Liquid hydrogen pump test system and test method thereof

Abstract

The application relates to the technical field of cryogenic pump testing, and provides a liquid hydrogen pump testing system and a testing method thereof, the liquid hydrogen pump testing system comprising a low-temperature testing end assembly, a fluid charging and discharging module connected to the low-temperature testing end assembly, and an automatic control system for controlling valves of the liquid hydrogen pump testing system; the liquid hydrogen pump testing system is provided with a cold box and can meet the testing requirement of the performance and critical net positive suction head of a pump under a low-temperature environment of not less than 20K (especially under a 20K liquid hydrogen and 77K liquid nitrogen environment); by testing key parameters such as temperature, pressure, flow rate and liquid level, the external characteristics and cavitation characteristics of a centrifugal submerged pump and a pipeline pump under different inlet pressures and flow rates in a liquid hydrogen temperature zone can be tested and evaluated; by testing the performance of the pump under actual operation conditions, the actual performance of the pump can be accurately evaluated and guidance can be provided for research and development and improvement work.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cryogenic pump testing, in particular to a liquid hydrogen pump testing system and a testing method thereof. BACKGROUND

[0002] In recent years, with the increasing global climate pressure and the acceleration of energy transformation, hydrogen energy has attracted global attention due to its zero pollution and high efficiency, and is regarded as the most potential clean energy in the 21st century, and is the strategic energy development direction of human beings. Hydrogen storage and transportation technology provides important support for the strategic significance of hydrogen energy. Liquid hydrogen storage and transportation is more economical than hydrogen storage and transportation, and is an important direction for future hydrogen storage and transportation. As an important component of liquid hydrogen transportation application, the liquid hydrogen pump is still a technical problem to be overcome in China. In the design process of the liquid hydrogen pump, it is essential to conduct sufficient testing under conditions close to the real operating environment. However, at present, there is no performance testing platform for liquid hydrogen pumps in China, and the traditional liquid nitrogen pump testing platform is adapted to a temperature zone of 77K, which cannot meet the testing requirements of heat leakage in the liquid hydrogen temperature zone. SUMMARY

[0003] An object of the present application is to provide a liquid hydrogen pump testing system and a testing method thereof, which can meet the performance and critical net positive suction head testing requirements of the pump under a low-temperature environment of not less than 20K, especially under a 20K liquid hydrogen and 77K liquid nitrogen environment, and lay a foundation for future research and performance improvement of liquid hydrogen pumps.

[0004] In one aspect, the present application provides a liquid hydrogen pump testing system, comprising:

[0005] A low-temperature testing end assembly, comprising a cold box, a liquid hydrogen storage tank arranged in the cold box, a test pipeline connected to the liquid hydrogen storage tank, a to-be-tested liquid hydrogen pump with an inlet and an outlet connected to the test pipeline and the liquid hydrogen storage tank respectively, and a parameter measurement assembly arranged on the inlet and outlet positions of the to-be-tested liquid hydrogen pump and the liquid hydrogen storage tank respectively, the parameter measurement assembly being used for measuring one or more parameters of pressure, temperature, flow rate and liquid level;

[0006] A fluid charging and discharging module connected to the low-temperature testing end assembly, used for realizing the exhaust of the test pipeline and the gas inlet and outlet of the liquid hydrogen storage tank and liquid charging;

[0007] The automatic control system is connected to the flow parameter measurement assembly and the fluid charging and discharging module, and is used for controlling the valve opening degree of the fluid charging and discharging module based on the parameters measured by the parameter measurement assembly, so as to realize the performance and pump net positive suction head testing of the to-be-tested liquid hydrogen pump.

[0008] In an embodiment of the present application, the fluid charging and discharging module comprises a test pipe exhaust pipeline connected to the outlet of the liquid hydrogen pump to be tested, a first valve arranged on the test pipe exhaust pipeline, a liquid hydrogen storage tank gas inlet pipeline, a liquid hydrogen storage tank gas outlet pipeline and a liquid hydrogen storage tank liquid inlet pipeline connected to the liquid hydrogen storage tank respectively, and a second valve, a third valve and a fourth valve arranged on the liquid hydrogen storage tank gas inlet pipeline, the liquid hydrogen storage tank gas outlet pipeline and the liquid hydrogen storage tank liquid inlet pipeline respectively; the parameter measurement assembly comprises one or more components of a pressure gauge, a thermometer, a flow meter and a liquid level gauge.

