Convective heat transfer enhancement of ionic wind under variable air pressures
Convective heat transfer enhancement of ionic wind under variable air pressures
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DOI：
10.1016/j.ijthermalsci.2020.106657
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发表时间：
2021-02
影响因子：
4.5
通讯作者：
Jun Rong Lee;E. V. Lau
中科院分区：
文献类型：
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作者：
Jun Rong Lee;E. V. Lau
目前，在了解离子风在受限或极端环境条件下的行为方面的研究有限。因此，本研究旨在研究不同气压影响下的离子风特性及其对流换热增强。这里，使用从锥体到网状配置产生的离子风。结果表明，在高于和低于大气压的压力下，放电电流（转化为功耗）和离子风的速度表现出相反的方式。将压力增加到大气压以上会导致正离子风和负离子风的速度降低，而在气压低于大气压时风速相对恒定。另一方面，正离子风的功耗也保持一致，而负离子风的功耗随着气压的增加而下降。在最低气压下负离子风的功耗最高。对对流换热的进一步研究表明，对于正离子风和负离子风来说，与自然对流相比，最大可实现 17% 的增强。正离子风和负离子风的最佳性能定义为传热增强率与离子风功耗之比，结果显示，正离子风和负离子风的效率均略低于大气压（0.9 巴），正离子风的效率比负离子风高出 17%。
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 bar for both positive and negative ionic wind, with the positive ionic wind superseding the efficiency of negative ionic wind by 17%.