阅读说明：本技术 一种具有表面微结构的物理屏蔽永磁电机 (Physical shielding permanent magnet motor with surface microstructure ) 是由 高莲莲 牛群 梁艳萍 于 2021-06-24 设计创作，主要内容包括：一种具有表面微结构的物理屏蔽永磁电机,解决了现有物理屏蔽永磁电机由于屏蔽套带来的过热的问题,属于电机领域。本发明包括定子和转子,定子上有定子屏蔽套,转子上有转子屏蔽套,定子屏蔽套和转子屏蔽套之间有气隙,所述气隙形成一次冷却水通道,且定子屏蔽套的气隙侧和转子屏蔽套的气隙侧均分布有仿生荷叶结构,作为一次冷却水通道的内壁,定子屏蔽套气隙侧的仿生荷叶结构的接触角大于转子屏蔽套气隙侧的仿生荷叶结构的接触角。本发明的物理屏蔽永磁电机在定转子屏蔽套中间通有一次冷却水,一次冷却水所在的通道具有荷叶仿生系统,可以避免狭窄的一次冷却水通道堵塞。(A physical shielding permanent magnet motor with a surface microstructure solves the problem that an existing physical shielding permanent magnet motor is overheated due to a shielding sleeve, and belongs to the field of motors. The bionic lotus leaf structure comprises a stator and a rotor, wherein a stator shielding sleeve is arranged on the stator, a rotor shielding sleeve is arranged on the rotor, an air gap is arranged between the stator shielding sleeve and the rotor shielding sleeve, a primary cooling water channel is formed by the air gap, the bionic lotus leaf structures are uniformly distributed on the air gap side of the stator shielding sleeve and the air gap side of the rotor shielding sleeve and serve as the inner wall of the primary cooling water channel, and the contact angle of the bionic lotus leaf structure on the air gap side of the stator shielding sleeve is larger than that of the bionic lotus leaf structure on the air gap side of the rotor shielding sleeve. The physical shielding permanent magnet motor is provided with primary cooling water in the middle of the stator and rotor shielding sleeves, and a channel where the primary cooling water is located is provided with a lotus leaf bionic system, so that the blockage of a narrow primary cooling water channel can be avoided.)

1. The utility model provides a physics shielding permanent-magnet machine with surface microstructure, physics shielding permanent-magnet machine includes stator and rotor, has stator shield (4) on the stator, has rotor shield (5) on the rotor, has the air gap between stator shield (4) and the rotor shield (5), its characterized in that, cooling water passageway (7) once are formed to the air gap, and the air gap side of stator shield (4) and the air gap side of rotor shield (5) equally divide cloth have bionical lotus leaf structure, as the inner wall of cooling water passageway (7) once, the contact angle of the lotus leaf bionic structure of stator shield (4) air gap side is greater than the bionical lotus leaf structure's of rotor shield (5) air gap side contact angle.

2. The physically shielded permanent magnet motor with the surface microstructure as claimed in claim 1, wherein the bionic lotus leaf structure on the air gap side of the rotor shielding sleeve (5) has a contact angle greater than 150 ° and less than 160 °, each mastoid on the bionic lotus leaf structure surface has a diameter of 10 to 12 microns, and the distance between mastoids is 10 microns;

the contact angle of the bionic lotus leaf structure at the air gap side of the stator shielding sleeve (4) is larger than 160 degrees, the diameter of each mastoid on the surface of the bionic lotus leaf structure is 5-7 microns, and the distance between the mastoids is 5 microns.

3. The physically shielded permanent magnet electric machine with surface microstructure of claim 2, characterized in that it further comprises an external heat exchanger (12);

the primary cooling water passage (7) further comprises a cooling water pipe which is respectively led out from the top end and the bottom end of the air gap and is communicated with the air gap, and an external heat exchanger (12) is arranged on the cooling water pipe.

