| dc.description.abstract | This numerical study utilized the electrohydrodynamics (EHD) techniques to generate the corona wind to enhance the heat convection inside the channe, so that the heat transfer . Numerical simulations results were used to compared with experiments to validate present numerical model, also, to clarify the physical mechanism and heat dissipation induced by EHD techniques.
First, two kind of electrode geometries setup including the needle-to-plate and the wire-to-grid were implemented. By comparing the applied voltage, corona current, flow velocity and heat transfer coefficient with the experimental data to validate the accuracy of the models. Next, the wire-to-plate geometry was simulated and the effects of different applied voltages (3~6 kV), different electrode separations (0.00175 and 0.00275 m) and different collecting electrode geometries on heat transfer were discussed, including cylindrical (case 1) and normal plate (case 2) inlet geometry. The results showed that the best convective flux efficiency could reached to 1.6 times of that of the traditional chanel flow without EHD effect. Numerical results show that the applied voltage is directly proportional to the flow velocity, convective coefficient, Nu (Nusselt no.) and heat transfer enhancement. The electrode separation is inversely proportional to the flow velocity, convective coefficient, Nu (Nusselt number) and heat transfer enhancement. The heat transfer efficiency in case 1 were 14.2 % better than that of case 2, however, the former consumes 18 mW higher than the latter. The space of electrode is inversely proportional to the flow velocity, heat convection coefficeint, Nu and heat transfer enhancement. Base on present study, EHD technology indeed provide a significant cooling effect on the channel flow.
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