Computational Fluid Dynamics in Torque Converters: Validation and Application

Abstract

This article describes some of the computational fluid dynamics (CFD) work being done on three-element torque converters using a commercially available package CFX TASCflow. The article details some of the work done to validate CFD results and gives examples of ways in which CFD is used in the torque-converter design process. Based on the validation study, it is shown that CFD can be used as a design and analysis tool to make decisions about design direction. Use of CFD in torque converters is a developing field. Thus, more work needs to be done before the requirement of hardware to validate designs can be fully eliminated. This article demonstrates the confidence level in torque converter CFD and demonstrates how it can be used to assist torqueconverter design today. Analyzing fluid flow within a torque converter using computational fluid dynamics (CFD) is a developing field. The close coupling of the elements in a torque converter and the fact that it is a closed-loop turbomachine give rise to complicated flows within a torque converter. The flow is threedimensional, and secondary flows are present. To improve the The authors thank Don Maddock, manager of the Advanced Torque Converter Group at GM Powertrain, for his support and direction. Appreciation also goes to Professor Ronald Flack at the Department of Mechanical and Aerospace Engineering of the University of Virginia and his students for their work on LDV measurements inside the torque converter. Likewise, thanks to Dr. Budugar Lakshminarayana at the Center for Gas Turbine and Power, Department of Aerospace Engineering, at The Pennsylvania State University and his students for their work with aerodynamic probe measurements inside the torque converter.Address correspondence to Jean Schweitzer, Advanced Power Transfer, GM Powertrain, MC 481-700-718, P.O. Box 935, Ypsilanti, MI 48197-0935, USA. E-mail: jean.m.schweitzer@gm.com performance of a torque converter, it is necessary to understand the flow of fluid within it. CFD can simulate this flow and thus can be used as an analysis and design tool. This article presents a comparison of CFD results with laser Doppler velocimetry (LDV) data, probe data, and dynamometer data. Velocity profiles at various locations in a torque converter are compared with LDV data, and pressure profiles are compared with probe data. A comparison of the standard performance parameters of a set of converters with dynamometer data is presented.Some of the applications of CFD in torque converter design and study are also presented. It has been used in element design, torus design, and cavitation study. CFD analysis results have also been used to optimize designs before fabricating experimental hardware. GRID DEFINITIONIn the pump and the turbine, one blade-centered H-grid block was constructed as shown in Figure 1a and b. Block-structured, boundary-fitted, nonorthogonal grids were constructed using the grid generator CFX Turbogrid (AEA Technology, 2000a). The grid elements inside the blade were blocked off and the grid lines were con...

Effect of Stator Shape on the Performance of Torque Converter

“…They concluded that the main reasons for this increase in torque ratio were the increased stator exit angle and decreased stator losses. Schweitzer and Gandham [10]had described some of the work done to validate CFD results and gave examples of ways in which CFD is used in the torque converter design process. Based on the validation studies, they concluded that CFD could be used as a design and analysis tool for torque converter development.…”

Experimental Research Concerning Hydrodynamic Clutches Controlled by Increasing Distance Between Rotors

“…The study [9] shows an evaluation of the possibilities to use an a typical working fluid (a mixture of oil and air) within a partially filled HC, on the basis of numerical 3D calculations and experimental research. Schweitzer and Gandham [10] conducted an analysis of a working fluid flow within the HTC using CFD methods, and the results of the numerical calculations are verified on a test station using laser Doppler velocimetry LDV. Similar research is shown in the studies [11,12,13,14,15,16,17].…”

Longitudinal speed control of autonomous vehicle based on a self‐adaptive PID of radial basis function neural network

“…The transmission system model includes a torque converter model, an automatic transmission model and a final drive model. The torque converter model and automatic transmission model are based on [24][25][26] and [27,28], respectively. The variables of the vehicle model are shown in the following Table 1.…”