Development and validation of a CFD based optimization procedure for the design of torque converter cascade

Cheng Liu,Changle Xiang,Qingdong Yan,Wei Wei,Cori Watson,Houston G Wood

doi:10.1080/19942060.2018.1562383

Abstract

ABSTRACTTraditional one-dimensional (1D) design theory no longer satisfies modern torque converter design requirements due to the lack of accuracy and long trial-and-error process. A computational fluid dynamics (CFD) based optimization approach was brought forward. This study is devoted to two key processes in bringing CFD into torque converter design – blade parameterization/evaluation and optimization. A six-parameter blade camber line design method was employed to represent the blade shape. The blade profile was evaluated based on manufacturability considerations. A low-fidelity CFD model was developed for parameter study and optimization, and a high-fidelity CFD model considering the transient and cavitation effects was employed to evaluate the optimization outcome. The parameter sensitivity study was performed using design of experiment (DOE) technique and the variables were categorized into primary design variable, effective design variable and insignificant design variable groups. Optimization on the primary variables was carried out using the genetic algorithm. Two optimum solutions were evaluated with the transient full 3D CFD model and then tested. The optimum torque converters’ test results indicated significant performance improvement. The proposed design procedure can improve the design efficiency & accuracy and shorten the design cycle by the application of different CFD models in conjunction with an optimization algorithm.

Highlights

A torque converter is a fluid coupling device which transfers power through the interaction of moving fluids and cascades
Real optimization problems found in turbomachinery cascade design involve too many design variables and several performance objectives, which would require a tremendous amount of design evaluations to achieve the optimized solutions
This research is devoted to the application of a CFDbased optimization approach to torque converter cascade design, with particular focus on parameterization method and optimization procedure

Summary

Introduction

A torque converter is a fluid coupling device which transfers power through the interaction of moving fluids and cascades. Torque converters are widely used in vehicle transmissions and industrial power transmissions It consists of a pump, which is driven by a prime mover, a turbine, which is connect to the working machine and a stator, which is fixed to the transmission case (Liu, Liu, & Ma, 2015). Real optimization problems found in turbomachinery cascade design involve too many design variables and several performance objectives, which would require a tremendous amount of design evaluations to achieve the optimized solutions. The solution for this contradiction is clear: First the evaluation process must be sped up and second the number

Methods

Results

Conclusion