Cooling system to improve the heat dissipation efficiency of the motor embedded in the turbojet engine

Abstract

The present invention discloses a cooling system for improving the heat dissipation efficiency of an embedded motor in a turbojet engine, and belongs to the technical field of turbojet engines. The system comprises a stator casing, a compressor and a motor, wherein the stator of the motor is connected to the stator casing, a forced air inlet hole is provided at the front of the stator casing, and a plurality of air bleed grooves arranged along the axial direction of the motor are provided between the motor stator and the stator casing; the motor is located in the compressor cavity and has a first gap; a second gap is provided between the rotor and the stator of the motor; a third gap is provided between the stator casing and the compressor; the forced air inlet hole, the air bleed groove, the first gap, the second gap and the third gap are connected. Based on the principle of forced air intake and centrifugal effect, the heat exchange coefficient between the motor and the surrounding environment is increased, thereby improving the heat dissipation capacity of the motor system, timely discharging the heat generated by the motor when it is working, and increasing the working capacity and reliability of the motor.

Description

Technical Field

[0001] The invention relates to a motor cooling system, in particular to a cooling system for improving the heat dissipation efficiency of a motor embedded in a turbojet engine, and belongs to the technical field of turbojet engines. Background Art

[0002] At present, small turbojet engines have been widely used in the field of unmanned aerial vehicles. In the past, the power supply for the onboard equipment of unmanned aerial vehicles was provided by onboard batteries. With the continuous development of technology, more and more micro-turbojet engines are designed with power generation systems embedded in turbojet engines. This type of design is compact and more cost-effective than onboard batteries.

[0003] However, as a high-temperature and high-pressure working machine, the turbojet engine itself has high temperatures of various components when working, and the motor (starter motor / generator) also generates heat when working, and the heat generation is positively correlated with the motor power. In order to ensure the reliability and efficiency of the motor, it is very important to control the motor operating temperature within a certain range. At present, the motor embedded in the turbojet engine mainly adopts natural cooling, or designs a special oil circuit to cool the motor. The former has limited cooling efficiency, and the latter has a complex structure and high cost. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a turbojet engine embedded motor cooling system with strong heat dissipation capability and high cooling efficiency.

[0005] In order to solve the above technical problems, the present invention provides a cooling system for improving the heat dissipation efficiency of an embedded motor in a turbojet engine, comprising a stator casing, a compressor and a motor, wherein the stator of the motor is connected to the stator casing, a forced air inlet hole is provided at the front of the stator casing, and a plurality of air ducting grooves are provided along the axial direction of the motor between the motor stator and the stator casing;

[0006] The motor is located in the compressor cavity and has a first gap, wherein the first gap is an axial plus radial gap;

[0007] A second gap is provided between the rotor and the stator of the motor, and the second gap is a radial gap;

[0008] A third gap is provided between the stator casing and the compressor, and the third gap is an axial gap;

[0009] The forced air inlet hole, the air guide groove, the first gap, the second gap and the third gap are communicated with each other.

[0010] In the present invention, centrifugal cooling holes are provided between the blades of the compressor, and the centrifugal cooling holes are radially arranged in the hub of the compressor and communicate with the first gap.

[0011] In the present invention, the number of the centrifugal cooling holes is in multiple relation with the number of compressor blades.

[0012] In the present invention, the diameter of the centrifugal cooling hole is 1-5 mm.

[0013] In the present invention, the forced air inlet hole is a central hole and / or a plurality of air inlet holes distributed on the wall surface of the flow channel in the stator casing.

[0014] In the present invention, the diameter of the forced air inlet hole is 20%-80% of the outer diameter of the motor.

[0015] In the present invention, the angle between the forced air intake hole and the engine axis is between 0-45°.

[0016] In the present invention, radial grooves are provided on the surfaces opposite to the stator casing and the compressor to form a third gap.

[0017] In the present invention, the third gap is 0.3-1.5 mm.

[0018] In the present invention, the second gap is 2-20 mm.

