A turbo-pump low-temperature bearing full-size working condition test system and method

Abstract

A turbo pump low-temperature bearing full-size working condition test system and method belong to the technical field of turbo pump test, the tested bearing is enclosed in a test main body, the test system comprises a liquid nitrogen main line and a nitrogen pressurizing system; the liquid nitrogen main line comprises a liquid nitrogen main storage tank, a liquid nitrogen high-pressure storage tank, a liquid nitrogen subcooler, a liquid supply and return valve group pipeline, the test main body, a liquid nitrogen recovery storage tank and a liquid nitrogen recovery pump group connected in sequence, the liquid nitrogen in the liquid nitrogen main line flows from the liquid nitrogen main storage tank to the liquid nitrogen recovery pump group; the liquid nitrogen recovery pump group of the liquid nitrogen main line is connected with the liquid nitrogen high-pressure storage tank, forming a liquid nitrogen circulating loop; the liquid nitrogen recovery pump group of the liquid nitrogen main line is connected with the liquid nitrogen main storage tank, forming a liquid nitrogen recovery loop. The turbo pump low-temperature bearing full-size working condition test system and method have strong low-temperature simulation capability, strong compatibility of full-size working condition, long test duration, and can meet the low-temperature, full-size and large-flow test requirements of turbo pump low-temperature bearings.

Description

Technical Field

[0001] This invention relates to the field of turbine pump testing technology, specifically to a full-scale operating condition testing system and method for cryogenic bearings of turbine pumps. Background Technology

[0002] In aerospace liquid rocket engines, the turbopump, as a core power component, directly affects the engine's reliability and lifespan. Turbopumps operate under extreme conditions, requiring them to withstand ultra-low temperatures (such as liquid oxygen -183℃, liquid hydrogen -253℃), ultra-high speeds (10,000–100,000 rpm), heavy loads, and complex alternating loads. Bearings, as critical transmission components, account for over 60% of turbopump failures. Traditional cryogenic bearing testing systems suffer from the following technical bottlenecks:

[0003] ① Insufficient low-temperature simulation capability: Traditional low-temperature bearing testing methods often use liquid nitrogen at -196℃ instead of liquid oxygen and liquid hydrogen. Because liquid nitrogen is very easy to exchange heat with the tank and pipeline during transportation, it will vaporize and form a vapor-liquid mixture. In addition, most tests need to simulate the working pressure of the turbopump (generally 0.5 to 5 MPa). Pressure changes will directly change the boiling point of liquid nitrogen. The above two problems will lead to the final liquid nitrogen temperature rising. According to experimental experience, the liquid nitrogen temperature will rise to -160 to -180℃, resulting in a large difference between the test temperature and the actual temperature in the turbopump.

[0004] ② Poor compatibility with full-size operating conditions: Traditional testing systems are mostly designed for specific bearing models, which are complex to disassemble and assemble and have low adaptability. In addition, the liquid nitrogen delivery flow rate and pressure are too uniform and cannot meet the requirements of full-size cryogenic bearing operating conditions.

[0005] ③ Short effective test time: Traditional cryogenic test systems mostly use storage tanks to directly supply liquid nitrogen to the test, and after the test, the liquid nitrogen is discharged into the recovery tank to vaporize. For the high flow rate test required for heavy-duty aerospace turbopump bearings, it cannot meet the long test requirements. Summary of the Invention

[0006] The purpose of this invention is to propose a full-scale operating condition test system and method for cryogenic bearings of turbopumps. It has strong low-temperature simulation capability, strong compatibility with full-scale operating conditions, and long test duration, which can meet the requirements of low-temperature, full-scale and high-flow-rate tests for cryogenic bearings of turbopumps.

[0007] The technical solution adopted in this invention is: a full-scale operating condition test system for cryogenic bearings of turbopumps, wherein the bearing under test is enclosed within the test body, and the test system includes a liquid nitrogen main circuit and a nitrogen pressurization system.

