An automotive electronic water pump thermal management calculation method

Abstract

The present application relates to the technical field of automobile electronic water pump, specifically to a kind of automobile electronic water pump thermal management calculation method, comprising the following steps: establishing complete electronic water pump model;Based on the geometric model processed, division body grid, the surface definition interaction surface between the cooling liquid drainage area, air drainage area and each solid domain;Activate heat transfer model, define motor core heat generation, copper wire winding heat generation, electronic component heat generation;Start heat transfer calculation, monitor the temperature change of motor, component one point or multiple points, after temperature value is stable, according to whether temperature exceeds maximum allowable limit to decide whether the temperature of electronic water pump meets the requirements.The present application can calculate the water pump head, cooling liquid flow into the isolating sleeve, overall temperature distribution and the like under different temperature, different speed, different flow conditions.Both can help design engineers to carry out optimization in electronic water pump design stage, and can make up the limitation of measurement means in sample stage.

Description

Technical Field

[0001] This invention relates to the field of automotive electronic water pump technology, specifically to a thermal management calculation method for automotive electronic water pumps. Background Technology

[0002] Currently, electronic water pumps, as the power component of water circulation, cooling, or water supply systems, are widely used in new energy vehicles, charging guns, charging piles, and are gradually replacing mechanical water pumps in gasoline-powered vehicles. Electronic water pumps are facing increasingly smaller size requirements, higher efficiency requirements, power ranging from a few watts to several kilowatts, and voltage ranging from 12V to 800V. This presents an increasing challenge to the heat dissipation of the motor and control components, as high temperatures can degrade motor performance, cause component failure, or even burn out. Therefore, comprehensive thermal management of electronic water pumps, effectively utilizing water-side cooling to achieve efficient heat dissipation for the motor and controller, is essential.

[0003] An electronic water pump mainly consists of three parts: controller components, motor stator and rotor assembly, hydraulic impeller and volute, and inlet and outlet water pipes. An isolation sleeve is often designed between the motor stator and rotor to isolate the coolant. Heat sources include the motor's copper windings and various heat-generating components in the electronic control system. Heat is carried away internally by the coolant and externally by the casing. Heat from the controller is transferred to the isolation sleeve via thermally conductive adhesive and then carried away by the coolant; alternatively, it is transferred to the casing via air and then dissipated into the environment. While the coolant is crucial for carrying away heat from the motor and components, the amount flowing into the isolation sleeve cannot be excessive. Too much coolant will affect the pump's hydraulic efficiency, while too little will not remove enough heat. Furthermore, the coolant must be evenly distributed; otherwise, it may lead to localized overheating of the motor or controller. Only by comprehensively considering the flow domain, solid domain, and heat exchange of the electronic water pump can a high-efficiency and reliable electronic water pump product be designed. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a calculation method for thermal management of automotive electronic water pumps.

[0005] The technical problem to be solved by this invention is achieved by the following technical solution:

[0006] A method for calculating the thermal management of an automotive electronic water pump includes the following steps:

[0007] Step (1) Establish a complete electronic water pump model, close the rotating impeller flow domain, close the coolant region, and close the air region;

[0008] Step (2) Based on the processed geometric model, the volume mesh is generated, and the interaction surfaces connecting the coolant flow domain, air flow domain and each solid domain are defined;

[0009] Step (3) Define the density, viscosity, specific heat, and thermal conductivity of the coolant and air, and define the density and thermal conductivity of the solid.

[0010] Step (4) Define three boundary conditions for the coolant region;

[0011] Step (5) First, conduct flow analysis on the fluid region, especially the coolant region. After the calculation is completed, check the head, flow field distribution, pressure distribution, flow rate into the motor isolation sleeve and its proportion of the total flow rate.

[0012] Step (6) Activate the heat transfer model and define the heat generation of the motor core, the heat generation of the copper wire winding, and the heat generation of the electronic control components;

[0013] Step (7) Start heat transfer calculation, monitor the temperature change of one or more points of the motor and components, and after the temperature value stabilizes, determine whether the temperature of the electronic water pump meets the requirements based on whether the temperature exceeds the maximum allowable limit.

