Low-temperature centrifugal pump

Abstract

The invention relates to the technical field of fluid machinery, and provides a low-temperature centrifugal pump which comprises a shell, a centrifugal pump body, a centrifugal pump body and a centrifugal pump body. The pump core is arranged in the shell in a penetrating manner, and an impeller assembly is arranged on the pump core; the driving structure comprises a rotor main body arranged on the pump core and a stator main body arranged on the shell, the rotor main body is arranged as a permanent magnet, and an armature winding arranged in the stator main body is arranged as a low-temperature superconductor; and the flow guide loop is arranged in the shell, penetrates through a gap between the stator main body and the rotor main body, and is suitable for guiding low-temperature fluid under the action of the impeller assembly. The rotor main body provided with the permanent magnets and the stator main body with the built-in armature winding as the low-temperature superconductor are matched with a low-temperature fluid environment, so that the critical transformation temperature of the superconductor can be met, heat production is reduced, energy consumption is low, and current carrying is high. The electromagnetic torques generated by the two do not need other matching structures, and the working reliability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of fluid machinery, and in particular to a low-temperature centrifugal pump. Background Art

[0002] Liquid rocket engines often use cryogenic liquids such as liquid oxygen + liquid hydrogen or liquid oxygen + methane as propellants. For such cryogenic liquids, various pumps are still needed to regulate their delivery.

[0003] At present, common cryogenic centrifugal pumps usually use mechanical bearings and a matching driven motor or other power source. With this arrangement, on the one hand, cryogenic mechanical bearings usually need to be developed and produced by professional organizations, and they need to be tested to simulate actual working conditions before they can be used. The manufacturing and experimental costs are high. At the same time, the cooling and lubrication of cryogenic bearings require special consideration. Usually, a separate cooling circuit is designed outside the cryogenic liquid environment to prevent the frictional heat of the bearing from causing the cryogenic liquid to vaporize, and the reliability is low under ultra-high speed operating conditions. On the other hand, the drive motor that provides power for the cryogenic centrifugal pump under low temperature conditions needs to be equipped with supporting insulation structures to prevent the heat of the motor from affecting the cryogenic liquid. The motor in this environment has high energy consumption and poor reliability. Summary of the invention

[0004] In view of this, the present invention provides a cryogenic centrifugal pump to solve the problems in the prior art that the mechanical bearings of the cryogenic centrifugal pump have high manufacturing and experimental costs, low reliability and complex cooling structure, and its driving motor has high energy consumption and poor reliability.

[0005] In the first aspect, the present invention provides a low-temperature centrifugal pump, comprising: a casing, comprising an inlet and an outlet, suitable for introducing a low-temperature fluid; a pump core, inserted in the casing, on which an impeller assembly is arranged; a driving structure, comprising a rotor body arranged on the pump core and a stator body arranged on the casing, the rotor body being arranged in a permanent magnet configuration, the armature winding built into the stator body being arranged in a low-temperature superconductor configuration, the stator body being suitable for connecting to an external power supply, and in a low-temperature environment, having a suspended working state in which the stator body is spaced apart from and rotates relative to the rotor body, the pump core being suitable for driving the impeller assembly to rotate under the action of the driving structure, and driving the low-temperature fluid to flow from the inlet to the outlet; a diversion circuit being arranged in the casing, passing through a gap between the stator body and the rotor body, and suitable for diverting the low-temperature fluid under the action of the impeller assembly.

[0006] Beneficial Effects

[0007] The rotor body with permanent magnets and the stator body with built-in armature windings as low-temperature superconductors are set. The driving structure formed by the two, in conjunction with the low-temperature fluid environment provided by the guide circuit and the impeller assembly, can meet the "0 resistance" critical transition temperature of the superconductor. Such a driving structure serves as a power source, reduces heat generation, has low energy consumption and high current carrying capacity. At the same time, the electromagnetic torque generated by the two can provide non-contact torque input, simplify the cryogenic pump structure, do not require other matching structures, and improve working reliability. Furthermore, the stator body of the low-temperature superconductor can produce radial constraints on the rotor, eliminating the need for mechanical bearings, reducing costs and structural complexity, and improving the reliability of the pump body for long-term operation and multiple starts.

