A CFD-based approach to study cavitation in high-pressure homogenizer valves. Part 1. Cavitation inception, extent and location

Hydrodynamic cavitation occurs in high-pressure homogenizer (HPH) valves, causes wear and influences emulsification. Substantial advances have previously been made studying HPH cavitation in experimental systems. However, there is a lack of understanding on how cavitation develops in industrially relevant valves. The series applies CFD to address this knowledge gap. This part combines a previously validated one-phase CFD model and a macroscopic cavitation model–previously seen to compare favourably to experimental cavitation visualization–to study inception, location and extent of cavitation, as a function of homogenizing pressure and Thoma number. Cavitation inception is predicted below a cavitation number of 0.20. Vapour accumulates in the large vortices of the outlet chamber, and the steady-state volume fraction of vapour accumulation decreases with cavitation number. Moreover, operating the HPH at a low Thoma number results in shifting the macroscopic flow. This helps explaining the observation of reduced emulsion breakup under extensive cavitation.