A low-temperature fluid flow electrostatic accumulation strength measurement experimental device and method

Abstract

A low-temperature fluid flow electrostatic accumulation strength measurement experimental device and method, including a transmission pipe section and a test pipe section; the outside of the test pipe section is wrapped with a bare copper wire, and the test pipe section is provided with a copper mesh shield and a stainless steel square cavity shield; the inlet of the stainless steel square cavity shield is connected with the outlet of a first low-temperature ball valve and a low-temperature orifice flowmeter, the inlet of the low-temperature orifice flowmeter is connected with a first low-temperature stop valve and a transmission pipeline, and the outlet of the stainless steel square cavity shield is connected with a second low-temperature stop valve; the inlet of the test pipe section is connected with the outlet of a second low-temperature ball valve and a low-temperature orifice flowmeter; silver electrodes are arranged at the inlet and the outlet of the test pipe section; the outlet pipeline of the test pipe section extends into the inner container of a Faraday cylinder, and the BNC connector of the Faraday cylinder, the silver electrodes, the bare copper wire, the stainless steel square cavity shield, the copper mesh shield and an electrostatic meter are connected; the application studies the electrostatic accumulation current strength generated by the low-temperature working medium flowing in the pipe, and provides support for the electrostatic safety of a low-temperature propellant pipeline transmission system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of static risk control and evaluation of space low-temperature propellant transmission pipeline, and particularly relates to a low-temperature fluid flow static accumulation strength measurement experimental device and method. BACKGROUND

[0002] In the process of low-temperature propellant transmission and storage, based on the double-electric-layer theory, when the liquid working medium flows through the wall surface of the transmission pipeline, the double-electric-layer structure is destroyed, the excess charge enters the main flow area from the diffusion layer near the wall surface, so that the fluid area electric neutralization is destroyed; and with the flow, the electric charge density in the liquid gradually increases with the increase of the flow distance, and finally accumulates in the low-temperature propellant storage tank. When the electric charge density in the storage tank reaches the critical value, there is a potential risk of static ignition and explosion.

[0003] The current standard of the space launch site stipulates that the in-pipe flow speed of low-temperature propellants such as liquid hydrogen should not be higher than 6 m / s, so as to ensure the static safety. However, the current standard does not give reliable theoretical and experimental basis, and foreign space departments such as NASA also have cases of low-temperature propellant transmission speed exceeding 6 m / s, so it is necessary to design and build a test bench to carry out in-depth research on the flow static accumulation strength of low-temperature propellants.

[0004] The existing research lacks in-depth study on the electrostatic accumulation strength of low-temperature fluids. Gao Xin et al. invented a device for detecting the electrostatic charge density of liquid pipelines (patent name: device for detecting the electrostatic charge density of liquid pipelines, application number: CN201810351850.4), which does not specifically address the characteristics of low-temperature fluids such as flow boiling and evaporation. It also does not consider measures such as electrostatic shielding and charge neutralization to protect the extremely low electrostatic signals generated by insulating working media. It does not achieve multiple variable operating condition measurement functions, including pipeline structure and particle flow effects. This invention is based on the measurement principle of potential difference and is easily affected by environmental noise. The measurement method is single, and the correctness of the results needs to be further verified. He Guoxi et al. proposed a test loop platform for emergency receiving and sending pump stations of pipeline transported refined oil (patent name: test loop platform for emergency receiving and sending pump stations of pipeline transported refined oil, application number: CN202211392268.5), which collects the current signal in the pipeline through the microammeter of the experimental platform to analyze the electrostatic accumulation of oil receiving and sending. It also has the problem of not being suitable for low-temperature working media. The test pipe section and the transmission pipe section do not take electrical insulation measures, which may cause test interference. It does not achieve multiple variable operating condition measurement functions, including pipeline structure and particle flow effects. It does not use a shielding cover, a charge neutralizer, or other components for electrostatic shielding. The measurement method is single, and other shortcomings exist. Liu Daosheng et al. proposed a liquid nitrogen flow charging measurement device for high-temperature superconducting transformers (patent name: liquid nitrogen flow charging measurement device for high-temperature superconducting transformers, application number: CN202210924411.4), which uses disc rotation instead of pipeline flow and cannot truly reflect the generation, development, and accumulation rules of electric charges along the flow direction in the pipeline flow electrostatic accumulation phenomenon. The method of using a Faraday cylinder to measure the current is single and difficult to verify the reliability of the results. It does not achieve multiple variable operating condition measurement functions, including pipeline structure and particle flow effects. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a low-temperature fluid flow electrostatic accumulation strength measurement experimental device and method, which can study the electrostatic accumulation current strength generated by low-temperature working media flowing in a pipeline, explore the influence of factors such as flow rate, pipe diameter, material, and particles on electrostatic accumulation strength, and provide reliable support for the electrostatic safety of low-temperature propellant pipeline transmission systems.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] The low-temperature fluid flow electrostatic accumulation strength measuring experimental device comprises a test pipe section 13, the test pipe section 13 is fixed in a stainless steel square cavity shielding cover 8 through insulating flanges 11 and insulating rings 9 at the input / output ends, the outside of the test pipe section 13 is wound with a pure copper bare wire 14, the outside of the pure copper bare wire 14 is provided with a copper mesh shielding cover 19, the copper mesh shielding cover 19 is arranged in the stainless steel square cavity shielding cover 8, the stainless steel square cavity shielding cover 8 and the copper mesh shielding cover 19 are connected with a grounding end 21 through a grounding wire 22, and the pure copper bare wire 14, the stainless steel square cavity shielding cover 8, the copper mesh shielding cover 19 and an electrometer 18 are connected;

