液化ガス用遠心ポンプに発生する旋回失速を抑制するためのディフューザベーンスリット形状最適化の検討

抄録

The diffuser rotating stall(DRS) is one of the biggest problems in pumps because unstable flow and pressure fluctuations are induced and the pump operating range is severely limited. However, it is difficult to quickly predict the flow rate of the DRS onset. The authors had already confirmed that the flow rate of DRS onset is shifted to lower flow rate by slitting the diffuser vanes in the experiment of previous research work. However, the optimized slit shape has not been sufficiently studied yet. In the previous study, the effect of the slit on the internal flow and the qualitative mechanism for suppressing the DRS were verified by unsteady RANS(Reynolds Averaged Navier Stokes) calculations. We also suggested a simple prediction method of diffuser rotating stall onset using steady state numerical simulation, and examined the evaluation function effectiveness for optimizing the slit shape. In this study, a multi-objective optimization with a simple prediction method of DRS onset using steady state numerical simulation was conducted for the slit width as a single design parameter. The effect of the slit on the pump performance and internal flow was investigated in order to refine the DRS suppression method.