A Surface Vorticity Analysis of Three-Dimensional Flow through Strongly Swept Turbine Cascades

Abstract

The two-dimensional surface vorticity theory of Martensen is extended to deal with the full three-dimensional flow through a swept turbine cascade, including end effects. Basic concepts of surface vorticity theories are dealt with initially, as also are three three-dimensional flow considerations for swept cascades. The paper goes on to develop two theoretical models for the representation of swept blade row flows. The first model assumes that the blade bound vorticity remains constant across the span of the blade. In the second model, this assumption is relaxed so that the blade bound vorticity is allowed to vary in the spanwise direction. In both cases the theories are applied to turbine nozzle cascades. Some of the solutions obtained are compared with experimental tests which were the subject of a previous paper.