[0009] In an embodiment of the present application, the parameter measurement assembly comprises a first pressure gauge, a first thermometer and a first liquid level gauge arranged on the liquid hydrogen storage tank, and the automatic control system comprises a liquid level control system connected to the first liquid level gauge and the fourth valve, which is used to control the fourth valve based on the data collected by the first liquid level gauge.

[0010] In an embodiment of the present application, the parameter measurement assembly further comprises a second pressure gauge and a second thermometer arranged at the inlet position of the liquid hydrogen pump to be tested, and a third pressure gauge and a third thermometer arranged at the outlet position of the liquid hydrogen pump to be tested, and the automatic control system comprises a pressure control system connected to the second pressure gauge and the third valve, which is used to control the third valve based on the data collected by the second pressure gauge.

[0011] In an embodiment of the present application, the outlet of the liquid hydrogen pump to be tested and the liquid hydrogen storage tank are further connected with a flow meter zero adjustment valve and a pneumatic regulating valve in sequence, the parameter measurement assembly comprises a liquid hydrogen flow meter arranged between the flow meter zero adjustment valve and the pneumatic regulating valve, and the automatic control system further comprises a flow control system connected to the liquid hydrogen flow meter and the pneumatic regulating valve, which is used to control the pneumatic regulating valve based on the parameters measured by the liquid hydrogen flow meter.

[0012] In an embodiment of the present application, the cold box comprises a cold box body and a cold box flange cover plate arranged on the cold box body, and the cold box flange cover plate is provided with a lead hole for leading out the lead of one or more components of the pressure gauge, the thermometer, the flow meter and the liquid level gauge of the parameter measurement assembly.

[0013] In an embodiment of the present application, the liquid hydrogen pump test system further comprises a storage tank heater arranged outside the liquid hydrogen storage tank.

[0014] In an embodiment of the present application, the working temperature zone of the liquid hydrogen test system is not lower than a low-temperature environment of 20K (especially in a 20K liquid hydrogen and 77K liquid nitrogen environment).

[0015] In an embodiment of the present application, the liquid hydrogen pump to be tested is connected with a motor, and the liquid hydrogen pump to be tested is a pipeline pump or an immersed pump; when the liquid hydrogen pump to be tested is an immersed pump, the liquid hydrogen pump test system further comprises a test tank for mounting the immersed pump, the test tank comprises a tank body and a test tank flange cover sealingly connected to the tank body, the tank body and the test tank flange cover are both provided with pipelines of the same diameter as the test pipeline and respectively welded to the test pipeline, and the immersed pump is hoisted on the test tank flange cover.

[0016] The present application also provides, in another aspect, a test method of a liquid hydrogen pump test system, comprising the steps of:

[0017] S2, performing pump performance test on the liquid hydrogen pump to be tested;

[0018] S21, setting the rotating speed of the liquid hydrogen pump to be tested, gradually opening the pneumatic regulating valve from closed, taking points in the target flow range, and after the valve opening degree of the pneumatic regulating valve is gradually changed and the liquid hydrogen pump to be tested is stably operated, recording the flow through the first flow meter, measuring the inlet and outlet pressures of the liquid hydrogen pump to be tested through the second and third pressure meters respectively, and measuring the voltage and current values of the motor connected with the liquid hydrogen pump to be tested;

[0019] S22, changing the rotating speed of the liquid hydrogen pump to be tested, and repeating the operation to obtain the pump performance curve at different rotating speeds;

[0020] S3, performing pump NPSH test on the liquid hydrogen pump to be tested;

[0021] S31, setting the initial rotating speed of the liquid hydrogen pump to be tested, fixing the valve opening degree of the pneumatic regulating valve, changing the inlet pressure of the liquid hydrogen pump to be tested, until the ratio of the head drop value to the pump head value reaches a specified value and is stable, and taking points in the target flow range, and recording the experiment in the process of gradually changing the valve opening degree of the pneumatic regulating valve;

[0022] S32, changing the rotating speed of the liquid hydrogen pump to be tested, and repeating the operation;

[0023] S4, after the operation is ended, draining and rewarming.

