Introducing Vortices via Vortex Generators as a method of Spent Vapour Removal during Jet Impingement Boiling

The simulation of boiling, specifically jet impingement boiling, is a complex topic that has received increasing attention in recent years due to the promising improvement in heat transfer of two-phase systems for micro-electronics cooling over conventional single-phase systems.

Previously Ludick et al (2023) found localised dry-out due to the formation of a vapour layer to be one of the greatest limitations in increasing the Critical Heat Flux (CHF) of jet impingement boiling systems. We, therefore, investigate the introduction of Vortex Generators as a method to remove the spent fluid (vapour) preventing the creation of a vapour layer, which may in turn increase the CHF of the system by allowing for re-wetting.

Here, we computationally investigate the proposed Vortex Generator implementation using an SST turbulence model coupled to an RPI Boiling model. Our simulations allow for detailed feedback that is not often available with experimental work, such as the dynamic variation of velocity and temperature fields throughout the domain.

Our simulations have been validated against the Stanton numbers derived from single-phase experiments of Eibeck & Eaton (1987) and also against microchannel heat-transfer experiments of Chen et al (2014) using vortex generators. We present simulations that span over critical flow (such as inlet Reynolds numbers) and geometrical parameters (such as span, angle of attack and aspect ratios) of our vortex generators. Our analysis aims to reveal how vortices can influence flow-boiling, and in particular flow-boiling heat transfer coefficient. We also demonstrate the relationship between CHF and key turbulence parameters such as the turbulent kinetic energy.