Investigation of the cavitation model in an inducer for water and liquid nitrogen

Abstract

Cavitation commonly occurs in the hydraulic machineries like inducers. Cavitation happening in the cryogens is sophisticated due to their complicated thermodynamic properties. Computational fluid dynamics could provide relatively precise prediction for water. However, existing computational fluid dynamics methods may fail to simulate the cryogens cavitation precisely. This study presents a computational fluid dynamics simulation of four major cavitation models in both the liquid nitrogen and the water in an inducer. Four different cavitation models analyzed in this work are full cavitation model, Kunz model, Zwart–Gerber–Belamri, and Schnerr & Sauer. And the computational fluid dynamics simulation results are verified by the experiment to ensure the cavitation model's applicability in both liquid. Comparison of cavitation in water and liquid nitrogen is conducted and analyzed. The four cavitation models can predict cavitation in water, but the Zwart–Gerber–Belamri model and Schnerr & Sauer model also feature high capability to predict tip vortex cavitation. The results show that the full cavitation model is suitable for simulating the liquid nitrogen cavitation without changing of the model constants. The empirical constants of the other models should be adjusted in the liquid nitrogen cavitation simulation. Full cavitation model features high robustness in various liquids. The Schnerr & Sauer model can achieve the best results by adopting different empirical constants. In addition, the inducer performs better in the liquid nitrogen than water at low cavitation number regime as the head coefficient drops smoothly in liquid nitrogen with decreasing cavitation number.

The effect of secondary passages on cavitation and radial forces in a liquid propellant turbopump

“…Schnerr-Sauer cavitation model, 13 which is a transport equation-based model, is chosen for the study as is also the practice in the past. 42 The bubble number density is specified as 10 13 and the turbulence factor with the default turbulence coefficient of 0.39 is enabled. Pressure-velocity coupling was achieved through SIMPLE algorithm.…”

Numerical study on the effects of installing an inducer on a pump in a turbopump

“…Also, Kamikura et al 13 and Kanamaru et al 14 applied asymmetric slits on the inducer blades for reducing instabilities. Since thermodynamic effect can take place in the inducer with cryogens, Zhang et al 15 tried to compare four cavitation models for simulating cryogens cavitation precisely. As a result, full cavitation model showed high robustness in various liquids and the inducer performance in liquid nitrogen was better than that in the water.…”