RU2795643C1 - Method for studying vortex flows of multicomponent gas mixtures and devices for its implementation - Google Patents

Abstract

FIELD: instrumentation.

SUBSTANCE: invention allows you to explore multi-component gas swirling flows and test vortex devices, flow swirlers, and can be used in fundamental and applied research in experimental aero- and gas dynamics, in the development of effective design and layout diagrams of devices for separating multi-component gas mixtures into individual components.

EFFECT: effective performance.

3 cl, 3 dwg

Description

The invention relates to instrumentation and allows you to explore multi-component gas swirling flows and test devices designed to swirl flows (vortex devices) and can be used in fundamental and applied research in experimental aero and gas dynamics, in the development of effective structural layout schemes devices for separating multicomponent gas mixtures into separate components.

At present, the vortex method of media separation is being used more and more widely, the use of which can significantly reduce energy costs and simplify media separation technologies, and can be used in various industries, in particular, chemical, oil and gas production and processing industries, thermal power and many others. productions. RF patents for inventions No. 2107197, 2368817 can be mentioned as examples of such devices [1, 2].

So, in accordance with the patent [2], the vortex unit is designed to separate the combustible component from the air. The vortex tube is made of two separate coaxially mounted parts. The pipe connector is located along the flow movement behind the swirler installed at the inlet section of the vortex pipe. An annular chamber is made on the outer side of the pipe, covering the connector. The connection of the end walls of the chamber with the pipe is made tight, with the possibility of axial movement of one of the parts of the vortex tube relative to its other parts, while an annular gap is formed for the outlet of the near-wall peripheral flow of the separated medium into the annular chamber. A regulating shut-off device is installed on the medium discharge pipeline. The end face of the vortex tube on the side of the flow outlet from the tube is made with a sharp edge.

To separate a gas mixture into individual components, so-called vortex tubes are widely used, which implement the so-called Ranque-Hilsch effect [3, 4]. Optimizing the parameters of such vortex flows makes it possible to increase the efficiency of separating a multicomponent gas mixture into individual components. At the same time, it is known that it is expedient to use Ranque-Hilsch vortex tubes for separating gas flows into high-energy (high-temperature) and low-energy (low-temperature) flows [5].

The study of the flow in a vortex tube presents significant difficulties, since it is three-coordinate, high-velocity and turbulent, which requires the creation of special measuring probes and coordinators. Even with the maximum possible reduction in the dimensions of the measuring equipment introduced into the flow, the latter creates noticeable perturbations and restructuring of the flow, which worsens the operation of the vortex tube. Also unacceptable in such studies are methods that do not cause perturbation of the flow, such as the Fouquet-Tepler shadow method, as well as the interference method. Attempts to visualize the flow with smoke are also unsuccessful, due to the high turbulence of the flow.

The only possible method is the sounding method, which makes it possible to determine the qualitative picture of the flow with an approximate qualitative estimate.

At the same time, in such studies, the main tasks are to determine the fields of velocities and pressures in gas flows. To solve these problems, optical methods for non-contact measurement of the velocity of various liquid and gas flows are widely used, which are laser Doppler anemometry (LDA), which allows measuring the velocity of particles accompanying the flow at a fixed point of the flow, and digital tracer visualization (PIV).

The disadvantage of LDA is that this method allows only successive measurements of velocity in space, moving from point to point of the studied flow, LDA diagnostics requires ensuring the stability of the experimental conditions and maintaining the regime parameters of the flows unchanged for a long time, which is sometimes technically difficult to implement.

The use of PIV, in contrast to LDA, makes it possible to obtain an instantaneous velocity distribution in the studied section and observe an instantaneous flow pattern within the two-dimensional plane of the light sheet. However, this method is the most efficient only for the case when one of the velocity components (perpendicular to the light cross section) can be neglected.

The separate use of the widely used optical measuring methods LDA (measurement of velocity by a laser Doppler anemometer) and PIV (analysis of the flow structure along particle tracks) often leads to distorted information, especially for transient and developed unsteady vortex flow regimes. Therefore, the joint use of LDA and PIV is more effective, which is implemented in the method of non-contact optical laser diagnostics of unsteady modes of vortex flows and a device for its implementation according to the RF patent for invention No. 2498319 [6].

The device [6] includes a pulsed laser with a pulse energy of at least 120 mJ, a response frequency of at least 16 Hz, two SDS cameras with a frequency resolution of 8 to 16 Hz, located at an angle of 30-120° to each other and at an angle of 15-60 ° to the axis of the channel behind the rotor, optical prisms, an image processor, an argon laser laser anemometer with an optical probe, and a Doppler signal processor, and a personal computer. The method includes measurements using LDA at two or more points of a non-stationary vortex flow behind the flow of a wind or hydroelectric unit to determine the time interval, illumination of the flow with a laser knife, fixing images of seeded particles with two SDS cameras and recording after a given time interval statistical averaging of instantaneous velocity fields for n=2…16 moments within the full period of fluctuations of the vortex structure, T of the selected velocity fields obtained with a time delay t=0, T, 2T… and (m+1)T, where m is the number of instantaneous velocity field measurements for statistical averaging. The technical result is a significant reduction in the random measurement error and the almost complete elimination of the systematic error associated with non-stationary changes in the flow structure.

A similar solution is described in the RF patent for the invention No. 2647157 [7], since the method is based on the joint use of LDA and PIV, including the transmission of laser radiation through the measuring volume, measurements to obtain the full period of pulsations, determination, based on the information obtained, determination of the interval between image series. Instantaneous PIV velocity fields are calculated from the images, illumination of the studied vortex flow with specific laser light. Image fixation by two SSD cameras that receive reflected light, and information recording in a given time interval. At the same time, when diagnosing a vortex flow induced by a rotating processing core (RPN), speed signals and reference signals are simultaneously formed using piezoceramic hydrophones or using precision condenser microphones located in the device for implementing the method, directly inside the research container after the swirler along the flow in in the form of separate conjugated pairs diametrically located in the horizontal and vertical planes. The technical result of the patent [7] is to expand the technical capabilities and reduce errors associated with a sharp change in the ratio of liquid and gas in vortex flows. Those. according to patent No. 2647157 [7], it is possible to diagnose two-phase flows, to establish the relationship between liquid and gas.

All the methods noted above, including the method according to the patent of the Russian Federation No. 2523737, have certain properties of diagnosing two-phase flows, however, none of these methods and devices that implement them make it possible to determine the distribution of the components of a multicomponent gas mixture during its vortex motion. These methods also do not allow to experimentally evaluate the efficiency of the swirling of the gas mixture, to determine the optimal parameters of the flow swirler, since there are still no adequate calculation models of the swirling motion of the gas mixture in the channels [7].

The proposed method for studying vortex flows of multicomponent gas mixtures is free from these shortcomings, which consists in creating in one way or another the translational rotational motion of a multicomponent gas mixture in a cylindrical channel, and in determining the physical, mechanical and chemical parameters of the flow in the cross sections of the channel in the radial and tangential directions and along the length of the channel. To assess the influence of external physical factors, such as gravitational fields and Coriolis acceleration on the processes of vortex formation, the channel can be fixed at different angles to the horizon plane, which makes it possible to test devices that swirl a multicomponent gas mixture.

An example of the need for such testing can be burner devices designed for the utilization (burning) of associated petroleum gas (APG) ballasted with up to 98% nitrogen [8,9] in a heat generator. The operation of the mentioned burners is based on the mechanism of spontaneous formation of a vortex translational motion of the gas mixture when it is fed into a cylindrical channel, discovered in the 90s of the last century [10], during which heavier molecules of hydrocarbon gases are concentrated in the near-wall zones of the channel, perforation the walls of which allows these components to be removed from the channel and utilized by burning APG. The choice of the optimal parameters of such burners is associated with great difficulties, since, as noted above, at present there are no reliable models for choosing the length of the channel, its diameter, positioning of the perforations of the channel, which would allow optimizing the process of enrichment of APG, ballasted with nitrogen, in terms of hydrocarbon components.

The experimental method for choosing the optimal parameters of burner devices is the most effective, which can be implemented in accordance with the proposed method.

