Enhancement of heat transfer via corona discharge by using needle-mesh and needle-fin electrodes

As a potential alternative of traditional heat transfer enhancement technology, ionic wind has drawn great attention. In this study, a direct comparison of the ionic wind devices with needle-mesh and needle-fin electrodes is carried out experimentally. The ionic characteristics and cooling performances of two electrode types here are tested and quantitatively analyzed by calculating the empirical correlations defining the relationship between electrohydrodynamics and heat transfer. The results indicate that the electrode gap d and the number of needle electrodes N are the main factors of ionic characteristics such as current, velocity and efficiency. And the results of heat transfer show that the needle-fin configuration has a superior performance, which has made a temperature drop from 54.5 degrees C to 39.1 degrees C with the low power consumption of 0.85 W. An empirical correlation for calculating the Nu Re relation in the case is developed, which reflects that the ionic wind is a fluid with thinner boundary layer and stronger convection. In addition, the heat transferred by the fins in the ionic wind device is more than twice that of the convection on the plate surface. Finally, the feasibility and advantages of using fins as collector electrodes are confirmed. (C) 2018 Elsevier Ltd. All rights reserved.