[0019] The beneficial effects of the present invention are: (1) through the air flow channel composed of the third gap between the stator casing and the compressor rotor and the first gap, the second gap, the air duct, and the forced air inlet hole, based on the principle of forced air intake and centrifugal effect, the heat exchange coefficient between the motor and the surrounding environment is increased, thereby improving the heat dissipation capacity of the motor system, timely discharging the heat generated by the motor when it is working, and increasing the working capacity and reliability of the motor; (2) the use of the above cooling system can ensure that a higher power motor can be installed in the same structural size environment, and such improvement does not require changes to the main engine of the turbojet engine, and is applicable to a variety of compressor structures. , only the air intake system and the compressor need to be modified to maintain the integrity of the turbojet engine without increasing costs; (3) The cooling air is used as the air flow from the outside of the aircraft (i.e., the external open atmosphere). The air flow can be regarded as an infinite source and no other device is required to provide an air source. The cooling air used eventually enters the turbojet engine to participate in combustion, and will not cause power loss due to intake / exhaust losses in the engine; (4) The centrifugal cooling holes between the compressor blades can further enhance the heat dissipation efficiency; (5) The third gap is formed by the radial grooves arranged on the opposite sides of the stator casing and the compressor, which can significantly improve the centrifugal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 Schematic diagram of the cooling system structure for improving the heat dissipation efficiency of the embedded motor in the turbojet engine;

[0022] Figure 2 It is an enlarged view of some structures, (a) is a schematic diagram of the structure, (b) is the AA section view in Figure (a), and (c) is an enlarged view of part B in Figure (a);

[0023] Figure 3 This is a schematic diagram of the cooling system structure for improving the heat dissipation efficiency of the embedded motor in a turbojet engine according to Example 2;

[0024] Figure 4 This is a schematic diagram of the cooling system structure for improving the heat dissipation efficiency of the embedded motor in a turbojet engine in Example 3.

[0025] In the figure, 1-stator casing, 2-mounting seat, 3-motor, 4-compressor, 5-center hole, 6-air inlet hole, 7-mounting seat cavity, 8-air bleed groove, 9-axial gap, 10-centrifugal cooling hole, 11-compressor cavity, 12-rotating shaft. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions 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. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0029] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They 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 position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0030] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0031] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0033] Compared with the traditional small turbojet engine power generation system, the present invention designs a cooling system for improving the heat dissipation efficiency of the embedded motor of the turbojet engine based on the principles of forced air intake and centrifugal effect. The system can effectively realize the forced flow of air around the motor, thereby improving the heat dissipation efficiency of the motor and the surrounding environment, and providing a good working environment for the motor.

[0034] like Figure 1 and 2 As shown, the cooling system for improving the embedded electric heat dissipation efficiency of a turbojet engine provided in this embodiment includes a stator casing 1, a mounting seat 2, a motor 3 and a compressor 4.

[0035] The mounting seat 2 is mounted at the center of the stator casing 1 and is located on the axis of the turbojet engine. A forced air inlet hole is provided at the front end of the mounting seat 2, and the forced air inlet hole is connected to the mounting seat cavity 7. Due to the pressure difference, the incoming air from the aircraft can pass through the forced air inlet hole through the mounting seat cavity 7 and flow backward along the axial direction.

[0036] The mounting base 2 is made of aluminum alloy to ensure a good heat transfer coefficient.

[0037] The forced air inlet hole is a central hole 5 opened at the front of the mounting seat 2 and a varying number of air inlet holes 6 distributed on the wall surface of the flow passage in the stator casing 1. Of course, only the central hole 5 or a varying number of air inlet holes 6 distributed on the wall surface of the flow passage in the stator casing 1 can be used as the forced air inlet hole.

[0038] In this embodiment, the forced air inlet hole is in a circular shape, but in actual use, it can be in a square or other shapes as needed.

[0039] The angle between the forced air intake hole and the engine axis is between 0-45°. Within this angle range, the ratio of the airflow tangential velocity to the axial velocity can better meet the forced air intake cooling requirements.

[0040] The diameter of the forced air intake hole is usually 20%-80% of the outer diameter of the motor 3. The diameter of the forced air intake hole needs to be determined according to the amount of air intake, otherwise the engine intake loss is large, affecting efficiency.

[0041] In this embodiment, the mounting base 2 is used to mount the motor 3. The stator of the motor 3 is arranged on the mounting base 2, and the rotor of the motor 3 is arranged on the rotating shaft 12 of the turbojet engine. A gap is provided between the stator and the rotor of the motor 3, and the gap is usually between 0.1-2 mm. If the gap between the stator and the rotor of the motor 3 is too large, the working efficiency of the motor will be affected, that is, the magnetic field is too far away, and the efficiency of the motor cutting the magnetic induction line decreases; if the gap is too small, there is a risk of collision between the motor rotor and the stator.

[0042] As an alternative, the rotor of the electric motor 3 may also be directly connected to the compressor 4 .

