Enhancement of Forced Convection Using a Two-Stage Electrohydrodynamic Gas Pump

A two-stage electrohydrodynamic (EHD) gas pump is numerically examined for its potential to enhance forced convection in a square channel. The EHD gas pump with 28 emitting electrodes in each stage is evaluated for a wide range of operating voltages starting from 20kV up to 28kV. The influence of electric field on the flow and temperature fields are also examined for a wide range of Reynolds numbers varying between 100 and 2000. The emitting electrodes of the EHD gas pump are flush mounted on the channel walls so that the corona wind produced can directly disturb the boundary layers to create the maximum enhancement. The pumping power required for the heat transfer enhancement is also critically evaluated. The maximum increase in the average Nusselt number is 30%, which is achieved at Reynolds number Re=200 with an applied voltage of 28kV. The overall effectiveness of the EHD gas pump in heat transfer enhancement is evaluated by the parameter of thermal hydraulic performance, (Nu/Nu(0))/(f/f(0)), which is found to be always greater than unity. These results reveal that EHD gas pump has a great potential for applications in thermal management.