Liquid rocket engine turbine pump combined seal test device and system

Abstract

The invention discloses a liquid rocket engine turbine pump combined seal test device and system, which combines high-pressure low-temperature end face sealing and normal-temperature circumferential segmented sealing together, and adds a nozzle on a gas medium supply system for throttling and pressure reduction before segmented sealing and simulation of a real airflow state. The real working conditions of low-temperature and high-pressure end face sealing and normal-temperature circumferential segmented sealing of a liquid rocket engine turbine pump in a low-temperature and normal-temperature mixed medium can be simulated, the real working conditions of different sealing pressures can be simulated, and meanwhile multiple dynamic sealing products can be completed at a time. And reliable test data support is provided for the development of the engine while the test efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-temperature sealing test for liquid rocket engines, and specifically relates to a test device and system that can simultaneously simulate the mixed assessment of two low-temperature and high-pressure end face seals and circumferential segmented seals in a turbo pump. Background Art

[0002] The current development of reusable liquid rocket engines has placed higher requirements on the reliability of turbo pumps. Reusable liquid rocket engines mostly use liquid oxygen and methane fuels, and turbo pumps mostly use a combination of end face seals and circumferential segmented seals to isolate liquid oxygen and liquid methane. Therefore, cryogenic end face seals and segmented seals are key components in turbo pumps and are crucial to the safe operation and function of turbo pumps. The working media isolated by the cryogenic end face seal and the circumferential segmented seal are different. The cryogenic end face seal is used to seal cryogenic liquids. The compression volume and working pressure of the two end face seals are different, and the circumferential segmented seal is used to seal gas.

[0003] Due to the reusability requirements of the engine and the special requirements of the dynamic seal working conditions, before the test run and launch of the liquid rocket engine, its key dynamic seal components need to be tested and verified to obtain its sealing performance and wear performance. However, the current dynamic seal test equipment can generally only conduct low-temperature or normal temperature operation tests on one or two products, and cannot simulate the actual working conditions of different types of dynamic seals in turbo pumps and dynamic seal combinations under different working conditions. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and provide a liquid rocket engine turbine pump combined seal test device and system, so as to realize the simultaneous simulation of the mixed assessment of two low-temperature and high-pressure end face seals and the circumferential segmented seals in the turbine pump, thereby providing basic support for the development of reusable liquid rocket engines.

[0005] The solution of the present invention is:

[0006] A combined seal test device for a liquid rocket engine turbine pump comprises a rotor assembly, a housing assembly and a medium supply system; a low-temperature end face seal to be tested is sleeved on the rotor assembly according to a certain compression amount and contacts with a dynamic ring of the rotor assembly; a circumferential segmented seal to be tested is sleeved on the rotor assembly and forms a sealing gap with a shaft sleeve of the rotor assembly; the end face seal and the circumferential segmented seal are both fixed on the housing assembly; a plurality of sealing cavities and leakage cavities are formed between the end face seal, the circumferential segmented seal, the housing assembly and the rotor assembly, and a medium supply system is connected with the sealing cavity and is used to provide a low-temperature liquid medium or a normal-temperature gas medium to the sealing cavity;

[0007] During the test, the rotor assembly rotates, the end face seal to be tested contacts the dynamic ring to dynamically seal the sealing cavity, the gap between the circumferential segmented seal and the shaft sleeve forms a dynamic seal for the gas medium, the inlet flow of each sealing cavity and the leakage of each leakage cavity are monitored, and the sealing characteristics and working stability of the low-temperature end face seal and the circumferential segmented seal are obtained.

[0008] Preferably, the housing assembly includes a first housing, a second housing, a third housing, a fourth housing, and a fifth housing;

[0009] The first shell side is marked as the front end, and the fifth shell side is marked as the rear end;

[0010] The rotor assembly comprises a main shaft, a front liquid seal wheel, a rear liquid seal wheel, a front bearing and a rear bearing;

[0011] The front end of the main shaft is fixedly mounted on the second housing through a front bearing, and the rear end is fixedly mounted on the fourth housing through a rear bearing;

[0012] The rear end of the main shaft is provided with spline teeth, and the end of the shaft is provided with a threaded hole; the front end of the main shaft is provided with a speed measuring tooth, and the end of the shaft is a plane structure;

