A method for optimizing bearing box cooling structure based on Fluent

Abstract

The application discloses a kind of based on Fluent to the method for optimizing bearing box cooling structure, comprising the following steps: 1) determine bearing box cooling structure parameter;2) establish cooling structure model, cooling structure model is imported ANSYA;3) division fluid domain, solid domain, while setting water inlet and water outlet, they are respectively named separately;4) carry out mesh division;5) establish heat transfer model, while determining wall surface thermal boundary;6) set boundary condition;7) solution;8) post-processing statistics;9) modify bearing box cooling structure parameter repeat step 2)-8);10) repeat step 9) several times, obtain cooling structure best parameter.The application utilizes Fluent software simulation simulation, by observing cooling liquid from water inlet into, after turning back from water outlet, observe the temperature distribution of entire temperature field, provide guidance for bearing box cooling structure optimization design, can improve efficiency, reduce cost.

Description

Technical Field

[0001] This invention belongs to the field of bearing housing cooling structure design technology, specifically relating to a method for optimizing bearing housing cooling structure based on Fluent. Background Technology

[0002] A bearing housing is a box-shaped component that supports and lubricates bearings. It often needs to maintain high speed, high precision, and long service life in harsh environments. The high temperature generated by the high-speed rotation of the bearing can cause the grease inside the housing to fail and the bearing to seize. Therefore, the cooling of the bearing housing is extremely important. Different cooling circuit structures have different cooling effects. Therefore, when designing the cooling structure of the bearing housing, the influence of various parameters must be considered comprehensively. However, conventional experimental methods will result in high time and economic costs. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a Fluent-based method for optimizing bearing housing cooling structures that is easy to operate, improves the efficiency of bearing housing cooling structure optimization, and reduces costs.

[0004] The technical solution adopted in this invention is: a method for optimizing the cooling structure of a bearing housing based on Fluent, comprising the following steps:

[0005] Step 1: Determine the cooling structure parameters of the bearing housing.

[0006] Step 2: Model the cooling structure of the bearing housing using modeling software to obtain the cooling structure model, and then import the cooling structure model into ANSYS;

[0007] Step 3: Divide the cooling structure model into fluid and solid domains, set inlet and outlet water inlets, and name the relevant components;

[0008] Step 4: Mesh the cooling structure model and check if the mesh quality meets the requirements;

[0009] Step 5: Establish a heat transfer model for the cooling structure model, and simultaneously determine the wall thermal boundary for the cooling structure model;

[0010] Step 6: Select the turbulence model based on the Reynolds number of the coolant, calculate the convective heat transfer coefficient h between the coolant and the bearing housing, open the energy equation, and set the fluid and solid material conditions, as well as the boundary conditions for the region, inlet, outlet, and wall.

[0011] Step 7: Create a new calculation monitoring, display the report file, initialize the cooling structure model and set the transient iterative calculation; solve; determine whether the calculation has converged. If the calculation residual is lower than the set value or the index in the report definition tends to be stable, it means that the calculation has converged and proceed to the next step; otherwise, it means that it has not converged and return to step 6.

[0012] Step 8: Enter CFD-Post post-processing and observe the temperature distribution of the entire temperature field as the coolant enters from the inlet, flows through the cooling channel, passes through the annular channel, and flows out from the outlet.

[0013] Step 9: Based on the temperature distribution of the temperature field in Step 8, the temperature of the coolant will rise every time it undergoes a return. The temperature difference between the inlet and outlet is compared.

[0014] Step 10: Modify the bearing housing cooling structure parameters, and repeat steps 2-9 after modification;

[0015] Step 11: Repeat step 10 several times and compare the data from multiple simulation analyses of the cooling structure model to obtain the optimal parameters of the cooling structure.

[0016] Furthermore, the bearing housing cooling structure parameters in step 1 include the inlet size, outlet size, number of inlets, number of outlets, and shape of the cooling circuit.

