Effect of Rotational Speed on the Average Flow Field at the Pump/Turbine Interface of an Automotive Torque Converter

Abstract

Abstract The internal flow fields of a pump/turbine interface in a torque converter were examined using laser velocimetry. The torque converter was operated at three different turbine/pump rotational speed ratios: 0.065 (near stall), 0.600, and 0.800 (near coupling point) and for each speed ratio three different pump and turbine speeds were used. Most importantly, the dimensional rotational speed had minimal effects on the flow fields — flow characteristics were Reynolds number independent. At the pump exit plane the flow is non-uniform in the blade-to-blade direction at all speed ratios and speeds. Velocities were fairly uniform in the core-to-shell direction. Through flow velocity non-uniformity became more pronounced as the speed ratio increased. The pump exit plane slip factors are near unity. At high speed ratios the flow in the turbine inlet plane flow is non-uniform in the blade-to-blade direction. Also at high speed ratios, velocities are fairly uniform in the core-to-shell direction but high velocities move near the shell at lower speed ratios. The turbine leading edge incidence angles were found to depend strongly on the speed ratio, ranging from positive to negative.