[0024] In an embodiment of the present application, before the step S2, the step S1 of pre-treating the liquid hydrogen pump test system is further included:

[0025] S11, performing air tightness test on the liquid hydrogen pump test system by using air inflation and pressure maintaining leak detection;

[0026] S12, performing nitrogen replacement operation on the pipelines of the liquid hydrogen pump test system;

[0027] S13, pre-cooling the pipelines of the liquid hydrogen pump test system after replacement by filling with liquid nitrogen;

[0028] S14, hydrogen replacement is performed on the pre-cooled liquid hydrogen pump test system;

[0029] S15, liquid hydrogen is filled into the liquid hydrogen pump test system after hydrogen replacement is completed.

[0030] The liquid hydrogen pump test system of the present application is provided with a cold box, and can meet the performance and critical net positive suction head test requirements of the pump under a low-temperature environment of not less than 20K (especially under a 20K liquid hydrogen and 77K liquid nitrogen environment). By testing key parameters such as temperature, pressure, flow rate and liquid level, the external characteristics and cavitation characteristics of the centrifugal submerged pump and the pipeline pump under different inlet pressures and flow rates in the liquid hydrogen temperature zone can be tested and evaluated. By testing the performance of the pump under actual operating conditions, the actual performance of the pump can be accurately evaluated and guidance can be provided for research and development and improvement work.

[0031] Further purposes and advantages of the present application will be fully apparent from the following description and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The structure diagram of the liquid hydrogen pump test system of the first preferred embodiment of the present application.

[0033] Figure 2 The structure diagram of the liquid hydrogen pump test system of the second preferred embodiment of the present application.

[0034] BRIEF DESCRIPTION OF DRAWINGS

[0035] Low-temperature test end assembly 1; cold box body 1-1; cold box flange cover plate 1-2; lead hole 1-2-1; liquid hydrogen storage tank 1-3; first pressure gauge 1-4; first temperature gauge 1-5; first liquid level gauge 1-6; test pipeline 1-7; second pressure gauge 1-8; second temperature gauge 1-9; liquid hydrogen pump to be tested 1-10; third pressure gauge 1-11; third temperature gauge 1-12; flowmeter zero adjustment valve 1-13; liquid hydrogen flowmeter 1-14; pneumatic regulating valve 1-15; storage tank heater 1-16;

[0036] Fluid charging and discharging module 2; test pipeline exhaust pipeline 2-2; first valve 2-1; liquid hydrogen storage tank gas inlet pipeline 2-4; second valve 2-3; liquid hydrogen storage tank exhaust pipeline 2-6; third valve 2-5; liquid hydrogen storage tank liquid inlet pipeline 2-7; fourth valve 2-8;

[0037] Liquid level control system 3-1; pressure control system 3-2; flow control system 3-3. DETAILED DESCRIPTION

[0038] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0039] Those skilled in the art should understand that, in the disclosure of this invention, the terms "vertical," "horizontal," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0040] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0042] The purpose of this invention is to provide a system for testing the external characteristics and net positive suction head (NPSH) of a liquid hydrogen temperature-range centrifugal submersible pump and its pipeline.

[0043] like Figure 1 As shown, the specific structure of the liquid hydrogen pump test system according to the first preferred embodiment of the present invention is explained.

[0044] Specifically, the testing system includes a cryogenic testing terminal component 1, a fluid filling and discharging module 2 connected to the cryogenic testing terminal component 1, and an automatic control system for controlling the valves of the liquid hydrogen pump testing system.

[0045] More specifically, the cryogenic testing terminal assembly 1 includes a cold box, a liquid hydrogen storage tank 1-3 disposed inside the cold box, a test pipeline 1-7 connected to the liquid hydrogen storage tank 1-3, a liquid hydrogen pump 1-10 to be tested whose inlet and outlet are respectively connected to the test pipeline 1-7 and the liquid hydrogen storage tank 1-3, and parameter measuring components disposed at the inlet and outlet positions of the liquid hydrogen pump 1-10 to be tested and on the liquid hydrogen storage tank 1-3, wherein the parameter measuring components are used to measure one or more parameters among pressure, temperature, flow rate, and liquid level.

[0046] In other words, the parameter measurement component includes one or more components selected from pressure gauges, thermometers, flow meters, and level gauges.

[0047] It is worth mentioning that the cold box includes a cold box body 1-1 and a cold box flange cover 1-2 covering the cold box body 1-1. The cold box flange cover 1-2 is provided with a lead hole 1-2-1 for leading out the lead wires of one or more components of the parameter measuring assembly, such as a pressure gauge, thermometer, flow meter and level gauge.

