Ultrahigh-rotating-speed methane electric pump adopting internal flow regeneration cooling

Abstract

The invention discloses an ultrahigh-rotating-speed methane electric pump adopting internal flow regenerative cooling. The ultrahigh-rotating-speed methane electric pump comprises a turbine pump, a motor and a backflow pipe. The turbine pump comprises a flow guide pipe, a main impeller, a pump shell and a pump cover. The main impeller is rotationally arranged in the pump shell, a gap is reserved between the lower end of the main impeller and the bottom of the inner wall of the pump shell, and a plurality of backpressure blades are arranged on the lower end face of the main impeller. The motor comprises a shell, a cover, a main shaft, a stator and a rotor; a machine cover is arranged at the upper end of the machine shell, a first bearing seat with a first overflowing hole is arranged in the machine cover, a second bearing seat with a second overflowing hole is arranged in the machine shell, and the main shaft is in running fit with the first bearing seat and the second bearing seat. The backflow pipe is connected between the bottom of the machine shell and the flow guide pipe. According to the device, a same-working-medium internal flow regeneration cooling mode is adopted, so that a part of methane fluid pressurized by the turbine pump can flow to the motor to cool the motor and then flow back to the turbine pump, and the problem that the motor is seriously heated when working at a high rotating speed for a long time is effectively solved.

Description

Technical Field

[0001] The invention relates to the field of turbo pumps, and in particular to an ultra-high speed methane electric pump using internal flow regeneration cooling. Background Art

[0002] The turbopump in a liquid rocket engine is an important part of the propulsion system. Its main function is to extract propellants (such as liquid fuel and oxidizer) from the tank and pressurize them into the combustion chamber. The turbopump ensures the stable operation of the engine under high pressure by efficiently delivering propellants. Traditional turbopumps mainly use a high-speed rotating turbine to accelerate the liquid, allowing it to enter the diffuser or volute, converting kinetic energy into pressure energy, thereby increasing the pressure of the fluid. The turbine is usually powered by a small gas turbine driven by the burning propellant, so it has a complex gas turbine structure, especially the design and cooling of the gas generator and high-temperature components are more complicated.

[0003] At present, with the development of technology, in order to simplify the complexity of the engine system, improve the thrust-to-weight ratio and reduce costs, electric pumps (motor-driven turbo pumps) have gradually become an alternative, especially in small and medium thrust engines. The electric pump directly drives the pump impeller through the motor, eliminating the complex system of the gas turbine, with a simpler structure, less thermal management requirements (no high-temperature gas) and potential high reliability. Since there is no combustion process, the electric pump can avoid component wear and thermal management problems caused by high temperature.

[0004] However, in current electric pumps, the motor speed is relatively low. This is because long-term high-speed operation of the motor will cause motor overheating and temperature rise problems. In addition, under high-speed conditions, in order to ensure the sealing of the pump, electric pumps are usually designed with complex dynamic and static sealing structures, which in turn leads to poor pump reliability. Therefore, optimization and improvement are needed. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide an ultra-high speed methane electric pump using internal flow regenerative cooling.

[0006] The technical solution of the present invention is as follows: an ultra-high speed methane electric pump using internal flow regenerative cooling, characterized in that it includes a turbine pump, a motor and a return pipe;

[0007] The turbine pump comprises a guide pipe, a main impeller, a pump casing and a pump cover; the pump casing is a volute with axial inflow and radial outflow, the axial inflow end of the pump casing is the upper end, a pump cover is arranged at the upper end of the pump casing, a static seal is arranged between the pump casing and the pump cover, the upper end of the pump cover is provided with the introduction pipe, and the introduction pipe is communicated with the pump casing;

[0008] The main impeller is rotatably arranged in the pump housing, the main impeller is a turbine with axial inflow and radial outflow, the axial inflow end of the main impeller is the upper end, a dynamic seal is arranged between the circumferential edge of the upper end of the main impeller and the pump cover, a gap is left between the lower end of the main impeller and the bottom of the inner wall of the pump housing, and a plurality of back pressure blades are arranged on the lower end surface of the main impeller;

[0009] The motor comprises a casing, a cover, a main shaft, a stator and a rotor; the casing is provided with the cover at the upper end, a first bearing seat with a first flow hole is provided in the cover, a second bearing seat with a second flow hole is provided in the casing, the main shaft is rotatably matched with the first bearing seat and the second bearing seat respectively, the casing is provided with the stator, the main shaft is provided with the rotor, and a gap is left between the rotor and the stator;

[0010] A first shaft hole is provided at the bottom of the pump housing, a second shaft hole is provided at the top of the machine cover, the main shaft passes through the second shaft hole and the first shaft hole upward and is connected to the main impeller, a graphite floating ring is provided in the second shaft hole, and the graphite floating ring is sleeved on the main shaft;

[0011] The return pipe is connected between the bottom of the housing and the flow guide pipe.