[0008] The liquid nitrogen main circuit includes a liquid nitrogen main storage tank, a liquid nitrogen high-pressure storage tank, a liquid nitrogen supercooler, a liquid supply and return valve group pipeline, a test body, a liquid nitrogen recovery storage tank, and a liquid nitrogen recovery pump group connected in sequence. Liquid nitrogen in the liquid nitrogen main circuit flows from the liquid nitrogen main storage tank to the liquid nitrogen recovery pump group.

[0009] The liquid nitrogen recovery pump set of the main liquid nitrogen circuit is connected to the liquid nitrogen high-pressure storage tank to form a liquid nitrogen circulation loop; the liquid nitrogen recovery pump set of the main liquid nitrogen circuit is connected to the main liquid nitrogen storage tank to form a liquid nitrogen recovery loop.

[0010] The nitrogen pressurization system includes a high-pressure nitrogen storage tank. The inlet of the high-pressure nitrogen storage tank is connected to the main liquid nitrogen storage tank through a pressurization vaporization component. The outlet of the high-pressure nitrogen storage tank is connected to the inlet of the high-pressure liquid nitrogen storage tank, the liquid nitrogen subcooler, the liquid nitrogen recovery storage tank, and the turbine gas supply pipeline, respectively.

[0011] The turbine air supply pipeline is connected to the test body and used to drive the tested bearing.

[0012] As a preferred option, the pressurized vaporization assembly includes a cryogenic booster pump and a vaporizer.

[0013] As a preferred option, the main liquid nitrogen storage tank is connected to a liquid nitrogen booster pump system for pressurizing it.

[0014] As a preferred embodiment, a nitrogen venting pipeline is connected to the gas phase interface of the main liquid nitrogen storage tank, and the nitrogen venting pipeline is connected to the inlet of the supply and return liquid valve group pipeline.

[0015] As a preferred embodiment, the supply and return valve assembly pipeline includes multiple supply branches and outlet branches connected in parallel on both sides of the test body. Each supply branch is equipped with a supply valve, a flow meter, and a pressure sensor, while the outlet branch is equipped with a return valve and a pressure sensor, making the flow rate of the supply branches adjustable.

[0016] As a preferred embodiment, there are six liquid supply branches, of which three have a flow rate adjustment range of 0.15 to 1.5 kg / s and the other three have a flow rate adjustment range of 0.6 to 6 kg / s. By selectively combining different liquid supply branches, the total liquid supply flow rate into the test body is controlled within a wide range of 0.15 to 18 kg / s.

[0017] As a preferred embodiment, the liquid nitrogen recovery storage tank is equipped with a level gauge, and the start and stop of the liquid nitrogen recovery pump group are automatically controlled by the control system based on the liquid level height signal detected by the level gauge.

[0018] As a preferred technical solution, the test body has a relatively closed test chamber and a vortex chamber; the test bearing is installed in the test chamber, and there are two liquid nitrogen ports on the side walls of the test chamber on both sides of the test bearing. A rotating shaft extending to the vortex chamber is fixed on the inner ring of the test bearing, and a turbine disk is fixed on the rotating shaft. There are two nitrogen ports on the side walls of the vortex chamber on both sides of the turbine disk.

[0019] A method for full-scale operating condition testing of cryogenic bearings for turbopumps, wherein the bearing under test is enclosed within the test body of a test system, and then selectively performs system purging, nitrogen pressurization, cyclic testing, and liquid nitrogen recovery.

[0020] System purging: Before the test begins, the liquid nitrogen main storage tank is pressurized by the liquid nitrogen booster pump pipeline. The nitrogen generated by the pressurization is introduced into the test body through the nitrogen purging pipeline to replace and purge the air in it.

[0021] Nitrogen pressurization: At the start of the test, the liquid nitrogen in the main liquid nitrogen storage tank is pressurized and vaporized by the pressurization vaporization component and then sent to the high-pressure nitrogen storage tank. The nitrogen in the high-pressure nitrogen storage tank pressurizes the liquid nitrogen high-pressure storage tank, the liquid nitrogen subcooler, the liquid nitrogen recovery storage tank and the turbine gas supply pipeline respectively.