[0013] A displacement sensor is provided at the front end of the spindle to monitor the axial vibration of the test device during high-speed operation and indirectly reflect the change of the axial force of the test device; a speed measurement sensor is provided at the radial position of the front end of the spindle to monitor the real-time speed of the test device during high-speed operation;

[0014] The end face seal I is installed at the front end of the third housing, and its compression amount is adjusted by the length of the front dynamic ring sleeve; the circumferential segment seal is installed at the rear end of the third housing; the end face seal II is installed at the front end of the fourth housing, and its compression amount is adjusted by the length of the rear dynamic ring sleeve;

[0015] The front liquid seal wheel is threadedly mounted on the front end of the main shaft, and the rear liquid seal wheel is threadedly mounted on the rear end of the main shaft. The thread rotation directions of the front liquid seal wheel and the rear liquid seal wheel are opposite, and the front liquid seal wheel is located between the first housing and the front bearing, and the rear liquid seal wheel is located between the fifth housing and the rear bearing. The front shaft seal is mounted on the main shaft and is located at the front end of the front liquid seal wheel; the rear shaft seal is mounted on the main shaft and is located at the rear end of the rear liquid seal wheel. The front liquid seal wheel and the front shaft seal, and the rear liquid seal wheel and the rear shaft seal form a rotor shaft head combined seal;

[0016] The end face seal I and the front liquid seal wheel form a sealed cavity I, whose sealing pressure is recorded as P1, and the low-temperature medium enters through the first medium inlet; the circumferential segmented seal forms a sealed cavity II inside, whose sealing pressure is recorded as P2, and the normal temperature gas medium enters through the second medium inlet; the end face seal II and the rear liquid seal wheel form a sealed cavity III, whose sealing pressure is recorded as P3, and the low-temperature medium enters through the third medium inlet; the first medium inlet and the second medium inlet are both the take-over nozzles of the third shell, and the third medium inlet is the take-over nozzle of the fourth shell;

[0017] A leakage chamber I is formed between the circumferential segment seal and the end face seal I, and a leakage chamber II is formed between the circumferential segment seal and the end face seal II.

[0018] Preferably, the outer ring of the front bearing is sleeved on the front bearing outer sleeve, and the front bearing outer sleeve is fixedly mounted on the second shell by bolts; the inner ring of the front bearing is mounted on the front bearing inner sleeve, and the inner ring and the front bearing inner sleeve are fixed to the main shaft by the front bearing pressure cap; the front end of the outer ring of the front bearing is in contact with the first disc spring, and the first disc spring is mounted on the first disc spring retainer, and the clamping and positioning is achieved by the front bearing pressure cover fixedly mounted on the front bearing outer sleeve and the front disc spring adjustment gasket, and the front disc spring adjustment gasket is installed between the first disc spring retainer and the front bearing pressure cover.

[0019] Preferably, the outer ring of the rear bearing is sleeved on the rear bearing outer sleeve, and the rear bearing outer sleeve is fixedly mounted on the fourth shell by bolts; the inner ring of the rear bearing is mounted on the rear bearing inner sleeve, and the inner ring and the rear bearing inner sleeve are fixed to the main shaft by the rear bearing pressure cap; the rear end of the outer ring of the rear bearing is in contact with the second disc spring, and the second disc spring is mounted on the second disc spring retainer, and is positioned by the rear bearing pressure cover fixedly mounted on the rear bearing outer sleeve and the rear disc spring adjustment gasket, and the rear disc spring adjustment gasket is installed between the second disc spring retainer and the rear bearing pressure cover.

[0020] Preferably, the front bearing and the front bearing jacket, the rear bearing and the rear bearing jacket are clearance fit, the front bearing outer ring and the front bearing jacket, the rear bearing outer ring and the rear bearing jacket are made of the same material, and the single-sided fit clearance at low temperature is 0.01-0.015 mm.

[0021] The axial preload of the front bearing is achieved by compression of the first disc spring, and the axial preload of the rear bearing is achieved by compression of the second disc spring. The compression amount of the first disc spring is achieved by adjusting the front disc spring adjustment gasket, and the compression amount of the second disc spring is achieved by adjusting the rear disc spring adjustment gasket.

[0022] Preferably, the front shaft seal and the rear shaft seal are both low-temperature leather cup contact seals.

