Electrical Field Effects on Boiling Heat Transfer of Low Global Warming Potential Coolant

Abstract

This paper presents an investigation of the influence of d.c. uniform electric field on boiling heat transfer characteristics of Fluorinated ketone (FK). One potential use of FK in high voltage plant is as the fluid within a thermosyphon, replacing conventional cooling that requires pumps and/or fans. The electric field's effect on the onset of boiling, nucleate boiling curve and critical heat transfer of FK was experimentally studied using a mesh-plane electrode arrangement. For this purpose, with the assistance of a steady state thermal finite element analysis (FEA) model, a novel grounded electrode with a ‘vacuum jacket’ and temperature sensor array was designed and manufactured. Moreover, detailed coolant boiling stages were observed and recorded via a high-speed image system. textbfThe results show that d.c. field reduces the first boiling hysteresis on FK coolants i.e. nucleate boiling starts at a lower superheated temperature. The d.e. field also increases the effective heat transfer coefficient. The significance of these results is that there is an electrohydrodynamic enhancement of the key heat transfer properties of FK due to the presence of a d.c. field.