Analysis of the Internal Flow Structure of Torque Converter Using Proper Orthogonal Decomposition under Transient Driving Conditions

Abstract

The characteristic structure of the flow field in a torque converter is quantitatively evaluated using proper orthogonal decomposition (POD) under transient driving conditions assuming start-up acceleration and deceleration of a vehicle. The time-series velocity data inside the torque converter to be input to POD is measured using a particle image velocimetry (PIV) technique. At first, in the case of changing the rotational speed of the impeller or turbine, dynamic cascades with changing rotational speed were observed to induce fluid motion. The flow field structure was gradually reformed according to the speed ratio after transition. In addition, the region of structural changes of the flow field was found to be larger for the decelerating driving condition compared to the case of start-up acceleration.