An experimental device for enhancing the condensation of wet steam in a Laval nozzle

Abstract

An experimental device for enhancing the condensation of wet steam in a Laval nozzle mainly includes an experimental medium supply system, a Laval nozzle system, and a schlieren test system. A ray source releases rays into the Laval nozzle as condensation nuclei to enhance the condensation effect; the schlieren display is used to directly observe the condensation effect of wet steam in the Laval flow field; a thermostat is used to eliminate the influence of heat exchange between the Laval nozzle and the surrounding environment on the condensation of internal wet steam. The inlet wet steam flow rate, pressure, humidity of the Laval nozzle of the present invention, as well as the ray source intensity and ray release position can all be flexibly adjusted, thus providing a scientific basis for studying the wet steam condensation law and optimizing the working parameters.

Description

Technical Field

[0001] The present invention discloses an experimental device for enhancing wet steam condensation in a De Laval nozzle, which relates to the field of wet steam condensation phase change. Background Art

[0002] When high-pressure natural gas passes through a De Laval nozzle, a significant temperature drop will occur, and saturated steam will condense and thus be separated from the gas phase. The De Laval refrigeration effect can be used to purify and dehydrate natural gas and even liquefy it. The structure of the De Laval nozzle can directly affect the condensation efficiency, and further affect the effect of natural gas purification and liquefaction. Accurately measuring the internal flow field of the De Laval nozzle is the key to structural optimization. Traditional flow field testing of the De Laval nozzle requires inserting a probe through a hole, and this intrusive measurement method will interfere with the flow field, thus affecting the accuracy of parameter measurement. In addition, traditional steam condensation inside the De Laval nozzle is mainly controlled by homogeneous nucleation, which needs to occur under a large supersaturation, and the condensation efficiency is low.

[0003] This invention patent discloses an experimental device for enhancing wet steam condensation in a De Laval nozzle. Based on the refrigeration effect of the traditional nozzle, it uses an external ray method to make ray particles serve as condensation nuclei to promote the condensation of wet steam and strengthen the condensation effect of the nozzle. At the same time, it uses the schlieren method to observe the condensation phenomenon without affecting the nozzle flow field. This invention can simply and efficiently enhance the condensation efficiency of the De Laval nozzle and observe the phenomenon. Summary of the Invention

[0004] The purpose of the present invention is to provide an experimental device for enhancing wet steam condensation in a De Laval nozzle, which promotes the condensation of wet steam in the nozzle by an external ray method, enhances the condensation effect, and at the same time uses the schlieren method to directly observe the internal condensation phenomenon of the De Laval nozzle, and can achieve non-intrusive measurement.

[0005] An experimental device for enhancing wet steam condensation in a De Laval nozzle disclosed by the present invention mainly includes an experimental medium supply system, a De Laval nozzle system, and a schlieren test system.

[0006] The described medium supply system mainly includes a compressor, a gas buffer tank, a filter, a high-pressure humidification tank, and a high-pressure micro-mist humidifier; the compressor, the gas buffer tank, and the filter are connected in sequence through pipelines, the filter is connected to the high-pressure humidification tank through a pipeline, and a gas flow meter and a gas volume regulating valve are provided on the pipeline between the filter and the high-pressure humidification tank; the high-pressure micro-mist humidifier is connected to the high-pressure humidification tank through a pipeline, a wet steam regulating valve is provided on the connecting pipeline between the high-pressure micro-mist humidifier and the high-pressure humidification tank, the high-pressure humidification tank is connected to the inlet of the Laval nozzle through a pipeline, and a temperature and humidity sensor and a pressure sensor are provided on the connecting pipeline between the high-pressure humidification tank and the inlet of the Laval nozzle; a pressure regulating valve, a temperature and humidity sensor, a pressure sensor, and a back pressure regulating valve are provided on the outlet pipe of the Laval nozzle;

