Enhancement of Evaporation of a Droplet Using EHD Effect. (Measurement of Steady-State Heat Flux During Evaporation of a Single Droplet).

Abstract

A further experiment was carried out to confirm EHD (electro-hydrodynamic) effect on enhancement of evaporation of a liquid droplet. A steady-state heat flux during evaporation of a single droplet was measured by controlling the flow rates of liquid and heat supplied to the droplet. The liquids used in this experiment were refrigerant R113 and ethanol. A DC electric voltage was applied between the heat transfer surface and a needle nozzle which was used to supply the test liquid. The result indicated that in the case of R113 droplet, a higher electric voltage was needed to enhance evaporation. On the other hand, in the case of ethanol droplet, evaporation enhancement was observed at a lower voltage, in particular at the region of low surface superheat. This tendency agreed with the result of a preceding report of this study in which the evaporation time of an ethanol droplet was measured. In the present experiment, the enhancement ratios of evaporation of R113 and ethanol droplets were 1∼2.8 and 1∼7.6, respectively.