環状案内翼列下流における二円板間の流動特性

抄録

Variable inlet guide vanes are installed at the impeller inlet in fluid machines, such as centrifugal compressors, pump turbines, and swirl generators. They are used for flow rate control, flow angle adjustment, reduction of the collision pressure loss at the blades, and expansion of the operation range. However, if the blade angle of the inlet guide vanes is set to be small, flow instabilities with a specific frequency occur downstream of the vanes. It is known that such unsteady flow is a two-dimensional phenomenon, and vibrations occur owing to the circumferential propagation of the cell structure. This study attempted to experimentally clarify the influence of the circular cylinder set at the outlet of the device on the flow instabilities generated downstream of the guide vanes. The pressure fluctuations were measured. Consequently, it was demonstrated that circular blockage can suppress the flow instabilities.