4. The physically shielded permanent magnet motor with a surface microstructure according to claim 3, wherein a bend of the cooling water pipeline is provided with a bionic lotus leaf mastoid.

5. The physically shielded permanent magnet motor with the surface microstructure according to claim 4, wherein a secondary cooling water channel (11) is arranged on the outer wall of the stator, and the surface of the secondary cooling water channel adopts a V-shaped groove structure.

6. The physically shielded permanent magnet motor with surface microstructure as claimed in claim 4, wherein the height of the V-shaped groove structure is 25 to 28 microns, the spacing between the V-shaped grooves is 30 to 33 microns, and the inclination angle of the V-shaped grooves is 55 ° to 60 °.

7. The physically shielded permanent magnet motor with surface microstructure according to claim 6, wherein the secondary cooling water channel (11) is provided with a secondary cooling water outlet valve (13) and a secondary cooling water inlet valve (14) at the upper and lower parts thereof, respectively.

8. The physically shielded permanent magnet motor with surface microstructure as claimed in claim 1, wherein the physically shielded permanent magnet motor is an internal rotor structure, the rotor comprises a rotating shaft (8), a rotor core (9), a rotor shielding sleeve (5) and an even number of permanent magnets (6);

the rotor iron core (9) is arranged on the outer surface of the rotating shaft (8), an even number of permanent magnets (6) are distributed on the outer surface of the rotor iron core (9), and the rotor shielding sleeve (5) is arranged on the outer surface of the permanent magnets (6).

9. The physically shielded permanent magnet motor with surface microstructure according to claim 6, characterized in that the stator comprises a stator winding (1), a stator core (2), stator slots (3), a stator shielding sleeve (4) and a stator frame (10); the stator core (2) is arranged on the outer surface of the stator shielding sleeve (4), the stator core (2) is provided with a stator slot (3), a stator winding (1) is arranged in the stator slot (3), the stator base (10) is arranged on the outer surface of the stator core (2), and the outer wall of the stator base (10) is provided with a secondary cooling water channel (11).

10. The physically shielded permanent magnet motor with the surface microstructure according to claim 1, wherein the air gap sides of the stator shielding sleeve (4) and the rotor shielding sleeve (5) are made of stainless steel materials, the stainless steel materials are processed by electrodeposition, a nickel film with a micro-nano structure is formed on the surface of the stainless steel materials by electrodeposition to serve as an intermediate coating, and then the nickel film is used as a catalyst to construct a micro-nano bionic lotus leaf structure on the intermediate coating by a chemical vapor deposition method; the secondary cooling water channel (11) is made of stainless steel materials, and the surface of the stainless steel is polished and ultrasonically cleaned by laser processing, so that a V-shaped groove structure is obtained.

Technical Field

The invention relates to a physical shielding permanent magnet motor with a surface microstructure, and belongs to the field of motors.

Background

The physically shielded permanent magnet motor is a key power device in chemical and aerospace systems, and is mainly used for conveying radioactive and corrosive media. Due to the particularity of the working environment of the physically shielded permanent magnet motor, a stator shielding sleeve and a rotor shielding sleeve are required to be added on two sides of an air gap respectively. The shielding sleeve is a special structural member of the physical shielding permanent magnet motor and is made of an alloy steel material with corrosion resistance and higher hardness. The conductivity of the corrosion-resistant alloy steel is lower, so that the shield sleeve inevitably generates eddy current loss under the action of an air gap rotating magnetic field, the shield sleeve loss of the physical shielding permanent magnet motor accounts for 50% of the total loss, and the shield sleeve loss is used as a main heat source of the physical shielding permanent magnet motor, so that the heat load of the physical shielding permanent magnet motor is greatly increased. The stator shielding sleeve and the rotor shielding sleeve on two sides of the air gap divide the physical shielding permanent magnet motor into two parts, so that heat generated by copper windings in the stator slot is remained in a cavity divided by the stator shielding sleeve, and the heat dissipation effect is poor. The stator shielding sleeve and the rotor shielding sleeve occupy the space of the air gap, so that the narrow air gap becomes smaller.