[0014] Preferably, the model in step (1) includes an axially stacked stator silicon steel sheet solid model, an axially stacked rotor silicon steel sheet solid model, a copper wire winding solid model, an overall controller circuit board model, and a connection pin model.

[0015] Preferably, the viscosity of the coolant in step (3) is 0.89 mPa·s and the density is 1034.77 kg / m³. 3 Its specific heat is 3532 J / kg·K and its thermal conductivity is 0.413 W / m·K.

[0016] Preferably, the viscosity of air in step (3) is 1.855e. -5 mPa·s, density 1.18 kg / m³ 3 Its specific heat is 1004 J / kg·K and its thermal conductivity is 0.026 W / m·K.

[0017] Preferably, the solid in step (3) includes aluminum, copper, plastic, silicone, steel, printed circuit board, and component packaging.

[0018] Preferably, the density of aluminum is 2702 kg / m³. 3 Specific heat is 903 J / kg·K, thermal conductivity is 152 W / m·K; density of copper is 8940 kg / m³. 3 Specific heat is 386 J / kg·K, thermal conductivity is 398 W / m·K; density of plastic is 1650 kg / m³. 3 Specific heat is 1500 J / kg·K, thermal conductivity is 0.3 W / m·K; density of silica gel is 2329 kg / m³. 3Specific heat is 702 J / kg·K, thermal conductivity is 3.5 W / m·K; density of steel is 8055 kg / m³. 3 Specific heat is 480 J / kg·K, thermal conductivity is 15.1 W / m·K; density of printed circuit board is 33 kg / m³. 3 Specific heat is 37 J / kg·K; thermal conductivity is 15 W / m·K in the circumferential direction and 1 W / m·K in the layer direction; the density of the component package is 5765 kg / m³. 3 Its specific heat is 213 J / kg·K and its thermal conductivity is 4.5 W / m·K.

[0019] Preferably, the three boundary conditions in step (4) are: the inlet is defined as a pressure boundary, given atmospheric pressure or measured pressure at the inlet; the outlet is defined as a negative flow rate, indicating that the coolant flows out from the outlet; the impeller rotation region is defined as a dynamic reference system model MRF, and then the rotation axis, rotation center point and rotation speed are defined.

[0020] Preferably, the head requirement in step (5) is close to the head requirement of the water pump.

[0021] Preferably, in step (6), the heat generation of the motor core and the heat generation of the copper wire winding are calculated by the motor magnetic circuit method or the finite element method, and the heat generation of the electronic control components is calculated by multiplying the maximum allowable current of the component by the square of the resistance.

[0022] Preferably, if the limit is exceeded in step (7), the arrangement of components, distribution, thickness, material selection, and flow rate of coolant flowing into the isolation sleeve need to be optimized. After optimization, return to step (1) to recalculate until the temperature of the electronic water pump is lower than the limit.

[0023] The beneficial effects of this invention are:

[0024] This invention can comprehensively obtain the flow field distribution and temperature field distribution of an electronic water pump, and can calculate the pump head, coolant flow rate into the isolation sleeve, and overall temperature distribution under different temperatures, speeds, and flow rates. It can help design engineers optimize electronic water pumps during the design phase and overcome the limitations of measurement methods at the prototype stage. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0026] Figure 1 This is a flowchart of the present invention;

[0027] Figure 2 This is a schematic diagram of the coolant flow area;

[0028] Figure 3 This is a schematic diagram of an airflow area.

[0029] Figure 4 This is a cross-sectional view of an electronic water pump;

[0030] Figure 5 This is a cross-sectional view of the pump casing area;

[0031] Figure 6 This is a diagram showing the coolant flow rate distribution.

[0032] Figure 7 This is a diagram showing the heat transfer coefficient distribution of the coolant near the wall.

