Abstract: The flows in hydrodynamic torque converter are extremely complicated 3D viscous and incompressible turbulences. At present, the flow field calculation is simplified to steady state, and then its transient characteristic is neglected. Only the result of transient calculation can be close to the real flow. The governing equations of transient flow field under rotating coordinate system are established. The governing equations are solved by using numerical calculation. During the calculation, all impeller channels are established as a solution domain, and the Sliding Mesh Method which is one of coupling algorithms for multi-flow regions is used to calculate the transient flow field of torque converter. By using the Sliding Mesh Method, all flow parameters between upstream impeller and downstream can be real-time transferred. Overall evaluation computation stability, accuracy and efficiency, the segregated steady implicit solver and the Realizable k-epsilon turbulent model are used in the simulation. SIMPLE arithmetic with first order upwind format is used in pressure velocity coupling. The transient flow characteristics and causes can be better known on the basis of numerical solution of the flow field. The performances of hydrodynamic torque converter are figured out on the basis of numerical solution of transient flow field. Compared with the experimental results, the error between them is small. It comes to the conclusion that the transient calculation method is correct and effective.

Key words: Hydrodynamic torque converter, Numerical simulation, Transient calculation