[0022] Cyclic test: Liquid nitrogen in the main liquid nitrogen storage tank is sent to the high-pressure liquid nitrogen storage tank. Liquid nitrogen in the high-pressure liquid nitrogen storage tank, after being pressurized by nitrogen, is sent to the liquid nitrogen subcooler for subcooling and heat exchange. After heat exchange, the liquid nitrogen is sent into the test body through the supply and return liquid valve group pipeline.

[0023] The liquid nitrogen discharged from the test body enters the liquid nitrogen recovery storage tank, and is then sent to the liquid nitrogen high-pressure storage tank by the liquid nitrogen recovery pump set. At the same time, the nitrogen high-pressure storage tank continuously replenishes the liquid nitrogen high-pressure storage tank to form a cycle.

[0024] Liquid nitrogen recovery: The liquid nitrogen discharged from the test body enters the liquid nitrogen recovery storage tank, and then is sent into the main liquid nitrogen storage tank by the liquid nitrogen recovery pump set.

[0025] As a preferred option, liquid nitrogen recovery includes two modes: Mode 1, after the test is stopped, all the liquid nitrogen accumulated in the liquid nitrogen recovery storage tank is transferred to the main liquid nitrogen storage tank; Mode 2, a high liquid level and a low liquid level are preset in the liquid nitrogen recovery storage tank, and the liquid nitrogen level in the liquid nitrogen recovery storage tank is monitored in real time during the test. If the liquid nitrogen level is higher than the preset high liquid level, the liquid nitrogen recovery pump group is controlled to simultaneously perform the circulation test and liquid nitrogen recovery; if the liquid nitrogen level is lower than the preset low liquid level, the liquid nitrogen recovery pump group is controlled to only perform the circulation test.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. This full-scale operating condition test system for cryogenic bearings of turbopumps simultaneously simulates bearing operating conditions and turbopump working pressure. It utilizes nitrogen pressurization and liquid nitrogen subcooling to suppress and compensate for the influence of turbopump working pressure changes on cryogenic bearing operating conditions, avoiding excessive differences between test temperature and actual temperature, and ensuring the accuracy of test data.

[0028] 2. The multi-branch combination method is used to simulate the supply of liquid nitrogen by a turbine pump, which facilitates precise flow adjustment and can meet the flow and pressure requirements of different sizes and working conditions, while ensuring accuracy.

[0029] 3. The test is conducted using a dual-tank system (main liquid nitrogen tank + high-pressure liquid nitrogen tank) and liquid nitrogen circulation, which can guarantee the test requirements for large flow rates. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the system of the present invention;

[0032] Figure 2 This is a partial cross-sectional schematic diagram of the test subject in this invention;

[0033] Figure 3 This is a schematic diagram of the liquid supply branch connection of the present invention;

[0034] Figure 4 This is a schematic diagram of the liquid outlet branch connection of the present invention;

[0035] Figure 5 This is a schematic diagram of liquid nitrogen recovery according to the present invention;

[0036] Figure 6 This is a schematic diagram of the cyclic test of the present invention;

[0037] Figure 7 This is a schematic diagram of nitrogen pressurization according to the present invention.

[0038] Reference numerals in the attached diagram: 1. Main liquid nitrogen storage tank; 2. High-pressure liquid nitrogen storage tank; 3. Liquid nitrogen supercooler; 4. High-pressure nitrogen storage tank; 5. Liquid nitrogen recovery storage tank; 6. Liquid nitrogen booster pump assembly pipeline; 7. Liquid nitrogen recovery pump assembly; 8. Supply and return liquid valve assembly pipeline; 9. Turbine gas supply pipeline; 10. Nitrogen venting pipeline; 11. Test body; 12. Cryogenic booster pump; 13. Vaporizer; 14. Liquid level gauge; 15. Test chamber; 16. Bearing under test; 17. Rotating shaft; 18. Vortex chamber; 19. Turbine disk; 20. Speed ​​sensor. Detailed Implementation