[0048] It is also worth mentioning that, in this specific embodiment, an O-ring is used to seal the cold box body 1-1 and the cold box flange cover 1-2. The inside of the cold box is evacuated, with a vacuum level requirement better than 10. -4 Pa.

[0049] Furthermore, in this specific embodiment, the liquid hydrogen pump 1-10 to be tested is rigidly connected to the cold box flange cover 1-2 using G10 or a low thermal conductivity hard material. The liquid hydrogen storage tank 1-3 is rigidly connected to the cold box flange cover 1-2 using G10 or a low thermal conductivity hard material, and the liquid hydrogen storage tank 1-3 is suspended on the cold box flange cover 1-2.

[0050] It is worth mentioning that the pipelines, liquid hydrogen storage tanks 1-3, and associated instruments or their pipelines (pressure gauges, thermometers, level gauges, and flow meters, etc.) in the cold box of the low-temperature test terminal component 1 are all wrapped and insulated with multi-layer insulation materials. The insulation materials can be glass fiber, asbestos, rock wool, etc., and the present invention does not limit them.

[0051] It is also worth mentioning that the liquid hydrogen pump testing system also includes a tank heater 1-16 located outside the liquid hydrogen storage tank 1-3.

[0052] Specifically, the liquid hydrogen testing system operates in a temperature range of ≥20K, which can meet the requirements for testing the performance and critical net positive suction head (NPSH) of pumps in low-temperature environments of not less than 20K (especially in liquid hydrogen environments of 20K and liquid nitrogen environments of 77K). By testing key parameters such as temperature, pressure, flow rate, and liquid level, the external characteristics and cavitation characteristics of centrifugal submersible pumps and pipeline pumps under different inlet pressures and flow rates in the liquid hydrogen temperature range can be tested and evaluated.

[0053] More specifically, the fluid filling and discharging module 2 is used to fill, exhaust, and fill the liquid hydrogen pump test system with gas, and includes a test pipeline exhaust pipe 2-2 connected to the outlet of the liquid hydrogen pump 1-10 under test, a first valve 2-1 installed on the test pipeline exhaust pipe 2-2, a liquid hydrogen storage tank inlet pipe 2-4, a liquid hydrogen storage tank exhaust pipe 2-6, and a liquid hydrogen storage tank liquid inlet pipe 2-7 respectively connected to the liquid hydrogen storage tank 1-3, and a second valve 2-3, a third valve 2-5, and a fourth valve 2-8 respectively installed on the liquid hydrogen storage tank inlet pipe 2-4, the liquid hydrogen storage tank exhaust pipe 2-6, and the liquid hydrogen storage tank liquid inlet pipe 2-7.

[0054] It is understood that the first valve 2-1 is the exhaust control valve of the test pipeline 1-7, the second valve 2-3 and the third valve 2-5 are the inlet and outlet control valves of the liquid hydrogen storage tank 1-3, and the fourth valve 2-8 is the filling control valve of the liquid hydrogen storage tank 1-3. By controlling the first to fourth valves 2-8, the filling, exhaust and filling control of the liquid hydrogen pump test system can be realized.

[0055] More specifically, the automatic control system is connected to the parameter measurement component and the fluid filling and draining module 2, and is used to control the opening degree of the valve of the fluid filling and draining module 2 based on the parameters measured by the parameter measurement component, thereby realizing the performance and pump net positive suction head (NPSH) test of the liquid hydrogen pump 1-10 under test.

[0056] It is understood that the number of parameter measuring components in the liquid hydrogen pump testing system of the present invention is multiple, and can be set according to actual testing needs. The present invention does not limit the specific number or instrument type. In the first preferred embodiment, the parameter measuring components specifically include a first parameter measuring component disposed on the liquid hydrogen storage tank 1-3, a second parameter measuring component disposed at the inlet and outlet positions of the liquid hydrogen pump 1-10 under test, and a third parameter measuring component.

[0057] Specifically, the first parameter measuring component includes a first pressure gauge 1-4, a first thermometer 1-5, and a first level gauge 1-6. The first pressure gauge 1-4 is used to measure the pressure of the liquid hydrogen storage tank 1-3, the first thermometer 1-5 is used to measure the temperature of the liquid hydrogen storage tank 1-3, and the first level gauge 1-6 is used to measure the liquid hydrogen level height filled into the liquid hydrogen storage tank 1-3.

