Design strategy for blade thickness of hydraulic torque converter based on the characteristics of NACA airfoils

In order to address the poor continuity of the three-dimensional blade morphology caused by the conventional design method that is based on the projection theorem for isoclinic angles, we present a strategy for designing the blade thickness of the hydraulic torque converter (TC) with the characteristics of the National Advisory Committee for Aeronautics (NACA) airfoil. By defining the subsection constraints of the NACA airfoil, the designed blade can meet the fluid-structure interaction requirements of the hydraulic TC, and confirm its airfoil function. In addition, based on the airfoil function and the rules for a ruled surface, we derived the blade thickness and normal thickening direction, and then obtained the blade thickness vector of the hydraulic TC, which realized the blades thickness design (called the normal thickening method, for short). Taking the blade design of the twin-turbine TC as an example, we used this method and the projective method for isoclinic angles to establish the model. By comparing the computational fluid dynamic (CFD) simulation and rack test results, we found that by using the proposed method, the design parameters of the blades could be effectively reduced. The designed drop-like blades could improve the efficiency of the hydraulic TC, and an automatic blade design can be realized. © 2016, Editorial Board of Journal of Harbin Engineering. All right reserved.