[0033] Figure 8 Temperature distribution diagram of electronic control components;

[0034] Figure 9 This is a temperature distribution diagram of the motor. Detailed Implementation

[0035] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] A thermal management calculation method for an automotive electronic water pump, the steps of which are as follows: Figure 1 As shown. Includes the following steps:

[0037] Step (1) Establish a complete electronic water pump model. The rotating impeller flow domain needs to be closed, the entire coolant region needs to be closed, and the entire air region needs to be closed. Simplify the axially stacked stator silicon steel sheets into a solid model; simplify the axially stacked rotor silicon steel sheets into a solid model; simplify the copper wire windings of each slot of the motor stator into a solid model; simplify the controller circuit board into a single model, retaining the main heat-generating components and the connection pin models between the heat-generating components and the circuit board. Ensure that the coordinate system is consistent between the coolant flow domain, the air flow domain, and the connection surfaces of each solid domain. Figure 2 This is an example of a coolant flow domain model. Figure 3 This is an example of an airflow basin model. Figure 4 Example of a cross-sectional view of an electric water pump.

[0038] Step (2) involves creating a volume mesh based on the processed geometric model. Interaction surfaces are defined to connect the coolant flow domain, air flow domain, and each solid domain. When performing calculations using commercial fluid dynamics software, mass, velocity, and energy can be transferred between these interaction surfaces.

[0039] Step (3) Define the density, viscosity, specific heat, and thermal conductivity of the coolant and air; define the density and thermal conductivity of each solid. See Table 1 and Table 2 for examples.

[0040] Table 1. Coolant and Air Properties

[0041] Material Viscosity (mPa·s) <![CDATA[Density kg / m 3 > Specific heat J / kg.K Thermal conductivity W / mK coolant 0.89 1034.77 3532 0.413 Air <![CDATA[1.855e- 5 ]]> 1.18 1004 0.026

[0042] Table 2 Material Properties of Various Components of the Electronic Water Pump

[0043]

[0044]

[0045] Step (4) For the coolant region, three main boundary conditions need to be defined: First, the inlet is defined as a pressure boundary, given atmospheric pressure or the measured pressure at the inlet; second, the outlet is defined as a negative flow rate, indicating that the coolant flows out from the outlet; third, the impeller rotation region is defined as a moving reference frame model, i.e., Moving Reference Frame, abbreviated as MRF, and then the rotation axis, rotation center point, and rotation speed are defined. The impeller rotation direction and inlet / outlet positions are as follows. Figure 4 , Figure 5 For example, the import and export boundaries are shown in Table 3.

[0046] Table 3 Inlet and outlet boundaries of coolant flow range for electronic water pumps

[0047] Part boundary numerical values import Pressure [pa] 101325 exit Volumetric flow rate [L / min] 200 Pump impeller area Rotational speed [rpm] 5250

[0048] Step (5) First, perform flow analysis on the fluid region, especially the coolant region. After the calculation is completed, check the head, flow field distribution, pressure distribution, flow rate into the motor isolation sleeve, and its proportion of the total flow rate. The head should be close to the required head of the water pump; otherwise, check the accuracy of the model or calculation boundary. The flow velocity distribution and the near-wall heat transfer coefficient distribution of the coolant are as follows: Figure 6 , Figure 7 Example.

[0049] Step (6) Activate the heat transfer model and define the heat generation of the motor core, the copper wire winding, and the electrical control components. The heat generation of the motor core and the copper wire winding can be calculated using the motor magnetic circuit method or the finite element method; the heat generation of the electrical control components can be obtained by multiplying the maximum allowable current of each component by the square of its resistance.

[0050] Step (7) begins the heat transfer calculation, monitoring the temperature changes at one or more points on the motor and components. Once the value stabilizes, the calculation is considered converged. The overall temperature distribution of the motor and components is then checked. The temperature of the electronic water pump is determined based on whether it exceeds the maximum allowable limit. If it does, optimization is needed for the component arrangement, the distribution and thickness of the thermal conductive adhesive, material selection, and the flow rate of the coolant flowing into the isolation sleeve. After optimization, the calculation is restarted from step 1 until the electronic water pump temperature is below the limit. The controller's calculated temperature distribution and the motor's calculated temperature distribution are shown below the limit. Figure 8 , Figure 9 Example.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely prisms of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An automotive electronic water pump thermal management calculation method, characterized by: The method comprises the following steps: Step (1) to establish a complete electronic water pump model, close the rotating impeller flow field, close the cooling liquid area, close the air area; Step (2) to divide the body grid based on the processed geometric model, and define the interaction surface between the cooling liquid flow field, the air flow field and the surface connecting each solid domain; Step (3) to define the density, viscosity, specific heat, thermal conductivity of the cooling liquid and air, and to define the density and thermal conductivity of the solid; Step (4) to define three boundary conditions for the cooling liquid area; Step (5) to first carry out flow analysis on the fluid area, especially the cooling liquid area, and after the calculation is completed, to check the head, flow field distribution, pressure distribution, flow rate of the cooling liquid flowing into the motor isolation sleeve and the proportion of the total flow rate; Step (6) to activate the heat transfer model, and to define the heat generation of the motor core, the heat generation of the copper wire winding and the heat generation of the electronic control components; Step (7) to start heat transfer calculation, monitor the temperature change of one or more points of the motor and components, and after the temperature value is stable, to determine whether the temperature of the electronic water pump meets the requirements according to whether the temperature exceeds the maximum allowable limit.

