Mechanisms of electrohydrodynamic flow boiling heat transfer in coaxial flow channels of dielectric refrigerant R-134a

摘要

Experimental and numerical investigations have been conducted to study the mechanisms involved in dielectric refrigerant R-134a electrohydrodynamic (EHD) flow boiling in a concentric horizontal flow channel. Numerical calculations of the electricfield distribution in two-phase flow with different gas-liquid distributions and interfacial geometries in a concentric electrode arrangement are conducted by a finite element method. The experiments conducted are performed at inlet qualities from 0 to20%, mass fluxes from 100 to 500 kg/m{sup}2s, heat flux from l0kW/m{sup}2 to 20 kW/m{sup}2 and applied voltage from 0 to 10kV. It was found that the application of an electrohydrodynamic body force to an R-134a evaporator can result in a significantaugmentation of heat transfer that may be partially explained by the numerically simulated electric field profiles near gas-liquid interfaces.