Disclosure of Invention

Aiming at the problem of overheating of the conventional physical shielding permanent magnet motor caused by a shielding sleeve, the invention provides a physical shielding permanent magnet motor with a surface microstructure.

The invention relates to a physical shielding permanent magnet motor with a surface microstructure, which comprises a stator and a rotor, wherein a stator shielding sleeve 4 is arranged on the stator, a rotor shielding sleeve 5 is arranged on the rotor, an air gap is arranged between the stator shielding sleeve 4 and the rotor shielding sleeve 5, a primary cooling water channel 7 is formed by the air gap, a bionic lotus leaf structure is distributed on the air gap side of the stator shielding sleeve 4 and the air gap side of the rotor shielding sleeve 5 to serve as the inner wall of the primary cooling water channel 7, and the contact angle of the bionic lotus leaf structure on the air gap side of the stator shielding sleeve 4 is larger than that of the bionic lotus leaf structure on the air gap side of the rotor shielding sleeve 5.

Preferably, the contact angle of the bionic lotus leaf structure at the air gap side of the rotor shielding sleeve 5 is more than 150 degrees and less than 160 degrees, the diameter of each mastoid on the surface of the bionic lotus leaf structure is 10 to 12 microns, and the distance between the mastoid and the mastoid is 10 microns;

the contact angle of the bionic lotus leaf structure at the air gap side of the stator shielding sleeve 4 is larger than 160 degrees, the diameter of each mastoid on the surface of the bionic lotus leaf structure is between 5 and 7 micrometers, and the distance between the mastoids is 5 micrometers.

Preferably, the physically shielded permanent magnet electric machine further comprises an external heat exchanger 12;

the primary cooling water passage 7 further includes a cooling water pipe led out from and communicated with the top and bottom ends of the air gap, respectively, and an exterior heat exchanger 12 is provided on the cooling water pipe.

Preferably, the bionic lotus leaf mastoid is arranged at the corner of the cooling water pipeline.

Preferably, a secondary cooling water channel 11 is arranged on the outer wall of the stator, and the surface of the secondary cooling water channel adopts a V-shaped groove structure.

Preferably, the height of the V-shaped groove structure is between 25 and 28 micrometers, the distance between the V-shaped grooves and the V-shaped grooves is between 30 and 33 micrometers, and the inclination angle of the V-shaped grooves is between 55 and 60 degrees.

Preferably, the upper and lower portions of the secondary cooling water passage 11 are provided with a secondary cooling water outlet valve 13 and a secondary cooling water inlet valve 14, respectively.

Preferably, the physical shielding permanent magnet motor is an inner rotor structure, and the rotor comprises a rotating shaft 8, a rotor iron core 9, a rotor shielding sleeve 5 and an even number of permanent magnets 6;

the rotor iron core 9 is arranged on the outer surface of the rotating shaft 8, the even number of permanent magnets 6 are distributed on the outer surface of the rotor iron core 9, and the rotor shielding sleeve 5 is arranged on the outer surface of the permanent magnets 6.

Preferably, the stator comprises a stator winding 1, a stator core 2, stator slots 3, a stator shielding sleeve 4 and a stator frame 10; the stator iron core 2 is arranged on the outer surface of the stator shielding sleeve 4, the stator iron core 2 is provided with a stator slot 3, a stator winding 1 is arranged in the stator slot 3, the stator base 10 is arranged on the outer surface of the stator iron core 2, and the outer wall of the stator base 10 is provided with a secondary cooling water channel 11.

Preferably, the air gap sides of the stator shielding sleeve 4 and the rotor shielding sleeve 5 are made of stainless steel materials, the stainless steel materials are processed in an electrodeposition mode, a nickel film with a micro-nano structure is formed on the surface of the stainless steel materials through electrodeposition to serve as an intermediate coating, and then the nickel film is used as a catalyst to construct a micro-nano bionic lotus leaf structure on the intermediate coating through a chemical vapor deposition method; the secondary cooling water channel 11 is made of stainless steel materials, and the surface of the stainless steel is polished and ultrasonically cleaned by laser processing, so that a V-shaped groove structure is obtained.

