CN-121978280-A - Multi-physical field testing method for layering and rolling process of low-temperature multi-component fluid

CN121978280ACN 121978280 ACN121978280 ACN 121978280ACN-121978280-A

Abstract

The invention discloses a multi-physical-field testing method for layering and rolling low-temperature multi-component fluid, which comprises the following steps of S1, completing assembly and construction of a testing device, S2, starting a vacuum pump, S3, introducing liquid nitrogen into a liquid nitrogen cold screen, S4, adding trace particles mixed with alcohol into a testing cabin, precooling the testing cabin after blowing out the alcohol by using nitrogen, adding fluorescent dye suitable for a testing temperature zone, S5, introducing one low-temperature fluid a into the testing cabin, S6, introducing another low-temperature fluid b into the testing cabin according to a preset initial volume ratio or mass ratio, S7, starting a control host, S8, collecting pressure data, speed field, temperature field and density field data of a vacuum low-temperature container, and S9, stopping testing after the planned testing time is reached. The invention can realize high-precision visual test of low-temperature multicomponent fluid, can accurately capture fine fluid state changes such as tiny layering, flowing vortex and the like, and comprehensively reveals a low-temperature heat and mass transfer coupling mechanism.

Inventors

YANG GUANG
WANG YE
LUO WEI
ZHANG HONGXING
MIAO JIANYIN
LI HAOZE
CAI AIFENG
WU JINGYI

Assignees

上海交通大学
北京空间飞行器总体设计部

Dates

Publication Date: 20260505
Application Date: 20260206

Claims (10)

