Effects of Bowed Stators on a Transonic Fan With Distorted Inlet

Abstract

The adverse impacts of inlet distortion on fan/compressor have been recognized as an important problem for several decades, and it is still a topic of considerable interest. Many research works indicate that it is possible to improve the performance and stability of a fan in clean and distorted inlet flow by using bowed stator blades. But, how bowed stator influences the flow field and what kind of bow patterns and angles can improve fan performance better are still not clearly studied. Therefore, a 3D analysis in fan flow field with different bowed stator blades is required. In this paper, a time-dependent three-dimensional Reynolds averaged Navier-Stokes equation composed in “Fluent Software Pack” is carried out in a parallel supercomputer. The fan with straight/different bowed stators is simulated with a clean/distorted inlet boundary condition to obtain a better understanding of bowed stators effects in distorted flow field. The analysis of results consists of three aspects. The first is about the effects of straight/bowed stators on the fan characteristics with clean and distorted inlet. Bowed stators can improve the fan performance significantly when inlet is distorted, especially at design point. But, when inlet is clean bowed stators even worsen the fan performance at design point. The effects of bowed stators on the fan performance at design point are analyzed secondly. It is found that different bow angles have different influence on rotor or stator flow field. Small bow angle stator reduces the flow loss in rotor but have no effect on stator flow field. Large bow angle stator can reduce the flow loss in stator markedly, but increases the rotor loss. Finally the patterns of flow loss caused by total pressure distortion with straight and different bowed stators are compared and analyzed in detail. The scale of vortex in stator is weakened by large bow angle blades significantly, which decreased the stator loss.