COMPUTATIONAL STUDIES OF EHD-ENHANCED CONDENSATION HEAT TRANSFER ON A DOWNWARD-FACING HORIZONTAL PLATE

摘要

This study aims to investigate the effect of uniform electric fields on the enhancement of condensation heat transfer from a downward facing horizontal plate by direct numerical simulations. The governing equations of fluid flow and electric field are solved using a front tracking/finite difference technique in the framework of Taylor's leaky dielectric model. The electric force comprises of the dielectrophoretic and the Coulomb forces. Both forces act on the phase boundary and their relative magnitude and directions affect the condensation rate. For the results shown here, the condensate drops are more elongated compared to the those in zero-electric field. It is shown that the electric field enhances the condensation rate in two ways: by increasing the number of the drops that are generated per unit surface due to destablizing the interface and by increasing the frequency of drop generation and pinch off. The mechanism of elongation of the condensate drops are explained by detailed examination of the distribution of the electric field at the phase boundary.