Flow and Loss Analysis of a Torque Converter Pump in the Higher Speed Ratio Range.

Abstract

The pump is often the major source of loss in a three-element automotive torque converter in the higher speed ratio range where vehicles are most frequently operated in everyday driving. The complex flow fields in the pump were analyzed using a three-dimensional CFD code in order to identify the loss generation mechanism in this speed ratio range. The results show that a low kinetic energy region is found in the corner where the suction and the core surfaces intersect, which qualitatively but essentially coincides well with flow visualization results obtained with the resin-film method. A reduction of the flow rate and an increase in the nonuniformity of the inlet circulatory velocity distribution increase the pump loss. A relatively greater loss is generated near the leading edge section and in a reverse flow region the area of which increases as the speed ratio increases. The secondary flows near passage walls and the change in the loss distribution between passage crosssections can be explained by the pressure field formed by the main stream.