Grounded Electrode Size Effect on Forced Convection Enhancement by a Single Stage EHD Gas Pump

Abstract

Abstract In this study, forced convection enhancement in a square channel by a single stage electrohydrodynamic (EHD) gas pump is numerically examined. The EHD gas pump having three different sizes of grounded electrode configurations: 0.5-inch, 1-inch, and 2-inch wide respectively are investigated for their effectiveness in the enhancement of forced convection and pumping power requirement. The EHD gas pump with 28 emitting electrodes is evaluated for a wide range of operating voltages starting from 20 kV up to 28 kV. The influence of electric field on the flow and temperature fields is also examined for a wide range of Reynolds numbers. The three-dimensional governing equations for the flow and temperature fields are solved using the finite volume method. The Reynolds numbers (Re) considered in this study varies in a range between 100 and 2000. At Re = 100, a maximum increase of 55% in the average Nusselt number is achieved with an applied voltage of 28 kV. The overall effectiveness of the EHD gas pump in heat transfer enhancement is evaluated by the thermal hydraulic performance parameter, (Nu/Nu0)/(f/f0), which is always greater than unity. These results disclose that EHD technique has a great potential for many engineering applications, particularly for thermal management.