Nonlinearity of Circulation Flow Inside Torque Converter

The information on the frequency characteristic of the internal circulation flow can be useful in determining the cause of fluid noise and vibration problems in the torque converter. In this paper, the internal flow field of an automotive torque converter is experimentally visualized, and the velocity field is measured using particle image velocimetry (PIV) in the cases of the speed ratio 0.1 and 0.7. The time series of the internal circulation flow is investigated to analyze the unsteady flow field due to the flow interactions between cascade blades of impeller, turbine, and stator. It is found by using FFT analysis that the frequency characteristics of flow rate have remarkable peak values at the blade passing frequency, its harmonics of each cascade, and combined frequencies. It was experimentally confirmed that the frequency characteristics of the internal circulation flow in the torque converter are similar to that of the multi-stage turbomachines.