[0058] The second parameter measuring component includes a second pressure gauge 1-8 and a second thermometer 1-9. The two pressure gauges are used to measure the pressure at the inlet of the liquid hydrogen pump 1-10 under test, and the second thermometer 1-9 is used to measure the temperature at the inlet of the liquid hydrogen pump 1-10 under test. It is required that the second pressure gauge 1-8 be positioned at the same horizontal level as the pump inlet, and the second thermometer 1-9 be positioned as close as possible to the pump inlet to accurately represent the inlet working fluid temperature.

[0059] The third parameter measurement component includes a third pressure gauge 1-11 and a third thermometer 1-12. The third pressure gauge 1-11 is used to measure the pressure at the outlet of the liquid hydrogen pump 1-10 under test, and the third thermometer 1-12 is used to measure the temperature at the outlet of the liquid hydrogen pump 1-10 under test.

[0060] Furthermore, the automatic control system includes a level control system 3-1 connected to the first level gauge 1-6 and the fourth valve 2-8, and a pressure control system 3-2 connected to the second pressure gauge 1-8 and the third valve 2-5. The level control system 3-1 is used to control the fourth valve 2-8 based on the data collected by the first level gauge 1-6, and the pressure control system 3-2 is used to control the third valve 2-5 based on the data collected by the second pressure gauge 1-8.

[0061] Furthermore, a flow meter zeroing valve 1-13 and a pneumatic regulating valve 1-15 are sequentially connected between the outlet of the liquid hydrogen pump 1-10 under test and the liquid hydrogen storage tank 1-3. The parameter measurement assembly also includes a liquid hydrogen flow meter 1-14 disposed between the flow meter zeroing valve 1-13 and the pneumatic regulating valve 1-15. The automatic control system also includes a flow control system 3-3 connected to the liquid hydrogen flow meter 1-14 and the pneumatic regulating valve 1-15. The flow control system 3-3 is used to control the pneumatic regulating valve 1-15 based on the parameters measured by the liquid hydrogen flow meter 1-14.

[0062] It is worth mentioning that the liquid hydrogen pump testing system of the present invention is suitable for performance testing and pump net positive suction head (NPSH) testing of pipeline pumps or submersible pumps.

[0063] Specifically, the liquid hydrogen pump 1-10 to be tested is connected to a motor. The liquid hydrogen pump 1-10 to be tested is either a pipeline pump or a submersible pump 1-10-1. When the liquid hydrogen pump 1-10 to be tested is a submersible pump 1-10-1, such as Figure 2 As shown, in the second preferred embodiment of the present invention, the liquid hydrogen pump testing system further includes a test tank for installing the submersible pump 1-10-1. The test tank includes a tank body 1-10-2 and a test tank flange cover 1-10-3 sealed to the tank body 1-10-2. Both the tank body 1-10-2 and the test tank flange cover 1-10-3 are provided with pipes of the same diameter as the test pipeline 1-7 and are respectively welded to the test pipeline 1-7. The submersible pump 1-10-1 is suspended on the test tank flange cover 1-10-3.

[0064] In other words, when the liquid hydrogen pump testing system of the present invention is used to test a pipeline pump, the pipeline pump is welded to the test portion of the test pipeline 1-7. When the liquid hydrogen pump testing system of the present invention is used to test a submersible pump 1-10-1, the submersible pump 1-10-1 is hoisted onto the test tank flange cover 1-10-3. The tank body 1-10-2 is sealed to the test tank flange cover 1-10-3 by welding. The top of the test tank flange cover 1-10-3 and the side of the tank body 1-10-2 both have pipelines of the same diameter as the test pipeline 1-7, which are welded to the test pipeline 1-7 respectively.

[0065] The working principle of the liquid hydrogen pump testing system of the present invention is as follows:

[0066] Before the test, the system underwent an airtightness test using a pressurized gas filling method to check for leaks. Following this, the pipelines were purged with nitrogen, then pre-cooled with liquid nitrogen. After settling, the liquid nitrogen in the tank was evaporated and discharged; a purging was considered successful if the oxygen concentration did not exceed 0.5%. The system was then filled with liquid, and the pressure and liquid level in the test tank were controlled by pressure gauge data feedback and an automatic venting valve. The test then commenced: pump performance and net positive suction head (NPSH) were tested separately.