[0023] Preferably, the total axial length H of the outer circle of the front liquid seal wheel and the rear liquid seal wheel is the same, and the inner diameter D1 of the blade is the same; the total axial length of the shell assembly is L, and the inner hole diameter of the shell assembly is D3, then D3-D 2前 =1mm, D3-D 2后 =1mm, where D 2前 D is the outer diameter of the front liquid seal wheel blade. 2后 is the outer diameter of the rear liquid seal wheel blade.

[0024] Preferably, the sealing pressures of the front liquid sealing wheel and the rear liquid sealing wheel are respectively denoted as P 前 , P 后 , the outer diameter is denoted as D 2前 , D 2后 When the pressure of the sealing chamber I and the pressure of the sealing chamber III are P1=P3, the axial force F generated by the front and rear ends of the main shaft 轴 =0, then the outer diameter D of the front and rear liquid seal wheels 2前 =D 2后 , at this time the sealing pressure satisfies P 前 =P 后 ≤0.5MPa, axial force F generated by the front and rear liquid seal wheels 轮 =0.

[0025] Preferably, when the pressure of the sealing chamber I and the pressure of the sealing chamber III are P1≠P3, the outer diameters D2 of the front liquid sealing wheel and the rear liquid sealing wheel are selected to be different sizes. 前 =P 后 ≤P 气 , P 气 is the vaporization pressure of liquid nitrogen under the local atmospheric pressure.

[0026] A liquid rocket engine turbo pump combined sealing test system, comprising a first cryogenic pressure vessel, a second cryogenic pressure vessel, a nitrogen bottle group, a cryogenic pneumatic stop valve, a cryogenic manual stop valve, a cryogenic mass flow meter, a manual stop valve, a pressure reducing valve, a normal temperature mass flow meter, a nozzle, a cryogenic electric regulating valve, a vaporizer, and a volume flow meter;

[0027] The first cryogenic pressure vessel is connected to the sealed chamber I through the first pipeline, and the second cryogenic pressure vessel is connected to the sealed chamber III through the first pipeline. A cryogenic pneumatic stop valve, a cryogenic manual stop valve, and a cryogenic mass flowmeter are sequentially arranged along the medium inflow direction on the first pipeline and the second pipeline. The cryogenic medium enters the sealed chamber I to cool the front bearing, and enters the sealed chamber III to cool the rear bearing. After that, a part of the medium is discharged after passing through the cryogenic electric regulating valve, a part is discharged through the front liquid seal wheel, the rear liquid seal wheel and its shaft seal, and the last part enters the leakage chamber I through the end face seal I, enters the leakage chamber II through the end face seal II, and finally is discharged through the vaporizer and the mass flowmeter in sequence;

[0028] The nitrogen cylinder group is connected to the sealed chamber II through a gas pipeline. A manual stop valve, a pressure reducing valve, a normal temperature mass flow meter and a nozzle are arranged on the gas pipeline in sequence. The nitrogen medium passes through the sealed chamber II and enters the leakage chamber I and the leakage chamber II respectively through the circumferential segmented seal, and is finally discharged through the vaporizer and the mass flow meter respectively.

[0029] The beneficial effects of the present invention compared with the prior art are:

[0030] (1) The test device of the present invention combines high-pressure and low-temperature end face seals and normal-temperature circumferential segmented seals together, and adds nozzles to the gas medium supply system to throttle and reduce pressure before segmented sealing and simulate real airflow conditions. It can simulate the real working conditions of low-temperature and high-pressure end face seals and normal-temperature circumferential segmented seals of liquid rocket engine turbine pumps in low-temperature and normal-temperature mixed media, and can simulate real working conditions with different sealing pressures. At the same time, it can complete multiple dynamic sealing products at one time, improve test efficiency, and provide reliable test data support for engine development.

[0031] (2) The main shaft of the test device of the present invention adopts a double liquid seal wheel sealing structure, and the front and rear ends both adopt a leather cup sealing structure, which can balance the axial forces generated by different low-temperature end face seals in the test device under different pressures and rotation speeds. At the same time, the test device adopts a double disc spring preload scheme, and the front and rear bearings can both move axially in the bearing sleeves. When the axial force changes significantly, its axial displacement can be reflected by the displacement sensor at the front end of the main shaft, thereby judging the working status of the bearing of the test device; at the same time, a speed sensor is set at the front end of the main shaft to monitor the real-time speed of the test device and judge the working status of the test device. Multiple monitoring methods have greatly improved the safety and reliability of the test device. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a combined seal test device for liquid rocket engine turbo pumps;

[0033] Figure 2 This is the local structural dimension drawing of the liquid seal wheel;

[0034] Figure 3 It is a combined seal test system for a liquid rocket engine turbo pump. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings.