[0012] Furthermore, an inducer is coaxially provided at the upper end of the main impeller and extends upward into the guide pipe.

[0013] Furthermore, a guide cone is coaxially provided on the upper end of the inducer.

[0014] Furthermore, the flow guide pipe is a pipeline component with low surface roughness and soft material.

[0015] Furthermore, the static seal and the dynamic seal are both labyrinth seals.

[0016] Furthermore, a first liquid collecting chamber is provided in the machine cover, and the first liquid collecting chamber is located on the upper side of the first bearing seat. A second liquid collecting chamber is provided at the bottom of the machine cover, and the second liquid collecting chamber is located on the lower side of the second bearing seat.

[0017] Furthermore, an outflow joint is provided at the bottom of the casing, a return joint is provided on the side wall of the flow guide pipe, and the flow guide pipe is connected between the outflow joint and the return joint.

[0018] Furthermore, an outlet flange pipe is provided in the radial direction of the pump housing, and a sealing ring is provided at the pipe opening of the outlet flange pipe.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This device adopts the same working fluid internal flow regeneration cooling method, which can make a part of the methane fluid after the turbo pump is pressurized flow to the motor to cool the motor, and then flow back to the turbo pump, effectively solving the problem of serious heating of the motor under long-term high-speed operation;

[0021] 2. The back of the main impeller of this device is provided with back pressure blades to form a back pressure liquid seal wheel, which can not only balance the axial force well, but also play the role of throttling and rectification;

[0022] 3. The dynamic and static sealing form of this device is simple, the complexity is low, the overall structure is simple and compact, and the reliability of use is high.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work:

[0025] Figure 1 It is an overall schematic diagram of the present invention;

[0026] Figure 2 yes Figure 1 Schematic cross-sectional view of AA in the figure;

[0027] Figure 3 yes Figure 2 Schematic diagram of the turbo pump part;

[0028] Figure 4 It is a front view of the main impeller part of the present invention;

[0029] Figure 5 yes Figure 4 Schematic cross-sectional view of AA in the figure;

[0030] Figure 6 It is a three-dimensional diagram of the main impeller part of the present invention;

[0031] Figure 7 yes Figure 2 Schematic diagram of the motor part;

[0032] Reference numerals:

[0033] 1. Turbine pump; 11. Guide pipe; 12. Main impeller; 13. Pump casing; 14. Pump cover; 15. Static seal; 16. Dynamic seal; 17. Back pressure blade; 18. Inducer; 19. Guide cone; 110. Return joint; 111. Outlet flange pipe;

[0034] 2. Motor; 21. Casing; 22. Cover; 23. Main shaft; 24. Stator; 25. Rotor; 26. First bearing seat; 27. Second bearing seat; 28. Graphite floating ring; 29. ​​First liquid collecting chamber; 210. Second liquid collecting chamber; 211. Outflow joint;

[0035] 3. Reflux pipe. DETAILED DESCRIPTION

[0036] 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. In the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", "vertical", "circumferential", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the description of the present invention, "first feature" and "second feature" may include one or more of the features. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0040] like Figure 1-Figure 5 An ultra-high speed methane electric pump using internal flow regenerative cooling is shown, comprising a turbine pump 1, a motor 2 and a return pipe 3.

[0041] The turbine pump 1 includes a guide tube 11, a main impeller 12, a pump casing 13 and a pump cover 14; the pump casing 13 is a volute with axial inflow and radial outflow, the axial inflow end of the pump casing 13 is the upper end, a pump cover 14 is provided at the upper end of the pump casing 13, and a static seal 15 is provided between the pump casing 13 and the pump cover 14, an introduction pipe is provided at the upper end of the pump cover 14, and the introduction pipe is communicated with the pump casing 13. The main impeller 12 is rotatably arranged in the pump casing 13, the main impeller 12 is a turbine with axial inflow and radial outflow, the axial inflow end of the main impeller 12 is the upper end, a dynamic seal 16 is provided between the upper circumferential edge of the main impeller 12 and the pump cover 14, a gap is left between the lower end of the main impeller 12 and the bottom of the inner wall of the pump casing 13, and a plurality of back pressure blades 17 are provided on the lower end surface of the main impeller 12.

[0042] That is to say, the turbine pump 1 is actually a centrifugal pump. In the field of centrifugal pumps, the distinction between axial and radial is based on the different directions of fluid movement. The axial direction refers to the flow of the fluid along the axis of the pump, while the radial direction refers to the direction in which the fluid diffuses out of the pump.

