Full-length visualization experimental device for capturing pressure fluctuation and flow pattern evolution of low-temperature blending

Abstract

A kind of whole section visualization test device for capturing low temperature mixing pressure pulsation and flow pattern evolution, including liquid supply system, gas supply system, measurement and data acquisition system, low temperature experiment cavity and quartz mixing cavity;Liquid supply system, gas supply system and quartz mixing cavity in low temperature experiment cavity are connected, and liquid supply system, gas supply system, quartz mixing cavity and measurement and data acquisition system are connected;Low temperature experiment cavity is internally provided with quartz mixing cavity surrounded by porous cooling screen, and first vacuum interlayer is arranged outside the porous cooling screen;Heat-insulating baffle is arranged at the top of quartz mixing cavity, and the upper portion of heat-insulating baffle is connected with flange plate arranged at the top of low temperature experiment cavity;Visual window connected outside the porous cooling screen extends out of low temperature experiment cavity, low temperature cold light source is arranged outside the visual window on one side, and high-speed camera and image acquisition system are arranged outside the visual window on the other side;The present application has the advantages of simple structure, realizing overall visualization effect, and having the functions of low temperature mixing pressure pulsation and flow pattern evolution.

Description

Technical Field

[0001] This invention relates to the field of gas-liquid two-phase flow technology, specifically to a full-section visualization experimental device for capturing low-temperature mixing pressure pulsations and flow pattern evolution. Background Technology

[0002] Cryogenic gas-liquid two-phase flow mixing and condensation is a common physical process in aerospace cryogenic propellant delivery pipelines, accompanied by unstable two-phase flow pattern evolution and low-frequency pressure pulsation. Visualization experiments are an effective means of capturing this phenomenon.

[0003] The existing low-temperature mixing visualization device (patent CN201510012811.8, titled: A visualization test device suitable for low-temperature gas-liquid two-phase mixing) is constructed by encapsulating two layers of quartz glass with sealing flanges and gaskets. The working principle is that gas flows into the inner quartz tube from the flange hole, thus mixing with the low-temperature liquid. The disadvantages are that the use of upper and lower flanges and screw connections inevitably results in obstructions at the gas-liquid mixing point, which cannot achieve an overall visualization effect; in addition, the gas path is opened on the flange, which is not transparent, so the flow pattern evolution in the gas path cannot be observed; and due to the presence of the gas collecting ring, the flange structure is too complicated and difficult to install. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a full-section visualization test device for capturing low-temperature mixing pressure pulsation and flow pattern evolution. It has a simple structure, is easy to install, achieves overall visualization effect, and has the function of detecting low-temperature mixing pressure pulsation and flow pattern evolution.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A fully visualized experimental device for capturing low-temperature mixing pressure pulsations and flow pattern evolution includes a liquid supply system A, a gas supply system B, a measurement and data acquisition system C, a low-temperature experimental chamber D, and a quartz mixing chamber E; the liquid supply system A, the gas supply system B, and the quartz mixing chamber E within the low-temperature experimental chamber D are connected, and the liquid supply system A, the gas supply system B, the quartz mixing chamber E, and the measurement and data acquisition system C are connected.

[0007] The working medium in the liquid supply system A is liquid nitrogen, liquid oxygen, liquid argon or other commonly used cryogenic liquid working medium, and the working medium in the gas supply system B is nitrogen, oxygen, argon or other commonly used gaseous working medium. The liquid supply system A and the gas supply system B must use the same working medium pair, that is, different phases of the same substance.

[0008] The liquid supply system A includes a subcooler A2, which is equipped with high vacuum multilayer insulation. The input of the subcooler A2 is connected to the helium cylinder A1 through the first pressure reducing valve A3. The top of the subcooler A2 has an exhaust port A4. The top of the subcooler A2 is connected to the first safety valve A5. The liquid supply pipe A6 is led out from the bottom of the subcooler A2, passes through the second shut-off valve A7, and is connected to the liquid main pipeline inlet of the quartz mixing chamber E.

[0009] The gas supply system B includes a high-pressure gas cylinder group B1. The output of the high-pressure gas cylinder group B1 is connected to the inlet of the gas pipeline through the second pressure reducing valve B2, the constant temperature heater B3, the second shut-off valve B5, the flow regulating valve B4, and the quartz mixing chamber E.

[0010] The thermostatic heater B3 adjusts the heating power to bring the working gas to different temperatures, and the flow rate of the working gas is adjusted by regulating the flow regulating valve B4.