[0036] In order to meet the development needs of reusable liquid rocket engines, different dynamic sealing structure combinations in turbopumps are simulated to achieve different compression volumes, sealing pressures and real working conditions of different media. At the same time, multiple dynamic sealing products can be completed at one time to improve the test efficiency. A reusable liquid rocket engine turbopump combined seal test device is proposed, which provides basic support for the development of reusable liquid rocket engines.

[0037] The main structural components of the full system combined sealing test device of the present invention are as follows: Figure 1 As shown, it includes a rotor assembly for rotation and a bearing and a housing assembly for supporting the rotor assembly and forming a test environment. The end face seal to be tested is mounted on the rotor assembly according to a certain compression amount, contacts the moving ring and is fixed to the housing assembly. The circumferential segmented seal to be tested is mounted on the rotor assembly to form a sealing gap with the shaft sleeve and is fixed to the housing assembly. Different sealing cavities and leakage cavities are formed between the end face seal, circumferential segmented seal, housing assembly and rotor assembly. The medium supply system is connected to the sealing cavity to provide low-temperature liquid medium or normal temperature gas medium to the sealing cavity; the leakage cavity is connected to the flowmeter to measure the leakage amount of each leakage cavity.

[0038] During the test, the rotor assembly rotates, the low-temperature end face seal to be tested contacts the dynamic ring to dynamically seal the sealing cavity, and the circumferential segmented seal and the shaft sleeve form a gap seal to dynamically seal the gas medium. By monitoring each inlet flow and each leakage cavity flow, the sealing characteristics and working stability of the low-temperature end face seal and the circumferential segmented seal are obtained at the same time.

[0039] The full-system combined sealing test device of the present invention comprises a housing assembly and a rotor component, wherein the housing comprises a first housing 1, a second housing 2, a third housing 3, a fourth housing 4, and a fifth housing 5;

[0040] One side of the first housing 1 is referred to as the front side, and one side of the fifth housing 5 is referred to as the rear side;

[0041] The rotor components include a main shaft 6, a front liquid seal wheel 7, a rear liquid seal wheel 34, a front bearing 10 and a rear bearing 23; the front bearing is located at the front side of the test device, and the rear bearing is located at the rear side of the test device.

[0042] One end of the main shaft 6 is fixedly mounted on the second housing 2 through the front bearing 10 and the front bearing sleeve 11, and the other end is fixedly mounted on the fourth housing 4 through the rear bearing 23 and the rear bearing sleeve 25;

[0043] The rear end shaft head of the main shaft 6 is provided with spline teeth, the number of teeth is 20, the module is 1.5, the pressure angle is 30°, and a threaded hole is provided at the end of the shaft head; the front end shaft head of the main shaft 6 is provided with speed measuring teeth, and the end of the shaft head is a planar structure.

[0044] A displacement sensor 39 is arranged at the end face of the front end shaft head of the main shaft 6 to monitor the axial vibration of the test device during high-speed operation, and can indirectly reflect the change of the axial force of the test device; a speed measurement sensor is arranged at the radial position of the front end shaft head of the main shaft 6 to monitor the real-time speed of the test device during high-speed operation.

[0045] The outer ring of the front bearing 10 is sleeved on the front bearing sleeve 11, and the front bearing sleeve 11 is fixedly mounted on the second housing 2 by bolts. The inner ring of the front bearing 10 is mounted on the front bearing inner sleeve 9, and the inner ring and the bearing inner sleeve 9 are fixed on the main shaft 6 by the front bearing pressure cap 8; the front end of the outer ring of the front bearing 10 is in contact with the first disc spring 261, and the first disc spring 261 is mounted on the first disc spring retainer 271 and is pressed and positioned by the front bearing pressure cap 291 fixedly mounted on the front bearing sleeve 11 and the disc spring adjustment gasket 28 between the two.

[0046] The outer ring of the rear bearing 23 is sleeved on the rear bearing sleeve 25, and the rear bearing sleeve 25 is fixedly mounted on the fourth housing 4 by bolts. The inner ring of the rear bearing 23 is mounted on the rear bearing inner sleeve 24, and the inner ring and the bearing inner sleeve 24 are fixed on the main shaft 6 by the rear bearing pressure cap 30; the rear end of the outer ring of the rear bearing 23 contacts the second disc spring 262, and the second disc spring 262 is mounted on the second disc spring retainer 272 and positioned by the rear bearing pressure cap 292 fixedly mounted on the rear bearing sleeve 25 and the disc spring adjustment gasket 28.