[0008] The inlet of the stainless steel square cavity shielding cover 8 is connected with the outlet of a first low-temperature ball valve 5 and a low-temperature orifice flowmeter 4, the inlet of the low-temperature orifice flowmeter 4 is connected with a first low-temperature stop valve 2 and a transmission pipeline 1, and a platinum resistance temperature sensor 3 is connected at the inlet of the low-temperature orifice flowmeter 4; the outlet of the stainless steel square cavity shielding cover 8 is connected with a second low-temperature stop valve 12.

[0009] The input end of the test pipe section 13 is connected with the outlet of a second low-temperature ball valve 6 and the low-temperature orifice flowmeter 4, the outlet of the second low-temperature ball valve 6 is connected with a charge neutralization silver mesh 7; the input end and the output end of the test pipe section 13 are connected with silver electrodes 10, and the silver electrodes 10 are connected with the electrometer 18.

[0010] The output pipeline of the test pipe section 13 extends into a Faraday cylinder inner container 25, the Faraday cylinder inner container 25 is fixed in a Faraday cylinder 23 through an insulating gasket 24; the Faraday cylinder 23 is connected with the grounding end 21 through the grounding wire 22; and a BNC connector 20 of the Faraday cylinder 23 is connected with the electrometer 18.

[0011] One end of the test pipe section 13 is provided with a particle feeding port 16, and a particle pile 15 is arranged in the test pipe section 13 below the particle feeding port 16.

[0012] The test pipe section 13 is provided with a groove structure 26.

[0013] The transmission pipeline, the valve and the connector of the experimental device need to be wrapped with thermal insulation cotton, a hard foamed thermal insulation shell is processed on the stainless steel square cavity shielding cover 8, and a low-temperature fluid in a supercooled state is introduced to ensure that the test pipe section 13 is in a pure liquid phase flow.

[0014] All data lines for transmitting electrical signals are connected with three coaxial data lines 17.

[0015] The measurement of the electrometer 18 should ensure that the current resolution is above 10 fA, the charge resolution is above 10 nC, and the voltage resolution is above 1 mV.

[0016] The low-temperature fluid in the transmission pipeline 1 is liquid hydrogen, liquid oxygen, liquid methane or liquid nitrogen.

