Characterization of Wicking Performance for Open Rectangular Microgrooves under Planar Electrohydrodynamics Effects in Two-phase Heat Transfer Devices

Advanced thermal management for future electronics have promoted the development and investigation of two-phase heat transfer devices (i.e., micro heat pipes, vapor chambers, capillary pumped loops etc.). The electrohydrodynamics (EHD) pumping is an attractive solution to insufficient liquid supply and dryout occurrence in wicks of such devices. In this study, the wicking performance of rectangular microgrooves is characterized and evaluated by axial maximum capillary wetting length at steady state and dynamic rise rate at transient state during rate-of-rise experiments. Two planar electrodes are used to generate electric field. The maximum axial capillary wetting length under EHD effects at steady state is experimentally conducted and theoretical analyzed, and the predicted results agree well with the experimental data. The dynamic wicking characteristics with considering the electric field are investigated at transient state, and the empirical correlations are obtained according to the fitting experimental data as ²~t curve at initial stage, and ~^- curve at long-term stage. EHD pumping mechanism is also analyzed. EHD effects can decrease the wall temperature of microgrooves. There exists an optimal electric voltage to obtain the highest economic efficiency and wicking performance in this study.