Experimental study on the melting characteristics of n-octadecane with passively installing fin and actively applying electric field

Abstract

This work extends our recent study (Sun et al., 2021 [1]) on the n-octadecane's melting with electric field inside a cavity. The combined heat-transfer enhancement technique involving a passive fin and active electric field is used to experimentally investigate the n-octadecane's melting inside a vertically heated cavity. The effects of magnitude and direction of applied voltage on phase-change heat transfer are studied with and without the fin. Results are provided for the real-time evolution of the melting front, the liquid fraction, as well as the velocity fields and the current-voltage curve. It is found that the adding of fin structure can solely reduce 40.0% total melting time in a 40.0 mm × 40.0 mm × 40.0 mm cavity. For the cavity without fin, a +20.0KV applied voltage from the left wall or right wall of cavity can separately increase 40.0% or decrease 33.3% melting time, respectively. But for a cavity with fin, a left or right side applied +20.0KV voltage will induce a 3.7% decrease or a 48.1% increase of melting time. It is also found that Coulomb force plays a dominant role on melting after the initial stage, and free space charges are mainly produced by the conduction mechanism.