[0011] The measurement and data acquisition system C includes: a gas flow meter C1, a liquid flow meter C2, a high-frequency low-temperature pressure sensor C3, a temperature sensor C4, a data acquisition system C5, a low-temperature cold light source C6, and a high-speed camera and image acquisition system C7; the gas flow meter C1, liquid flow meter C2, high-frequency low-temperature pressure sensor C3, temperature sensor C4, low-temperature cold light source C6, high-speed camera and image acquisition system C7, and data acquisition system C5 are connected; the first gas flow meter C1, the first high-frequency low-temperature pressure sensor C3, and the first temperature sensor C4 are connected to the gas supply pipeline at the outlet of the constant temperature heater B3; the liquid flow meter C2, the second high-frequency low-temperature pressure sensor C3, and the second temperature sensor C4 are connected to the liquid supply pipeline at the outlet of the subcooler A2; and the third high-frequency low-temperature pressure sensor C3 and the fourth high-frequency low-temperature pressure sensor C3 are respectively connected to the bottom of the low-temperature experimental chamber D and the outlet of the quartz mixing chamber E.

[0012] The data acquisition system C5 collects pressure signals to capture the low-frequency pressure pulsation phenomenon during the low-temperature mixing process; the high-speed camera and image acquisition system C7 captures the flow pattern evolution phenomenon during the low-temperature mixing process through high-speed camera shooting; the low-temperature cold light source C6 provides illumination supplement to the high-speed camera and image acquisition system C7, and does not have heat output.

[0013] The cryogenic experimental chamber D is insulated under high vacuum and contains a quartz mixing chamber E enclosed by a porous cooling screen D1. A first vacuum interlayer D7 is located on the outside of the porous cooling screen D1. An insulating baffle D4 is installed on the top of the quartz mixing chamber E, and the upper part of the insulating baffle D4 is connected to a flange D8 installed on the top of the cryogenic experimental chamber D. A pressure regulating valve D5 and a second safety valve D6 connected to the insulating baffle D4 extend out of the flange D8. The displacement gas and pre-cooled liquid drain ports D3 of the quartz mixing chamber E extend out of the insulating baffle D4 and the flange D8. A visualization window D2 connected to the outside of the porous cooling screen D1 extends out of the cryogenic experimental chamber D. A cryogenic cold light source C6 is installed on the outside of one side of the visualization window D2, and a high-speed camera and image acquisition system C7 is installed on the outside of the other side of the visualization window D2.

[0014] The quartz mixing chamber E is entirely made of welded quartz glass and includes a liquid main pipeline E1, two air inlet pipelines E2 and E3, and a second vacuum interlayer E4. The liquid main pipeline E1 extends vertically through the second vacuum interlayer E4, which includes a vacuum port E5. The two air inlet pipelines E2 and E3 extend into the second vacuum interlayer E4 and are connected to the liquid main pipeline E1. The air inlet pipelines E2 and E3 and the liquid nitrogen main pipeline E1 of the quartz mixing chamber E are connected to the top of the cryogenic experimental chamber D through polytetrafluoroethylene sleeves, thereby communicating with the gas supply and liquid supply pipelines respectively. The quartz mixing chamber E is suspended inside the cryogenic experimental chamber D.

[0015] The vacuum level in the first vacuum interlayer D7 and the second vacuum interlayer E4 reaches 10. -3 Below Pa.

[0016] The length of the air inlet pipe inside the second vacuum interlayer E4 shall not be less than 10cm.

[0017] Compared with the prior art, the present invention has at least the following beneficial effects:

[0018] Because this invention uses a high-frequency low-temperature pressure sensor, it can accurately measure the low-frequency pressure pulsation during the low-temperature mixing process. Since the quartz mixing chamber in this invention is integrally welded from quartz glass, its structure is simple, requires no additional mechanisms, and is robust and durable. Furthermore, the entire test section is completely transparent, enabling full visualization of the low-temperature mixing process, including observation of the flow pattern evolution within the gas pipeline. Because this invention includes a subcooler extraction port and a flow controller, it allows for free adjustment of gas flow rate, gas temperature, liquid flow rate, liquid subcooling, and back pressure. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the quartz mixing cavity of the present invention.

[0021] Figure 3 This is a physical image of the quartz mixing cavity of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to embodiments and accompanying drawings, but this does not constitute any limitation on the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope thereof. All modifications that can be directly derived or conceived by those skilled in the art from the content disclosed in the present invention are still within the scope of the claims of the present invention.