The physical shielding permanent magnet motor has the beneficial effects that the primary cooling water is introduced into the middle of the stator and rotor shielding sleeves, and the channel where the primary cooling water is located is provided with the lotus leaf bionic system, so that the blockage of the narrow primary cooling water channel can be avoided. The secondary cooling water channel is arranged on the outer side of the shell and adopts a V-shaped groove structure, the flow path of the secondary cooling water is advection, and based on the principle of groove resistance reduction, the resistance of the flow of the secondary cooling water can be reduced, the pressure of an external heat exchanger is reduced, and the service life of the external heat exchanger is prolonged.

Drawings

FIG. 1 is a circumferential cross-sectional view of a physically shielded permanent magnet electric machine of the present invention;

FIG. 2 is a circumferential detail cross-sectional view of a physically shielded permanent magnet electric machine of the present invention;

FIG. 3 is a sectional view taken along line A-A of FIG. 1;

FIG. 4 is a schematic view of a bionic lotus leaf structure at the air gap side of the stator shielding sleeve 4 in the invention;

FIG. 5 is a schematic view of a bionic lotus leaf structure on the air gap side of a rotor shield 5 according to the present invention;

FIG. 6 is a detail view of the surface of the secondary cooling water passage of the present invention;

FIG. 7 is a minimum unit diagram of the V-groove structure of the present invention;

FIG. 8 is a diagram of a minimum unit of a bionic lotus leaf structure at the air gap side of a rotor shield 5 according to the present invention;

fig. 9 is a minimum unit diagram of a bionic lotus leaf structure at the air gap side of the stator shielding sleeve 4 in the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.

In the physical shielding permanent magnet motor with the surface microstructure, an air gap is formed between a stator shielding sleeve 4 and a rotor shielding sleeve 5 to form a primary cooling water channel 7, bionic lotus leaf structures are distributed on the air gap side of the stator shielding sleeve 4 and the air gap side of the rotor shielding sleeve 5 to serve as the inner wall of the primary cooling water channel 7, and the contact angle of the bionic lotus leaf structure on the air gap side of the stator shielding sleeve 4 is larger than that of the bionic lotus leaf structure on the air gap side of the rotor shielding sleeve 5;

the secondary cooling water channel 11 can be arranged on the outer wall of the stator, the surface of the secondary cooling water channel adopts a V-shaped groove structure, the height of the V-shaped groove structure is 25-28 micrometers, the distance between the V-shaped grooves is 30-33 micrometers, and the inclination angle of the V-shaped grooves is 55-60 degrees.

The physical shielding permanent magnet motor of the embodiment comprises a stator winding 1, a stator iron core 2, a stator slot 3, a stator shielding sleeve 4, a rotor shielding sleeve 5, a permanent magnet 6, a primary cooling water channel 7, a rotating shaft 8, a rotor iron core 9, a secondary cooling water channel 11, a stator base 10, an external heat exchanger 12, a secondary cooling water outlet valve 13 and a secondary cooling water inlet valve 14;

a stator core is arranged in the stator base, the stator shielding sleeve is arranged on the inner wall of the stator core, an even number of permanent magnets which are uniformly distributed are arranged on the inner wall of the rotor shielding sleeve, a rotor core is arranged on the inner wall of the permanent magnets, and a rotating shaft is arranged on the inner wall of the rotor core;

the primary cooling water passage 7 further includes a cooling water pipe led out from and communicated with the top and bottom ends of the air gap, respectively, and an exterior heat exchanger 12 is provided on the cooling water pipe.

The turning of the cooling water pipeline is provided with a bionic lotus leaf mastoid, so that the uniform heat dissipation effect is ensured.