[0017] Furthermore, in step 3, first create the Surf edge surface; then select the fill command, choose face as the extraction type, and extract the required fluid domain, while the remaining area is the solid domain.

[0018] Furthermore, in step 4, the cooling structure model is first imported into Fluent Meshing. Depending on the complexity of the cooling structure model, local dimensions are selected for different regions. Minimum and maximum dimensions are set to generate surface meshes. The geometry is described as consisting of fluid and solid regions. The label type is used to update the boundary layer. Regions are created based on the number of extracted fluid domains. The number of boundary layers is related to the Reynolds number Re. Finally, the volume mesh is generated, and the final mesh quality is checked to see if it meets the requirements. The element quality check range is 0 to 1, with the closer to 1 indicating better element quality.

[0019] Furthermore, heat transfer occurs through three methods: conduction, convection, and radiation. Here, the coolant cools the bearing housing via convection. Using the wall as the convection condition, Fluent calculates the wall heat flux using the following formula:

[0020] q = h f (T W -T f )+q rad

[0021] =h ext (T ext -T W );

[0022] Where: h f T is the local heat transfer coefficient on the fluid side;W The temperature on the wall surface; T f q represents the temperature of the fluid adjacent to the wall. rad h is the radiative heat flux. ext T is the specified external convective heat transfer coefficient. ext The specified external temperature.

[0023] Furthermore, in step 6, the convective heat transfer coefficient h between the coolant and the bearing housing is calculated using the following formula:

[0024]

[0025] Where: N ur λ is the Nusselt number; λ is the thermal conductivity of the coolant; r is the pipe radius of the cooling structure; during the cooling process, the inlet is set as the velocity inlet and the outlet is set as the pressure outlet, which is the standard atmospheric pressure.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention, based on research into bearing housing cooling structures in actual production, uses finite element simulation software to simulate the cooling effects of different bearing housing structures, such as the size and number of inlet and outlet ports, and the shape of the internal cooling circuit. The transient thermal analysis module of Fluent in Workbench is used for temperature field simulation analysis. Before simulation analysis, material properties need to be defined, including density, elastic modulus, Poisson's ratio, coefficient of thermal expansion, specific heat capacity, and thermal conductivity. The convective heat transfer coefficient h is calculated based on similarity theory in heat transfer, and the Reynolds number of the coolant is used for judgment. The simulated flow state is turbulent flow to ensure that the simulation results are close to reality. The process of coolant entering the bearing housing is simulated, and the temperature distribution of the entire temperature field is monitored. According to the monitoring report, the temperature rise varies with each return flow of the coolant. The ratio of the temperature difference between the inlet and outlet is used to evaluate the quality of the cooling structure. This invention can significantly reduce the time and cost required for experiments and improve the optimization efficiency of bearing housing cooling structures. Attached Figure Description

[0028] Figure 1 This is the overall flowchart of the present invention.

[0029] Figure 2 This is a structural diagram of a cooling circuit with a pair of inlet and outlet water ports for a bearing housing.

[0030] Figure 3 This is a temperature distribution diagram of a pair of inlet and outlet cooling structures in a bearing housing.

[0031] Figure 4 This is a structural diagram of the cooling circuit with two pairs of inlet and outlet water ports for the bearing housing.

[0032] Figure 5 This is a temperature distribution diagram of the two pairs of inlet and outlet cooling structures of the bearing housing.

[0033] Figure 6 This is a structural diagram of the cooling circuit with three pairs of inlet and outlet water ports for the bearing housing.

[0034] Figure 7 This is a temperature distribution diagram of the three pairs of inlet and outlet water cooling structures of the bearing housing. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the accompanying drawings.

[0036] Taking the optimization of the cooling structure of a certain bearing housing as an example, the cooling structure of the bearing housing is as follows: Figure 2 As shown, the inlet 1 and outlet 2 are both circular with a radius of 6.5mm. The cooling circuit is a serpentine circuit, and there is one inlet 1 and one outlet 2.