The device that implements the proposed method, the scheme of which is shown in Fig. 1, contains a container 1 with a multicomponent gas mixture, in which such assemblies are fixed on gas ducts 2, such as a starting electro-pneumatic valve 3, at the outlet of which a reducer 4 with a flow washer 5 is installed, after which a tee 6 is built into the gas path, to one of fittings of which is connected by means of a branch pipe 7 to a starting electro-pneumatic valve 8, which is installed on the branch pipe of a container 9 with a color gas ingredient intended for coloring a multicomponent gas medium. The second fitting of the tee 6 is connected by means of a flexible pipeline 10 to the inlet pipe of the flow swirler 11, which is mounted on the hinge 12, with the possibility of its angular positioning relative to the horizon plane. A cylindrical channel 13 is connected to the outlet of swirler 11 with elements of the system for diagnosing flow parameters 14 shown in FIG. 2.

As part of the system for diagnosing gas flows in channel 13 (Fig. 1), the channel body 13 is made of an optically transparent material. In FIG. 2, reference numeral 15 denotes the body of the cylindrical channel. To identify the patterns of changes in the parameters of the movement of a multicomponent gas mixture through the channel and its chemical composition in the volume of the channel, holes 16 are made in the channel body, the longitudinal axes of which lie in planes perpendicular to the longitudinal axis of the channel 15, 12 holes in each plane, which form measurement belts located at different distances from each other. At the same time, in each measurement belt, the axes of neighboring holes are located relative to each other at an angle of 30°, which makes it possible to study changes in flow parameters not only along the channel length, but also along the angular coordinate. In any of the holes 16 can be inserted into the probe to measure the static 17 or dynamic pressure 18, having the appropriate performance, to a particular depth. To measure the pressure at one point or another of the channel, each of the probes is connected to the corresponding pressure sensors, for example, of the LH type, indicated in Fig. 2 position 19, with signal amplifiers 20 and recording equipment 21. A number of probes, for example, 22 devices are used to take gas samples to determine their chemical (component) composition using gas analyzers 23 (chromatographs). To reveal the structure of the vortex flow through probes 24, silk threads 25, 26 can be introduced into the cavity of the channel 15, the position of which in the moving gas mixture flow through the channel 15 makes it possible to visually assess the behavior of the streamlines. Visual fixation of the behavior (position) of silk threads 25,26 is carried out using video cameras 27. As part of the use of RGB technologies (or schlieren photographs) to identify the structure of gas flows in channel 15 by taking into account color shades in different flow zones, video recording devices such as video cameras 27 are used or camera 28, and to increase the contrast of fixation of the structure of the flow, coloring gases from container 7 can be added to it (Fig. 1).

To measure small values of pressure drops and small values of pressure in gas mixtures, which take place for devices for separating air into components [1, 2], when the energy of processes is determined by the energy of a normal atmospheric wind load, pressure drop sensors 29 of the IKD TDF type can be used. , designed to measure pressures from 10 mm to 300 mm of water column, the signals of which are amplified in amplifiers 30 and recorded by recording equipment 21. To measure pressures (pressure drops) of small nominal values, V-shaped manometers 31 can be used.

Since the operation of devices for separating a multicomponent gas mixture into individual components, made in accordance, for example, with schemes according to patents [1,2,8-10], has shown the efficiency of using low-pressure gas flows, the scheme of a device intended for diagnosing air vortex flows and testing of air flow swirlers, which are reflected in the diagram shown in Fig. 3.

A device for diagnosing low-pressure air flows and testing swirlers of the air flow contains an engine 32 with an injection fan 33, which creates an air flow entering the confuser 34. from an optically transparent material, a cylindrical channel 37 with a system for diagnosing the air flow moving through it, similar to that shown in Fig. 2. All of the above elements and assemblies are installed on the traverse 39, which is fixed on the support 41 with the help of a hinge 40 with the possibility of angular positioning of the traverse 39 relative to the horizon plane.

The devices work as follows.

For experimental studies, the installation, the scheme of which is shown in Fig. 1, it is necessary to prepare for conducting experiments, based on the goals and objectives of the experiments. In particular, the design of the flow swirler 11 is selected and its adjustment is carried out (positioning parameters of the swirler elements are selected, for example, the number and shape of the swirler blades, their fixation points along the swirler path, etc.) and fixing the parameters. Next, the installation is assembled, the scheme of which is shown in Fig. 1. At the same time, the required pressure of the gas mixture in the ducts of the device and its flow rate are calculated. In accordance with the obtained calculated values of pressure and flow, the reducer 4 is adjusted and the flow washer 5 is selected. After assembling the individual components of the device into a single circuit, as shown in Fig. 1, container 9 is filled with non-ferrous gas. On channel 12 (Fig. 1), elements of the system are installed for measuring the physico-chemical parameters of the flow in accordance with the scheme in Fig. 2. After completing these operations, the device is ready for use.