The upper and lower portions of the secondary cooling water passage 11 of the present embodiment are provided with a secondary cooling water outlet valve 13 and a secondary cooling water inlet valve 14, respectively.

In the embodiment, the air gap sides of the stator shielding sleeve 4 and the rotor shielding sleeve 5 are made of stainless steel materials, the stainless steel materials are processed by electrodeposition, a nickel film with a micro-nano structure is formed on the surface of the stainless steel materials by electrodeposition to serve as an intermediate coating, and then the nickel film is used as a catalyst to construct a micro-nano bionic lotus leaf structure on the intermediate coating by a chemical vapor deposition method. In this embodiment, the secondary cooling water channel 11 is made of a stainless steel material, and a laser processing method is adopted for the stainless steel material, and the surface of the stainless steel is firstly polished and ultrasonically cleaned, laser parameters are adjusted, the surface of the stainless steel is processed, and finally the surface of the stainless steel is ultrasonically cleaned, so that a V-shaped groove structure is obtained.

The principle of optimizing the heat dissipation of the V-shaped groove structure is explained below, a flow direction vortex is generated in the process of converting the laminar flow to the turbulent flow, and the change of the position of the flow direction vortex reduces the viscous resistance, and meanwhile, as the secondary cooling water channel adopts the V-shaped groove structure, a secondary vortex is generated, as shown in fig. 8. The existence of the secondary vortex enables the surface area of the groove in contact with the high-speed fluid to be smaller, so that the shearing force of the wall surface is reduced, and the resistance reduction is realized.

Only when the surface of the groove is turbulent, the obvious drag reduction effect can be achieved, namely the Reynolds number is ensured to be more than 4000. In order to ensure that the fluid state of the secondary cooling water pipeline is turbulent, the Reynolds number needs to be calculated. For liquid flowing in a pipeline, the Reynolds number is calculated by the following formula:

where ρ is the density of water, v is the incoming flow velocity, μ_dThe kinematic viscosity of water and the hydraulic diameter are d, and the calculation formula is as follows:

wherein A is the cross-sectional area in the water flow direction, and P is the cross-sectional perimeter.

The initial turbulence intensity calculation formula is as follows:

I＝0.16(Re)^-1/8

the initial turbulent kinetic energy calculation formula is as follows:

where m is the mass flow rate.

The initial turbulent dissipation ratio calculation formula is as follows:

C_μ＝0.09

l＝0.07L

wherein, C_μThe empirical constants specified in the turbulence model are L the turbulence scale and L the pipe diameter.

Assuming that the average velocity of the water flow in the secondary cooling water channel is between 10.7m/s and 22.2m/s, i.e. the mass flow rate is in the range of 0.00089kg/s-0.00316kg/s, the average velocity of 10.7m/s is substituted into the formula to obtain the Reynolds number of 7120, i.e. the turbulence model in this case.

Aiming at the very complex motion characteristic of turbulent motion, a Reynolds average N-S equation is selected for solving, and the equation is

Wherein the content of the first and second substances,is the time-averaged value of the turbulent velocity,in order to be the reynolds stress tensor,is the pressure.

Introducing variablesCoefficient of diffusionSource item Can be taken as different variables, substituted thereinAnd the diffusion coefficient and the source term are taken as proper expressions, so that a general expression form of the control equation can be obtained:

by performing finite volume discretization on the above equation, the equation can be written as:

integrating the above formula in Δ t and Δ x, and after dispersion, the equation is:

obtaining the shear stress tau on the grid node according to the Newton's law of internal friction_W(ii) a And integrating the shear stress of each node on the whole groove surface to obtain the total shear stress:

F＝∫τ_WdA

and then according to the total shear stress, solving the friction coefficient of the smooth surface as follows:

and the coefficient of friction resistance of the groove surface is as follows:

wherein, F_s，F_gTotal shear stress, A, for smooth and grooved surfaces, respectively_s,A_gRespectively, the cross-sectional areas of the smooth surface and the groove surface.