[0037] like Figure 1 As shown, it includes the following steps:

[0038] Step 1: Determine the cooling structure parameters of the bearing housing. The cooling structure parameters of the bearing housing include the inlet size, outlet size, number of inlets, number of outlets, and shape of the cooling circuit.

[0039] Step 2: Model the bearing housing cooling structure using modeling software such as SolidWorks (or Pro / E, etc.) to obtain the cooling structure model, and then import the cooling structure model into ANSYS;

[0040] Step 3: Use Design Modeler to divide the cooling structure model into fluid and solid domains, set the inlet and outlet, and name the relevant components. The specific steps are as follows: First, create the Surf edge surface, i.e., the inlet and outlet surfaces. Then, use the fill command, selecting "by face" as the extraction type, to extract the required fluid domain; the remaining area is the solid domain.

[0041] Step 4: Mesh the cooling structure model using Fluent Meshing and check if the mesh quality meets the requirements. The specific steps are as follows: First, import the cooling structure model into Fluent Meshing. Depending on the complexity of the cooling structure model, select whether to add local dimensions for different regions. Set minimum and maximum dimensions to generate surface meshes. Describe the geometry as consisting of fluid and solid regions. Use the label type to update the boundary layers. Create regions based on the number of extracted fluid domains. The number of boundary layers is related to the Reynolds number (Re), typically 3 layers. Finally, perform volume mesh generation and check if the final mesh quality meets the requirements. The element quality check range is 0 to 1; the closer to 1, the better the element quality.

[0042] Step 5: Establish a heat transfer model for the cooling structure model, and simultaneously determine the wall thermal boundaries for the cooling structure model. Heat transfer occurs through three methods: conduction, convection, and radiation. Here, the coolant cools the bearing housing through convection. The wall is selected as the convection condition. Fluent uses the following formula to calculate the wall heat flux:

[0043] q = h f (T W -T f )+q rad

[0044] =h ext (T ext -T W );

[0045] Where: h f T is the local heat transfer coefficient on the fluid side; W The temperature on the wall surface; T f q represents the temperature of the fluid adjacent to the wall. rad h is the radiative heat flux. ext T is the specified external convective heat transfer coefficient. ext The specified external temperature.

[0046] Step 6: Select a turbulence model based on the Reynolds number of the coolant, calculate the convective heat transfer coefficient h between the coolant and the bearing housing, open the energy equation, and set the fluid and solid material conditions, as well as the boundary conditions for the inlet, outlet, and wall. The convective heat transfer coefficient h between the coolant and the bearing housing is calculated using the following formula:

[0047]

[0048] Where: N ur λ is the Nusselt number; λ is the thermal conductivity of the coolant; r is the pipe radius of the cooling structure; during the cooling process, the inlet is set as the velocity inlet and the outlet is set as the pressure outlet, which is the standard atmospheric pressure.

[0049] Step 7: Create a new calculation monitoring file, display the report file, initialize the model and set transient iterative calculation, and solve it; determine whether the calculation has converged. If the calculation residual is lower than the set value or the index in the report definition tends to be stable, it means that the calculation has converged and proceed to the next step; otherwise, it means that it has not converged and return to step 6.

[0050] Step 8: After entering the CFD-Post post-processing stage, observe the temperature distribution of the coolant as it enters from the inlet, flows through the cooling channel, passes through the annular channel, and exits from the outlet. The results are as follows. Figure 3 As shown.

[0051] Step 9: Based on the temperature distribution of the temperature field in Step 8, the temperature of the coolant will rise every time it undergoes a return. The temperature difference ratio between the inlet and outlet is compared.

[0052] Step 10: Modify the bearing housing cooling structure parameters, and repeat steps 2-9 after modification;

[0053] Step 11: Repeat step 10 several times and compare the data from multiple simulation analyses of the cooling structure model to obtain the optimal parameters of the cooling structure.

