration device based on the shock tube. According to the calibration process, the uniform gas parameters after the shock wave are controlled by the measured values of the pressure, the temperature and the shock wave speed of the low-pressure section before the shock wave runs, and the temperature and the pressure of the gas after the shock wave can be calculated through accurate shock wave theory solution.

Therefore, the temperature tracing of the calibration absorption spectrum is converted into the speed measurement precision of the ionization probe, the temperature measurement precision (near room temperature) of the low-pressure section before the test, and the pressure measurement precision of the pressure sensor. The measurement accuracy of the temperature sensor and the pressure sensor can be checked and calibrated by using national measurement standards. The speed precision mainly depends on the repeatability of a plurality of pressure sensors and acquisition circuit channels and the time sequence control precision, wherein the time sequence control precision is mostly in ns precision, the influence can be ignored, the rising edge time response of the circuit can also be sent to a metering department for checking. Through error transfer evaluation, under the existing sensors and measurement accuracy, the uncertainty of the post-wave temperature is about +/-0.75%.

The embodiments of the present invention have been described in detail, but the present invention is not limited to the embodiments described above as examples. It will be appreciated by those skilled in the art that various equivalent changes and modifications can be made without departing from the spirit and scope of the invention, and it is intended to cover all such modifications and alterations as fall within the true spirit and scope of the invention.

Claims

1. The utility model provides a high temperature calibration method of TDLAS temperature measurement based on shock tube, adopts a high temperature calibration equipment of TDLAS temperature measurement based on shock tube which characterized in that, equipment includes: the high-pressure inflating device, the low-pressure inflating device, the vacuumizing device, the collecting device and the TDLAS device are arranged on the shock tube;

the high-pressure inflating device is connected with the driving section of the shock tube and used for filling gas into the driving section, the low-pressure inflating device and the vacuumizing device are arranged on one side of the driving section and connected with the driving section through a first metal pipeline, and the collecting device is arranged on the other side of the driving section and used for collecting initial parameters in the shock tube;

the TDLAS device is arranged at the tail end of the shock tube driving section and used for testing the temperature and the gas component concentration in the shock tube;

the method comprises the following steps:

pumping the driving section in the shock tube by using a vacuum pumping device, and filling test gas into the driving section by using a low-pressure gas filling device until the driving section is in a vacuum state;

measuring the temperature, the pressure and the gas components of the gas flow of a driving section in the shock tube by adopting an initial parameter measuring device;

changing gas pressure in a driving section in a shock tube by using a high-pressure inflating device so as to form an initial shock wave in the driving section by pressure difference at the moment of rupture of a diaphragm positioned between the driving section and the driving section;

measuring the initial shock wave by using a speed measuring device to obtain a pressure signal, and sending the pressure signal to a time sequence controller;

calculating gas flow parameters according to the shock wave velocity, the gas flow temperature, the gas pressure and the gas components, wherein the gas flow parameters comprise: theoretical temperature, which is the gas temperature in the driving section after the shock wave flows;

2. The method of claim 1, wherein the low pressure inflator comprises: the system comprises a standard gas cylinder, a first valve, a water tank, a high-purity nitrogen cylinder, an atomizer, a second valve, an electric heating belt, a first vacuum gauge and a third valve;

the vacuum gauge and the third valve are arranged on the first metal pipe.

3. The method of claim 1, wherein the evacuation device comprises: the vacuum pump, the fourth valve and the second vacuum gauge;

4. The method of claim 1, wherein a diaphragm for isolating gas is disposed between the driving section and the driving section of the shock tube, and the diaphragm comprises any one of: dacron diaphragm, aluminium membrane piece and stainless steel diaphragm.

5. The method of claim 1, wherein the acquisition device comprises: a speed measuring device and an initial parameter measuring device;

the speed measuring device comprises a sensor transmitter and a plurality of high-frequency pressure sensors arranged on the wall surface of the shock tube driving section, and the shock wave speed is determined by recording the lifting time of each high-frequency pressure sensor;

the initial parameter measuring device is connected with the driving section through a second metal pipeline and is used for measuring the gas flow temperature, the gas pressure and the gas components in the driving section.

6. The method of claim 5, wherein the initial parameter measuring device comprises: the gas temperature measuring device comprises a temperature detector for measuring the temperature of the gas flow in the driving section, a pressure sensor for measuring the pressure of the gas in the driving section, and an analyzer for measuring the components and the concentration of the gas in the driving section.

7. The method of claim 6, wherein the acquisition device further comprises: and the time schedule controller is connected with the speed measuring device and the TDLAS device through cables respectively, and when the time schedule controller receives the voltage signal sent by the speed measuring device, the time schedule controller sends a trigger signal to the TDLAS device.

8. The method of claim 1, wherein the TDLAS device comprises: a transmitting end and a receiving end, wherein the transmitting end and the receiving end are oppositely arranged at two sides of the driving section.

9. The method of claim 1, wherein calculating gas flow parameters from the shock wave velocity, gas flow temperature, gas pressure, and gas composition comprises: