Abstract
Turbopumps are generally operated close to the design specifications, but diffuser pumps such as for the liquid natural gas in particular can be required in a wide range of flow rates. If the flow rate is lower than the design specifications, an unstable phenomenon called diffuser rotating stall(DRS) will occur, which will interfere with the operation of the pump. However, it is difficult to predict the flow rate onset DRS. Unsteady state analysis by computational fluid dynamics is commonly used to investigate the internal flow of DRS to pumps in detail, but the computational cost is huge and the design process is inefficient. In this study, authors investigated the effectiveness of the design method and the optimaized inlet angle of the target pump using the DRS simple prediction method using steady-state analysis of computational fluid dynamics. Then, it was confirmed that the DRS simple prediction method can be used qualitatively in the target pump. It was also confirmed that the optimaized inlet angle of the diffuser vane for the target pump was in the range of 6 degree to 7 degree.
