Numerical simulation of bubble dynamics at a single nucleation site during pool nucleate boiling under a non-uniform electric field via lattice Boltzmann method

In low-gravity environments, devices utilizing pool nucleate boiling for heat dissipation face the risk of deteriorated heat transfer, which primarily arises from inhibited detachment of bubbles from the heating surface. To explore the potential of electrohydrodynamics for enhancing heat transfer under such conditions, this study employed a hybrid thermal lattice Boltzmann model coupled with an ideal dielectric electric field model to simulate complete life cycles of bubbles at a single nucleation site under an inverted non-uniform electric field and reduced gravitational accelerations, while comparing the results across different electric field configurations. The results indicated that even under this specific electric field configuration, bubble detachment could be promoted. Different electric field strengths exerted a disproportionate influence on this promotion, which is correlated with anomalous effects on local heat flux. Notably, bubble detachment significantly altered the electric field distribution. Furthermore, this distribution was affected by bubble's internal temperature and density, along with the surrounding velocity field. In turn, these observations suggest that the electric field directly influenced the top and neck of the detaching bubble and likely indirectly affected its middle section and the nucleation site by modifying the surrounding fluid behavior. By comparing relevant bubble detachment parameters under the inverted electric field configuration with those under other configurations, it was found that the dominant mechanism by which the electric field influences detachment likely differs across configurations. This discovery offers new insight for applying electrohydrodynamics to enhance bubble detachment in pool nucleate boiling under such special conditions.