[0067] The specific working process of the liquid hydrogen pump testing system of the present invention is as follows:

[0068] Step S1: Perform pretreatment on the liquid hydrogen pump test system.

[0069] It should be understood that the present invention will perform pretreatment processes such as airtightness testing, pipeline nitrogen purging, liquid nitrogen precooling, and liquid hydrogen filling on the liquid hydrogen pump test system before the test. The appropriate treatment method can be selected according to the specific test needs, and the present invention does not limit it.

[0070] The present invention will now specifically illustrate the pretreatment process of the liquid hydrogen pump testing system, taking the liquid hydrogen pump testing system specifically used for pump performance testing and pump net positive suction head (NPSH) testing as an example.

[0071] Step S1 specifically includes the following steps:

[0072] S11. Perform an airtightness test on the liquid hydrogen pump test system, using an air-filling and pressure-holding leak detection method;

[0073] S12. Perform nitrogen purging on the pipeline of the liquid hydrogen pump test system.

[0074] In step S12, the nitrogen source pressure is manually adjusted to 0.2 MPa on-site. Reduced-pressure nitrogen is introduced from an external high-pressure nitrogen storage cylinder into the pipeline system of the liquid hydrogen pump test system to purge the internal circulation system (including the liquid hydrogen pump test system and the liquid hydrogen pump under test) for at least 20 minutes. First valve 2-1, third valve 2-5, and fourth valve 2-8 are closed, and the nitrogen pressure in the pipeline is increased to 0.2 MPa. After stabilizing for 1 minute, the nitrogen in the pipeline is released through first valve 2-1. This nitrogen purging and purging process is repeated at least 10 times, and on-site sampling and analysis are performed. The replacement is considered successful if the nitrogen dew point is not higher than -52℃ and the oxygen concentration is not higher than 0.5%. Finally, the nitrogen pressure inside the circulation system is maintained at 0.2 MPa. S13: After successful replacement, the pipeline of the liquid hydrogen pump test system is pre-cooled with liquid nitrogen.

[0075] In step S13, the liquid nitrogen source pressure is manually adjusted to 0.2 MPa on-site. Liquid nitrogen is then connected to the pipeline system, and the charge level is checked using the first level gauge 1-6. The system is allowed to stand for 20 minutes, while the third valve 2-5 is controlled to maintain a stable pressure inside the tank not exceeding 2 MPa. The temperature inside the liquid hydrogen storage tank 1-3 and the test pipeline is observed using the first thermometer 1-5. After standing, the tank heater 1-16 and the third valve 2-5 are opened to allow the liquid nitrogen in the liquid hydrogen storage tank 1-3 to evaporate and be discharged. On-site sampling and analysis are then performed. The replacement is considered successful if the nitrogen dew point is not higher than -52℃ and the oxygen concentration is not higher than 0.5%. Finally, the nitrogen pressure in the main pipeline is maintained at 0.15 MPa.

[0076] S14. The pre-cooled liquid hydrogen pump test system is purged with hydrogen.

[0077] In step S14, the hydrogen source pressure is manually adjusted to 0.2 MPa for on-site hydrogen purging. The depressurized hydrogen is then connected to the pipeline system to purge the system for 20 minutes. First valve 2-1 and third valve 2-5 are closed, and the hydrogen pressure in the pipeline is increased to 0.2 MPa. After stabilizing for 1 minute, the hydrogen is released. This hydrogen purging and releasing process is repeated 20 times, with on-site sampling and analysis. The purging is considered successful if the dew point in the hydrogen is not higher than -52℃ and the oxygen concentration is not higher than 0.5%. Finally, the hydrogen pressure in the main pipeline is maintained at 0.12 MPa.

[0078] S15. Fill the liquid hydrogen pump test system with liquid hydrogen after the hydrogen replacement is completed.

[0079] In step S15, the system is then filled with liquid: the liquid hydrogen source pressure is manually adjusted to 0.12 MPa on site, the liquid hydrogen is connected to the pipeline system, the liquid hydrogen is slowly poured in while the system is cooled, and the pressure and liquid level of the liquid hydrogen storage tank 1-3 are controlled by the pressure control system 3-2.

[0080] The present invention further includes: step S2, performing pump performance testing on the liquid hydrogen pumps 1-10 to be tested.

