Numerical Predictions of Cavitating Flow Within a Liquid Hydrogen Inducer

Abstract

With the recent interest in using liquid hydrogen as a fuel source for energy production and transportation, predicting the performance of pumping systems which handle hydrogen has become an important issue. Liquid hydrogen is a cryogenic fluid which exists at extremely low temperatures and presents a myriad of design challenges to ensure a safe, efficient, and robust fuel delivery system. In addition, the typical operating conditions for pumps handling liquid hydrogen are such that vapor formation due to cavitation is present in the flow even when the head rise is relatively unaffected. Cavitation can cause severe damage to pump components and lead to shortened life and eventual failure, especially at the temperatures associated with liquid hydrogen. The present work was focused on validating CFD methods for accurately predicting cavitating flow in a pump inducer handling cryogenic hydrogen. The CFD code used in this study was Ansys CFX, which is a general-purpose commercial solver with models available for simulating cryogenic cavitation in turbomachinery. The specific model employed for cavitation utilized a Rayleigh-Plesset based multiphase formulation in conjunction with thermodynamic property tables appropriate for cryogenic liquid hydrogen. Adjustments to cavitation model parameters were introduced as a function of fluid temperature to account for the thermal suppression head effects that are present at cryogenic thermal conditions.