[0039] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0040] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," etc., used in the specification and claims of this patent application do not express a limitation on quantity, but rather indicate the presence of at least one; the terms "first," "second," and "third," as used herein, should not be considered as a limitation on the order of components, but are merely for distinguishing different components; the terms "comprising," "including," etc., indicate that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0041] To more clearly describe this full-scale operating condition test system and method for cryogenic bearings of turbopumps, in conjunction with the attached... Figure 1-7 This embodiment is described as follows:

[0042] like Figure 1-7 As shown, a full-scale operating condition test system for cryogenic bearings of turbopumps is disclosed. The bearing under test is enclosed within the test body 11, which includes a liquid nitrogen main circuit and a nitrogen pressurization system.

[0043] The liquid nitrogen main pipeline includes a liquid nitrogen main storage tank 1 (50m) connected in sequence. 3 ), 2 liquid nitrogen high-pressure storage tanks (25m) 3 The system includes an intermediate pressure storage tank, a liquid nitrogen supercooler 3, a supply and return liquid valve group pipeline 8, a test body 11 (used to simulate a turbo pump), a liquid nitrogen recovery storage tank 5 (recovery storage tank), and a liquid nitrogen recovery pump group 7 (cryogenic pump). Liquid nitrogen in the main liquid nitrogen line flows from the main liquid nitrogen storage tank 1 to the liquid nitrogen recovery pump group 7.

[0044] The liquid nitrogen recovery pump set 7 of the main liquid nitrogen circuit is connected to the high-pressure liquid nitrogen storage tank 2 to form a liquid nitrogen circulation loop; the liquid nitrogen recovery pump set 7 of the main liquid nitrogen circuit is connected to the main liquid nitrogen storage tank 1 to form a liquid nitrogen recovery loop.

[0045] The nitrogen pressurization system includes a high-pressure nitrogen storage tank 4 (high-pressure gas storage tank). The inlet of the high-pressure nitrogen storage tank 4 is connected to the main liquid nitrogen storage tank 1 through a pressurization vaporization component. The outlet of the high-pressure nitrogen storage tank 4 is connected to the inlet of the high-pressure liquid nitrogen storage tank 2, the liquid nitrogen subcooler 3, the liquid nitrogen recovery storage tank 5, and the turbine gas supply pipeline 9, respectively.

[0046] The turbine air supply pipeline 9 is connected to the test body 11 and is used to drive the test bearing 16.

[0047] See Figure 2 The test body 11 has a relatively enclosed test chamber 15 and a vortex chamber 18. The test bearing 16 is installed in the test chamber 15. There are two liquid nitrogen ports on the side walls of the test chamber 15 on both sides of the test bearing 16. The two liquid nitrogen ports are connected to the supply and return liquid valve group pipeline 8. After the liquid nitrogen enters the test chamber 15, it forms a pressure difference on both sides of the test bearing 16 in the axial direction, and then passes through the gap of the test bearing 16. A rotating shaft 17 extending to the vortex chamber 18 is fixed on the inner ring of the test bearing 16. A turbine disk 19 is fixed on the rotating shaft 17. There are two nitrogen ports on the side walls of the vortex chamber 18 on both sides of the turbine disk 19. One of the nitrogen ports is connected to the outlet of the turbine gas supply pipeline 9. After the nitrogen enters the vortex chamber 18, it forms a pressure difference on both sides of the turbine disk 19, and then drives the turbine disk 19, the rotating shaft 17 and the inner ring of the test bearing 16 to rotate, simulating the working state of the test bearing 16.

[0048] The test body 11 is also equipped with a speed sensor 20 for measuring the rotational speed of the shaft 17, which can meet the simulation requirements of the turbine pump under different speed conditions.

[0049] In the above embodiments, the pressurized vaporization assembly includes a cryogenic booster pump 12 and a vaporizer 13.

[0050] In the above embodiment, the liquid nitrogen main storage tank 1 is connected to a liquid nitrogen booster pump group pipeline 6 for pressurizing it, which can generate nitrogen gas of ≤0.8MPa through self-pressurization; a nitrogen venting pipeline 10 is connected to the gas phase interface of the liquid nitrogen main storage tank 1, and the nitrogen venting pipeline 10 is connected to the inlet of the supply and return liquid valve group pipeline 8, so that the test body 11 is vented by the nitrogen gas generated by self-pressurization before the test.