[0043] On the mating surface of the mounting seat 2 and the stator of the motor 3, a plurality of air ducting grooves 8 are arranged along the axial direction of the motor 3, and the plurality of air ducting grooves 8 are evenly spaced along the circumferential direction. The air in the mounting seat cavity 7 flows through the air ducting grooves 8 from front to back to cool the outer ring of the motor 3.

[0044] A compressor cavity 11 is provided on the inner hub of the compressor 4 . The diameter of the compressor cavity 11 matches the outer diameter of the motor 3 . The motor 3 is axially arranged in the compressor cavity 11 .

[0045] A gap is provided between the compressor cavity 11 and the stator of the motor 3 in the axial direction, and the gap is usually 2-20 mm. The gap is arranged here according to the needs of the centrifugal cooling hole 10, and the size of the gap is determined by the amount of bleed air, the length of the shaft system, and the stress of the centrifugal cooling hole. If the gap is too large, on the one hand, it will cause high stress in the center hole of the compressor, and on the other hand, it will cause unnecessary growth of the shaft system, which is not worth the loss.

[0046] In this embodiment, the rotor of the compressor 4 is mounted on the rotating shaft 12 , and the rotor of the compressor 4 is located behind the mounting seat 2 and inside the stator casing 1 .

[0047] The mounting seat end face radial groove and the compressor end face radial groove are correspondingly arranged on the surface opposite to the mounting seat 2 and the compressor 4. The two opposite radial grooves form an axial gap 9, which is used to form a centrifugal effect in a small range when the compressor 4 rotates, and quickly discharge the air. Here, the size of the axial gap 9 is preferably 0.3-1.5mm. In this embodiment, a small gap is required to form the end face centrifugal effect. If the gap is too large, the effect of the centrifugal effect is weak, and if the gap is too small, there is a risk of collision between the compressor and the stator casing.

[0048] The compressor 4 is provided with centrifugal cooling holes 10 between the blades, and the number of the centrifugal cooling holes 10 is generally in multiple relation with the number of the blades. The diameter of the centrifugal cooling holes 10 is 1-5 mm, which is generally determined by combining the cooling gas volume and the size of the opening stress.

[0049] The centrifugal cooling hole 10 is radially arranged in the hub of the compressor 4 and axially arranged between the gap between the compressor cavity and the stator of the motor 3. The centrifugal cooling hole 10 radially connects the inner hub cavity of the compressor 4 and the inner flow channel of the compressor 4.

[0050] The centrifugal cooling holes 10 discharge air through the centrifugal effect and the difference between the forced intake pressure in the compressor cavity 11 and the pressure in the compressor flow channel, thereby achieving forced flow of air around the motor 3 .

[0051] The centrifugal cooling hole 10 is connected with the axial gap 9, the air ducting groove 8, and the gap between the stator and the rotor of the motor 3.

[0052] In this embodiment, the mounting seat 2 and the stator casing 1 are connected by assembly. In actual use, the mounting seat 2 and the stator casing 1 can also be integrally processed, that is, the stator casing 1 is directly provided with a corresponding mounting position of the motor.

[0053] During the operation of the turbojet engine, the rotating shaft 12 of the turbojet engine is connected to the compressor 4 through cooperation, thereby driving the compressor 4 to rotate and inhale the incoming air;

[0054] Air from the aircraft enters the mounting seat cavity 7 at the head of the stator casing 1 through the central hole 5 and the air inlet 6 of the mounting seat 2. A portion of the air in the mounting seat cavity 7 passes through the gap between the stator and the rotor of the motor 3 to cool the motor 3 and then enters the compressor 4 cavity.

[0055] Another part of the air in the mounting seat cavity 7 flows through the outer surface of the motor 3 through the air bleed groove 8 and then enters the axial gap 9 between the mounting seat 2 and the compressor 4;

[0056] Most of the air in the compressor cavity 11 is discharged radially outward through the centrifugal cooling holes 10 on the compressor 4 due to the centrifugal effect generated by the rotation of the compressor 4, and enters the inner flow channel of the compressor 4; a small part of the air enters the axial gap 9 between the mounting seat 2 and the compressor 4;

[0057] By evenly distributing radial grooves on the mounting seat end surface and radial grooves on the compressor end surface on the mounting seat 2 and the compressor 4 end surfaces respectively, a centrifugal effect is formed in a small range of the axial gap 9 between the mounting seat 2 and the compressor 4, and the air in the axial gap 9 between the mounting seat 2 and the compressor 4 is guided to be discharged into the flow channel; the air used for cooling the motor 3 is finally sucked into the engine by the compressor 4.