1. The low-temperature multi-component fluid layering and rolling process multi-physical field testing method is realized by adopting a low-temperature multi-component fluid layering and rolling process multi-physical field testing device, wherein the low-temperature multi-component fluid layering and rolling process multi-physical field testing device comprises a vacuum low-temperature container, a schlieren background plate, a vacuum pump, a data acquisition device, a camera system, a lens group, a control host, a laser system, a heating system and a BOS light source; The vacuum low-temperature container comprises a vacuum cabin, a liquid nitrogen cold screen and a test cabin, wherein the vacuum cabin, the liquid nitrogen cold screen and the test cabin are coaxially arranged and are not in direct contact with each other, the liquid nitrogen cold screen is positioned in the vacuum cabin, the test cabin is positioned in the liquid nitrogen cold screen and is fixed on a top end cover of the vacuum cabin, and the heating system comprises a heating film and a power supply, which are attached to the outer wall surface of the test cabin; The vacuum low-temperature container, the schlieren background plate, the vacuum pump, the camera system, the lens group, the laser system and the BOS light source are all arranged on the ground in the shading chamber, and the schlieren background plate is arranged between the BOS light source and the vacuum low-temperature container; the vacuum pump is used for vacuumizing the vacuum low-temperature container, and the data acquisition device, the camera system, the laser system, the heating system and the BOS light source are respectively connected with the control host; The laser system, the BOS light source and the camera system are respectively opposite to different vacuum glass windows on the side surface of the vacuum cabin, the camera system comprises 3 cameras which are respectively used for collecting BOS, PIV and LIF images, a schlieren background plate is arranged between the BOS light source and the vacuum glass window opposite to the BOS light source, the lens group is arranged between the camera system and the vacuum low-temperature container, and the lens group comprises a band-pass spectroscope and a plurality of reflecting lenses which are used for respectively transmitting light source signals into the corresponding cameras; The method is characterized by comprising the following steps of: s1, completing assembly and construction of a multi-physical-field testing device in a layering and rolling process of low-temperature multi-component fluid; s2, starting a vacuum pump until the pressure in the vacuum low-temperature container is less than or equal to 5E-3Pa; s3, introducing liquid nitrogen into the liquid nitrogen cold screen until the temperature of the liquid nitrogen cold screen reaches below-180 ℃ and is stable; S4, adding trace particles mixed with alcohol into the test cabin, blowing out the alcohol by using nitrogen, pre-cooling the test cabin, and adding fluorescent dye suitable for a test temperature zone; S5, introducing a low-temperature fluid a into the test cabin until the liquid level reaches a design position; s6, introducing another low-temperature fluid b into the test cabin according to a preset initial volume ratio or mass ratio so as to fully mix the low-temperature fluid b with the low-temperature fluid a; S7, starting a control host to set wall heat flow conditions, gradually forming thermal stratification and density stratification of mixed fluid in the test cabin under the wall heating effect, and starting a camera system, a laser system, a BOS light source and an acquisition program after the initial stratification conditions of the mixed fluid are formed; S8, continuously acquiring pressure data of the vacuum low-temperature container, acquiring PIV, LIF and BOS images once every 1-10 minutes by a camera system, and synchronously acquiring data of a speed field, a temperature field and a density field; and S9, stopping the camera system, the laser system and the BOS light source after the planned test time is reached, and stopping the heating system and the vacuum pump when no residual liquid exists in the test cabin and the temperature is restored to normal temperature.
2. The method for testing the multiple physical fields of the layering and tumbling process of the low-temperature multi-component fluid according to claim 1, wherein the steps S1-S9 are repeated for a plurality of times, the wall heat flow conditions are set to be different from each other in the step S7, and the influence of different wall heating conditions on the thermal layering, natural convection, evaporation and layering tumbling characteristics of the low Wen Duozu split fluid is studied by changing the wall heat flow conditions.
3. The method for testing multiple physical fields in a layering and tumbling process of low-temperature multi-component fluid according to claim 1, wherein S1-S9 are repeated multiple times, and the initial volume ratio or mass ratio preset in step S6 is different from each other, and the influence of the initial components on the thermal layering, natural convection, evaporation and layering tumbling characteristics of the initial components is studied.
4. The method for testing multiple physical fields in a layering and tumbling process of low-temperature multi-component fluid according to claim 1, wherein the steps S1-S9 are repeated for a plurality of times, and the pressures in the vacuum low-temperature containers in the step S2 are different from each other, and the influence of the pressure in the test cabin on the layering, natural convection, evaporation and layering tumbling characteristics of the low Wen Duozu split-flow body is studied by changing the pressure in the test cabin.
5. The method for testing multiple physical fields in the layering and tumbling process of low-temperature multicomponent fluid according to claim 1, wherein the vacuum chamber comprises a vacuum chamber body, the vacuum chamber body is made of stainless steel, three vacuum glass windows positioned at the same height are arranged on the side surface of the vacuum chamber body, two of the three vacuum glass windows are coaxial, and the axis of the other vacuum glass window is perpendicular to the axis of the coaxial two vacuum glass windows; The top end cover is arranged at the top of the vacuum cabin body, a temperature measuring Dewar tube, a top heat sink inlet and outlet Dewar tube, a cable connector a and a test cabin inlet and outlet Dewar tube are arranged on the top end cover, and a side heat sink inlet and outlet Dewar tube, a vacuum pump interface and a cable connector b are arranged on the side face of the vacuum cabin body.
6. The multi-physical field testing method for the layering and tumbling process of the low-temperature multi-component fluid is characterized in that the liquid nitrogen cold screen is made of red copper, comprises a circular pipe-shaped side wall and a circular bottom plate, the circular bottom plate is fixed on the inner wall of a vacuum chamber through a plurality of supporting rods, copper pipes are coiled on the side wall of the liquid nitrogen cold screen, and the copper pipes are connected with external liquid nitrogen supply equipment through a top heat sink inlet/outlet dewar pipe and a side heat sink inlet/outlet dewar pipe.
7. The multi-physical field testing method for the layering and tumbling process of the low-temperature multi-component fluid according to claim 5, wherein the testing chamber is a square container made of stainless steel, three testing glass windows which are located at the same height are arranged on the side face of the testing chamber, the testing glass windows are made of high borosilicate materials and correspond to the three vacuum glass windows of the vacuum chamber one by one, an exhaust pipe and a liquid inlet and outlet pipe set are further arranged on the side face of the testing chamber, and the exhaust pipe and the liquid inlet and outlet pipe set extend to the outside of the vacuum chamber through a liquid inlet and outlet Dewar pipe of the testing chamber.
8. The method of claim 1, wherein the heating films are formed on the outer walls of the six sides of the test chamber, and the heating films are made of a polyacetamide heating film.
9. The multi-physical field testing method for the layering and rolling process of the low-temperature multicomponent fluid is characterized in that the data acquisition device comprises a pressure sensor, a temperature sensor, a multicomponent analyzer, a vacuum gauge and a flowmeter, wherein the pressure sensor and the temperature sensor are respectively connected with a cable connector a and a cable connector b, the multicomponent analyzer and the flowmeter are connected with an exhaust pipe of a test chamber through pipelines, the vacuum gauge is fixed on the side surface of a vacuum chamber body through a flange, and the cable connector a, the cable connector b, the multicomponent analyzer, the vacuum gauge and the flowmeter are respectively and electrically connected with a control host.
10. The method of claim 5, wherein the vacuum pump interface is connected to a vacuum pump via a pipeline, and the vacuum pump is a vacuum pump set comprising a mechanical pump and a molecular pump.

