Heat Transfer Engineering, Vol.25, No.6, 14-22, 2004
An analytical model for EHD-enhanced microscale thin-film evaporation
An analytical model has been developed to predict the heat transfer and flow characteristics of electrohydrodynamic (EHD)-enhanced microscale ultra thin-film evaporation. The model described in this paper is based on a previously published microcooling device [1] that incorporated an active evaporative cooling surface, an EHD micropump, and temperature sensors into a single chip. The device was fabricated using microelectromechanical systems fabrication technology, allowing the EHD electrodes and temperature sensors to be integrated directly onto the cooling surface. One end of the device was immersed in a pool of liquid. The film originated at the liquid-vapor interface and flowed upward under the influence of the electric field. The model predicts the film thickness, dryout location, local and average heat transfer coefficients, and velocity profile. The agreement between the model and the experimental data is satisfactory. Both the analytical model developed in this study and the experimental results reported previously will facilitate the design of new microcooling devices capable of operating at high power levels.