[0047] The front bearing 10 and the front bearing jacket 11, the rear bearing 23 and the rear bearing jacket 25 are all clearance fits, the material of the bearing outer ring and the front bearing jacket 11, the rear bearing jacket 25 are the same, and the single-sided fit clearance at low temperature is 0.01-0.015mm. When the axial force changes, the bearing outer ring can move axially in the front and rear bearing jackets, and at the same time, the main shaft 6 can move axially.

[0048] The axial preload force of the front bearing 10 and the rear bearing 23 is achieved by compression of the disc spring, and the compression amount of the disc spring can be achieved by disc spring adjustment gaskets with different thicknesses at the front end or the rear end.

[0049] The end face seal I16 is installed at the front end of the third shell 3, and its compression amount is adjusted by the front dynamic ring sleeve 15 of different lengths; the circumferential segmented seal 18 is installed at the rear end of the third shell 3; the end face seal II19 is installed at the front end of the fourth shell 4, and its compression amount is adjusted by the rear dynamic ring sleeve 20 of different lengths. Figure 1 14 and 22 are dynamic rings, 13, 21 and 30 are compression nuts

[0050] The liquid sealing wheels are installed at the front and rear ends of the main shaft 6, including a front liquid sealing wheel 7 and a rear liquid sealing wheel 34, which are matched with the main shaft 6 through threads, and the threads of the front liquid sealing wheel 7 and the rear liquid sealing wheel 34 are in opposite directions.

[0051] The front liquid seal wheel 7 is located between the first housing 1 and the front bearing, and the rear liquid seal wheel 34 is located between the fifth housing 5 and the rear bearing; the front and rear liquid seal wheels and the shaft seal form a rotor shaft head combined seal.

[0052] The shaft seal is a low-temperature leather cup contact seal. The leather cup 35 and the leather cup gasket 36 are respectively installed on the first shell 1 and the fifth shell 5 through the leather cup gland 37. The leather cup 35 and the main shaft 6 are interference fit, and the single-side interference is 0.03-0.05mm.

[0053] The front liquid seal wheel 7 and the first housing 1, the rear liquid seal wheel 34 and the fifth housing 5 are in clearance fit, and the key dimensions of the liquid seal wheel seal are as follows: Figure 2 As shown, the sealing pressure of the liquid seal wheel is calculated according to the following formula.

[0054]

[0055] Where: P is the impeller sealing pressure, n is the impeller speed, D1 is the inner diameter of the liquid seal wheel blade, D2 is the outer diameter of the liquid seal wheel, ρ is the density of the test medium in the sealing chamber, g is the acceleration of gravity, h is the height of the liquid seal wheel blade 23, δ is the axial distance between the impeller and the casing assembly, and k is the back pressure coefficient, which is determined according to the structure and usage conditions.

[0056] The inner diameters D1 of the blades of the front liquid seal wheel 7 and the rear liquid seal wheel 34 are the same, and the outer diameters D2 of the liquid seal wheels are different in size; Figure 2 In the figure, the total axial length of the shell is L, the total axial length of the outer circle of the liquid seal wheel is H, and the inner hole diameter of the shell is D3, then D3-D2=1mm, L≥H+δ.

[0057] The end face seal I16 and the front liquid seal wheel 7 form a sealed chamber I, whose sealing pressure is recorded as P1, and the low-temperature medium enters through the first medium inlet; the circumferential segmented seal 18 forms a sealed chamber II inside, whose sealing pressure is recorded as P2, and the normal temperature gas medium enters through the second medium inlet; the end face seal II19 and the rear liquid seal wheel 24 form a sealed chamber III, whose sealing pressure is recorded as P3, and the low-temperature medium enters through the third medium inlet. The first medium inlet and the second medium inlet are both the nozzles of the third shell, and the third medium inlet is the nozzle of the fourth shell. A leakage chamber I is formed between the circumferential segmented seal 18 and the end face seal I16, and a leakage chamber II is formed between the circumferential segmented seal 18 and the end face seal II19.