[0081] Specifically, step S2 includes the following steps:

[0082] S21. Set the speed of the liquid hydrogen pump 1-10 under test, gradually open the pneumatic regulating valve 1-15 from closed, take points within the target flow range, and after gradually changing the valve opening of the pneumatic regulating valve 1-15 to make the liquid hydrogen pump 1-10 under test run stably, record the flow rate through the first flow meter 1-14, measure the inlet and outlet pressures of the liquid hydrogen pump 1-10 under test through the second pressure meter 1-8 and the third pressure meter 1-11 respectively, and measure the voltage and current values ​​of the motor connected to the liquid hydrogen pump 1-10 under test.

[0083] S22. Change the speed of the liquid hydrogen pump 1-10 under test, repeat the operation, and obtain the pump performance curves at different speeds.

[0084] The present invention further includes: step S3, performing a pump net positive suction head (NPSH) test on the liquid hydrogen pumps 1-10 to be tested.

[0085] Specifically, step S3 includes the following steps:

[0086] S31. Set the initial speed of the liquid hydrogen pump 1-10 to be tested, fix the valve opening of the pneumatic regulating valve 1-15, and change the inlet pressure of the liquid hydrogen pump 1-10 to be tested until the ratio of the head drop value to the pump head value reaches the specified value and stabilizes, for example, reaching the specified value (3%); take points within the target flow range, and conduct experiments and record the results while gradually changing the valve opening of the pneumatic regulating valve 1-15.

[0087] S32. Change the speed of the liquid hydrogen pump 1-10 under test and repeat the operation;

[0088] The present invention further includes: step S4, after the operation is terminated, draining and rewarming the liquid.

[0089] It is worth mentioning that the above-mentioned target flow range can be selected according to the specific test experiment of the liquid hydrogen pump test system, and the present invention does not limit the specific flow range.

[0090] The liquid hydrogen pump testing system of this invention is equipped with a cold chamber, which can meet the requirements for testing the pump performance and critical net positive suction head (NPSH) in cryogenic environments of not less than 20K (especially 20K liquid hydrogen and 77K liquid nitrogen). By testing key parameters such as temperature, pressure, flow rate, and liquid level, the system can test and evaluate the external characteristics and cavitation characteristics of centrifugal submersible pumps 1-10-1 and pipeline pumps under different inlet pressures and flow rates in the liquid hydrogen temperature range. By conducting performance tests on the pump under actual operating conditions, the system can accurately evaluate the actual performance of the pump and provide guidance for research and development and improvement.

[0091] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0092] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A liquid hydrogen pump testing system, characterized in that, include: The cryogenic testing terminal assembly includes a cold box, a liquid hydrogen storage tank disposed inside the cold box, a test pipeline connected to the liquid hydrogen storage tank, a liquid hydrogen pump to be tested whose inlet and outlet are respectively connected to the test pipeline and the liquid hydrogen storage tank, and parameter measuring components disposed at the inlet and outlet positions of the liquid hydrogen pump to be tested and on the liquid hydrogen storage tank, the parameter measuring components being used to measure pressure, temperature, flow rate, and liquid level; A fluid filling and discharging module, connected to the cryogenic test end assembly, is used to realize the venting of the test pipeline and the inlet and outlet of gas and the filling of liquid hydrogen storage tank. An automatic control system, connected to the parameter measurement component and the fluid filling and discharging module, is used to control the valve opening of the fluid filling and discharging module based on the parameters measured by the parameter measurement component, thereby realizing the performance and pump net positive suction head (NPSH) test of the liquid hydrogen pump under test. The fluid filling and discharging module includes a test pipeline exhaust pipe connected to the outlet of the liquid hydrogen pump under test, a first valve installed on the test pipeline exhaust pipe, a liquid hydrogen storage tank inlet pipe, a liquid hydrogen storage tank exhaust pipe and a liquid hydrogen storage tank inlet pipe respectively connected to the liquid hydrogen storage tank, and a second valve, a third valve and a fourth valve respectively installed on the liquid hydrogen storage tank inlet pipe, the liquid hydrogen storage tank exhaust pipe and the liquid hydrogen storage tank inlet pipe; the parameter measurement components include a pressure gauge, a thermometer, a flow meter and a level gauge; The parameter measurement components include a first pressure gauge, a first thermometer, and a first level gauge installed on the liquid hydrogen storage tank. The automatic control system includes a level control system connected to the first level gauge and the fourth valve. The level control system is used to control the fourth valve based on the data collected by the first level gauge. The parameter measurement component further includes a second pressure gauge and a second thermometer disposed at the inlet position of the liquid hydrogen pump under test, and a third pressure gauge and a third thermometer disposed at the outlet position of the liquid hydrogen pump under test. The automatic control system includes a pressure control system connected to the second pressure gauge and the third valve. The pressure control system is used to control the third valve based on the data collected by the second pressure gauge. A flow meter zeroing valve and a pneumatic regulating valve are connected in sequence between the outlet of the liquid hydrogen pump under test and the liquid hydrogen storage tank. The parameter measurement component includes a liquid hydrogen flow meter disposed between the flow meter zeroing valve and the pneumatic regulating valve. The automatic control system also includes a flow control system connected to the liquid hydrogen flow meter and the pneumatic regulating valve. The flow control system is used to control the pneumatic regulating valve based on the parameters measured by the liquid hydrogen flow meter. A tank heater is installed outside the liquid hydrogen storage tank.