[0051] See Figure 3-7The supply and return liquid valve assembly pipeline 8 includes multiple supply and outlet branches connected in parallel on both sides of the test body 11. Each supply branch is equipped with a supply valve, a flow meter, and a pressure sensor, while the outlet branch is equipped with a return valve and a pressure sensor, making the flow rate of the supply branches adjustable. For example, there are six supply branches, three of which have a flow rate adjustment range of 0.15–1.5 kg / s, and the other three have a flow rate adjustment range of 0.6–6 kg / s. By selectively combining different supply branches, the total supply flow rate into the test body 11 is controlled within a wide range of 0.15–18 kg / s, with a control reading accuracy of ±5%. The supply pressure is 0.4–4 MPa, with a control reading accuracy of ±2%, thus expanding the adjustment range while ensuring control accuracy.

[0052] In the above embodiment, a liquid nitrogen recovery storage tank 5 is equipped with a liquid level gauge 14, which is used to measure the height of the liquid nitrogen level. The start and stop of the liquid nitrogen recovery pump group 7 are automatically controlled by the control system based on the liquid level height signal detected by the liquid level gauge 14.

[0053] A method for full-scale operating condition testing of cryogenic bearings for turbopumps involves enclosing the bearing 16 under test within the test body 11 of a test system, followed by selective system purging, nitrogen pressurization, cyclic testing, and liquid nitrogen recovery.

[0054] System purging: Before the test begins, the main liquid nitrogen storage tank 1 is self-pressurized through the liquid nitrogen booster pump group pipeline 6. First, the liquid nitrogen pipeline is closed, and the nitrogen generated by self-pressurization is introduced into the test body 11 through the nitrogen purging pipeline 10 and the supply and return liquid valve group pipeline 8. After the air in the nitrogen is replaced and purged, the nitrogen purging pipeline 10 is closed.

[0055] Nitrogen pressurization: At the start of the test, the liquid nitrogen in the main liquid nitrogen storage tank 1 is pressurized and vaporized by the pressurization vaporization component and then sent to the high-pressure nitrogen storage tank 4. The nitrogen in the high-pressure nitrogen storage tank 4 pressurizes the liquid nitrogen high-pressure storage tank 2, the liquid nitrogen subcooler 3, the liquid nitrogen recovery storage tank 5 and the turbine gas supply pipeline 9 respectively.

[0056] Cyclic test: Liquid nitrogen in the main liquid nitrogen storage tank 1 is sent to the high-pressure liquid nitrogen storage tank 2. Liquid nitrogen in the high-pressure liquid nitrogen storage tank 2, after being pressurized by nitrogen, is sent to the liquid nitrogen subcooler 3 for subcooling and heat exchange. After heat exchange, the liquid nitrogen is sent to the test body 11 through the supply and return liquid valve group pipeline 8 (at this time, the nitrogen venting pipeline 10 is closed).

[0057] The liquid nitrogen discharged from the test body 11 enters the liquid nitrogen recovery storage tank 5, and then is sent to the liquid nitrogen high pressure storage tank 2 through the liquid nitrogen recovery pump group 7. At the same time, the nitrogen high pressure storage tank 4 continuously replenishes the liquid nitrogen high pressure storage tank 2 to form a cycle.

[0058] Liquid nitrogen recovery: Liquid nitrogen discharged from the test body 11 enters the liquid nitrogen recovery storage tank 5, and then is sent into the main liquid nitrogen storage tank 1 through the liquid nitrogen recovery pump group 7.

