Numerical Torque Converter Performance Predictions: Validation and Application to a Rapid One Dimensional Approach

The flow field in an automotive torque converter was analysed using the munerical results given by a commercially available package CFD code: FLUENT 5 TM. Calculations are performed for different speed ratio between pump and turbine in order to cover the total range of operation assuming no transient effects. The different number of blades of the torque converter components (pump, turbine and stator) are taken into account. The use of a close loop domain allows the circulating mass flow rate to be adjust itself depending on the computed flow. Local flow patters and evolutions with speed ratio are analysed and discussed. Overall numerical results are compared with experimental standard performances like torque ratio K, pump Y factor and efficiency. Results of these numerical analysis are taken into account in order to improve an existing one dimensional approach. The resulting modifications have been applied in a complete set of different converter geometries with good results.