[0007] The described Laval nozzle system mainly includes: a Laval nozzle, a radiation source, a guide rail, and a temperature controller; the Laval nozzle mainly consists of a Laval channel plate, a front cover plate, and a rear cover plate; there are 2 channel plates, and their structures are symmetric up and down. The front cover plate and the rear cover plate are respectively installed on both sides of the two channel plates, so that a Laval-type channel for fluid passage is formed between the two channel plates; the channel plate is made of metal material, and the front cover plate and the rear cover plate are both made of transparent quartz glass. The guide rail is parallel to the axis of the Laval nozzle, the starting and ending points of the guide rail are respectively located at the inlet and outlet of the Laval nozzle, the radiation source is installed on the guide rail and can move back and forth along the guide rail, and the radiation material used by the radiation source can be americium or cesium; the temperature controller is connected to the Laval channel plate through a wire.

[0008] The described schlieren test system mainly includes a point light source, a front convex lens, a rear convex lens, a blade, a high-speed camera, an optical platform, and a position control component. Among them, the point light source, the front convex lens, the rear convex lens, the blade, and the high-speed camera are placed in sequence and on the same optical axis, and the front convex lens and the rear convex lens are respectively located on the front and rear sides of the Laval nozzle.

[0009] The point light source is set at one end of the optical platform, and the front convex lens is at a distance of one focal length from the point light source. The light emitted by the point light source becomes parallel light after passing through the front convex lens. After the parallel light passes through the flow field of the Laval nozzle channel, the parallel light is focused by the rear convex lens. The distance between the blade and the rear convex lens is one focal length of the rear convex lens; a high-speed camera is provided after the blade. The point light source, the front convex lens, the rear convex lens, the blade, and the camera are all installed on the position control component. The bottom of the position control component is installed on the base of the optical platform and can be adjusted vertically and horizontally according to needs.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] (1) By the method of adding an external radiation source, a condensation core is provided for the wet steam in the nozzle, and the condensation effect of the Laval nozzle is enhanced conveniently and quickly;

[0012] (2) By using the schlieren method, the condensation phenomenon can be observed intuitively and clearly, achieving the effect of non-invasive measurement.

[0013] (3) A temperature control device is provided in the Laval nozzle, which can overcome the influence of heat exchange between the nozzle and the surrounding environment on the condensation of moisture. Description of the Drawings

[0014] Figure 1 It is a flow chart of the generation of humid air and the external ray.

[0015] Figure 2 It is a layout diagram of the schlieren device of the present invention.

[0016] Figure 3 It is a composition diagram of the ray source of the present invention.

[0017] Figure 4 It is a schematic diagram of the schlieren effect of the present invention.

[0018] 1 - Compressor; 2 - Buffer tank; 3 - Filter; 4 - Vortex flowmeter; 5 - Gas flow control valve; 6 - High-pressure micro-mist humidity generator; 7 - Humidity control valve; 8 - High-pressure humidification tank; 9 - Pressure control valve; 10 - Temperature and humidity sensor; 11 - Pressure sensor; 12 - Laval nozzle; 13 - Ray source; 14 - Guide rail; 15 - Temperature controller; 15 - Laval nozzle; 16 - Back pressure control valve; 17 - Laval channel; 18 - Front cover plate; 19 - Rear cover plate; 20 - Point light source; 21 - Front convex lens; 22 - Rear convex lens; 23 - Blade; 24 - High-speed camera; 25 - Optical platform; 26 - Position adjustment component. Detailed Embodiments

[0019] An experimental device for enhancing the condensation of wet steam in a Laval nozzle disclosed by the present invention mainly includes an experimental medium supply system, a Laval nozzle system, and a schlieren test system.

[0020] The described medium supply system mainly includes a compressor 1, a gas buffer tank 2, a filter 3, a high-pressure humidification tank 8, and a high-pressure micro-mist humidifier 6; the compressor 1, the gas buffer tank 2, and the filter 3 are connected in sequence through pipelines, the filter 3 is connected to the high-pressure humidification tank 8 through a pipeline, and a gas flow meter 4 and a gas flow regulating valve 5 are provided on the pipeline between the filter 3 and the high-pressure humidification tank 8; the high-pressure micro-mist humidifier 6 is connected to the high-pressure humidification tank 8 through a pipeline, and a wet steam regulating valve 7 is provided on the connecting pipeline between the high-pressure micro-mist humidifier 6 and the high-pressure humidification tank 8, the high-pressure humidification tank 8 is connected to the inlet of a Laval nozzle 12 through a pipeline, and a temperature and humidity sensor 10 and a pressure sensor 11 are provided on the connecting pipeline between the high-pressure humidification tank 8 and the inlet of the Laval nozzle 12; a pressure regulating valve 9, a temperature and humidity sensor 10, a pressure sensor 11, and a back pressure regulating valve 16 are provided on the outlet pipe of the Laval nozzle 12.

