Sustaining nucleate boiling in zero gravity using asymmetric sinusoidal base-plate oscillation

Abstract

This work presents Direct Numerical Simulations to study the effect of base plate oscillations on nucleate boiling heat transfer at low superheat, in the isolated bubble regime, under zero gravity conditions. An in-house solver, based on sharp interface dual grid level set method (SI-DGLSM), is used to carry out the numerical simulations. To enable nucleate boiling in zero gravity, an asymmetric periodic motion of the base plate is proposed, in which the average acceleration of the plate is different along the two plate-normal directions. This time-asymmetry in plate motion imparts net motion of bubbles away from the plate, which in turn sustains nucleate boiling. The departure of the bubble is presented first for cases with no phase change, where the effect of varying plate oscillation parameters on the departure of single bubble over the plate is studied for zero gravity conditions. Thereafter, the effect of the plate motion on nucleate boiling characteristics is presented, and the regime in which nucleate boiling is sustained is identified. We report the effect of plate motion on time series of bubble departure radius, Nusselt number and overall flow dynamics during nucleate boiling in zero gravity. The proposed technique for the sustenance of nucleate boiling in zero gravity conditions has numerous space-related applications for heat transfer enhancement.