Predicting the Onset of Cavitation in Automotive Torque Converters—Part II: A Generalized Model

Abstract

The objective of this investigation was to develop a dimensionless model for predicting the onset of cavitation in torque converters applicable to general converter designs. Dimensional analysis was applied to test results from a matrix of torque converters that ranged from populations comprised of strict geometric similitude to those with more relaxed similarities onto inclusion of all the torque converters tested. Stator torque thresholds at the onset of cavitation for the stall operating condition were experimentally determined with a dynamometer test cell using nearfield acoustical measurements. Cavitation torques, design parameters, and operating conditions were resolved into a set of dimensionless quantities for use in the development of dimensionless empirical models. A systematic relaxation of the fundamental principle of dimensional analysis, geometric similitude, was undertaken to present empirical models applicable to torque converter designs of increasingly diverse design parameters. A stepwise linear regression technique coupled with response surface methodology was utilized to produce an empirical model capable of predicting stator torque at the onset of cavitation with less than 7% error for general automotive torque converter designs.

Influence of Charging Oil Condition on Torque Converter Cavitation Characteristics

“…converters has been reported decades ago [8] [9], and continuous efforts have been put into the investigation and control of cavitation in torque converters [10].…”

“…The microwave telemetry technique [11]and the nearfield acoustic test approach [12]were proposed to investigate cavitation phenomena in a series of torque converters. In another approach, Robinette et al tested a matrix of torque converters and developed a dimensionless model for predicting cavitation [13]. Reynolds measured the sound power level in torque converters over various speed ratios and developed a response surface model to estimate the sound power of a working torque converters [14].…”

Development of a Dimensionless Model for Predicting the Onset of Cavitation in Torque Converters

“…A second order function was assumed for the RSM used in this investigation, which contains linear, quadratic and two factor interactions as used by [12]:…”

Numerical Simulation of Transient Cavitation Characteristics of Valve-Controlled Liquid-Filled Hydrodynamic Coupling

“…Liu et al [7][8] studied the influence of the stator blade shape on the cavitation process of a hydraulic torque converter and found that cavitation is directly related to the internal mass flow rate. Robinette et al [9][10][11] investigated the effects of torque converter design and operating conditions on the onset of cavitation during vehicle launch using a nearfield acoustical technique. From their numerical results, Dong et al [12] determined that the cavitation on the stator leading edge grew in size with increasing pump speed, resulting in severe performance degradation in the torque converter.…”