Estimation of axial compressor body forces using three-dimensional flow computations

Abstract

This thesis presents an examination of body force distributions in a single stage low speed compressor. The body force distributions are developed using two different computational procedures, an axisymmetric streamline curvature calculation and an unsteady, three-dimensional flow simulation. A two-dimensional body force representation is defined as a benchmark to evaluate the departures of the computed forces from two-dimensional behavior. The most important contribution to this departure (for both the streamline curvature calculation and the three-dimensional simulation) is identified as the change in streamtube height across the blade rows. The magnitude of the departures increase with blade loading and, for the compressor examined, are smaller than five per cent of the two-dimensional estimate at design but show values up to 50 per cent near stall.