[0058] The sealing pressures of the front liquid seal wheel 7 and the rear liquid seal wheel 34 are respectively denoted as P前 , P 后 , the outer diameter is denoted as D 2前 , D 2后 When the pressure of the sealing chamber I and the pressure of the sealing chamber III are P1=P3, the axial force F generated by the front and rear ends of the main shaft 轴 =0, then the outer diameter D of the front liquid seal wheel 7 and the rear liquid seal wheel 34 2前 =D 2后 , at this time the sealing pressure satisfies P 前 =P 后 ≤0.5MPa, axial force F generated by front liquid seal wheel 7 and rear liquid seal wheel 34 轮 =0.

[0059] When the pressure of the sealing chamber I12 and the pressure of the sealing chamber III P1≠P3, the outer diameters D2 of the front liquid sealing wheel 7 and the rear liquid sealing wheel 34 are selected to be liquid sealing wheels of different sizes. 前 =P 后 ≤P 气 , P 气 is the vaporization pressure of liquid nitrogen under local atmospheric pressure. When P1>P3, then D 2前 >D 2后 , and the axial force F generated by the front liquid seal wheel 7 and the rear liquid seal wheel 34 轮 The axial force F generated by the front and rear ends of the spindle 轴 equal.

[0060] The principle of the medium supply system of the test device is as follows Figure 3 As shown. For low-temperature medium: the low-temperature medium of sealing chamber I and sealing chamber III is supplied through two low-temperature pressure vessels 40 respectively, and then passes through low-temperature pneumatic stop valve 42, low-temperature manual stop valve 43, and low-temperature mass flowmeter 44. The low-temperature medium enters sealing chamber I and sealing chamber III respectively to cool the front bearing 10 and rear bearing 23. A part of the low-temperature medium is discharged after passing through low-temperature electric regulating valve 49, and a part of the low-temperature medium is discharged through front liquid seal wheel 7, rear liquid seal wheel 34 and the shaft seal thereafter. The last part enters leakage chamber I and leakage chamber II respectively through end face seal I16 and end face seal II19, and finally is discharged through vaporizer 50 and mass flowmeter 51.

[0061] For nitrogen medium, the nitrogen medium in the nitrogen bottle group 41 passes through the manual stop valve 45, the pressure reducing valve 46, the normal temperature mass flowmeter 47, and the nozzle 48 in sequence and then enters the sealing chamber II, and respectively enters the leakage chamber I and the leakage chamber II through the circumferential segmented seal 18, and finally is discharged through the vaporizer 50 and the mass flowmeter 51.

[0062] The nozzle 48 mainly plays the role of throttling and reducing the pressure of the upstream nitrogen, and can supply the actual gas flow state after passing through the nozzle 48 to the circumferential segment seal 18.

[0063] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A liquid rocket engine turbo pump combined seal test device, characterized in that: It includes a rotor assembly, a housing assembly, and a medium supply system; the low-temperature end face seal to be tested is sleeved on the rotor assembly according to a certain compression amount and contacts the moving ring of the rotor assembly; the circumferential segmented seal to be tested is sleeved on the rotor assembly and forms a sealing gap with the shaft sleeve of the rotor assembly; the end face seal and the circumferential segmented seal are both fixed on the housing assembly; a number of sealing cavities and leakage cavities are formed between the end face seal, the circumferential segmented seal, the housing assembly and the rotor assembly, and the medium supply system is connected to the sealing cavity to provide a low-temperature liquid medium or a normal-temperature gas medium to the sealing cavity; During the test, the rotor assembly rotates, the end face seal to be tested contacts the dynamic ring to dynamically seal the sealing cavity, the gap between the circumferential segmented seal and the shaft sleeve forms a dynamic seal for the gas medium, the inlet flow of each sealing cavity and the leakage of each leakage cavity are monitored, and the sealing characteristics and working stability of the low-temperature end face seal and the circumferential segmented seal are obtained.