[0017] The method for measuring the strength of electrostatic accumulation of a low-temperature fluid flow by using an experimental device comprises the following steps:

[0018] 1) The inner wall of the test pipe 13 is irrigated with acetone, and the test pipe 13 and the external pure copper bare wire 14 are scrubbed with acetone by using an anti-static cloth; for the test condition of particle flow, the particles are first irrigated with acetone and put into the test pipe 13 from the particle feeding port 16, and the preparation work is completed after the test component is dried;

[0019] 2) The second low-temperature ball valve 6 is closed, the first low-temperature ball valve 5 is opened, the low-temperature fluid flows into the stainless steel square cavity shield 8, the test pipe section 13 in the square cavity and the surrounding environment are cooled, then the fluid is discharged through the second low-temperature stop valve 12, and the pre-cooling is completed after the test pipe section 13 is cooled to the required temperature;

[0020] 3) The first low-temperature ball valve 5 is closed, the second low-temperature ball valve 6 is opened, the low-temperature fluid enters the test pipe section 13, the first low-temperature stop valve 2 is adjusted, the reading of the low-temperature orifice flowmeter 4 reaches the set value and is maintained stable, the multi-channel scanning measurement function of the low-temperature electrostatic meter 18 is started, the measurement time is more than 3 minutes, after the signal acquisition is completed, the first low-temperature stop valve 2 is closed, the low-temperature liquid flow is stopped, and the single condition test is completed;

[0021] 4) Change the working condition:

[0022] 4.1) Change the flow rate of the low-temperature fluid, measure the flow rate by using the low-temperature orifice flowmeter 4, the flow rate ranges from 5 to 1000 kg / h, and covers laminar flow and turbulent flow conditions;

[0023] 4.2) Change the pipe diameter of the test pipe section 13, and the pipe diameter is 2, 5 or 10 mm;

[0024] 4.3) Change the roughness of the test pipe section 13, and the inner surface roughness Ra is 0.2, 0.8 or 1.6 μm;

[0025] 4.4) Change the material of the test pipe section 13, and the material is stainless steel, pure copper, aluminum alloy or polytetrafluoroethylene;

[0026] 4.5) Change the inner surface structure of the test pipe section 13, and the inner surface is a light pipe or a groove structure 26 (the distribution density, depth and width of the groove can be changed);

[0027] 4.6) Whether to contain particle flow: the particle feeding port 16 is used to put particles of different materials, different particle sizes and different quantities, and the particle materials are polytetrafluoroethylene, PMMA, PVC, aluminum alloy, copper and the like, and the particle size is directly between 0.1 and 1 mm.

[0028] Compared with the prior art, the method has the following beneficial effects:

[0029] The low-temperature fluid flow electrostatic accumulation strength measuring experimental device provided by the application can directly simulate and test the flow electrostatic phenomenon caused by the low-temperature propellant flowing in a pipe, with the liquid flow range being 5-1000 kg / h and the flow velocity range being 0.1-10 m / s, covering the flow and flow velocity conditions of the low-temperature propellant pipeline filling and transmission in a space launch site.

[0030] The application adopts the pure copper bare wire 14, the Faraday cylinder 23 and the silver electrode 10, simultaneously measures the pipe wall leakage current, measures the total charge of the outflow liquid and measures the potential difference between the inlet and the outlet, directly / indirectly measures the flow current characteristic physical quantity in the flow electrostatic phenomenon through three test methods, can be verified with each other, and the test result is more reliable.

[0031] The application is aimed at the characteristic that the conductivity of the low-temperature propellant is far lower than that of the common insulation fluid, adopts the measures such as arranging the current neutralization silver net 7 at multiple positions, grounding the transmission pipe segment at multiple positions, the insulation flange 11 and the insulation collar 9 and the like, isolates the interference of the flow electrostatic signal of the non-test pipe segment, adopts the double-layer shielding cover of the copper net 19 and the stainless steel cavity 8 and the like, realizes the closed-loop electrostatic shielding of the electric signal measurement through the three coaxial data lines 17 and the like, isolates the electric signal interference of the external environment, simultaneously clearly requires the test accuracy of the electrometer, and the extremely small resolution ensures that the electrostatic signal can be captured and collected.

[0032] The application adopts the variable working condition test scheme, researches the influencing factors such as the material, the pipe diameter and the roughness of the test pipe segment 13, obtains the change rule of the low-temperature fluid flow electrostatic strength under different pipe materials, pipe diameters and roughnesses, and the corresponding analysis result can be widely applied to the real working condition of the low-temperature propellant filling and transmission system in a space launch site. In addition, the inner surface of the test pipe segment 13 is processed with grooves to explore the weakening effect of the surface structure on the flow electrostatic strength.