[0008] In addition, with this arrangement, the rotor body is in a suspended state when working, and the length of the rotor structure is shorter than that of a conventional motor rotor, which relatively simplifies the dynamic calculation problems related to the rotor inside the pump and reduces the difficulty of subsequent calculations, designs and experiments.

[0009] In an optional embodiment, the shell includes: a main shell, on which an inlet and an outlet are provided, the inlet is provided at one end of the main shell, and the outlet is provided on the side wall of the main shell; an axial cavity, provided in the main shell, in which the pump core is housed, and a stator body is correspondingly provided on the inner side wall away from the inlet, one end of the axial cavity is connected with the inlet, and the other end away from the inlet is closed; an outlet cavity, extended along the radial direction of the axial cavity, respectively connected with the axial cavity and the outlet, and correspondingly provided between the inlet and the stator body, and accommodating at least part of the impeller assembly therein.

[0010] In an optional embodiment, the diversion circuit includes: a first flow path, which is arranged between the shell and the pump core and extends from the flow inlet to the flow outlet; a second flow path, which is arranged between the shell and the pump core and extends from the flow outlet to the gap between the rotor body and the stator body; a third flow path, which is arranged in the pump core, with one end leading to one side of the flow inlet and the other end being adjacent to and connected to the gap between the rotor body and the stator body.

[0011] In an optional embodiment, the diversion circuit also includes: a lateral flow path, which is arranged on the pump core, connected to one end of the third flow path toward the inlet, extends along the radial direction of the pump core, and is connected to the first flow path.

[0012] In an optional embodiment, the impeller assembly includes: a centrifugal wheel, which is limitedly arranged on the pump core and has an arc-shaped flow guide hole built therein, wherein the arc-shaped flow guide hole is arranged on the first flow path, and the two ends of the arc-shaped flow guide hole are respectively oriented toward and connected to the inlet and the outlet;

[0013] In an optional embodiment, the cryogenic centrifugal pump further comprises: a pressure regulating assembly, which is arranged on the inner wall of the outlet cavity, movably cooperates with the centrifugal wheel, and is suitable for regulating the axial pressure of the impeller assembly.

[0014] In an optional embodiment, the pressure regulating assembly includes: a first ring body, which is arranged at the junction of the outlet cavity and the axial cavity, and is correspondingly arranged on the side of the centrifugal wheel facing the inlet, the side of the first ring body facing the axial cavity is rotatably connected to the centrifugal wheel, and the side of the first ring body facing the outlet cavity is spaced apart from the centrifugal wheel; a second ring body, which is arranged on the inner wall of the outlet cavity away from the first ring body, and a first side convex structure is arranged on the side of the first ring body facing the centrifugal wheel, and a second side convex structure is arranged on the side of the centrifugal wheel facing the second ring body, the first side convex structure and the second side convex structure have a staggered sealing abutment, and are formed with a first position of a closed flow-containing cavity, and a second position away from each other so that the flow-containing cavity is open; the centrifugal wheel is suitable for reciprocating between the first ring body and the second ring body under the axial force of the fluid, and the first side convex structure and the second side convex structure are converted between the first position and the second position.

[0015] In an optional embodiment, the axial distance between the rim of the centrifugal wheel and the side of the first ring body facing the axial cavity is set to A, and the axial distance between the rim of the centrifugal wheel and the inner wall of the flow cavity facing the axial cavity is set to B, B>A.

[0016] In an optional embodiment, the impeller assembly further includes: an inducer, disposed on the pump core and adjacent to the end of the pump core near the inlet, the inducer being adapted to rotate when driven by the pump core and driving the cryogenic fluid to move toward the centrifugal wheel.

[0017] In an optional embodiment, the cryogenic centrifugal pump further comprises: an anti-wear layer, which is respectively arranged on the opposite sides of the stator body and the rotor body, and the anti-wear layer is made of a low-temperature resistant and wear-resistant non-metallic material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of the internal structure of a cryogenic centrifugal pump according to an embodiment of the present invention;

[0020] Figure 2 for Figure 1 Schematic diagram of the flow direction of cryogenic fluid in a cryogenic centrifugal pump shown;

[0021] Description of reference numerals:

