Numerical investigation of the entropy produciton in the liquid hydrogen cavitating flow around an ogive considering thermodynamic effect

The objective of this paper is to investigate the irreversible energy loss in cavitation flow and explore the impact of thermodynamic effects. Considering the thermal sensitivity of liquid hydrogen, modifications are made to the simulation method used in this study. An entropy production theory is introduced to determine and evaluate the energy loss during cavitation in liquid hydrogen. To elucidate the intrinsic relationship between cavitation and irreversible energy loss, different entropy production terms are established to characterize its source. The results demonstrate a strong correlation between entropy production and cavitation evolution. Irreversible energy loss primarily occurs in the rear part of the cavitation area, as well as near the ogive and tunnel wall. Velocity gradients contribute significantly to irreversible energy loss in thermal cavitation flow, while temperature gradients have a negligible effect despite considering thermodynamic effects. Velocity gradient emerges as one of the main factors influencing irreversible energy losses. The model presented herein can be utilized for predicting flow losses in cryogenic fluids with thermo-sensitive properties such as liquefied natural gas (LNG), thereby guiding optimization design efforts.