Analysis of mixed-flow rotor cascades

Abstract

Mixed-flow rotor cascades present a formidable design problem since rotational effects such as coriolis forces exclude the use of stationary cascade experimental data. This report discusses the general influence of these effects upon the energy transfer process and the parameters which govern the efficiency of a mixed-flow fan. An outline is presented of two cascade theories for predicting aerodynamic rotor cascade characteristics in detail. One deals with a restricted family of Joukowski type aerofoils providing a broad range of exact solutions by conformal transformation. The second theory involves the extension of Martensen's method to include relative eddy effects and also to allow for changes in meridional streamline thickness (AVR). This method which is applicable to any profile on any stream-surface of revolution is shown to produce accurate predictions compared with the exact solutions.