[0022] 1. Shell; 11. Inlet; 12. Outlet; 13. Main shell; 14. Shaft cavity; 15. Outlet cavity; 2. Pump core; 21. Compression nut; 3. Centrifugal wheel; 31. Arc-shaped flow guide hole; 32. Second side convex structure; 33. Flow-containing cavity; 4. Inducer wheel; 5. Rotor body; 6. Stator body; 7. Diversion circuit; 71. First flow path; 72. Second flow path; 73. Third flow path; 74. Lateral flow path; 8. First ring body; 9. Second ring body; 91. First side convex structure; 10. Anti-wear layer. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0024] like Figure 1-Figure 2 In a first aspect, the present invention provides a cryogenic centrifugal pump, comprising: a casing 1 , a pump core 2 , a driving structure and a flow guide circuit 7 .

[0025] The shell 1 includes an inlet 11 and an outlet 12. A low-temperature fluid is introduced into the shell 1. The low-temperature fluid flows in from the inlet 11 and flows out from the outlet 12.

[0026] The pump core 2 is inserted into the housing 1 and is specifically in the shape of a straight rod, preferably a cylinder. An impeller assembly is fixedly arranged on the pump core 2. The connection method may be interference fit, clamping limit, or integral molding, etc. The impeller assembly can rotate with the pump core 2.

[0027] The driving structure includes a rotor body 5 provided on the pump core 2 and a stator body 6 provided on the housing 1 .

[0028] The armature winding built into the stator body is a low-temperature superconductor, which can be specifically made of copper oxide superconducting materials, etc. The rotor body 5 is a permanent magnet, and the material can be NdFeB rare earth permanent magnets, etc. The stator body 6 can be connected to an external power supply, and in a low-temperature environment, has a suspended working state in which it is spaced apart from and rotates relative to the rotor body 5. The pump core 2 is suitable for driving the impeller assembly to rotate under the action of the driving structure, and driving the low-temperature fluid to flow from the inlet 11 to the outlet 12.

[0029] In this embodiment, the temperature of the cryogenic fluid is lower than or equal to the "0 resistance" critical transition temperature of the superconductor in the stator body. For example, when the armature winding material built into the stator body is Cu1234 superconductor Cuba 2 Ca 3 Cu 4 O 10+δ When the superconducting starting transition temperature is 120K or above, the temperature of the cryogenic fluid can correspond to 20K of liquid hydrogen, 88K of liquid oxygen, 115K of liquid methane, or lower; when the armature winding material built into the stator body is copper oxide superconducting material, it can correspond to 77K of liquid nitrogen, or lower.

[0030] The flow guide circuit 7 is arranged in the housing 1 and passes through the gap between the stator body 6 and the rotor body 5, and is suitable for guiding the low-temperature fluid under the action of the impeller assembly.

[0031] The rotor body 5 with permanent magnets and the stator body with built-in armature windings as low-temperature superconductors are provided. The driving structure formed by the two, in cooperation with the low-temperature fluid environment provided by the guide circuit 7 and the impeller assembly, can meet the "0 resistance" critical transition temperature of the superconductor. Such a driving structure serves as a power source, reduces heat generation, has low energy consumption and high current carrying capacity. At the same time, the electromagnetic torque generated by the two can provide non-contact torque input, simplify the structure of the cryogenic pump, do not require other matching structures, and improve working reliability. Furthermore, the stator body of the low-temperature superconductor can produce radial constraints on the rotor, eliminating the need for mechanical bearings, reducing costs and structural complexity, and improving the reliability of the long-term operation and multiple starts of the pump body.

[0032] In addition, with this arrangement, the rotor body 5 is in a suspended state during operation, and the length of the rotor structure is shorter than that of a conventional motor rotor, which relatively simplifies the dynamic calculation problems related to the rotor inside the pump and reduces the difficulty of subsequent calculations, designs and experiments.

[0033] In this embodiment, the housing 1 includes: a main shell 13 , a shaft cavity 14 and an outlet cavity 15 .

[0034] An inlet 11 and an outlet 12 are provided on the main shell 13. The inlet 11 is provided at one end of the main shell 13, and the outlet 12 is provided on the side wall of the main shell 13. In the present embodiment, the main shell 13 comprises three parts: a front shell, a support shell and an end cover. The front shell is provided with an inlet 11, and the front shell and the support shell are jointly formed with the outlet 12. The side of the support shell facing away from the front shell is fixedly connected to the end cover to achieve closure. Preferably, the front shell, the support shell and the end cover are detachably connected and can be connected to each other by connecting parts such as screws. It can be understood that two of the three, or all of the three, can be formed as one piece.