[0023] Reference Figure 1 A fully visualized experimental device for capturing low-temperature mixing pressure pulsations and flow pattern evolution includes a liquid supply system A, a gas supply system B, a measurement and data acquisition system C, a low-temperature experimental chamber D, and a quartz mixing chamber E; the liquid supply system A, the gas supply system B, and the quartz mixing chamber E within the low-temperature experimental chamber D are connected, and the liquid supply system A, the gas supply system B, the quartz mixing chamber E, and the measurement and data acquisition system C are connected.

[0024] The working medium in the liquid supply system A is liquid nitrogen, and the working medium in the gas supply system B is nitrogen gas.

[0025] The liquid supply system A includes: a helium cylinder A1, a supercooler A2, a first pressure reducing valve A3, an extraction port A4, a first safety valve A5, a liquid supply pipe A6, and a first shut-off valve A7. The supercooler A2 is equipped with high-vacuum multilayer insulation. The input of the supercooler A2 is connected to the helium cylinder A1 through the first pressure reducing valve A3. An extraction port A4 is located at the top of the supercooler A2. The first safety valve A5 is connected to the top of the supercooler A2. The liquid supply pipe A6 extends from the bottom of the supercooler A2, passes through the second shut-off valve A7, and then connects to the quartz mixing chamber. The liquid main pipeline inlet of E; during the experiment, by opening the first pressure reducing valve A3, high-pressure helium gas in helium cylinder A1 is introduced into supercooler A2, thereby squeezing out the cryogenic liquid nitrogen in supercooler A2; in addition, the evacuation port A4 is used to apply supercooling to the cryogenic liquid nitrogen. By evacuating, the pressure in supercooler A2 is reduced to below the saturated vapor pressure of cryogenic liquid nitrogen. The cryogenic liquid nitrogen will partially evaporate into saturated nitrogen gas, which is then extracted from the evacuation port A4. At the same time, the temperature of the cryogenic liquid nitrogen decreases, thereby achieving a certain degree of supercooling.

[0026] The gas supply system B includes: a high-pressure gas cylinder group B1, a second pressure reducing valve B2, a constant temperature heater B3, a flow regulating valve B4, and a second shut-off valve B5. The output of the high-pressure gas cylinder group B1 is connected to the inlet of the quartz mixing chamber E through the second pressure reducing valve B2, the constant temperature heater B3, the second shut-off valve B5, the flow regulating valve B4, and the gas inlet pipe. High-pressure nitrogen is discharged from the high-pressure gas cylinder group B1, flows into the constant temperature heater B3 after passing through the second pressure reducing valve B2, and the constant temperature heater B3 can adjust the heating power to make the nitrogen reach different temperatures. The flow rate of the nitrogen can be adjusted by adjusting the flow regulating valve B4.

[0027] The measurement and data acquisition system C includes: a gas flow meter C1, a liquid flow meter C2, a high-frequency low-temperature pressure sensor C3, a temperature sensor C4, a data acquisition system C5, a low-temperature cold light source C6, and a high-speed camera and image acquisition system C7; the gas flow meter C1, liquid flow meter C2, high-frequency low-temperature pressure sensor C3, temperature sensor C4, low-temperature cold light source C6, high-speed camera and image acquisition system C7, and data acquisition system C5 are connected; the first gas flow meter C1, the first high-frequency low-temperature pressure sensor C3, and the first temperature sensor C4 are connected to the gas supply pipeline at the outlet of the constant temperature heater B3, and the liquid flow meter C2, the second high-frequency... The low-temperature pressure sensor C3 and the second temperature sensor C4 are connected to the liquid supply line at the outlet of the supercooler A2. The third high-frequency low-temperature pressure sensor C3 and the fourth high-frequency low-temperature pressure sensor C3 are connected to the bottom of the low-temperature experimental chamber D and the outlet of the quartz mixing chamber E, respectively. The data acquisition system C5 can collect pressure signals to capture the low-frequency pressure pulsation phenomenon during the low-temperature mixing process. The high-speed camera and image acquisition system C7 can capture the flow pattern evolution phenomenon during the low-temperature mixing process through high-speed camera shooting. The low-temperature cold light source C6 provides illumination supplement to the high-speed camera and image acquisition system C7, and has no heat output to prevent the low-temperature system from becoming unstable due to heat.

