Study on Effects of Blade Geometric Scale on the Unsteady Turbomachinery Flows

A three-dimensional (3D) Navier-Stokes method is applied to calculate unsteady turbomachinery flows. The 4-stage Runge-Kutta time-marching scheme and time-consistent multi-grid technique are adopted in the calculations. In this study, the multi-passage computation and single passage computation are performed on the actual and scaled configurations respectively. The results from multi-passage computation and singe passage computations are compared. Results in the form of isentropic efficiency, mass flow, entropy and unsteady aerodynamic force on the blades are presented. It has been found that the blade geometry scaling changes the axial position of the wakes, which leads to greater amplitude of efficiency fluctuation. The blade geometry scaling brings notable effects on the first four harmonics of unsteady tangential force.