[0021] As Figure 1 shown, the Laval nozzle system mainly includes: a Laval nozzle 12, a radiation source 13, a guide rail 14, and a temperature controller 15. As Figure 2 shown, the described Laval nozzle 12 mainly consists of a Laval channel plate 17, a front cover plate 18, and a rear cover plate 19. There are 2 Laval channel plates 17, and their structures are symmetric up and down. The front cover plate 18 and the rear cover plate 19 are respectively installed on both sides of the two channel plates 17, so that a Laval channel for fluid passage is formed between the two channel plates 17; the channel plate 17 is made of a metal material, and the front cover plate 18 and the rear cover plate 19 are both made of transparent quartz glass. As Figure 3 shown, the guide rail 14 is parallel to the axis of the Laval nozzle 12. The starting and ending points of the guide rail 14 are respectively located at the inlet and outlet of the Laval nozzle 12. The radiation source 13 is installed on the guide rail 14 and can move back and forth along the guide rail 14. The radiation material used for the radiation source 13 can be americium 241 or cesium 137; the temperature controller 15 is connected to the Laval channel plate 17 through a wire and can adjust the flow channel temperature of the Laval nozzle 12.

[0022] As Figure 4 shown, the schlieren test system mainly includes a point light source 20, a front convex lens 21, a rear convex lens 22, a blade 23, a high-speed camera 24, an optical platform 25, and a position control component 26. Among them, the point light source 20, the front convex lens 21, the rear convex lens 22, the blade 23, and the high-speed camera 24 are placed in sequence and on the same optical axis, and the front convex lens 21 and the rear convex lens 22 are respectively located on the front and rear sides of the Laval nozzle 12.

[0023] The point light source 20 is arranged at one end on the optical platform 25, and the front convex lens 21 is at a distance of one focal length from the point light source 20. The light rays emitted by the point light source 20 become parallel light rays after passing through the front convex lens 21. After the parallel light rays pass through the flow field of the Laval nozzle channel, the parallel light rays are focused by the rear convex lens 22. The distance between the blade 23 and the rear convex lens 22 is one focal length of the rear convex lens 22; a high-speed camera 24 is arranged behind the blade 23. The point light source 20, the front convex lens 21, the rear convex lens 22, the blade 23, and the camera 24 are all installed on the position control assembly 26. The bottom of the position control assembly 26 is installed on the base of the optical platform 25 and can be adjusted vertically in height and horizontally in position as needed.

[0024] The working process of the present invention is described as follows:

[0025] As Figure 1 shown, the high-pressure compressed air coming out of the compressor 1 passes through the buffer tank 2. The pressure fluctuation of the gas is eliminated through buffering, and then the oil droplets, solid particles and other pollution media are filtered out through the filter 3. Subsequently, after the flow rate is measured by the gas flowmeter 4, it enters the high-pressure humidifying tank 8. The water mist coming out of the high-pressure micro-mist humidifier 6 also enters the high-pressure humidifying tank 8 after the flow rate is adjusted by the wet steam regulating valve 7. After the high-pressure air and the high-pressure wet steam are mixed in the high-pressure humidifying tank 8, they are communicated with the inlet of the Laval nozzle 12 through a pipeline.

[0026] The pressure of the air flow entering the Laval nozzle 12 can be adjusted through the pressure regulating valve 9, and the humidity of the air flow is adjusted through the high-pressure micro-mist humidifier 6. The temperature and humidity sensor 10 is used to measure the temperature and humidity of the high-pressure wet gas, and the pressure sensor 11 measures the pressure of the high-pressure wet gas.

