Study on the influence of inducer and its guide vanes on cryogenic cavitation and pressure fluctuation characteristics of an LNG pump

Liquefied natural gas (LNG) pumps are prone to cavitation under cryogenic operation. This study establishes a numerical model to investigate the influence of an inducer and its guide vanes on the cavitation and pressure fluctuation characteristics of a two-stage LNG pump. Simulations with and without the inducer were conducted using a thermodynamically modified Zwart-Gerber-Belamri cavitation model and the SST k-ω turbulence model. Results show that the inducer elevates the impeller inlet pressure, increases the head coefficient from 1.74 to 1.88, and reduces the critical cavitation number from 0.0628 to 0.041, thereby delaying cavitation onset. The guide vanes organize the inflow and intensify pressure fluctuation periodicity within the impeller passages, dominated by the guide vane passing frequency, while exerting negligible effect on pressure fluctuation at the impeller outlet and diffuser inlet. This work provides a basis for optimizing inducer and guide vane designs to enhance cavitation resistance and operational stability.