2. A liquid rocket engine turbo pump combined seal test device according to claim 1, characterized in that: The housing assembly comprises a first housing (1), a second housing (2), a third housing (3), a fourth housing (4), and a fifth housing (5); One side of the first shell (1) is marked as the front end, and one side of the fifth shell (5) is marked as the rear end; The rotor assembly comprises a main shaft (6), a front liquid seal wheel (7), a rear liquid seal wheel (34), a front bearing (10) and a rear bearing (23); The front end of the main shaft (6) is fixedly mounted on the second housing (2) via a front bearing (10), and the rear end thereof is fixedly mounted on the fourth housing (4) via a rear bearing (23); The rear end shaft head of the main shaft (6) is provided with spline teeth, and the end of the shaft head is provided with a threaded hole; the front end shaft head of the main shaft (6) is provided with a speed measuring tooth, and the end of the shaft head is a plane structure; A displacement sensor is provided at the front end of the spindle (6) to monitor the axial vibration of the test device during high-speed operation and indirectly reflect the change of the axial force of the test device; a rotation speed measurement sensor is provided at the radial position of the front end of the spindle (6) to monitor the real-time rotation speed of the test device during high-speed operation; The end face seal I (16) is installed at the front end of the third housing (3), and its compression amount is adjusted by the length of the front dynamic ring sleeve (15); the circumferential segment seal (18) is installed at the rear end of the third housing (3); the end face seal II (19) is installed at the front end of the fourth housing (4), and its compression amount is adjusted by the length of the rear dynamic ring sleeve (20); The front liquid seal wheel (7) is threadedly mounted on the front end of the main shaft (6), and the rear liquid seal wheel (34) is threadedly mounted on the rear end of the main shaft (6). The thread rotation directions of the front liquid seal wheel (7) and the rear liquid seal wheel (34) are opposite, and the front liquid seal wheel (7) is located between the first housing (1) and the front bearing, and the rear liquid seal wheel (34) is located between the fifth housing (5) and the rear bearing. The front shaft seal is mounted on the main shaft and is located at the front end of the front liquid seal wheel; the rear shaft seal is mounted on the main shaft and is located at the rear end of the rear liquid seal wheel. The front liquid seal wheel and the front shaft seal, and the rear liquid seal wheel and the rear shaft seal form a rotor shaft head combined seal. The end face seal I (16) and the front liquid seal wheel (7) form a sealed cavity I, whose sealing pressure is recorded as P1, and the low-temperature medium enters through the first medium inlet; the circumferential segment seal (18) forms a sealed cavity II inside, whose sealing pressure is recorded as P2, and the normal temperature gas medium enters through the second medium inlet; the end face seal II (19) and the rear liquid seal wheel (24) form a sealed cavity III, whose sealing pressure is recorded as P3, and the low-temperature medium enters through the third medium inlet; the first medium inlet and the second medium inlet are both the take-over nozzles of the third shell, and the third medium inlet is the take-over nozzle of the fourth shell; A leakage chamber I is formed between the circumferential segment seal (18) and the end face seal I (16), and a leakage chamber II is formed between the circumferential segment seal (18) and the end face seal II (19).

3. A liquid rocket engine turbo pump combined seal test device according to claim 2, characterized in that: The outer ring of the front bearing (10) is sleeved on the front bearing sleeve (11), and the front bearing sleeve (11) is fixedly mounted on the second housing (2) by bolts; the inner ring of the front bearing (10) is mounted on the front bearing inner sleeve (9), and the inner ring and the front bearing inner sleeve (9) are fixed to the main shaft by a front bearing pressure cap (8); the front end of the outer ring of the front bearing (10) contacts the first disc spring (261), and the first disc spring (261) is mounted on the first disc spring retainer (271), and the front bearing pressure cover (291) fixedly mounted on the front bearing sleeve (11) and the front disc spring adjustment gasket are used to achieve compression and positioning, and the front disc spring adjustment gasket is installed between the first disc spring retainer (271) and the front bearing pressure cover (291).

4. A liquid rocket engine turbo pump combined seal test device according to claim 3, characterized in that: The outer ring of the rear bearing (23) is sleeved on the rear bearing sleeve (25), and the rear bearing sleeve (25) is fixedly mounted on the fourth housing (4) by bolts; the inner ring of the rear bearing (23) is mounted on the rear bearing inner sleeve (24), and the inner ring and the rear bearing inner sleeve (24) are fixed to the main shaft (6) by a rear bearing pressure cap (30); the rear end of the outer ring of the rear bearing (23) contacts the second disc spring (262), and the second disc spring (262) is mounted on the second disc spring retainer (272), and positioning is achieved by a rear bearing pressure cover (292) fixedly mounted on the rear bearing sleeve (25) and a rear disc spring adjustment gasket, and the rear disc spring adjustment gasket is mounted between the second disc spring retainer (272) and the rear bearing pressure cover (292).