[0035] The shaft cavity 14 is arranged in the main housing 13, and the pump core 2 is built therein. The stator body 6 is correspondingly arranged on the inner side wall away from the inlet 11. One end of the shaft cavity 14 along the axial direction is connected with the inlet 11, and the other end away from the inlet 11 is closed.

[0036] The outlet cavity 15 is extended along the radial direction of the shaft cavity 14, communicated with the shaft cavity 14 and the outlet port 12 respectively, and is correspondingly arranged between the inlet port 11 and the stator body 6, and contains at least part of the impeller assembly.

[0037] As a convertible embodiment, the outlet 12 can be arranged opposite to the inlet 11 on the main housing 13 .

[0038] The flow guiding circuit 7 includes a first flow path 71 , a second flow path 72 and a third flow path 73 .

[0039] The first flow path 71 is arranged between the housing 1 and the pump core 2, and extends from the inlet 11 to the outlet 12; the second flow path 72 is arranged between the housing 1 and the pump core 2, and extends from the outlet 12 to the gap between the rotor body 5 and the stator body 6; the third flow path 73 is arranged in the pump core 2, one end of which leads to the side of the inlet 11, and the other end is adjacent to and connected to the gap between the rotor body 5 and the stator body 6.

[0040] In this embodiment, the low-temperature fluid flows along the first flow path 71 from the inlet 11 to the outlet 12, and part of the low-temperature fluid at the rim position of the impeller assembly flows along the second flow path 72 to the gap between the rotor body 5 and the stator body 6, and enters the third flow path 73 through the other end of the third flow path 73, and flows out through one end of the third flow path 73 leading to the inlet 11 to achieve circulation.

[0041] The third flow path 73 is provided in the pump core 2 so that the balanced impeller assembly can be subjected to axial force. At the same time, as a part of the circulatory guide loop 7, the stator body 6 and the rotor body 5 can be stably cooled.

[0042] In addition, the flow guide circuit 7 also includes a lateral flow path 74, which is arranged on the pump core 2. In this embodiment, the pump core 2 includes a core body and a clamping nut 21 arranged at one end of the core body facing the inlet 11. The core body has a built-in third flow path 73, and the clamping nut 21 has a built-in lateral flow path 74, which are interconnected. The lateral flow path 74 extends along the radial direction of the pump core 2 and is connected to the first flow path 71. This arrangement can avoid the lateral flow path 74 and the first flow path 71 from having opposite flow directions of the cryogenic liquid, and accelerate the flow of the cryogenic liquid from the lateral flow path 74 to the first flow path 71 according to the flow velocity difference.

[0043] The impeller assembly includes a centrifugal wheel 3, which is limitedly arranged on the pump core 2. In this embodiment, the pump core 2 is provided with a plurality of limit shoulders, which can correspond to the limit of the centrifugal wheel 3 and the rotor body 5. The centrifugal wheel 3 has an arc-shaped guide hole 31 built therein, and the arc-shaped guide hole 31 is arranged on the first flow path 71, and the two ends of the arc-shaped guide hole 31 are respectively oriented to and connected with the inlet 11 and the outlet 12.

[0044] In addition, the cryogenic centrifugal pump further comprises a pressure regulating assembly, which is arranged on the inner wall of the outlet cavity 15 and movably cooperates with the centrifugal wheel 3 and is suitable for regulating the axial pressure of the impeller assembly.

[0045] Specifically, the voltage regulating assembly includes: a first ring body 8 and a second ring body 9 .

[0046] The first ring body 8 is arranged at the junction of the outlet cavity 15 and the shaft cavity 14, and is correspondingly arranged on the side of the centrifugal wheel 3 facing the inlet 11. The side of the first ring body 8 facing the shaft cavity 14 is rotatably connected to the centrifugal wheel 3, and the side facing the outlet cavity 15 is spaced apart from the centrifugal wheel 3. Preferably, a seal is provided on the side of the first ring body 8 facing the outlet cavity 15, which is movably sealed with the centrifugal wheel 3. The seal may be a labyrinth seal or other low-temperature resistant elastic seal.