Claims

1. A method for optimizing the cooling structure of a bearing housing based on Fluent, comprising the following steps: Step 1: Determine the cooling structure parameters of the bearing housing. Step 2: Model the cooling structure of the bearing housing using modeling software to obtain the cooling structure model, and then import the cooling structure model into ANSYS; Step 3: Divide the cooling structure model into fluid and solid domains, set inlet and outlet water inlets, and name the relevant components; Step 4: Mesh the cooling structure model and check if the mesh quality meets the requirements; Step 5: Establish a heat transfer model for the cooling structure model, and simultaneously determine the wall thermal boundary for the cooling structure model; Step 6: Select the turbulence model based on the Reynolds number of the coolant, calculate the convective heat transfer coefficient h between the coolant and the bearing housing, open the energy equation, and set the fluid and solid material conditions, as well as the boundary conditions for the region, inlet, outlet, and wall. Step 7: Create a new calculation monitoring, display the report file, initialize the cooling structure model and set the transient iterative calculation; solve; determine whether the calculation has converged. If the calculation residual is lower than the set value or the index in the report definition tends to be stable, it means that the calculation has converged and proceed to the next step. Conversely, if the convergence is not achieved, return to step 6; Step 8: Enter CFD-Post post-processing and observe the temperature distribution of the entire temperature field as the coolant enters from the inlet, flows through the cooling channel, passes through the annular channel, and flows out from the outlet. Step 9: Based on the temperature distribution of the temperature field in Step 8, the temperature of the coolant will rise every time it undergoes a return. The temperature difference between the inlet and outlet is compared. Step 10: Modify the bearing housing cooling structure parameters, and repeat steps 2-9 after modification; Step 11: Repeat step 10 several times and compare the data from multiple simulation analyses of the cooling structure model to obtain the optimal parameters of the cooling structure.

2. According to claim 1, the method for optimizing the cooling structure of the bearing housing based on Fluent, the cooling structure parameters of the bearing housing in step 1 include the inlet size, outlet size, number of inlets, number of outlets, and shape of the cooling circuit.

3. According to the method for optimizing the cooling structure of the bearing housing based on Fluent as described in claim 1, in step 3, a Surf edge surface is first created, and then the fill command is selected, with the extraction type set to face, to extract the required fluid domain, and the remaining area is the solid domain.

4. In the method for optimizing the cooling structure of bearing housing based on Fluent according to claim 1, in step 4, the cooling structure model is first imported into Fluent Meshing. Depending on the complexity of the cooling structure model, local dimensions are selected for different regions. Minimum and maximum dimensions are set to generate surface meshes. The geometry is described as consisting of fluid and solid regions. The label type is used to update the boundary layer. Regions are created based on the number of extracted fluid domains. The number of boundary layers is related to the Reynolds number Re. Finally, the volume mesh is generated, and the final mesh quality is checked to see if it meets the requirements. The element quality check range is 0~1, and the closer to 1, the better the element quality.

5. In the method for optimizing the cooling structure of the bearing housing based on Fluent according to claim 1, in step 5, the heat transfer methods include the following three types: heat conduction, heat convection, and heat radiation. Here, the coolant cools the bearing housing through heat convection, and the wall surface is selected as the convection condition. Fluent uses the following formula to calculate the heat flux of the wall surface: ； In the formula: The local heat transfer coefficient on the fluid side; The temperature on the wall surface; The temperature of the fluid adjacent to the wall; For radiative heat flux; The specified external convective heat transfer coefficient; The specified external temperature.

6. In the method for optimizing the cooling structure of the bearing housing based on Fluent according to claim 1, in step 6, the convective heat transfer coefficient h between the coolant and the bearing housing is calculated by the following formula: ； In the formula: For Nuschelt numbers; The thermal conductivity of the coolant; The radius of the cooling pipe is denoted as . During the cooling process, the inlet is set as the velocity inlet, the outlet is set as the pressure outlet, and the outlet pressure is set to standard atmospheric pressure.

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