[0033] The application processes a hard foamed heat preservation shell which is in close contact with the outer shape of the stainless steel square cavity shielding cover 8 to realize heat preservation and heat insulation, cooperates with the linkage operation of the first low-temperature ball valve 5 and the second low-temperature ball valve 12, realizes the pre-cooling of the test pipe segment 13, makes the gas-liquid two-phase flow stage of the test pipe segment 13 in the initial flow stage quickly escape, and avoids the influence of the gas-liquid two-phase flow on the test result.

[0034] Furthermore, in actual space launch site cryogenic propellant loading and transfer systems, the presence of solid impurity particles and the solidification of gaseous impurities at low temperatures inevitably lead to particle-containing flow. This invention achieves the function of measuring the electrostatic intensity of particle-containing flow by setting a particle feeding port 16 in the inlet section of the test tube section 13, and directly explores the influence of the presence of particles on the electrostatic intensity of flow.

[0035] In summary, the experimental device for measuring the electrostatic accumulation intensity of cryogenic fluid flow proposed in this invention has a simple structure, is easy and flexible to operate, has a clear and direct principle, offers a variety of reliable measurement methods, and has reasonable and varied operating conditions. It can directly address the electrostatic flow problems of cryogenic propellant refueling and transmission pipeline systems at aerospace launch sites, providing experimental support for the electrostatic safety of cryogenic propellants in my country. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the device of the present invention.

[0037] Figure 2 This is a schematic diagram of the test tube section of the device of the present invention.

[0038] Figure 3 This is a schematic diagram of the groove structure inside the test tube section of the device of the present invention. Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] Reference Figure 1 , Figure 2 A low-temperature fluid flow electrostatic accumulation intensity measurement experimental device includes a test tube section 13. The input / output ends of the test tube section 13 are fixed inside a stainless steel square cavity shielding cover 8 via insulating flanges 11 and insulating collars 9. Pure copper bare wires 14 are wound around the outside of the test tube section 13. A copper mesh shielding cover 19 is provided outside the pure copper bare wires 14 and is placed inside the stainless steel square cavity shielding cover 8. The pure copper bare wires 14 are connected to an electrometer 18 via a triaxial data cable 17. The stainless steel square cavity shielding cover 8 and the copper mesh shielding cover 19 are connected to a grounding terminal 21 via a grounding wire 22. The stainless steel square cavity shielding cover 8, the copper mesh shielding cover 19, and the electrometer 18 are connected.

[0041] The inlet of the stainless steel square cavity shield 8 is connected to the outlet of the first low-temperature ball valve 5 and the low-temperature Coriolis flow meter 4. The inlet of the low-temperature Coriolis flow meter 4 is connected to the transmission pipeline 1 through the first low-temperature shut-off valve 2. The inlet of the low-temperature Coriolis flow meter 4 is connected to the platinum resistance temperature sensor 3. The outlet of the stainless steel square cavity shield 8 is connected to the second low-temperature shut-off valve 12.

[0042] The input end of the test pipe section 13 is connected with the outlet of the second low-temperature ball valve 6 and the low-temperature flowmeter 4, and the outlet of the second low-temperature ball valve 6 is connected with the charge neutralization silver mesh 7; the input end and the output end of the test pipe section 13 are connected with the silver electrode 10, and the silver electrode 10 is connected with the electrometer 18.

[0043] The output pipeline of the test pipe section 13 extends into the Faraday cylinder inner container 25, and the Faraday cylinder inner container 25 is fixed in the Faraday cylinder 23 through the insulating gasket 24; the Faraday cylinder 23 is connected with the grounding end 21 through the grounding wire 22; and the BNC connector 20 of the Faraday cylinder 23 is connected with the electrometer 18.

[0044] One end of the test pipe section 13 is provided with the particle feeding port 16, and the test pipe section 13 below the particle feeding port 16 is provided with the particle pile 15.

[0045] Referring to Figure 3 , the test pipe section 13 is provided with the groove structure 26.