[0059] Liquid nitrogen recovery includes two modes: Mode 1, after the test is stopped, all the liquid nitrogen stored in liquid nitrogen recovery tank 5 is transferred to liquid nitrogen main storage tank 1; Mode 2, a high liquid level and a low liquid level are preset in liquid nitrogen recovery tank 5. During the test, the liquid nitrogen level in liquid nitrogen recovery tank 5 is monitored in real time. If the liquid nitrogen level is higher than the preset high liquid level, the liquid nitrogen recovery pump group 7 is controlled to simultaneously perform circulation test and liquid nitrogen recovery; if the liquid nitrogen level is lower than the preset low liquid level, the liquid nitrogen recovery pump group 7 is controlled to only perform circulation test. In actual use, either mode can be selected as needed according to the test duration and the storage capacity of the tank.

[0060] The liquid nitrogen recovery capacity was tested and verified, and at a supply flow rate of 15 kg / s, the continuous testing time is ≥60 min. Without liquid nitrogen recovery and directly emptying the system, the continuous testing time is ≥40 min at a supply flow rate of 18 kg / s. The liquid nitrogen circulation and recovery system can extend the testing time by more than 50%, effectively improving the efficiency of liquid nitrogen utilization and testing.

[0061] The parts not described in detail in the above embodiments are existing technologies.

[0062] It should be noted that although the present invention has been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A full-scale operating condition test system for cryogenic bearings of turbine pumps, wherein the bearing under test (16) is enclosed within a test body (11), characterized in that: It includes a liquid nitrogen main pipeline and a nitrogen pressurization system; the liquid nitrogen main pipeline includes a liquid nitrogen main storage tank (1), a liquid nitrogen high-pressure storage tank (2), a liquid nitrogen supercooler (3), a liquid supply and return valve group pipeline (8), a test body (11), a liquid nitrogen recovery storage tank (5) and a liquid nitrogen recovery pump group (7) connected in sequence, and the liquid nitrogen in the liquid nitrogen main pipeline flows from the liquid nitrogen main storage tank (1) to the liquid nitrogen recovery pump group (7); The liquid nitrogen recovery pump group (7) of the main liquid nitrogen circuit is connected to the liquid nitrogen high-pressure storage tank (2) to form a liquid nitrogen circulation loop; the liquid nitrogen recovery pump group (7) of the main liquid nitrogen circuit is connected to the main liquid nitrogen storage tank (1) to form a liquid nitrogen recovery loop. The nitrogen pressurization system includes a nitrogen high-pressure storage tank (4), the inlet of the nitrogen high-pressure storage tank (4) is connected to the liquid nitrogen main storage tank (1) through a pressurization vaporization component, and the outlet of the nitrogen high-pressure storage tank (4) is connected to the inlet of the liquid nitrogen high-pressure storage tank (2), the liquid nitrogen subcooler (3), the liquid nitrogen recovery storage tank (5) and the turbine gas supply pipeline (9); The turbine air supply pipeline (9) is connected to the test body (11) and is used to drive the test bearing (16). The test body (11) has a relatively closed test chamber (15) and a vortex chamber (18); the test bearing (16) is installed in the test chamber (15), and there are two liquid nitrogen ports on the side walls of the test chamber (15) on both sides of the test bearing (16). A rotating shaft (17) extending to the vortex chamber (18) is fixed on the inner ring of the test bearing (16), and a turbine disk (19) is fixed on the rotating shaft (17). There are two nitrogen ports on the side walls of the vortex chamber (18) on both sides of the turbine disk (19).

2. The full-scale operating condition test system for cryogenic bearings of turbine pumps according to claim 1, characterized in that: The pressurized vaporization assembly includes a cryogenic booster pump (12) and a vaporizer (13).

3. The full-scale operating condition test system for cryogenic bearings of turbine pumps according to claim 1, characterized in that: The main liquid nitrogen storage tank (1) is connected to a liquid nitrogen booster pump assembly pipeline (6) for pressurizing it.

4. The full-scale operating condition test system for a cryogenic bearing of a turbine pump according to claim 3, characterized in that: A nitrogen venting pipeline (10) is connected to the gas phase interface of the main liquid nitrogen storage tank (1), and the nitrogen venting pipeline (10) is connected to the inlet of the supply and return liquid valve group pipeline (8).

