Numerical Analysis on Dynamic Evolution Characteristics of Cryogenic Cavitation Through a Venturi Tube

Abstract

Venturi tube is always used to measure the flow rate of stable single-phase fluid, which plays an important role in chemical industry, energy, aerospace and other fields. When the cryogenic medium flows through Venturi tube, the local pressure will be reduced and cryogenic cavitation is easily induced, leading to serious vibration and wall destroy of Venturi tube. Due to the unique thermal sensitivity of cryogenic medium, traditional cavitation model is not able to accurately predict detailed dynamic evolution of cryogenic cavitation. In this paper, the dynamic evolution characteristics of cryogenic cavitation inside a Venturi tube were studied under different pressure ratios by using a modified cryogenic cavitation model. The evolution of cryogenic cavitation was obtained and discussed in detail as well as the relationship between cavitation and vortex structure by using Q-criterion. In addition, the energy transfer of cryogenic fluid were studied by considering the turbulent kinetic energy dissipation and entropy production in cryogenic Venturi tube. The entropy production caused by velocity gradient change, turbulence dissipation and wall shear stress was explored and analyzed by entropy diagnosis method, revealing energy loss in dynamic evolution process of cryogenic cavitation in Venturi tube.

Keywords: Cryogenic cavitation, Thermodynamic effect, Cavitation evolution, Vortex structure, Entropy production