2. The liquid hydrogen pump testing system according to claim 1, characterized in that, The cold box includes a cold box body and a cold box flange cover plate covering the cold box body. The cold box flange cover plate is provided with lead wire channels for leading out leads of one or more components of the parameter measuring assembly, such as pressure gauges, thermometers, flow meters, and level gauges.

3. The liquid hydrogen pump testing system according to any one of claims 1 to 2, characterized in that, The operating temperature range of the liquid hydrogen pump testing system is no less than 20K.

4. The liquid hydrogen pump testing system according to any one of claims 1 to 2, characterized in that, The liquid hydrogen pump under test is connected to a motor. The liquid hydrogen pump under test is either a pipeline pump or a submersible pump. When the liquid hydrogen pump under test is a submersible pump, the liquid hydrogen pump testing system also includes a test tank for installing the submersible pump. The test tank includes a tank body and a test tank flange cover that is sealed to the tank body. Both the tank body and the test tank flange cover are provided with pipelines of the same diameter as the test pipeline and are respectively welded to the test pipeline. The submersible pump is suspended on the test tank flange cover.

5. A test method for a liquid hydrogen pump test system according to any one of claims 1 to 3, characterized in that, Including the following steps: S2. Perform pump performance testing on the liquid hydrogen pump under test: S21. Set the speed of the liquid hydrogen pump under test, gradually open the pneumatic regulating valve from closed, take points within the target flow range, and after gradually changing the valve opening of the pneumatic regulating valve to make the liquid hydrogen pump under test run stably, record the flow rate through the liquid hydrogen flow meter, measure the inlet and outlet pressures of the liquid hydrogen pump under test through the second and third pressure gauges respectively, and measure the voltage and current values ​​of the motor connected to the liquid hydrogen pump under test. S22. Change the speed of the liquid hydrogen pump under test, repeat the operation, and obtain the pump performance curves at different speeds; S3. Perform a pump net positive suction head (NPSH) test on the liquid hydrogen pump under test: S31. Set the initial speed of the liquid hydrogen pump under test, fix the valve opening of the pneumatic regulating valve, and change the inlet pressure of the liquid hydrogen pump under test until the ratio of the head drop value to the pump head value reaches the specified value and stabilizes; take points within the target measurement flow range, and conduct experiments and record the results while gradually changing the valve opening of the pneumatic regulating valve. S32. Change the speed of the liquid hydrogen pump under test and repeat the operation; S4. After the operation ends, drain the liquid and reheat it.

6. The test method for the liquid hydrogen pump test system according to claim 5, characterized in that, Before step S2, a pre-processing step S1 for the liquid hydrogen pump testing system is also included: S11. Perform an airtightness test on the liquid hydrogen pump test system, using an air-filling and pressure-holding leak detection method; S12. Perform nitrogen purging on the pipeline of the liquid hydrogen pump test system. S13. Pre-cool the pipeline of the liquid hydrogen pump test system after the replacement is qualified by filling it with liquid nitrogen. S14. The pre-cooled liquid hydrogen pump test system is purged with hydrogen. S15. Fill the liquid hydrogen pump test system with liquid hydrogen after the hydrogen replacement is completed.

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