5. The full-scale operating condition test system for a cryogenic bearing of a turbine pump according to claim 1, characterized in that: The supply and return valve assembly pipeline (8) includes multiple supply branches and outlet branches connected in parallel on both sides of the test body (11). Each supply branch is equipped with a supply valve, a flow meter and a pressure sensor, and the outlet branch is equipped with a return valve and a pressure sensor, so that the flow rate of the supply branch is adjustable.

6. The full-scale operating condition test system for cryogenic bearings of turbine pumps according to claim 5, characterized in that: There are six liquid supply branches, three of which have a flow rate adjustment range of 0.15 to 1.5 kg / s, and the other three have a flow rate adjustment range of 0.6 to 6 kg / s. By selectively combining different liquid supply branches, the total liquid supply flow rate into the test body (11) is controlled within a wide range of 0.15 to 18 kg / s.

7. The full-scale operating condition test system for cryogenic bearings of turbine pumps according to claim 1, characterized in that: The liquid nitrogen recovery storage tank (5) is equipped with a level gauge (14), and the start and stop of the liquid nitrogen recovery pump group (7) are automatically controlled by the control system based on the liquid level height signal detected by the level gauge (14).

8. A method for full-scale testing of cryogenic bearings for turbine pumps under various operating conditions, characterized in that, The test method involves enclosing the test bearing (16) within the test body (11) of the test system as described in any one of claims 1-7, and then selectively performing system purging, nitrogen pressurization, cyclic testing, and liquid nitrogen recovery. System purging: Before the test begins, the main liquid nitrogen storage tank (1) is pressurized by the liquid nitrogen booster pump group pipeline (6). The nitrogen generated by the pressurization is introduced into the test body (11) through the nitrogen purging pipeline (10) to replace and purge the air in it. Nitrogen pressurization: At the start of the test, the liquid nitrogen in the main liquid nitrogen storage tank (1) is pressurized and vaporized by the pressurization vaporization component and then sent to the high-pressure nitrogen storage tank (4). The nitrogen in the high-pressure nitrogen storage tank (4) pressurizes the liquid nitrogen high-pressure storage tank (2), the liquid nitrogen subcooler (3), the liquid nitrogen recovery storage tank (5) and the turbine gas supply pipeline (9). Cyclic test: The liquid nitrogen in the main liquid nitrogen storage tank (1) is sent to the high-pressure liquid nitrogen storage tank (2). The liquid nitrogen in the high-pressure liquid nitrogen storage tank (2) after being pressurized by nitrogen is sent to the liquid nitrogen subcooler (3) for subcooling and heat exchange. The liquid nitrogen after heat exchange is sent into the test body (11) through the supply and return liquid valve group pipeline (8). Liquid nitrogen discharged from the test body (11) enters the liquid nitrogen recovery storage tank (5), and is then sent into the liquid nitrogen high-pressure storage tank (2) through the liquid nitrogen recovery pump group (7). At the same time, the nitrogen high-pressure storage tank (4) continuously pressurizes the liquid nitrogen high-pressure storage tank (2) to form a cycle. Liquid nitrogen recovery: Liquid nitrogen discharged from the test body (11) enters the liquid nitrogen recovery storage tank (5), and then is sent into the liquid nitrogen main storage tank (1) through the liquid nitrogen recovery pump group (7).

9. The method for full-scale testing of cryogenic bearings for turbine pumps according to claim 8, characterized in that, Liquid nitrogen recovery includes two modes: Mode 1, after the test is stopped, all the liquid nitrogen stored in the liquid nitrogen recovery tank (5) is transported to the main liquid nitrogen tank (1); Mode 2, a high liquid level point and a low liquid level point are preset in the liquid nitrogen recovery tank (5), and the liquid nitrogen level in the liquid nitrogen recovery tank (5) is monitored in real time during the test. If the liquid nitrogen level is higher than the preset high liquid level point, the liquid nitrogen recovery pump group (7) is controlled to perform both the circulation test and liquid nitrogen recovery at the same time; if the liquid nitrogen level is lower than the preset low liquid level point, the liquid nitrogen recovery pump group (7) is controlled to perform only the circulation test.

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