Parametric Design and Optimization of the Impeller Geometry for an Automotive Torque Converter Using DOE Method

Design of experiment (DOE) and computational fluid dynamics (CFD) techniques are applied to obtain an optimal design of the impeller geometry for an automotive torque converter. A new parametric geometric design method of impeller is proposed by means of parametric equations and Creo software. Eleven design parameters are used to obtain the parametric model and can be represented by six parameters including impeller blade number, blade thickness, bias angle, scroll angle, inlet angle and exit angle. DOE method is used to investigate the relative importance of the six design parameters for each response (stall torque ratio and peak efficiency). The impeller bias angle is found to exert the greatest influence on stall torque ratio while the impeller exit angle has the strongest impact on the peak efficiency. Three optimized cases for the impeller geometry of an automotive torque converter are obtained based on desirability function approach. The new parametric design and optimization methods can provide fundamental guidelines for performance enhancement in the design process of impeller geometry for an automotive torque converter.