The operation of the device begins with the opening of the valve 3, after which the gas mixture enters the tract of the device, passing through the reducer 4, the flow washer 5, pipelines 2, 10, and enters the flow swirler 11, where it is swirled. The swirling flow after the swirler 11 enters the channel 12. During the movement of the gas mixture through the channel, probes 17, 18, pressure sensors 19, 29, as well as pressure drops at various spatial points of the channel along its length and along the angular coordinate, build the pressure field in the channel. The pressure distribution (pressure diagrams) along the radius is determined by moving the probes to a certain depth into the channel body. The signals taken from the sensors 19, 29 are amplified in signal amplifiers 20, 30 and recorded on data carriers 21. At low pressures and pressure drops, a V-shaped differential pressure gauge 31 can be used, which allows measuring both pressure drops and static pressure, as well as the magnitude of the dynamic head for various points in the channel due to one or another design of the corresponding probes and deepening them by one or another amount into the gas mixture flow.

The chemical composition of the gas mixture at various points of the channel is determined by sampling the gas mixture from the corresponding points of the channel using probes 22, and the chemical composition of the sample is determined using gas analyzers 23. By fixing the position of the silk threads 25, 26 introduced with a video camera 27 or a camera 28 through probes 24 into the cavity of the channel, one can judge the nature of the behavior of gas flows in the channel. This can also be judged by the color shades of individual sections of gas flows in channel 15 (Fig. 2), by processing photographs of the flow produced using camera 28, in accordance with RGB technologies, moreover, to increase the contrast of individual stream streams, the flow can be the coloring gas component can be introduced from the container 9 (Fig. 1) by opening the electro-pneumatic valve 8 and supplying the coloring component through one of the fittings 6 to the pipeline 10.

A device for diagnosing low-pressure air flows, the scheme of which is shown in Fig. 3, involves the assembly (mounting) of all components of the device on the traverse 39. The flow laminator 35 included in the device is designed to eliminate turbulent manifestations in the flow. Measurements of the flow parameters in channel 37 can be made in the same way as for the device, the scheme of which is shown in Fig. 1, and the structure of the parameter measurement system is shown in Fig. 2, and the flow diagnostic process itself is similar to that described above for the device, the diagram of which is shown in FIG. 1. Before testing using the device, the scheme of which is shown in Fig. 3, the required setting of the flow swirler 36 is given.

At the same time, during the experiments, as for the device, the scheme of which is shown in Fig. 1 as well as in FIG. 3, by moving the corresponding probes in a radial direction relative to the channel, it can be carried out in fact in real time diagnostics of the gas mixture (air) in the channel 37, as well as testing (evaluating the effectiveness) of the flow swirler 36.

In order to evaluate the effect of Coriolis acceleration (Coriolis force) on the processes of vortex formation in the channels for both experimental devices, the schemes of which are shown in Fig. 1 and FIG. 3, it is possible to install the channel 12 (Fig. 1), 37 (Fig. 3) at different angles to the horizon plane, which makes it possible to provide different angles of intersection of the lines of the velocity vectors of the translational movement of the gas along the channel and the vector of the angular velocity of the rotation of the globe, for which flow swirler 11 in FIG. 1 is attached by means of a hinge 14 to a support not indicated by a separate position in FIG. 1, and the traverse 39 (Fig. 3) is also installed on the base 41 by means of a hinge 40. The experiments are carried out at fixed angles of inclination of the longitudinal axis of the channel to the horizon plane, and the fixing elements of the device along this angle in FIG. 1 and FIG. 3 are not shown.

Thus, a method is proposed for diagnosing vortex flows of multicomponent gas mixtures in order to increase the efficiency of separating a gas mixture into individual components and improve the design and layout diagrams of flow swirlers. The practical implementation of the results of such experiments on the devices implementing the method will allow optimizing the design of burners for various purposes, including burners designed for burning associated petroleum gas ballasted with nitrogen.

List of sources used

1. RF patent for the invention No. 2107197. A method for separating media with an inhomogeneous density field and components with different molecular weights and a vortex device for its implementation / G.N. Erchenko. IPC: F04F5/00; F 25 B 9/02. Published 1997.06.10.

