Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : March 17, 2018 - March 18, 2018
As the cause of vibration that be caused to the whirling motion at the rotating machine, It exists in the rotordynamic fluid forces. Vibration arisen by the forces is primarily called self-excited vibration. It is difficult to operate by the vibration more than natural frequency because it has the characteristics that amplitude is not reduced even if rotational speed is increased. In this study, the effect of pressure around the blades and fluid forces occurs to the whirling motion internally are investigated by making use of CFD. Also, it is enable to reproduce the whirling motion by producing rotating lattice between the casing and the axial fan. As the investigation of circumferential pressure, it is confirmed that pressure difference is increased by changing of eccentricity. Additionally, it is found that the changes of whirling speed ratio are gained the force which try to press fluid to the casing and pressure is increased. The investigation of normal and tangential fluid forces at the whirling speed ratio Ω/ω revealed that tangential fluid force tends to decrease linearly with increasing Ω/ω. Also, it is found that the tangential force works in the direction of promoting the whirling motion at the range of -0.1<Ω/ω<0.
