The Effect of Pulsating Dielectrophoresis on Liquid Film Flow Boiling

Electrohydrodynamics (EHD) has been explored for a variety of applications, including thermal management of electronics for both terrestrial and space applications. EHD conduction pumping of dielectric liquids provides a lightweight, low-power, and solid-state method for cooling. Dielectrophoresis (DEP) offers a mechanism for phase-separation of liquid and vapor for enhancement of two-phase heat transfer. EHD conduction pumping of a thin liquid film in conjunction with DEP vapor extraction is being explored as a next generation thermal management technology for satellites and deep space missions. This study is exploring the effect of a pulsating diverging electric field applied to boiling heat transfer of a thin liquid film. The results show that there is an optimal frequency of application at a given heat flux, which can be related to the frequency of bubble departure from the heated surface. In addition, at higher heat fluxes, the void fraction of vapor increases and the measured electric current decreases. The heat transfer enhancement of continuous DC voltage application is greater than the pulsating cases due to the electroconvection and mixing being stronger. However, there are potential efficiency benefits due to the periodic application of voltage.