Numerical analysis and optimization of heat transfer enhancement on a flat plate by an EHD jet

Abstract

EHD-jets are a novel means of active flow control that enhances heat transfer rate and overcomes restrictions of traditional rotary cooling systems in miniature electronic apparatus. This article investigates the hydrodynamic and hydrothermal performance of a small-scale Electrohydrodynamic jet (EHD-jet) for enhancing convective heat transfer on a flat impinging plate, while monitoring power consumption. The effect of variations of numerous parameters including the wire position (L), EHD-jet distance from the impingement plate (H), collecting electrodes inclination angle (α), and applied voltage (φ) is inspected. The results demonstrate that increasing α and φ causes a decrease in the average Nusselt number and power consumption. Although the growth of the H does not affect the power consumption very much, it is influential on the change of average Nusselt number. Also, Response Surface Method (RSM) with the face-centered Central Composite Design (CCD) was used to investigate the interactive effect of parameters on system performance. Results show that the effect of variable H and L on Nusselt number is at its peak when the applied voltage is maximized. Additionally, an increased α results in a more prominent effect of parameter H on the Nusselt number. In the end, a desirability-based multi-objective optimization approach is used to maximize the Nusselt number and minimize power consumption. The proposed optimum structure increased the Nusselt number by over 82% and lowered power consumption by over 52% compared to the reference case.