貫流羽根車における下壁面とアスペクト比の関係

抄録

The experimental studies were performed to clarify the upper and lower boundaries of the fan. A crossflow fan is rotated in the open space, i.e. without casing. The fan diameter is 78 mm. The impeller includes 29. The blade angles at the inside and the outside are 90 and 150 degrees, respectively. The experiments were conducted under three conditions of the upper and lower boundaries of the fan: lower wall only, upper and lower wall, and no wall. The amplitude fluctuation at the impeller outlet are measured using a hot-wire anemometry. FFT analysis and the phase difference show that forward and backward vibration of one cell occurs under each condition. It became clear that the fluctuation tended to turn forward due to the upper and lower boundary walls of the fan. The calculation results show the mechanism, what changes the forward or backward direction and makes eccentric vortexes.