The drag reduction ratio thus obtained was:

the V-shaped groove drag reduction rate is 3.177-4.155% under the condition that the flow speed of cooling water is 10.7-22.2 m/s according to calculation.

The Knoop number is obtained from empirical formula

Wherein P is_rThe values are the prandtl number, and μ f and μ W are the dynamic viscosity.

Further, the convection heat transfer coefficient is obtained as follows:

where λ is the thermal conductivity of water and α is the convective heat transfer coefficient.

Respectively substituting the data of the smooth plane and the V-shaped groove surface to obtain that the convection heat transfer coefficient of the smooth surface is 2013.66W/(m)²The convection heat transfer coefficient of the V-shaped groove surface is 2234.67W/(m)²And the temperature is lowered, and the heat dissipation condition of the motor can be really improved by adopting the V-shaped groove through theoretical calculation.

The reasonable design of the V-shaped groove shape has an important influence on the heat dissipation of a cooling system, and experiments prove that the V-shaped groove on the surface of the secondary cooling water channel has the height of 25-28 micrometers, the distance between the grooves is 30-33 micrometers, and the heat dissipation effect is the best when the inclination angle of the grooves is 55-60 degrees.

The principle of optimizing heat dissipation of the bionic lotus leaf structure is explained below, when fluid flows through the super-hydrophobic surface, due to the existence of surface tension, gas retained at the micro-nano structure cannot be taken away, the gas-liquid contact generates a vortex pad effect, so that the fluid speed of a boundary layer slides, the near-wall surface boundary layer is stabilized, the resistance reduction effect is achieved, and meanwhile, the apparent contact angle can be expressed as

cosθ_c＝f₁ cosθ₁+f₂ cosθ₂

Wherein, theta_cIs an apparent contact angle, f₁ f₂Expressed as the area fraction of the liquid-solid and gas-liquid interfaces, θ, respectively₁And theta₂Expressed as intrinsic contact angles of the liquid-solid and gas-liquid interfaces, respectively.

The contact angle of the bionic lotus leaf structure can affect the surface hydrophobicity, so that the drag reduction rate and the convective heat transfer coefficient are affected, the larger the contact angle is, the better the hydrophobic effect is, in order to balance the water flow rates at two sides of a primary cooling water channel, through relevant experimental verification, the contact angle of the bionic lotus leaf structure at the air gap side of the rotor shielding sleeve 5 is larger than 150 degrees and smaller than 160 degrees, the diameter of each mastoid on the surface of the bionic lotus leaf structure is between 10 and 12 micrometers, and the distance between the mastoid and the mastoid is 10 micrometers; the contact angle of the bionic lotus leaf structure at the air gap side of the stator shielding sleeve 4 is larger than 160 degrees, the diameter of each mastoid on the surface of the bionic lotus leaf structure is between 5 and 7 micrometers, the distance between the mastoid and the mastoid is 5 micrometers, and in order to ensure that the contact angle of the bionic lotus leaf structure close to the stator shielding sleeve side is larger than 160 degrees, the average diameter of the mastoid on the surface of the bionic lotus leaf structure is required to be ensured to be between 5 and 7 micrometers, the average distance between the mastoid and the mastoid is 5 micrometers, the minimum unit of the bionic lotus leaf structure close to the rotor shielding sleeve side is shown in figure 8, and the minimum unit of the bionic lotus leaf structure close to the stator shielding sleeve side is shown in figure 9.

The cooling water cooling system can effectively cool the stator and rotor shielding sleeves and the permanent magnet, takes away heat on the stator and rotor shielding sleeves and the permanent magnet, simultaneously can avoid pipeline blockage caused by cooling water impurity deposition, improves the problem of uneven heat dissipation of a primary cooling water channel, reduces resistance of flowing of cooling water, enhances the heat dissipation effect of a physical shielding permanent magnet motor cooling system, and reduces operation and maintenance cost.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.