[0047] The second ring body 9 is arranged on the inner wall of the outflow cavity 15 away from the first ring body 8, and a first side convex structure 91 is arranged on the side facing the centrifugal wheel 3, and a second side convex structure 32 is arranged on the side facing the second ring body 9. The first side convex structure 91 and the second side convex structure 32 are staggered and sealed and abutted, and a first position of a closed flow-containing cavity 33 is formed, and a second position away from each other so that the flow-containing cavity 33 is opened;

[0048] In this embodiment, the first side convex structure 91 includes two first convexities along the radial direction, which are frame-shaped or ring-shaped as a whole. The second side convex structure 32 also includes two second convexities along the radial direction, which are frame-shaped or ring-shaped as a whole. A movable sealing member is provided on the second convexity relatively far away from the pump core 2 in the radial direction, which is staggered and abutted with the adjacent first convexity. A graphite ring is provided at the end of the second convexity relatively close to the pump core 2 in the radial direction, which can abut with the end of the adjacent first convexity.

[0049] The centrifugal wheel 3 is suitable for reciprocating between the first ring body 8 and the second ring body 9 under the axial force of the fluid, and switching between the first side convex structure 91 and the second side convex structure 32 between the first position and the second position.

[0050] Further preferably, the axial distance between the rim of the centrifugal wheel 3 and the side of the first ring body 8 facing the shaft cavity 14 is set to A, and the axial distance between the rim of the centrifugal wheel 3 and the inner wall of the flow cavity 33 facing the shaft cavity 14 is set to B, and B>A. As a convertible embodiment, the two can also be equal.

[0051] By such arrangement, the total fluid pressure on the side of the centrifugal wheel 3 axially away from the inlet 11 is greater than the total fluid pressure on the side close to the inlet 11, thereby providing the centrifugal wheel 3 with an axial resultant force pointing leftward in the diagram, dynamically balancing the fluid dynamic pressure on the centrifugal wheel 3 when the pump body is started, so that the rotor of the cryogenic centrifugal pump is always in a stable suspended state, eliminating the cryogenic pump dynamic sealing structure, and realizing a "leakage-free" design.

[0052] Furthermore, the impeller assembly also includes: an inducer 4, which is arranged on the pump core 2 and adjacent to the end of the pump core 2 close to the inlet 11. The inducer 4 is suitable for rotating under the drive of the pump core 2 and driving the low-temperature fluid to move toward the centrifugal wheel 3.

[0053] In addition, the cryogenic centrifugal pump further comprises an anti-wear layer 10, which is respectively arranged on the opposite sides of the stator body 6 and the rotor body 5, and is made of a low-temperature and wear-resistant non-metallic material, such as polytetrafluoroethylene.

[0054] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A cryogenic centrifugal pump, characterized in that: include: The housing (1) comprises an inlet (11) and an outlet (12) suitable for introducing a cryogenic fluid; A pump core (2) is inserted into the housing (1) and is provided with an impeller assembly; The drive structure comprises a rotor body (5) arranged on the pump core (2) and a stator body (6) arranged on the housing (1), wherein the rotor body (5) is arranged as a permanent magnet, and the armature winding built into the stator body (6) is arranged as a low-temperature superconductor, and the stator body (6) is suitable for connecting to an external power supply, and in a low-temperature environment, has a suspended working state in which it is spaced apart from and rotates relative to the rotor body (5), and the pump core (2) is suitable for driving the impeller assembly to rotate under the action of the drive structure, and driving the low-temperature fluid to flow from the inlet (11) to the outlet (12); A flow guide circuit (7) is arranged in the housing (1), passes through the gap between the stator body (6) and the rotor body (5), and is suitable for guiding low-temperature fluid under the action of the impeller assembly.

2. The cryogenic centrifugal pump according to claim 1, characterized in that: The housing (1) comprises: A main shell (13) is provided with an inlet (11) and an outlet (12), wherein the inlet (11) is provided at one end of the main shell (13), and the outlet (12) is provided on a side wall of the main shell (13); An axial cavity (14) is arranged in the main housing (13), and contains the pump core (2). A stator body (6) is correspondingly arranged on the inner side wall away from the inlet (11). One end of the axial cavity (14) along the axial direction is connected to the inlet (11), and the other end away from the inlet (11) is closed. The outlet cavity (15) is arranged to extend radially along the shaft cavity (14), is communicated with the shaft cavity (14) and the outlet port (12) respectively, and is correspondingly arranged between the inlet port (11) and the stator body (6), and contains at least a portion of the impeller assembly.

