Internal Flow Visualization of a High Specific Speed Diagonal-Flow Fan

Abstract

In order to clarify the mechanism of unstable characteristics of a high specific speed diagonal-flow fan, flow visualization of the internal flow fields ahead and after the rotor was performed with tuft method. Behavior of the flow fields in a low flow range including rotating stall, and the relation to the characteristics of the fan were investigated. The effects of tip clearance on the unstable characteristics and internal flow fields were also discussed.