[0058] like Figure 3 As shown, the structure of the embodiment 2 is basically the same as that of the embodiment 1, and the centrifugal cooling hole 10 on the compressor 4 is cancelled in the embodiment 2. In this way, the air forced into the head of the aircraft is discharged through the centrifugal effect formed by the pressure difference and the axial gap 9 formed by the rotation of the compressor 4 and the end face of the stator casing 1, and forced heat dissipation can also be achieved. The heat dissipation amount is reduced compared with that of the embodiment 1, but the modification is simple, and this embodiment is suitable for a working environment with relatively small heat generation.

[0059] like Figure 4 As shown, Example 3 adopts the axial flow compressor 4 scheme based on Example 1 to indicate that this patent is applicable to various types of compressor structures.

[0060] The present invention improves the design of the stator casing and the compressor, and based on the principles of forced air intake and centrifugal effect, increases the heat exchange coefficient between the motor and the external environment, thereby increasing the heat dissipation of the motor per unit time, allowing a larger capacity motor to be arranged within the same environmental size and improving its working reliability.

[0061] The cooling system of the present invention for improving the heat dissipation efficiency of the embedded motor of a turbojet engine is suitable for different compressor structures, such as centrifugal compressors, axial flow compressors, etc.; and is adaptable to a variety of motors, such as inner rotor motors, outer rotor motors, disc motors, etc., and has good versatility.

[0062] The cooling air used in the design of the present invention is the air flowing from the outside of the aircraft (i.e., the outside open atmosphere). The airflow can be regarded as an unlimited source, and no other device is required to provide an air source. The cooling air used eventually enters the turbojet engine to participate in combustion, and will not cause power loss due to intake / exhaust loss of the engine. In the present invention, the forced intake and centrifugal effect structures can be used together or separately, and can also improve the heat dissipation capacity of the motor.

[0063] The present invention provides a cooling system for improving the heat dissipation efficiency of an embedded motor in a turbojet engine. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the protection scope of the present invention. All components not specified in this embodiment can be implemented using existing technologies.

Claims

1. A cooling system for improving the heat dissipation efficiency of an embedded motor in a turbojet engine, comprising a stator casing, a compressor and a motor, characterized in that: The stator of the motor is connected to the stator casing, a forced air inlet hole is provided at the front of the stator casing, and a plurality of air ducting grooves are provided along the axial direction of the motor between the motor stator and the stator casing; The motor is located in the compressor cavity and has a first gap, wherein the first gap is an axial plus radial gap; A second gap is provided between the rotor and the stator of the motor, and the second gap is a radial gap; A third gap is provided between the stator casing and the compressor, and the third gap is an axial gap; The forced air inlet hole, the air guide groove, the first gap, the second gap and the third gap are connected; Centrifugal cooling holes are provided between the blades of the compressor. The centrifugal cooling holes are radially arranged in the hub of the compressor and communicate with the first gap.

2. The cooling system for improving the heat dissipation efficiency of the built-in motor of a turbojet engine according to claim 1, characterized in that: The number of the centrifugal cooling holes is in multiple relation with the number of compressor blades.

3. The cooling system for improving the heat dissipation efficiency of the built-in motor of a turbojet engine according to claim 2, characterized in that: The centrifugal cooling hole has a diameter of 1-5 mm.

4. The cooling system for improving the heat dissipation efficiency of the built-in motor of a turbojet engine according to any one of claims 1 to 3, characterized in that: The forced air inlet hole is a central hole and / or a plurality of air inlet holes distributed on the wall surface of the flow channel in the stator casing.

5. The cooling system for improving the heat dissipation efficiency of the built-in motor of a turbojet engine according to claim 4, characterized in that: The diameter of the forced air inlet hole is 20%-80% of the outer diameter of the motor.

6. The cooling system for improving the heat dissipation efficiency of the built-in motor of a turbojet engine according to claim 4, characterized in that: The angle between the forced air intake hole and the engine axis is between 0-45°.

7. The cooling system for improving the heat dissipation efficiency of the built-in motor of a turbojet engine according to any one of claims 1 to 3, characterized in that: The stator casing and the compressor facing surface are both provided with radial grooves to form a third gap.

8. The cooling system for improving the heat dissipation efficiency of the built-in motor of a turbojet engine according to claim 7, characterized in that: The third gap is 0.3-1.5 mm.

9. The cooling system for improving the heat dissipation efficiency of an embedded motor in a turbojet engine according to any one of claims 1 to 3, characterized in that: The second gap is 2-20 mm.

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