[0027] The flow channel of the Laval nozzle 12 is of a gradually shrinking and then expanding type. After the high-pressure wet gas enters the Laval nozzle 12, condensation occurs due to expansion and cooling. To improve the condensation efficiency, a radiation source 13 is used to radiate charged particles as the condensation core. The radiation source 13 can move through the guide rail 14 and emit particles to different positions of the Laval nozzle 12, so as to study the differences in the condensation effects at different positions. The temperature controller 15 controls the temperature of the Laval nozzle channel plate 17 to compensate for the influence of the ambient temperature on the temperature field inside the Laval nozzle 12. The temperature controller 15 determines whether to perform temperature adjustment by measuring the ambient temperature and the temperature of the nozzle channel plate, so that the temperature of the nozzle surface is always equal to the outside ambient temperature, thereby realizing the adiabatic of the nozzle and the environment. A back pressure valve 16 is arranged on the pipeline connected to the outlet of the Laval nozzle 12 for the pressure regulation and control of the back pressure. At the same time, a temperature and humidity sensor 10 and a pressure sensor 11 are arranged to monitor the temperature, humidity and pressure of the outlet air flow.

[0028] The condensation observation and recording of the flow field inside the Laval nozzle 12 are completed by the schlieren system. The specific implementation scheme is as follows:

[0029] (1) Fix the point light source 20, the front convex lens 21, the Laval nozzle 12, the rear convex lens 22, the blade 23, and the high-speed camera 24 on the base of the optical platform 25 through the position adjustment assembly 26.

[0030] (2) Adjust the high-speed camera 24, the blade 23, the rear convex lens 22, the front convex lens 21, and the point light source 20 so that their centers are on the same axis.

[0031] (3) Connect the high-speed camera 24 to the power supply, adjust the lens, adjust the size and brightness of the field of view, and adjust the height of the high-speed camera 24 so that an object appears in the lens.

[0032] (4) Turn on the point light source 20. The light emitted by the point light source 20 becomes a parallel light beam after passing through the front convex lens 21. Adjust the distance between the point light source 20 and the front convex lens 21 to be about one focal length of the convex lens.

[0033] (5) Adjust the distance between the lens of the high-speed camera 24 and the blade 23 so that the focal length of the lens of the high-speed camera 24 is equal to the distance between it and the blade 23.

[0034] (6) Adjust the distance between the rear convex lens 22 and the blade 23 so that the focal length of the rear convex lens 22 is equal to the distance between it and the blade 23.

[0035] (7) Adjust the distances between the front convex lens 21, the rear convex lens 22, and the Laval nozzle 12 respectively so that the light can pass through the cross-section of the Laval nozzle 12 to be measured in parallel. The cross-section of the Laval nozzle 12 is rectangular. By slightly adjusting the angle of the nozzle, the light can pass through the Laval nozzle 12 vertically.

[0036] (8) The light beam after passing through the Laval nozzle 12 is converged by the rear convex lens 22, and the converged light beam is blocked by the blade 23.

[0037] (9) A part of the light beam blocked by the blade 23 enters the lens of the high-speed camera 24 to obtain a schlieren pattern.

[0038] (10) Observe the image in the lens at this time to see if a clear image of the Laval nozzle 12 appears, and make a bright and clear pattern appear in the lens by slightly adjusting the distance and angle, etc.

[0039] (11) The wet steam from the high-pressure micro-mist humidifier 6 and the high-pressure air from the compressor 1 are mixed in the high-pressure humidification tank 8 and then enter the Laval nozzle 12. When the high-pressure wet air passes through the Laval nozzle 12, the flow schlieren pattern at this time is photographed using the high-speed camera 24. When it is necessary to enhance the condensation effect, the ray source 13 can be adjusted to release ray particles into the Laval nozzle 12 as condensation nuclei. By adjusting the position of the ray source 13 on the guide rail 14, the ray condensation effect at different positions can be studied. When it is necessary to change the intensity of the ray source, the mass of the ray material (i.e., americium 241 or cesium 137) can be adjusted.

