Analysis of Flow Within Pump Impeller of Torque Converter

Abstract

It is difficult to measure flow patterns within rotating elements of a torque converter due to the complicated construction. Therefore, the numerical calculation is considered to be an effective tool to know the internal flow. Three-dimensional incompressible turbulent flow within a pump impeller of an automotive torque converter was analyzed numerically at three different speed ratios, 0.02, 0.4 and 0.8 under the same inlet boundary condition. The speed ratio was defined as the ratio of rotating speed of the turbine impeller to that of the pump. The governing equations using the k-ε model in the physical component tensor form were solved with a boundary-fitted coordinate system fixed on a rotating impeller. The solution algorithm was the SIMPLE method applied to the curvilinear coordinate system. The computed results were compared with those obtained experimentally by an oil film flow visualization technique for the pressure, suction, core and shell surfaces. Moreover, the results at three different speed ratios were examined in detail in order to clarify the behavior of secondary flow patterns. The computed results showed good agreement with the experimental results and clarified the behavior of the complicated flow patterns. The secondary flow patterns were strongly influenced by the correlation between the intensities of the Corinlis force (COF) and the centrifugal force due to the passage curvature in the meridional plane (CMF).

Internal Flow Structure of Torque Converter Analyzed with Dynamic Mode Decomposition under Steady Driving Condition

“…Significant analysis results for flow field characteristics, such as separated and secondary flows, have been reported. (1)(2)(3)(4) With the assistance of more advanced computers, large eddy simulations have been applied to the internal flow in a torque converter, and the results indicated that it is necessary to perform unsteady calculations to understand the internal flow field. (5) However, CFD still has limitations, and must be validated by actual experimental results.…”

Analysis of Flow in the Lock-up Clutch of an Automotive Torque Converter

“…The pump was shown to be the major source of loss in the speed ratio range where vehicles are most frequently operated in everyday driving. Flows through the pump impeller (10), (11) as well as through the three elements (9), (12) were computed by using CFD codes. Some of the computational results showed good qualitative agreement with the measured flow patterns.…”