Abstract

In this study, the heat transfer by forced convection over a circular cylinder was studied numerically in the presence of an electric field and the effects of the installation angle of discharge electrode, wire–cylinder spacing and electrohydrodynamic (EHD) number were also investigated. The results showed that the location of discharge electrodes has a considerable effect on changing the flow pattern, velocity profile, and scheme of thermal boundary layer. It was found that the corona wind can increase the local and average Nusselt numbers. However, in some cases, the EHD actuator had a negative effect on the convective heat transfer rate due to the interaction between the corona wind and the main flow. In addition, EHD enhancement is more effective at high EHD numbers and low wire–cylinder spacing values. Based on the results, a maximum enhancement of 42.1% was observed in the average Nusselt number using the EHD technique. Finally, the EHD efficiency was calculated as an outstanding result to assess the performance of the EHD actuator. The results revealed that although the EHD is more effective at higher electric field strengths in terms of thermal enhancement, it is not cost-effective because of the high power consumption.

摘要

在这项研究中，在存在电场的情况下，对圆柱上的强制对流传热进行了数值研究，并研究了放电电极安装角度、线-圆柱间距和电流体动力学 (EHD) 数的影响。结果表明，放电电极的位置对改变流动模式、速度分布和热边界层方案有相当大的影响。发现日冕风可以增加当地和平均努塞尔数。然而，在某些情况下，由于电晕风和主流之间的相互作用，EHD 致动器对对流换热率有负面影响。此外，EHD 增强在高 EHD 数量和低线筒间距值下更有效。根据结果​​，使用 EHD 技术在平均努塞尔数中观察到了 42.1% 的最大增强。最后，EHD 效率被计算为评估 EHD 执行器性能的出色结果。结果表明，虽然 EHD 在较高的电场强度下在热增强方面更有效，但由于高功耗，它不具有成本效益。