[0046] The transmission pipeline, the valve, the connector and the like of the experimental device need to be wrapped with the thermal insulation cotton, the thickness of the thermal insulation cotton is greater than 5 cm, and the environmental heat leakage is reduced; the stainless steel square cavity shielding cover 8 is externally processed with a hard foamed thermal insulation shell which is externally fitted, and the density of the hard foamed material is 40-60 kg / m 3 , so that the best thermal insulation effect is achieved; the low-temperature fluid in the supercooled state is introduced, and the sensible heat of the fluid is used to compensate the external heat leakage, so that the pure liquid phase flow in the test pipe section 13 is ensured.

[0047] For the test pipe section 13, the stainless steel square cavity shielding cover 8 and the 40-mesh copper mesh shielding cover 19 are used for double-layer shielding, and the shielding cover is grounded, so that the external electromagnetic signal interference is isolated; all the data lines for transmitting the electrical signals are connected with the three coaxial data lines 17.

[0048] For the test pipe section 13 and the data lines for transmitting the signals, the charge conduction caused by the direct contact with other experimental components needs to be avoided; for the solid wall surface of the test pipe section 13 and the transmission pipeline 1, the insulating flange 11 is used for connection, so that the electrical insulation is realized; for the solid wall surface of the test pipe section 13 and the stainless steel square cavity shielding cover 8, the polytetrafluoroethylene insulating sleeve ring 9 is used for cooperation sealing, so that the electrical insulation is realized; for the fluid in the test pipe section 13 and the upstream fluid, the charge neutralizer is arranged at two positions of the flanges of the outlet of the second low-temperature ball valve 6 and the inlet of the test pipe section 13, and the charge neutralizer is actually the 40-mesh charge neutralization silver mesh 7; the function of the charge neutralization silver mesh 7 is to connect and neutralize the charges in the fluid and the opposite charges in the solid pipe wall of the test pipe section 13 through the silver mesh, so that the fluid entering the test pipe section 13 is not charged, and the electrical insulation is realized.

[0049] The measurement of the electrometer 18 should ensure that the current resolution is greater than 10 fA, the charge resolution is greater than 10 nC, and the voltage resolution is greater than 1 mV.

[0050] The cryogenic fluid in the transmission pipeline 1 is liquid hydrogen, liquid oxygen, liquid methane, liquid nitrogen, etc.

[0051] The working principle of this invention is as follows:

[0052] When fluid flows over a solid surface, the double-layer structure at the solid-liquid interface is disrupted. High-concentration charges within the double layer diffuse to the mainstream region, causing the fluid to carry charge. Simultaneously, an equal amount of opposite charges transfer to the solid region, maintaining overall charge neutrality. As the flow continues, the charges diffused to the mainstream region accumulate downstream, causing the fluid's charge density to gradually increase. In the experimental apparatus of this invention, the charges in the fluid enter the Faraday cylinder 23 after flowing out of the test tube 13. The instantaneous total charge Q1 inside the cylinder is measured. Differentiating Q1 with respect to time t yields the net current entering the inner liner 25 of the Faraday cylinder, i.e., the priming current I1 at the outlet of the test tube 13. Simultaneously, the grounding current I2 on the wall of the test tube 13 is measured using an electrometer 18. Integrating I2 with respect to time t gives the total charge accumulated on the solid tube wall, Q2. The priming current generated by the charged liquid flow in the test tube 13 is equivalent to a current source within the test tube 13, resulting in a potential difference U3 between the input and output ends of the test tube 13. According to the formula...

[0053]

[0054] The conductivity λ can be obtained simply by considering the length l of the test tube section 13 and the physical properties of the liquid. t and the cross-sectional area A of test pipe section 13 c The current I3 can then be derived by reverse calculation. Theoretically, excluding leakage current, charge relaxation dissipation, and measurement errors, I1 equals I2 equals I3, and Q1 equals Q2. Based on the above principle, Q1, I2, and U3 are measured respectively to verify the measurement of the electrostatic accumulation intensity of the cryogenic fluid from multiple perspectives.

[0055] A method for measuring the electrostatic accumulation intensity of a low-temperature fluid flow experimental device includes the following steps:

[0056] 1) Rinse the inner wall of the test pipe 13 with acetone, and wipe the test pipe 13 and the bare copper wire 14 on the outside with an antistatic cloth dipped in acetone. For test conditions containing particle flow, the particles must be rinsed with acetone in advance and the particles are put into the test pipe 13 from the particle feeding port 16. The preparation work is completed after the test components are dried.

