Fluid Structure Interaction Investigation And Lightweight Optimization For Torque Converter

In order to investigate the blade pressure load and further achieve the goal of lightweight Optimization of torque converter,the flow pressure fluctuation induced structure deformation and vibration are still far from fully understood.In this research,the two way fluid-structure interaction（FSI）simulation and pressure-strain measuring experiment were adopted to s-tudy the relationship between the pressure instantaneous force and corresponding structure vibration respond.A two-way fluid-structure instantaneous simulation model for torque converter was built based on the dynamic mesh.The spring smoothing model was used as the method to dy-namically update the fluid grid.The geometrical shape of the fluid mesh element changed following the structure deformation and fitted the new fluid-structure boundary.Degree of freedom of structure and fluid-structure interfaces were set separately for the steel-stamping and aluminum-cast torque converter.The time step was calculated based on the interaction interval of rotor-stator phenomenon of the pump and turbine.The structure deformation and vibration,together with the fluid pressure fluctuation were acquired by the FSI simulations.Several monitor points were set at or near the location of maximum deformation,structure stress concentration and the highest fluid pressure,to record every instantaneous data in the whole simulation.Characters of fluid regime and struc-ture deformation has obvious variation at different speed ratio.The dominating frequency of fluid pressure fluctuation and structure vibration is same,corresponding to the flow-induced vibration in the torque converter.The dominating frequency shows a simple relationship with pump blade number,the speed ratio and the pump rotation speed:f _PT=Z_Pf _Pshaft（1-SR）.A method of stator blade surface pressure-strain measuring in a closed chamber of turbo-machinery was conducted in this paper.The time-averaged and spectral results in both time and frequency domains were validated.The structural lightweight optimization was performed base on the thickness parametric design and the fluid-structure interaction simulation.The relationship between the deforma-tion characters and the varying thickness ration was acquired.Several results obtained from the conduction of optimization design were check to ensure the performance of torque con-verter.