Description

Multi-physical field testing method for layering and rolling process of low-temperature multi-component fluid Technical Field The invention belongs to the technical field of low-temperature multi-component fluid testing, and particularly relates to a multi-physical-field testing method for layering and rolling processes of low-temperature multi-component fluid. Background Low-temperature multi-component fluid (such as liquefied natural gas, liquid air, low-temperature refrigeration working medium, aerospace low-temperature propellant and the like) has become a core working medium in the strategic fields of energy storage and transportation, low-temperature refrigeration, aerospace and the like due to high energy density and special physical and chemical characteristics. Due to the difference of evaporation rates of different components, the multicomponent fluid can generate rolling phenomenon due to thermodynamic imbalance in the storage process, and the deep research of layering and rolling process characteristics is important to the technical development of the related fields. The prior art faces three major core challenges in the research, namely, the traditional normal-temperature fluid visualization technology (such as high-speed photography) cannot adapt to a low-temperature environment, the resolution is insufficient, a window is easy to interfere, fine flow state changes (such as layered diffusion and tiny vortex) of low-temperature multi-component fluid are difficult to capture rapidly, the heat and mass transfer process is a result of multi-parameter dynamic coupling of temperature, pressure, flow rate and concentration, the traditional test method adopts a single parameter independent measurement mode, spatial deviation exists in each parameter measurement area, data acquisition frequency is inconsistent, real-time association of multiple parameters cannot be established, a coupling mechanism is difficult to be comprehensively revealed, the low-temperature fluid physical property changes rapidly, transient phenomena are difficult to record in real time by the traditional data acquisition method, trace particles and fluorescent dyes in the low-temperature fluid are easy to broadcast unevenly and agglomerate, and the depth of mechanism research is limited. Therefore, a testing method and a testing process which are suitable for a low-temperature environment, can realize synchronous measurement of multiple physical fields and solve the problem of trace particle distribution are needed, and provide key technical support for mechanism research and engineering application of low-temperature multi-component fluid. Disclosure of Invention In order to solve the technical problems, the invention provides a multi-physical field testing method for a low-temperature multi-component fluid layering and rolling process, which can accurately capture the fine fluid state change of the multi-component fluid in a low-temperature environment, can realize synchronous correlation measurement of temperature, pressure, flow speed and concentration and discloses a heat and mass transfer coupling mechanism. The technical scheme adopted by the invention is as follows: The low-temperature multi-component fluid layering and rolling process multi-physical field testing method is realized by adopting a low-temperature multi-component fluid layering and rolling process multi-physical field testing device, wherein the low-temperature multi-component fluid layering and rolling process multi-physical field testing device comprises a vacuum low-temperature container, a schlieren background plate, a vacuum pump, a data acquisition device, a camera system, a lens group, a control host, a laser system, a heating system and a BOS light source; The vacuum low-temperature container comprises a vacuum cabin, a liquid nitrogen cold screen and a test cabin, wherein the vacuum cabin, the liquid nitrogen cold screen and the test cabin are coaxially arranged and are not in direct contact with each other, the liquid nitrogen cold screen is positioned in the vacuum cabin, the test cabin is positioned in the liquid nitrogen cold screen and is fixed on a top end cover of the vacuum cabin, and the heating system comprises a heating film and a power supply, which are attached to the outer wall surface of the test cabin; The vacuum low-temperature container, the schlieren background plate, the vacuum pump, the camera system, the lens group, the laser system and the BOS light source are all arranged on the ground in the shading chamber, and the schlieren background plate is arranged between the BOS light source and the vacuum low-temperature container; the vacuum pump is used for vacuumizing the vacuum low-temperature container, and the data acquisition device, the camera system, the laser system, the heating system and the BOS light source are respectively connected with the control host; The laser system, the BOS light source and the camera system ar