[0057] 2) Close the second cryogenic ball valve 6 and open the first cryogenic ball valve 5 to allow the cryogenic fluid to flow into the stainless steel square cavity shield 8, cool the test tube section 13 and the surrounding environment inside the square cavity, and then the fluid is discharged through the second cryogenic shut-off valve 12. After the test tube section 13 is cooled down to the required temperature, the pre-cooling ends.

[0058] 3) Close the first cryogenic ball valve 5, open the second cryogenic ball valve 6, so that the cryogenic fluid enters the test pipe section 13; adjust the first cryogenic stop valve 2, so that the cryogenic flowmeter 4 reads the set value and maintains stability; turn on the cryogenic electrostatic meter 18 multi-channel scanning measurement function, measure the real-time data of Q1, I2, U3, and the measurement time is more than 3 minutes to ensure that the electrostatic signal overcomes the initial stage to reach stability; after the signal collection is completed, close the first cryogenic stop valve 2, stop the cryogenic liquid flow, and the single working condition test is completed;

[0059] 4) Change of working condition setting:

[0060] 4.1) Change the flow rate of the cryogenic fluid, measure the flow rate through the cryogenic flowmeter 4, the flow rate range is 5-1000 kg / h, covering laminar and turbulent flow conditions;

[0061] 4.2) Change the pipe diameter of the test pipe section 13, the pipe diameter is 2, 5, 10 mm;

[0062] 4.3) Change the roughness of the test pipe section 13, the inner surface roughness Ra is 0.2, 0.8, 1.6 μm;

[0063] 4.4) Change the material of the test pipe section 13, the material is stainless steel, pure copper, aluminum alloy, and polytetrafluoroethylene;

[0064] 4.5) Change the inner surface structure of the test pipe section 13: the inner surface is a light pipe and a groove structure 26 (the distribution density, depth, and width of the groove can be changed); the groove structure 26 can make the solid surface invaginate, the invaginated area has small flow disturbance and small damage to the double-layer, and the inner charge is less diffused to the main flow area;

[0065] 4.6) Whether to contain particle flow: to study the influence of particle collision electrification on electrostatic accumulation, set a particle feeding port 16 in the test pipe section 13, and feed particles of different materials, different particle sizes, and different quantities, the particle materials are polytetrafluoroethylene, PMMA, PVC, aluminum alloy, copper, etc., and the particle size is directly between 0.1-1 mm.

[0066] The above examples only illustrate the basic principles and characteristics of the present application, and the present application is not limited to the above examples. Without departing from the spirit and scope of the present application, various changes and modifications can be made, and all deformations directly derived or thought by those skilled in the art from the disclosed content should be considered as falling within the protection scope of the present application.

Claims

1. A low temperature fluid flow electrostatic accumulation strength measurement apparatus comprising a test pipe section (13), characterized in that: The test pipe section (13) is fixed in the stainless steel square cavity shield (8) through the insulating flange (11) and the insulating collar (9) at both input and output ends; the outside of the test pipe section (13) is wrapped with the pure copper bare wire (14), and the outside of the pure copper bare wire (14) is provided with the copper mesh shield (19) arranged in the stainless steel square cavity shield (8); the stainless steel square cavity shield (8) and the copper mesh shield (19) are connected to the grounding end (21) through the grounding wire (22), and the pure copper bare wire (14), the stainless steel square cavity shield (8), the copper mesh shield (19) and the electrometer (18) are connected; The inlet of the stainless steel square cavity shield (8) is connected to the outlet of the first low-temperature ball valve (5) and the low-temperature orifice flowmeter (4), the inlet of the low-temperature orifice flowmeter (4) is connected to the first low-temperature stop valve (2) and the transmission pipeline (1), and the platinum resistance temperature sensor (3) is connected to the inlet of the low-temperature orifice flowmeter (4); the outlet of the stainless steel square cavity shield (8) is connected to the second low-temperature stop valve (12); The input end of the test pipe section (13) is connected to the outlet of the second low-temperature ball valve (6) and the low-temperature orifice flowmeter (4), and the outlet of the second low-temperature ball valve (6) is connected to the charge neutralization silver mesh (7); the input end and the output end of the test pipe section (13) are connected to the silver electrode (10), and the silver electrode (10) is connected to the electrometer (18); The output pipeline of the test pipe section (13) extends into the Faraday cylinder inner container (25), and the Faraday cylinder inner container (25) is fixed in the Faraday cylinder (23) through the insulating gasket (24); the Faraday cylinder (23) is connected to the grounding end (21) through the grounding wire (22); and the BNC connector (20) of the Faraday cylinder (23) is connected to the electrometer (18).

