Experimental study on electrohydrodynamically induced heat transfer enhancement in a minichannel

Effect of electric field on heat transfer enhancement and pressure drop for different Reynolds numbers is experimentally investigated in a minichannel for laminar flow. The test section consists of a square channel with a heater embedded in its bottom. The high voltage electrode is a wire, placed on top of the test section of channel and the bottom is considered as ground. The side walls in the test section are thermally and electrically insulated. Secondary flow, as a result of charge injection from high voltage electrode through the liquid, disrupts the boundary layer and leads to higher convective heat transfer coefficients and higher amounts of pressure drop. By increasing electric field intensity cooling performance was improved for all Reynolds numbers. Results show that presence of electric field is more effective in lower Reynolds numbers and as the mass flow rate increases the effect of electric field decreases. Performance Evaluation Criterion (PEC) is calculated and as an outstanding result its values were upper than unity which in most of the enhancement techniques is not. PEC value increases by raising electric field intensity or decreasing Reynolds number.