Mechanisms of cavity windage heating on the performance of an axial compressor

The windage heating effect constitutes a significant contributor to the loss mechanisms of cavity leakage flow. This paper adopts a simplified cavity flow model consisting of injection at the stator inlet and flow suction at the stator outlet to investigate the mechanisms of cavity leakage windage heating. A series of parametric studies on the leakage flow ratio and the leakage total temperature are conducted at different rotational speeds and incidences. In the first place, the effectiveness of the numerical method is validated against the experimental results in terms of the overall compressor performance and the detailed flow field. Then the verification of the simplified cavity model is performed against the full-scale cavity model. At last, a detailed discussion is conducted on the compressor performance and mean flow field. The results show that the compressor performance deterioration is strongly correlated with increased cavity windage heating and is more sensitive at a large leakage flow ratio. The majority of additional efficiency loss due to the windage heating originates within the cavity passage. The increased leakage flow ratio significantly affects the stator velocity and temperature fields by promoting leakage migration and hub corner separation. Additionally, the rise in leakage temperature substantially elevates the temperature along the leakage path, intensifying the diffusion of local entropy loss. These results provide a further understanding of the cavity windage heating effect and useful guidance for cavity seal optimization.