2. RF patent for the invention No. 2368817. Vortex installation for the separate separation of the combustible component and carbon dioxide from the air / G.N. Erchenko. IPC: F 04M F 5/00. Published 2009.09.27.

3. Ivanov S.V. Vortex tube for air enrichment with oxygen / S.V. Ivanov // Proceedings of the Moscow State Technical University. I.E. Bauman. - M. Publishing house of Moscow Higher Technical School, 1976. - No. 240. - S. 129-131.

4. Zhidkov M.A. The use of a vortex tube in the processes of low-temperature separation of hydrogen sulfide gases / M.A. Zhidkov, G.A. Komarova, I.G. Klimov // Combustion processes and environmental protection: materials of the II All-Russian. scientific tech. conf. - Rybinsk. Rybin Publishing House. state aviation technol. academy. - 1997. - S. 32 - 36.

5. Ternopolsky A.V. Vortex heat power devices / A.V. Ternopil. - Penza, Penza State University Publishing House, 2007. - 183 p.

6. RF patent for the invention No. 2498319. The method of non-contact optical-laser diagnostics of non-stationary regimes of vortex flows and a device for its implementation / V.L. Okulov, V.G. Meledin, I.V. Naumov. IPC 6: G 01 P 5/26.

7. RF patent for the invention No. 2647157. A method for complex express diagnostics of a periodic non-stationary vortex flow and a device for its implementation / V.L. Okulov, I.V. Litvinov, Yu.S. Popov, S.I. Shtork, I.V. Naumov. IPC 6: G 01 H 5/26.

8. RF patent for utility model No. 134289. Universal burner / V.V. Short, Yu.V. Fedorov. IPC 6: F 23 D 17/00. Published 11/10/2013. Bull. No. 31.

9. RF patent for utility model No. 134288. Burner device (options) / V.V. Short, Yu.V. Fedorov. IPC 6: F 23 D 17/00. Published 11/10/2013. Bull. No. 31.

10. Arsibekov D.V. Utilization of associated petroleum gas / D.V. Arsibekov, V.V. Short, N.P. Kuznetsov, N.A. Melchukova // Ecology of industrial production, 2019, No. 2. - P. 2-8.

Claims (3)

1. A method for studying vortex flows of multicomponent gas mixtures in order to improve technologies for separating a gas mixture into individual components, which consists in creating, using a swirler, a vortex translational motion of a gas mixture in a cylindrical channel with optically transparent walls, the structure of which is studied using known methods for determining the distribution fields of static and dynamic gas pressure in the channel cavity, as well as optical methods for determining inhomogeneities in the gas flow, as well as determining the distribution of individual components of a multicomponent gas mixture along the channel length and along its radial directions by taking gas samples using probes from individual spatial points of the channel and analyzing the composition samples taken using gas analyzers, since the vortex translational motion of a multicomponent mixture separates the multicomponent gas mixture into annular one-component regions, and the efficiency of such stratification depends both on the geometric characteristics of the channel and on the efficiency of the swirler swirling the flow. 2. A device for studying vortex flows of multicomponent gas mixtures, containing a source of a gas mixture and a cylindrical channel for its movement, a path with a starting valve and a gearbox included in it, which differs by the fact that the channel walls are made of an optically transparent material, and a flow swirler is installed at its inlet, and to determine the spatial fields of static and dynamic pressure values in the channel space, holes are made in the channel wall to accommodate probes of the appropriate design with sensors installed on them pressure, and to determine the distribution of individual components of the gas mixture along the length and along the radial directions of the channel, gas samples taken from the channel are processed by gas analyzers that are part of the device, and the structural features of the vortex flow in the channel are determined using optical methods for fixing inhomogeneities in the gas flow using cameras and video cameras included in the device, and to increase the contrast of the gas flow structure, a source of coloring of a multicomponent gas mixture is introduced into the device, and the channel of the device can be fixed at a different angle to the horizon plane. 3. The device according to claim 2, characterized in that it is designed to study low-pressure vortex air flows in a cylindrical channel, which is created by a fan that directs the air flow into the inlet confuser of the gas-dynamic tract, which includes a laminarization unit for the air injected into the duct, at the outlet from which a flow swirler with a cylindrical channel is installed to form a translational rotational movement of air.

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