An experimental investigation on fluid dynamics and performance of an automotive torque converter.

摘要

The automotive torque converter is a complex turbomachine used to transfer power from the engine to the transmission. It consists of a mixed-flow pump, a mixed-flow turbine, and an axial-flow stator, employing oil as the working fluid. The flow field inside the torque converter is very complex due to the highly three-dimensional geometry of the elements, high angle of blade turning, large flow path curvature, and a wide range of operating conditions. The objective of this investigation is to gain an in-depth understanding of the internal flow field of the automotive torque converter with emphasis on experimental and analytical approaches in order to improve the overall performance of the automatic transmission system.; The flow field inside a baseline model turbine (C-Turbine) rotor passage was measured using a high frequency-response rotating five-hole probe measurement technique. A “jet-wake” flow pattern was observed inside the turbine rotor passage. The pressure and velocity distributions are highly non-uniform inside the rotor passage. It is concluded that the flow field is strongly subjected to the influences of the upstream pump exit flow, the flow path curvature effect, and rotation at high speed ratios. The performance of the turbine was analyzed by combining the data both inside the turbine rotor passage and the data upstream, downstream of the turbine rotor. A large portion of the static pressure drop is due to the centrifugal force, and the flow turning effect is significantly augmented by the rotation effect.; The flow field near the pump leading edge was measured using the rotating probe measurement technique. Furthermore, the flow fields for different pump/turbine configurations were also analyzed, and the relationship between the flow field and the overall performance parameters were established.; Based on the experimental data and analysis, recommendations are proposed for the hydrodynamic design of automotive torque converters.