Rotating Probe Measurements of the Pump Passage Flow Field in an Automotive Torque Converter

Abstract

The relative flow in an automotive torque converter pump passage was measured at three locations inside the passage (mid-chord, 3/4-chord, and 4/4-chord) using a miniature high-frequency response five-hole probe in the pump rotating frame. A custom-designed brush-type slip-ring unit is used in the rotating probe system to transmit the amplified signal from the probe in the rotating frame to the stationary frame. At speed ratio of 0.6, a weak “jet-wake” flow pattern is observed at the pump mid-chord. High flow loss is observed in the core-suction corner due to the “wake” flow caused by the flow separation. A strong clockwise secondary flow is found to dominate the flow structure at the pump mid-chord. The Coriolis force and the through flow velocity deficit near the core at the pump inlet are the main reasons for this secondary flow. The jet-wake flow pattern at the 3/4-chord is enhanced by the upstream secondary flow. A jet-wake flow pattern is also observed at the pump 4/4-chord, with concentration of the flow near the passage pressure side. The secondary flow changes its direction of rotation from the 3/4-chord to 4/4-chord. This is mostly caused by the passage meridional curvature and the flow concentration. High loss is found in the core-suction corner wake flow due to a low kinetic energy flow accumulation and the flow separation. Finally, the pump flow field is assessed through the mass-averaged total pressure and relative pressure loss parameter. The data are also analyzed to assess the effect of the speed ratio on the flow field.