Parametric Optimization Design Method for Friction Plates of Hydro-Viscous Clutches

This study focused on design friction pace for hydro vascular scratch. Aim to achieve high tuck transmission while reducing oil film temperatures. Our study developed an optimization method, combining front assays and the response surface methodology for friction plate structure design.

The method is applicable to friction plate of various settings, offering versatility and efficiency. To begin, open the workbench workstation and drag the geometry from toolbox, component systems, and geometry into the project schematic area. Right click on the geometry select import geometry model to import the completed model, and click to edit the geometry model in space claim.

In the space claim toolbar, click on repair, then select additional edges and split edges to complete the repair, merging the affected split lines. Then click on design and selection, in selection. Select the inner surface of the model and click create NS in the group, naming it inlet.

Using the same process, click on the outer surface and name it outlet. Then click on the smooth lower wall surface and name it B as the wall surface, where the oil film contacts the passive friction pad. Select all unnamed surfaces and name them Z as the rotating wall surface where the oil film contacts the active friction pad.

Now, exit space claim and save the file to complete the pre-processing of the model. In the workbench workstation, drag fluent from toolbox component systems, and fluent into the project schematic area where the geometry has been added. Click on geometry and drag the mouse to the mesh in the fluent project to link its mesh module to the upstream data of the geometry.

Double click to open the mesh and select watertight geometry for mesh partitioning, then follow the workflow step-by-step to import the geometry model and add local sizing. Click generate surface mesh. Set the minimum size to 0.3 millimeters, the maximum size to eight millimeters, and the curvature norm angle to 10.

After setting these parameters, click generate the surface mesh. Check the surface mesh quality by right clicking on the generated surface mesh and selecting insert improved surface mesh quality. Set the minimum mesh quality to 0.7 and click okay to complete the improvement.

Click describe geometry model. Selecting the geometry model as consisting solely of a fluid region with no gaps, keeping other options at their defaults sequentially. Click describe geometry structure and update region type settings, maintaining the default settings and completing the process.

Click add boundary layer, selecting three for the number of layers while keeping other settings at their defaults. Click generate volume mesh and insert an improved volume mesh quality to ensure its quality exceeds 0.12. After generating the mesh, click switch to solution and wait for the mesh partitioning and import to the analysis module to complete.

Switch from mesh partitioning to solver mode. Once the mesh has finished loading, click on check in the general menu to validate the effectiveness of the finite element model, and check whether the mesh has any negative volume. Open the energy equation in the model settings.

Enter the viscous model settings interface. Select the laminar model and enable the viscous heating option. Modify the material parameters according to the properties of the two materials provided, adjusting the liquid material named air and the solid material named aluminum.

Click boundary conditions. Select the active friction pad wall surface, named Z.Click on momentum settings and set it as a rotating wall surface at 100 radians per second around the Y axis with a sheer condition of no slip. Click boundary conditions.

Select the passive friction pad wall surface, named B.Click on momentum settings and set it as a stationary wall surface with a sheer condition of no slip. Set the energy transfer related boundary conditions via system coupling. Next, set the outlet boundary conditions by selecting outlet, setting it to pressure outlet with a gauge pressure of zero.

Set the inlet boundary conditions by selecting inlet, setting it to velocity inlet with a flow velocity of one meter per second, and an inlet temperature of 30 degrees celsius. Click on the solution settings. Select the simplec algorithm for the solution method.

Choose the first order upwind format for momentum and energy and keep the residual values at default. Set the state of the computational domain at the initial moment with an initial temperature of 26 degrees Celsius, pressure of zero pascal, and zero velocity in the X, Y, and Z directions. Set the number of iterations to 300.

Click calculate and wait for the results. Once the calculations are complete, click results followed by reports and fluxes. Select mass flow rate and fluxes and check inlet and outlet values to ensure the error is less than 0.1%Analyze the results by clicking results, followed by reports and forces, selecting torque around the Y axis for wall surface B and interpret the viscous value as the sheer torque from the oil film.

Now, exit the fluid flow calculation module. Drag results from toolbox component systems and results into the project schematic where the simulation is complete. Then link the solution to the results module.

Enter the results, click on calculators, select function calculator to solve for the average temperature of the oil film, and click calculate to obtain the result. In design expert software, click on new design. Under response surface, select box Ben Ken to establish a three factor, two level optimization model.

Click on numeric factors to select three factors, the number of radial oil grooves in the friction pad, the depth of the grooves, and the arc length of the oil grooves. Then fill in the corresponding table. Enter the high and low level values obtained from the analysis of the three influencing factors into the corresponding table.

Set the center points per block to five, then click on the next step to change the response variables to two, which are the torque transmitted by the oil film and the average temperature of the oil film. Click finish to generate 17 sets of random sample points. Repeat the simulation analysis process to obtain the transmitted torque and average temperature of the oil film after recombination.

Merge the predicted variables A, B, and C of the three influence combinations with the simulated results to form a new variable table. Then select quadratic for the process order in the model. Choose polynomial for the model type and keep other settings that default.

After establishing the response surface model, calculate both torque and average temperature. Conduct an error analysis of the model by clicking on analysis of variants and analyzing R squared and adec precision values in fit statistics, to verify compliance with standards. Click on optimization, followed by numerical and criteria, keeping the ranges for the three influencing factors unchanged.

Then click solutions to find the maximum torque and minimum average temperature for the approximate values. Calculate the results for different arrays, labeling combination one as the optimal solution for the model. The modeling and simulation process identified and optimized friction plate groove parameters that significantly influence oil film temperature and transmitted torque.

The transmitted torque decreases as the number of radial oil grooves increases, but the average oil film temperature decreases accordingly. Similarly, increasing the groove depth arc length of radial grooves and number of circumferential oil grooves, caused a similar reduction in transmitted torque, and a marked decrease in average oil film temperature to different extents. Three representative groove structures produced distinct oil film temperature distributions, with notable differences in the outer ring's high temperature zones.

The response surface model for average oil film temperature and torque showed a good alignment between predicted and actual values. The interaction of radial groove number and groove depth produced a sloped surface for torque response, while the interaction of groove depth and arc length showed a steeper gradient. The interaction of radial groove number and groove depth created a gradual gradient in average oil film temperature, while groove depth and arc length interaction yielded a sharper color transition.