[0040] The present invention provides an experimental device for enhancing the condensation of wet steam in a Laval nozzle. By applying rays as condensation nuclei, the condensation effect is enhanced, and through schlieren display, the condensation effect of wet steam in the Laval flow field can be intuitively observed. The present invention can overcome the influence of heat exchange between the Laval nozzle and the surrounding environment on the condensation of internal wet air through a thermostat. The inlet wet air flow rate, pressure, humidity of the Laval nozzle of the present invention, as well as the ray source intensity and ray release position can all be flexibly adjusted, thereby providing a scientific basis for studying the condensation law of wet steam and optimizing working parameters.

Claims

1. An experimental device for enhancing the condensation of wet steam in a Laval nozzle, characterized in that: It mainly includes an experimental medium supply system, a Laffal nozzle system and a schlieren test system; the medium supply system mainly includes a compressor (1), a gas buffer tank (2), a filter (3), a high-pressure humidification tank (8), and a high-pressure micro-mist humidifier (6); the compressor (1), the gas buffer tank (2), and the filter (3) are connected in sequence through pipelines, the filter (3) is connected to the high-pressure humidification tank (8) through a pipeline, and a gas flowmeter (4) and a gas flow regulating valve (5) are provided on the pipeline between the filter (3) and the high-pressure humidification tank (8); the high-pressure micro-mist humidifier (6) is connected to the high-pressure humidification tank (8) through a pipeline, and a wet steam regulating valve (7) is provided on the connecting pipeline between the high-pressure micro-mist humidifier (6) and the high-pressure humidification tank (8), the high-pressure humidification tank (8) is connected to the inlet of the Laffal nozzle (12) through a pipeline, and a temperature and humidity sensor (10) and a pressure sensor (11) are provided on the connecting pipeline between the high-pressure humidification tank (8) and the inlet of the Laffal nozzle (12); a pressure regulating valve (9), a temperature and humidity sensor (10), a pressure sensor (11) and a back pressure regulating valve (16) are provided on the outlet pipe of the Laffal nozzle (12). The Laffal nozzle system mainly includes: a Laffal nozzle (12), a radiation source (13), a guide rail (14), and a temperature controller (15); the Laffal nozzle is mainly composed of a Laffal channel plate (17), a front cover plate (18), and a rear cover plate (19), there are 2 channel plates (17), and their structures are symmetric up and down, the front cover plate (18) and the rear cover plate (19) are respectively installed on both sides of the two channel plates (17), so that a Laffal-type channel for fluid passage is formed between the two channel plates (17); the guide rail (14) is parallel to the axis of the Laffal nozzle (12), the starting and ending points of the guide rail (14) are respectively located at the inlet and outlet of the Laffal nozzle (12), the radiation source (13) is installed on the guide rail (14) and can move back and forth along the guide rail (14), and the radiation material used by the radiation source (13) can be americium or cesium; the temperature controller (15) is connected to the Laffal channel plate (17) through a wire. The schlieren test system mainly includes a point light source (20), a front convex lens (21), a rear convex lens (22), a blade (23), a high-speed camera (24), an optical platform (25) and a position control component (26), the point light source (20), the front convex lens (21), the rear convex lens (22), the blade (23), and the high-speed camera (24) are placed in sequence and on the same optical axis, wherein the front convex lens (21) and the rear convex lens (22) are respectively located on the front and rear sides of the Laffal nozzle (12); the distance between the blade (23) and the rear convex lens (22) is one focal length of the rear convex lens (22). A high-speed camera (24) is provided after the blade (23).

2. The experimental device for enhancing condensation of wet steam in a Laval nozzle according to claim 1, wherein: The channel plate (17) is made of a metal material, and the front cover plate (18) and the rear cover plate (19) are both made of transparent quartz glass.

3. The experimental device for enhancing the condensation of wet steam in a Laval nozzle according to claim 1, characterized in that: The point light source (20), front convex lens (21), rear convex lens (22), blade (23), and camera (24) are all installed on the position control component (26). The bottom of the position control component (26) is installed on the base of the optical platform (25), and the vertical height and horizontal position can be adjusted as needed.

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