PIV Measurement on the Flow Field Around a Stator Cascade of Automotive Torque Converter 2001-01-0868
The automotive torque converter is one of the most important component parts in the automatic transmission. In recent years, the design demands have been for both high performance and compact size. For the optimized design to satisfy with these demands, it is necessary to analyze the internal flow field of torque converters.
The internal flow field around the stator of an automotive torque converter is investigated experimentally in this study by using Particle Image Velocimetry (PIV) technique. The objective of this investigation is to understand the flow field around the stator which has the important role to characterize the torque converter performance. The three-dimensional flow field is reconstructed by using the two-dimensional PIV results at two orthogonal planes.
The stream lines (starting points of the stream lines are 3[mm] upstream from leading edge of the stator blade) shows that the flow field is uniform and smooth along the stator blades profile in all the passage near both shell and core sides at the high speed ratio condition. However, the small flow diffraction near the core side and the large flow diffraction near the shell side can be observed at the low speed ratio condition. These flow diffractions indicate the flow separation and reversed flow occurrence which may affect the torque converter performance.
The existences of the clockwise secondary flow circulation at the stator mid-chord suction side can be seen clearly from the time averaged velocity vectors at the low speed ratio condition. No secondary flow can be found at the high speed ratio condition. The clockwise secondary flow circulation at the stator mid-chord is considered to be caused by inlet flow condition which is hard to simulate in the most widely used Computational Fluid Dynamics (CFD) software (Standard k-ε model).
The three-dimensional data obtained by this study can be used to optimize the stator design for torque converter performance improvement. It can be used to validate the accuracy of CFD also.