[0028] The cryogenic experimental chamber D includes: a porous cooling screen D1, a visualization window D2, a displacement gas and pre-cooled liquid drain port D3, an insulating baffle D4, a pressure regulating valve D5, a second safety valve D6, a first vacuum jacket D7, and a flange D8. The cryogenic experimental chamber D employs high-vacuum insulation and contains a quartz mixing cavity E enclosed by the porous cooling screen D1. The first vacuum jacket D7 is located outside the porous cooling screen D1, and the vacuum level within the first vacuum jacket D7 reaches 10⁻⁶. -3Below Pa; an insulating baffle D4 is installed at the top of the quartz mixing chamber E to isolate heat leakage from the top end face; the upper part of the insulating baffle D4 is connected to the flange D8 installed at the top of the low temperature experimental chamber D, and the pressure regulating valve D5 and the second safety valve D6 connected on the insulating baffle D4 extend out of the flange D8; the displacement gas and pre-cooled liquid drain port D3 of the quartz mixing chamber E extends out of the insulating baffle D4 and the flange D8; the visualization window D2 connected to the outside of the porous cooling screen D1 extends out of the low temperature experimental chamber D, and a low temperature cold light source C6 is installed on the outside of the visualization window D2 on one side, and a high-speed camera and image acquisition system C7 is installed on the outside of the visualization window D2 on the other side.

[0029] Before the experiment begins, the second pressure reducing valve B2, the second shut-off valve B5, and the outlet for the replacement gas and pre-cooled liquid D3 need to be opened to introduce nitrogen gas from the high-pressure gas cylinder group B1 into the cryogenic experimental chamber D, and discharge it from the outlet for the replacement gas and pre-cooled liquid D3 to replace the air in the cryogenic experimental chamber. Then, the first pressure reducing valve A3 and the first shut-off valve A7 are opened to discharge the cryogenic liquid nitrogen. At this time, the cryogenic liquid nitrogen and nitrogen gas will flow into the quartz mixing chamber E in the cryogenic experimental chamber D from the liquid supply line and the gas supply line, respectively. After flowing through the quartz mixing chamber E, the nitrogen gas will be continuously discharged from the outlet for the replacement gas and pre-cooled liquid D3. The liquid nitrogen will accumulate at the bottom of the quartz mixing chamber E. Under the action of the porous cooling screen D1, the liquid nitrogen is drawn into the porous cooling screen D1 by the core, and the entire porous cooling screen D1 will be wetted, thereby further achieving the effect of heat insulation.

[0030] Reference Figure 1 , Figure 2 , Figure 3 The quartz mixing chamber E is entirely made of welded quartz glass and includes a main liquid pipeline E1, two air inlet pipelines E2 and E3, and a second vacuum jacket E4. The main liquid pipeline E1 runs vertically through the second vacuum jacket E4, which includes a vacuum port E5 for evacuation at any time, requiring a vacuum level of 10. -3 Below Pa; two air inlet pipes E2 and E3 extend into the second vacuum jacket E4 and connect to the main liquid pipe E1. The length of the air inlet pipe in the second vacuum jacket E4 must not be less than 10cm. If it is less than 10cm, a thermal bridge will be formed on the air inlet pipe in the second vacuum jacket E4. In the case of external heat leakage, a frost layer will form on the outside of the quartz mixing cavity E, thus affecting the visualization observation. The air inlet pipes E2 and E3 and the main liquid pipe E1 of the quartz mixing cavity E are connected to the top of the low temperature experimental chamber D through a polytetrafluoroethylene sleeve, thus connecting to the gas supply and liquid supply pipes respectively. The quartz mixing cavity E is suspended in the low temperature experimental chamber D.