5. A liquid rocket engine turbo pump combined seal test device according to claim 4, characterized in that: The front bearing (10) and the front bearing jacket (11), and the rear bearing (23) and the rear bearing jacket (25) are all clearance-matched, the front bearing outer ring and the front bearing jacket (11), and the rear bearing outer ring and the rear bearing jacket (25) are made of the same material, and the single-side clearance at low temperature is 0.01-0.015 mm. The axial preload force of the front bearing (10) is achieved by compression of the first disc spring, and the axial preload force of the rear bearing (23) is achieved by compression of the second disc spring. The compression amount of the first disc spring is achieved by adjusting the front disc spring adjustment gasket, and the compression amount of the second disc spring is achieved by adjusting the rear disc spring adjustment gasket.

6. A liquid rocket engine turbo pump combined seal test device according to claim 2, characterized in that: The front shaft seal and the rear shaft seal are both low-temperature leather cup contact seals.

7. A liquid rocket engine turbo pump combined seal test device according to claim 2, characterized in that: The total axial length H of the outer circles of the front liquid seal wheel (7) and the rear liquid seal wheel (34) is the same, and the inner diameter D1 of the blades is the same; the total axial length of the shell assembly is L, and the inner hole diameter of the shell assembly is D3, then D3-D 2前 =1mm, D3-D 2后 =1mm, where D 2前 D is the outer diameter of the front liquid seal wheel (7) blades, 2后 is the outer diameter of the blades of the rear liquid seal wheel (34).

8. A liquid rocket engine turbo pump combined seal test device according to claim 2, characterized in that: The sealing pressures of the front liquid sealing wheel (7) and the rear liquid sealing wheel (34) are respectively denoted as P 前 , P 后 , the outer diameter is denoted as D 2前 , D 2后 When the pressure of the sealing chamber I and the pressure of the sealing chamber III are P1=P3, the axial force F generated by the front and rear ends of the main shaft 轴 = 0, then the outer diameter D of the front liquid seal wheel (7) and the rear liquid seal wheel (34) 2前 =D 2后 , at this time the sealing pressure satisfies P 前 =P 后 ≤0.5MPa, the axial force F generated by the front liquid seal wheel (7) and the rear liquid seal wheel (34) 轮 =0.

9. A liquid rocket engine turbo pump combined seal test device according to claim 8, characterized in that: When the pressure of the sealing chamber I and the pressure of the sealing chamber III are P1≠P3, the outer diameters D2 of the front liquid sealing wheel (7) and the rear liquid sealing wheel (34) are selected to be different sizes. 前 =P 后 ≤P 气 , P 气 is the vaporization pressure of liquid nitrogen under the local atmospheric pressure.

10. A liquid rocket engine turbo pump combined seal test system, characterized in that: It includes a first cryogenic pressure vessel, a second cryogenic pressure vessel, a nitrogen cylinder group, a cryogenic pneumatic stop valve, a cryogenic manual stop valve, a cryogenic mass flow meter, a manual stop valve, a pressure reducing valve, a normal temperature mass flow meter, a nozzle, a cryogenic electric regulating valve, a vaporizer, and a volume flow meter; The first cryogenic pressure vessel is connected to the sealed chamber I through the first pipeline, and the second cryogenic pressure vessel is connected to the sealed chamber III through the first pipeline. A cryogenic pneumatic stop valve, a cryogenic manual stop valve, and a cryogenic mass flow meter are sequentially arranged on the first pipeline and the second pipeline along the medium inflow direction. The cryogenic medium enters the sealed chamber I to cool the front bearing, and enters the sealed chamber III to cool the rear bearing. After that, a part of the medium is discharged after passing through the cryogenic electric regulating valve, a part is discharged through the front liquid seal wheel (7), the rear liquid seal wheel (34) and its shaft seal, and the last part enters the leakage chamber I through the end face seal I (16), enters the leakage chamber II through the end face seal II (19), and finally is discharged through the vaporizer and the mass flow meter in sequence. The nitrogen cylinder group is connected to the sealed chamber II through a gas pipeline. A manual stop valve, a pressure reducing valve, a normal temperature mass flow meter and a nozzle are arranged on the gas pipeline in sequence. The nitrogen medium passes through the sealed chamber II and enters the leakage chamber I and the leakage chamber II respectively through the circumferential segmented seal (18), and is finally discharged through the gasifier (50) and the mass flow meter (51).

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