2. The method of claim 1, wherein: The model in step (1) comprises an axially superimposed stator silicon steel sheet solid model, an axially superimposed rotor silicon steel sheet solid model, a copper wire winding solid model, a controller circuit board integral model and a connecting pin model.

3. The method of claim 1, wherein: The viscosity of the coolant in step (3) was 0.89 mPa.s, the density was 1034.77 kg / m 3 , the specific heat was 3532 J / kg.K, and the thermal conductivity was 0.413 W / m.K.

4. The automotive electronic water pump thermal management calculation method of claim 1, wherein: The viscosity of air in step (3) is 1.855e -5 mPa.s, the density is 1.18 kg / m 3 , the specific heat is 1004 J / kg.K, and the thermal conductivity is 0.026 W / m.K.

5. The automotive electronic water pump thermal management calculation method of claim 1, wherein: The solid in step (3) comprises aluminum, copper, plastic, silica gel, steel, printed circuit board and component packaging.

6. The automotive electronic water pump thermal management calculation method of claim 5, wherein: Aluminum has a density of 2702 kg / m 3 , a specific heat of 903 J / kg.K and a thermal conductivity of 152 W / m.K; copper has a density of 8940 kg / m 3 , a specific heat of 386 J / kg.K and a thermal conductivity of 398 W / m.K; plastic has a density of 1650 kg / m 3 , a specific heat of 1500 J / kg.K and a thermal conductivity of 0.3 W / m.K; silica gel has a density of 2329 kg / m 3 , a specific heat of 702 J / kg.K and a thermal conductivity of 3.5 W / m.K; steel has a density of 8055 kg / m 3 , a specific heat of 480 J / kg.K and a thermal conductivity of 15.1 W / m.K; printed circuit board has a density of 33 kg / m 3 , a specific heat of 37 J / kg.K and a thermal conductivity of 15 W / m.K in the circumferential direction and 1 W / m.K in the thickness direction; component packaging has a density of 5765 kg / m 3 , a specific heat of 213 J / kg.K and a thermal conductivity of 4.5 W / m.K.

7. The method of claim 1, wherein: The three boundary conditions in step (4) are: the inlet is defined as a pressure boundary, and the atmospheric pressure or the measured pressure at the inlet is given; the outlet is defined as a negative flow rate, indicating that the cooling liquid flows out from the outlet; and the rotating area of the impeller is defined as a moving reference system model MRF, and the rotating shaft, rotating center point and rotating speed are defined.

8. The automotive electronic water pump thermal management calculation method of claim 1, wherein: In step (5), the head requirement is close to the required head of the water pump.

9. The automotive electronic water pump thermal management calculation method of claim 1, wherein: In step (6), the heat generation of the motor core and the heat generation of the copper wire winding are calculated by the motor magnetic circuit method or the finite element method, and the heat generation of the electronic control components is calculated by multiplying the maximum allowable current of the components by the square of the resistance.

10. The method of claim 1, wherein: In step (7), if the limit value is exceeded, the arrangement of the components, the distribution, thickness and material selection of the heat-conducting glue, and the flow rate of the cooling liquid flowing into the isolation sleeve need to be optimized, and after the optimization is completed, the calculation is returned to step (1) until the temperature of the electronic water pump is lower than the limit value.

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