[0043] The motor 2 includes a casing 21, a cover 22, a main shaft 23, a stator 24 and a rotor 25; the casing 21 is provided with a cover 22 at the upper end, a first bearing seat 26 with a first flow hole is provided in the cover 22, a second bearing seat 27 with a second flow hole is provided in the casing 21, the main shaft 23 is rotatably matched with the first bearing seat 26 and the second bearing seat 27 respectively, a stator 24 is provided in the casing 21, a rotor 25 is provided on the main shaft 23, and a gap is left between the rotor 25 and the stator 24.

[0044] A first axial hole is provided at the bottom of the pump casing 13, and a second axial hole is provided at the top of the machine cover 22. The main shaft 23 passes upward through the second axial hole and the first axial hole and is connected to the main impeller 12. A graphite floating ring 28 is provided in the second axial hole, and the graphite floating ring 28 is sleeved on the main shaft 23; the return pipe 3 is connected between the bottom of the casing 21 and the guide pipe 11.

[0045] The working process of the device will be described below by taking methane as an example. Of course, those skilled in the art can also use the device for other fluids as required, and there is no limitation on this here.

[0046] The methane fluid first flows from the guide pipe 11 to the main impeller 12, which can reduce the pressure drop of the methane fluid before pressurization, and then flows from the main impeller 12 to the pump casing 13. When the main shaft 23 of the motor 2 rotates at a high speed, it can drive the main impeller 12 to rotate at a high speed, thereby pressurizing the methane fluid.

[0047] After being pressurized, part of the methane fluid will flow out directly through the radial direction of the pump housing 13, while the other part of the methane fluid will flow to the back of the main impeller 12 through the gap reserved between the main impeller 12 and the pump housing 13. Since a plurality of back pressure blades 17 are provided on the lower end surface of the main impeller 12, during the rotation of the main impeller 12, the back of the main impeller 12 will be equivalent to forming a back pressure liquid seal wheel, which will generate back pressure and dynamic sealing effects during the rotation process. The generated back pressure is completely opposite to the axial force caused by the impact and pressure of methane in the axial direction, and while offsetting the axial force, it can also throttle and rectify the methane fluid leaking downward.

[0048] The methane fluid flowing through the liquid seal wheel will continue to flow through the graphite floating ring 28 along the main shaft 23. In the pre-cooling state before the pump is started, the graphite floating ring 28 will play a static sealing role. After that, the methane fluid will flow through the first bearing seat 26 to flush, cool and lubricate the bearing on the first bearing seat 26, and then flow through the flow holes of the first bearing seat 26 to the gap between the stator 24 and the rotor 25 of the motor 2 to cool the working coil of the motor 2. Then the methane fluid will flow through the second bearing seat 27 to flush, cool and lubricate the bearing on the second bearing seat 27, and finally flow through the flow holes of the second bearing seat 27 to the bottom of the casing 21, and flow back to the guide pipe 11 through the return pipe 3 again, and start a new round of pressurization.

[0049] In this device, in order to ensure that the methane fluid does not leak or return to the upstream, the turbo pump 1 needs to have good sealing performance. Since there is no relative movement between the pump housing 13 and the pump cover 14, a static seal 15 is used to seal between the two. Since the main impeller 12 rotates during operation, there is relative movement between the main impeller 12 and the pump cover 14, so a dynamic seal 16 is used to seal between the main impeller 12 and the pump cover 14. After sealing, the methane fluid can only flow to the pump housing 13 after flowing out of the main impeller 12, and will not return to the upstream.

[0050] The static seal 15 and the dynamic seal 16 in the device are preferably labyrinth seals, which increase the length and tortuosity of the fluid leakage path by setting multiple tortuous channels, thereby improving the sealing effect. Compared with other sealing technologies, labyrinth seals have low costs, relatively simple structures, no complex mechanical parts, and are relatively easy to maintain and replace.

[0051] In a further configuration, the upper end of the main impeller 12 is coaxially provided with an inducer 18 extending upward into the guide tube 11, and the upper end of the inducer 18 is coaxially provided with a guide cone 19. As a result, the methane fluid will first flow through the guide cone 19 and the inducer 18, and then flow to the main impeller 12. After the methane fluid flows through the guide cone 19, the guide cone 19 provided helps to compress the cavitation in the local area of ​​the wheel rim, so as to improve the anti-cavitation performance of the inducer 18. After that, the fluid passes through the inducer 18 to increase the cavitation margin, which can prevent cavitation from occurring and increase the static pressure in front of the main impeller 12, thereby reducing the net positive suction pressure of the main impeller 12.

[0052] The guide pipe 11 used is a pipeline component with low surface roughness and relatively soft material, which can prevent the inducer 18 from rubbing against the pipe wall during rotation to generate sparks.

[0053] An outlet flange pipe 111 is provided in the radial direction of the pump housing 13 to facilitate connection with other pipelines. A sealing ring is also provided at the pipe opening of the outlet flange pipe 111 .