2. The apparatus of claim 1, wherein: One end of the test pipe section (13) is provided with the particle feeding port (16), and the test pipe section (13) below the particle feeding port (16) is provided with the particle pile (15).

3. The apparatus of claim 1, wherein: The test pipe section (13) is provided with the groove structure (26).

4. The apparatus of claim 1, wherein: The transmission pipeline, the valve and the connector of the experimental device need to be wrapped with thermal insulation cotton.

5. The apparatus of claim 1, wherein: A hard foamed thermal insulation shell is processed on the outer shape of the stainless steel square cavity shield (8).

6. The apparatus of claim 1, wherein: The low-temperature fluid in the supercooled state is introduced to ensure that the test pipe section (13) is in a pure liquid phase flow.

7. The apparatus of claim 1, wherein: All data lines for transmitting electrical signals are connected by using three coaxial data lines (17).

8. The apparatus of claim 1, wherein: The measurement of the electrometer (18) should ensure that the current resolution is above 10 fA, the charge resolution is above 10 nC, and the voltage resolution is above 1 mV.

9. The apparatus of claim 1, wherein: The low-temperature fluid in the transmission pipeline (1) is liquid hydrogen, liquid oxygen, liquid methane or liquid nitrogen.

10. A method of using the low temperature fluid electrostatic accumulation strength measurement test device according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: 1) The inner wall of the test pipe (13) is irrigated with acetone, and the test pipe (13) and the external pure copper bare wire (14) are scrubbed with acetone dipped in the anti-static cloth; for the test working condition of the particle flow, the particles are put into the test pipe (13) from the particle feeding port (16) after the particles are irrigated with acetone in advance, and the test components are dried. 2) Close the second cryogenic ball valve (6) and open the first cryogenic ball valve (5) to make the cryogenic fluid flow into the stainless steel square cavity shield (8), cool the test pipe section (13) and the surrounding environment, and then the fluid is discharged through the second cryogenic stop valve (12). When the test pipe section (13) is cooled to the required temperature, the precooling is completed; 3) Close the first cryogenic ball valve (5) and open the second cryogenic ball valve (6) to make the cryogenic fluid enter the test pipe section (13); adjust the first cryogenic stop valve (2) to make the cryogenic orifice flowmeter (4) reading reach the set value and maintain stable; turn on the cryogenic utilization electrometer (18) multi-channel scanning measurement function, and the measurement time is more than 3 min; close the first cryogenic stop valve (2) to stop the cryogenic liquid flow, and the single working condition test is completed; 4) Change the working condition settings: 4.1) Change the cryogenic fluid flow rate, measure the flow rate through the cryogenic orifice flowmeter (4), the flow rate range is 5-1000 kg / h, covering laminar and turbulent flow conditions; 4.2) Change the pipe diameter of the test pipe section (13), the pipe diameter is 2, 5, and 10 mm; 4.3) Change the roughness of the test pipe section (13), the inner surface roughness Ra is 0.2, 0.8, and 1.6 μm; 4.4) Change the material of the test pipe section (13), the material is stainless steel, pure copper, aluminum alloy, and polytetrafluoroethylene; 4.5) Change the inner surface structure of the test pipe section (13): the inner surface is a light pipe and a groove structure (26), and the distribution density, depth, and width of the groove can be changed; 4.6) Whether to contain particle flow: at the particle feeding port (16), different materials, different particle sizes, and different quantities of particles are fed, the particle materials are polytetrafluoroethylene, PMMA, PVC, aluminum alloy, and copper, and the particle size is directly between 0.1-1 mm.

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