Claims

1. A full-section visualization experimental device for capturing low-temperature mixing pressure pulsations and flow pattern evolution, characterized in that: It includes a liquid supply system (A), a gas supply system (B), a measurement and data acquisition system (C), a cryogenic experimental chamber (D), and a quartz mixing chamber (E); the liquid supply system (A), the gas supply system (B), and the quartz mixing chamber (E) within the cryogenic experimental chamber (D) are connected; the liquid supply system (A), the gas supply system (B), the quartz mixing chamber (E), and the measurement and data acquisition system (C) are also connected. The low-temperature experimental chamber (D) is insulated under high vacuum and has an internal quartz mixing chamber (E) surrounded by a porous cooling screen (D1). A first vacuum jacket (D7) is provided on the outside of the porous cooling screen (D1). An insulating baffle (D4) is installed on the top of the quartz mixing chamber (E). The upper part of the insulating baffle (D4) is connected to a flange (D8) installed on the top of the low-temperature experimental chamber (D). A pressure regulating valve (D5) and a second safety valve (D6) connected to the insulating baffle (D4) extend out of the flange (D8). The displacement gas and pre-cooled liquid drain ports (D3) of the quartz mixing chamber (E) extend out of the insulating baffle (D4) and the flange (D8). A visualization window (D2) connected to the outside of the porous cooling screen (D1) extends out of the low-temperature experimental chamber (D). A low-temperature cold light source (C6) is provided on the outside of one side of the visualization window (D2), and a high-speed camera and image acquisition system (C7) is provided on the outside of the other side of the visualization window (D2). The liquid supply system (A) includes a subcooler (A2), which is equipped with high vacuum multilayer insulation. The input of the subcooler (A2) is connected to a helium cylinder (A1) through a first pressure reducing valve (A3). The top of the subcooler (A2) has an exhaust port (A4). The top of the subcooler (A2) is connected to a first safety valve (A5). The liquid supply pipe (A6) is led out from the bottom of the subcooler (A2), passes through a second shut-off valve (A7), and is connected to the liquid main pipeline inlet of the quartz mixing chamber (E). The gas supply system (B) includes a high-pressure gas cylinder group (B1), and the output of the high-pressure gas cylinder group (B1) is connected to the inlet of the gas pipeline of the second pressure reducing valve (B2), the constant temperature heater (B3), the second shut-off valve (B5), the flow regulating valve (B4), and the quartz mixing chamber (E). The measurement and data acquisition system (C) includes: a gas flow meter (C1), a liquid flow meter (C2), a high-frequency low-temperature pressure sensor (C3), a temperature sensor (C4), a data acquisition system (C5), a low-temperature cold light source (C6), and a high-speed camera and image acquisition system (C7); the gas flow meter (C1), liquid flow meter (C2), high-frequency low-temperature pressure sensor (C3), temperature sensor (C4), low-temperature cold light source (C6), high-speed camera and image acquisition system (C7), and data acquisition system (C5) are connected; the first gas flow meter (C1), the first high-frequency low-temperature pressure sensor (C3), and the first temperature sensor (C4) are connected to the gas supply pipeline at the outlet of the constant temperature heater (B3); the liquid flow meter (C2), the second high-frequency low-temperature pressure sensor (C3), and the second temperature sensor (C4) are connected to the liquid supply pipeline at the outlet of the subcooler (A2); and the third high-frequency low-temperature pressure sensor (C3) and the fourth high-frequency low-temperature pressure sensor (C3) are respectively connected to the bottom of the low-temperature experimental chamber (D) and the outlet of the quartz mixing chamber (E).

2. The apparatus according to claim 1, characterized in that: The quartz mixing chamber (E) is entirely made of welded quartz glass and includes a liquid main pipeline (E1), two gas inlet pipelines (E2, E3), and a second vacuum interlayer (E4). The liquid main pipeline (E1) runs vertically through the second vacuum interlayer (E4), which includes a vacuum port (E5). The two gas inlet pipelines (E2, E3) extend into the second vacuum interlayer (E4) and connect to the liquid main pipeline (E1). The gas inlet pipelines (E2, E3) and the liquid main pipeline (E1) of the quartz mixing chamber (E) are connected to the top of the low-temperature experimental chamber (D) via polytetrafluoroethylene sleeves, thereby connecting to the gas supply and liquid supply pipelines respectively. The quartz mixing chamber (E) is suspended inside the low-temperature experimental chamber (D).

3. The apparatus according to claim 2, characterized in that: The vacuum level in the first vacuum interlayer (D7) and the second vacuum interlayer (E4) reaches 10. -3 Below Pa.

4. The apparatus according to claim 2, characterized in that: The length of the air inlet pipe in the second vacuum interlayer (E4) shall not be less than 10 cm.

5. The apparatus according to claim 1, characterized in that: The working medium in the liquid supply system (A) is liquid nitrogen, liquid oxygen, liquid argon or other cryogenic liquid working medium, and the working medium in the gas supply system (B) is nitrogen, oxygen, argon or other gaseous working medium. The liquid supply system (A) and the gas supply system (B) must use the same working medium pair, that is, different phases of the same substance.

6. The apparatus according to claim 1, characterized in that: The thermostatic heater (B3) adjusts the heating power to bring the working gas to different temperatures, and adjusts the flow rate of the working gas by adjusting the flow regulating valve (B4).

7. The apparatus according to claim 1, characterized in that: The data acquisition system (C5) collects pressure signals to capture the low-frequency pressure pulsation phenomenon during the low-temperature mixing process; the high-speed camera and image acquisition system (C7) captures the flow pattern evolution phenomenon during the low-temperature mixing process through high-speed camera shooting; the low-temperature cold light source (C6) provides illumination supplement to the high-speed camera and image acquisition system (C7) and does not have heat output.

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