Aerodynamic effects of blade sweep and skew in low-speed axial flow rotors at the design flow rate: An overview

Abstract

A detailed literature survey is presented herein in order to overview the aerodynamic impact of non-radial blade stacking techniques applied to axial flow fan and compressor rotors. The literature suggests a consensus that forward blade sweep and skew provides a means for the following advantages in the part load operational range of low-speed axial flow turbofan and compressor rotors: improvement of efficiency and performance, and extension of stall-free operating range. However, the published research results are rather diversified regarding the judgment of performance and loss modifying effects of sweep and skew at the design point. The current paper summarizes the major aerodynamic phenomena related to such blade stacking techniques, in order to contribute to a general reasoning of performance and efficiency modification at the design flow rate. Furthermore, it provides guidelines how to consider these phenomena in tailoring the blade geometry for potential efficiency gain and for achievement of the prescribed total pressure rise at the design point. The role of adequate computational fluid dynamics tools was considered in the paper to be essential in evaluation of aerodynamic effects of non-radial blade stacking, as well as in incorporation of sweep and skew in systematic blade design techniques.