[0054] A first liquid collecting chamber 29 is provided in the machine cover 22, and the first liquid collecting chamber 29 is located on the upper side of the first bearing seat 26. A second liquid collecting chamber 210 is provided at the bottom of the machine cover 22, and the second liquid collecting chamber 210 is located on the lower side of the second bearing seat 27. The two liquid collecting chambers are conducive to the smooth flow of methane fluid.

[0055] An outflow joint 211 is provided at the bottom of the casing 21, a return joint 110 is provided on the side wall of the flow guide pipe 11, and the flow guide pipe 11 is connected between the outflow joint 211 and the return joint 110. The outflow joint 211 and the return joint 110 here can use common threaded joints.

[0056] In summary, this device has the following characteristics:

[0057] 1. This device adopts the same working fluid internal flow regeneration cooling method, which can make a part of the methane fluid after the turbo pump 1 is pressurized flow to the motor 2, cool the motor 2, and then flow back to the turbo pump 1, effectively solving the problem of serious heating of the motor 2 under long-term high-speed operation;

[0058] 2. The back of the main impeller 12 of the device is provided with a back pressure blade 17 to form a back pressure liquid seal wheel, which can not only balance the axial force well, but also play the role of throttling and rectification;

[0059] 3. The dynamic and static sealing form of this device is simple, the complexity is low, the overall structure is simple and compact, and the reliability of use is high.

[0060] Although a portion of the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations to these embodiments are within the scope of protection of the claims of the present invention without departing from the principles and purpose of the present invention.

Claims

1. An ultra-high speed methane electric pump using internal flow regenerative cooling, characterized in that: Includes a turbo pump, motor and return pipe; The turbine pump comprises a guide pipe, a main impeller, a pump casing and a pump cover; the pump casing is a volute with axial inflow and radial outflow, the axial inflow end of the pump casing is the upper end, a pump cover is arranged at the upper end of the pump casing, a static seal is arranged between the pump casing and the pump cover, the upper end of the pump cover is provided with the introduction pipe, and the introduction pipe is communicated with the pump casing; The main impeller is rotatably arranged in the pump housing, the main impeller is a turbine with axial inflow and radial outflow, the axial inflow end of the main impeller is the upper end, a dynamic seal is arranged between the circumferential edge of the upper end of the main impeller and the pump cover, a gap is left between the lower end of the main impeller and the bottom of the inner wall of the pump housing, and a plurality of back pressure blades are arranged on the lower end surface of the main impeller; The motor comprises a casing, a cover, a main shaft, a stator and a rotor; the casing is provided with the cover at the upper end, a first bearing seat with a first flow hole is provided in the cover, a second bearing seat with a second flow hole is provided in the casing, the main shaft is rotatably matched with the first bearing seat and the second bearing seat respectively, the casing is provided with the stator, the main shaft is provided with the rotor, and a gap is left between the rotor and the stator; A first shaft hole is provided at the bottom of the pump housing, a second shaft hole is provided at the top of the machine cover, the main shaft passes through the second shaft hole and the first shaft hole upward and is connected to the main impeller, a graphite floating ring is provided in the second shaft hole, and the graphite floating ring is sleeved on the main shaft; The return pipe is connected between the bottom of the housing and the flow guide pipe.

2. The ultra-high speed methane electric pump using internal flow regenerative cooling according to claim 1, characterized in that: An inducer is coaxially arranged at the upper end of the main impeller and extends upward into the guide pipe.

3. The ultra-high speed methane electric pump using internal flow regenerative cooling according to claim 2 is characterized in that: A guide cone is coaxially arranged on the upper end of the induction wheel.

4. The ultra-high speed methane electric pump using internal flow regenerative cooling according to claim 2, characterized in that: The flow guide pipe is a pipeline component with a rough surface and soft material.

5. The ultra-high speed methane electric pump using internal flow regenerative cooling according to claim 1, characterized in that: The static seal and the dynamic seal are both labyrinth seals.

6. The ultra-high speed methane electric pump using internal flow regenerative cooling according to claim 1, characterized in that: A first liquid collecting chamber is provided in the machine cover, and the first liquid collecting chamber is located on the upper side of the first bearing seat. A second liquid collecting chamber is provided at the bottom of the machine cover, and the second liquid collecting chamber is located on the lower side of the second bearing seat.

7. The ultra-high speed methane electric pump using internal flow regenerative cooling according to claim 1, characterized in that: An outflow joint is provided at the bottom of the casing, a return joint is provided on the side wall of the flow guide pipe, and the flow guide pipe is connected between the outflow joint and the return joint.

8. The ultra-high speed methane electric pump using internal flow regenerative cooling according to claim 1, characterized in that: An outlet flange pipe is provided in the radial direction of the pump housing, and a sealing ring is provided at the pipe opening of the outlet flange pipe.

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