ケーシングスリットがファン騒音に及ぼす影響についての圧縮性流れ解析による分析

抄録

The flow and sound fields around a small axial fan in a duct are directly predicted based on the compressible Navier-Stokes equations, where the flow around rotating blades is reproduced by the volume penalization method. The computational methods are validated by comparing the predicted performance and the sound pressure spectrum with those measured. Moreover, the effects of the slits in the casing on the flow and sound are focused on. It is shown that more intense tip vortices are generated in the casing with the slits compared with that without a slit. In the wake of the fan, the regions with velocity deficit due to the tip vortices are formed in addition to those in the downstream of the blades. As a result, the radiated sound due to the wake and the struts is affected by the slits of the casing.