3. The cryogenic centrifugal pump according to claim 2, characterized in that: The flow guiding loop (7) comprises: A first flow path (71) is arranged between the housing (1) and the pump core (2), and extends from the inlet (11) to the outlet (12); A second flow path (72) is provided between the housing (1) and the pump core (2), and extends from the outlet (12) to a gap between the rotor body (5) and the stator body (6); The third flow path (73) is arranged in the pump core (2), one end of which leads to the side of the inlet (11), and the other end of which is adjacent to and communicates with the gap between the rotor body (5) and the stator body (6).

4. The cryogenic centrifugal pump according to claim 3, characterized in that: The flow guiding loop (7) further comprises: A lateral flow path (74) is arranged on the pump core (2), is connected to one end of the third flow path (73) facing the inlet (11), is extended in the radial direction of the pump core (2), and is connected to the first flow path (71).

5. The cryogenic centrifugal pump according to claim 3, characterized in that: The impeller assembly includes: The centrifugal wheel (3) is limitedly arranged on the pump core (2) and has an arc-shaped flow guide hole (31) built therein. The arc-shaped flow guide hole (31) is arranged on the first flow path (71), and its two ends are respectively oriented toward and connected to the inlet (11) and the outlet (12).

6. The cryogenic centrifugal pump according to claim 5, characterized in that: Also includes: The pressure regulating assembly is arranged on the inner wall of the outlet cavity (15), movably cooperates with the centrifugal wheel (3), and is suitable for regulating the axial pressure of the impeller assembly.

7. The cryogenic centrifugal pump according to claim 6, characterized in that: The voltage regulating assembly comprises: A first ring body (8) is arranged at the junction of the outlet cavity (15) and the shaft cavity (14), and is correspondingly arranged on the side of the centrifugal wheel (3) facing the inlet (11). The side of the first ring body (8) facing the shaft cavity (14) is rotatably connected to the centrifugal wheel (3), and the side of the first ring body (8) facing the outlet cavity (15) is spaced apart from the centrifugal wheel (3); A second ring body (9) is arranged on the inner wall of the outlet cavity (15) away from the first ring body (8), and a first side convex structure (91) is arranged on the side facing the centrifugal wheel (3), and a second side convex structure (32) is arranged on the side facing the second ring body (9), the first side convex structure (91) and the second side convex structure (32) having a first position in which the first side convex structure (91) and the second side convex structure (32) are in staggered sealing contact and form a closed flow-containing cavity (33), and a second position in which the first side convex structure (91) and the second side convex structure (32) are away from each other so that the flow-containing cavity (33) is open; The centrifugal wheel (3) is suitable for reciprocating between the first ring body (8) and the second ring body (9) under the axial force of the fluid, and the first side convex structure (91) and the second side convex structure (32) are converted between the first position and the second position.

8. The cryogenic centrifugal pump according to claim 7, characterized in that: The axial distance between the rim of the centrifugal wheel (3) and the side surface of the first ring body (8) facing the axial cavity (14) is set to A, and the axial distance between the rim of the centrifugal wheel (3) and the inner wall of the flow-containing cavity (33) facing the axial cavity (14) is set to B, and B>A.

9. The cryogenic centrifugal pump according to claim 5, characterized in that: The impeller assembly also includes: An inducer wheel (4) is arranged on the pump core (2) and is adjacent to the end of the pump core (2) close to the inlet (11). The inducer wheel (4) is suitable for rotating under the drive of the pump core (2) and driving the low-temperature fluid to move toward the centrifugal wheel (3).

10. The cryogenic centrifugal pump according to any one of claims 1-5 and 7-9, characterized in that: Also includes: The anti-wear layer (10) is respectively arranged on the opposite sides of the stator body (6) and the rotor body (5), and the anti-wear layer (10) is made of a low-temperature resistant and wear-resistant non-metallic material.

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