고압펌프용 인듀서의 성능해석 및 설계

초록

Multistage pumps have been successfully built with inducers, which accept low pressure from a tank and increase the head sufficiently to avoid cavitation. The onset of cavitation causes head and efficiency of the pump to be reduced significantly and generates noise. Exposing on cavitation for quite a period time made pump impellers and casing to be permanently damaged. Most of the inducer is designed at a maximum efficiency point of the pump, therefore suction performance decrease due to effects of flow separation and inlet inverse flow at off-design points is often observed. Variation of output energy as NPSH (Net Positive Suction Head) decreases was observed in this experiment. Pressure fluctuations in cavitation regions were also measured at inducer inlet using pressure transducer. To verify and supplement the empirical formula for loading and loss coefficients at off-design points, the unsteady and complex flow-fields in inducer impellers are numerically simulated using large-eddy simulation. The computed pressure distributions from single-phase are compared with experimental data to predict the onset of cavitation