抄録
In a high specific speed type open shrouded centrifugal impeller, a periodic unstable flow occurs at small flow rates due to both inducer stall and diffuser stall. In the present study, the effect of diffuser width on diffuser stall was analyzed by a numerical simulation, in which the 3-Dturbulent flow in the impeller and vaneless diffuser was calculated by using a commercial CFD code of the CFX-TASCflow together with the κ-ω turbulence model. The numerical simulation shows the reverse flow in the vaneless diffuser disappears significantly by reducing the diffuser width from 15 to 10[mm]. The experimental result shows that, by the reduction of diffuser width, the unstable flow due to diffuser stall was suppressed effectively at small flow rates without deteriorating the diffuser performance.
