Convective heat transfer enhancement of ionic wind under variable air pressures

Abstract

Abstract Presently, limited studies are available in understanding the ionic wind s behaviour under restricted or extreme environmental conditions. Thus, this study aims to investigate ionic wind characteristics and its convective heat transfer enhancement under the influence of varying air pressures. Here, an ionic wind generated from a cone to mesh configuration was used. Results showed that the discharge current (which translates to power consumption) and velocity of the ionic wind behaved in opposing manners at pressures above and below atmospheric pressure. Increasing the pressure above the atmospheric pressure led to a decrease in velocity for both positive and negative ionic wind, while the wind velocity was relatively constant at air pressures below atmospheric pressure. On the other hand, the power consumption was also seen to be consistent for positive ionic wind, while the negative ionic wind showed a power consumption decline with increasing air pressure. The highest power consumption was observed for the negative ionic wind at the lowest air pressure. Further investigations on the convective heat transfer showed a maximum achievable enhancement of 17% over natural convection for both positive and negative ionic wind. The optimum performance, which is defined as the heat transfer enhancement ratio over power consumption of the ionic wind, was found to be at just beneath the atmospheric pressure at 0.9\xa0bar for both positive and negative ionic wind, with the positive ionic wind superseding the efficiency of negative ionic wind by 17%.