This paper describes results from an experimental study of the effect of an electric field on nucleate boiling and the critical heat flux (CHF) in pool boiling at atmospheric pressure. A dielectric liquid ofHFE-7100 (3 M Co.) was used as working fluid. A heating surface was polished with the surface roughness (Ra) of 0.05 ßm. A microsized electrode, in which the slits were provided, was designed in order to generate non uniform high electric fields and to produce electrohydrodynamic (EHD) effects with the application of high voltages. The obtained results confirmed the enhancement of CHF since the EHD effects increased the CHF to 4TWIcn? at the voltage of -1500V, which was three times as much as CHF for the free convection boiling. From the observations of the behavior of bubbles over the electrode and of the boiling surface condition, the instability between the liquid and the vapor increased the heat flux, the heat transfer coefficient (HTC), and the CHF. The usual traveling wave on the bubble interface induced by the KelvinHelmholtz instability was modified by adding the EHD effects. The ratio of critical heat flux increase with and without the electric field was sufficiently predicted by the frequency ratio of liquid-vapor surface at the gap between the boiling surface and the electrode.

Effects of electrostatic force on boundary surfaces between the liquid and the vapor in pool boiling has been investigated experimentally ． An electrode design was considered so as to remove vapor bubbles 丘om a heat transfer

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The paper describes results from an experimental study of the effect of an electric field on nucleate boiling and the critical heat flux (CHF) in pool boiling at atmospheric pressure with polished smooth boiling surface. A micro scaled electrode with slits for bubbles to come out was designed in order to create non uniform high electric field strength and to produce electrohydrodynamics (EHD) convection with the application of dc voltage. The application of high electric field strongly enhanced the heat flux and the heat transfer coefficient. From observations of the behavior of bubbles over the electrode and the boiling surface condition, the instability between the liquid and the vapor increased the heat flux, the heat transfer coefficient and the CHF.