A fast iterative inverse method for turbomachinery blade design

Abstract

An improved formulation for an iterative inverse design method is presented. The method solves the time dependent Euler equations in a numerical domain where the blade sections are iteratively modified, until a prescribed blade load distribution is reached. The mean tangential velocity and thickness distributions are imposed as design variables. Each design iteration starts with a blade section modification that is impressed on the camber line. After generating a new mesh, the flow-field is updated by performing one finite volume time iteration. The blade modifications and the time-marching computation converge simultaneously to the required geometry and to the steady state flow solution. The present time-lagged formulation introduces a new blade thickness distribution term that improves the convergence rate. An empirical study on the existence and uniqueness problem is presented for the iterative inverse design method. Results for different blade cascade geometries showed the improvement of the convergence rate and the robustness of the method, for the imposed set of design conditions.