Flow Field in the Turbine Rotor Passage in an Automotive Torque Converter Based on the High Frequency Response Rotating Five-hole Probe Measurement Part I: Flow Field at the Design Condition (Speed Ratio 0.6)

Abstract

The relative flow field in an automotive torque converter turbine was measured at three locations inside the passage (turbine 1/4 chord, mid-chord, and 4/4 chord) using a highfrequency response rotating five-hole-probe. “Jet-Wake” flow structure was found in the turbine passage. Possible flow separation region was observed at the core/suction side at the turbine1/4chord and near the suction side at the turbine mid-chord. The mass averaged stagnation pressure drop is almost evenly distributed along the turbine flow path at the design condition(SR=0.6). The pressure drop due to centrifugal and Coriolis forces is found to be appreciable. The rotary stagnation pressure distribution indicates that there are higher losses at the first half of the turbine passage than at the second half. The major reasons for these higher losses and inefficiency are possible flow separation and a mismatch between the pump exit and the turbine inlet flow field. The fuel economy of a torque converter can be improved through redesign of the core region and by properly matching the pump and the turbine. The Part I of the paper deals with the design speed ratio(SR=0.6), and Part II deals with the off-design condition(SR=0.065)and the effects of speed ratio.