Electrohydrodynamic can significantly improve flow boiling heat transfer. However, pin electrode configuration has not been investigated comprehensively. This study explores the flow boiling performance of vertical minichannels in non-uniform electric field formed by pin electrode. The influences of pin electrode spacing and array region on flow pattern and heat transfer under electric field are studied. Flow patterns of bubbly, slug and confined bubble flow were captured and analyzed by using visualization techniques. The results demonstrate that the volume of bubbles decreases and the number increases under electric field. Besides, electric field mitigates bubble coalescence and delays the flow pattern transition. The electric field enhancement ratio is up to 1.64. The enhancement effect of these tested electrode configurations is related to the length to diameter ratio for the bubble. Under present experimental conditions, when the average length-to-diameter ratio exceeds 3.12, the electric field enhancement effect begins to diminish. In the theoretical aspect, we perform numerical simulations of the detachment behavior of the bubbles under different electrode arrangements. Furthermore, simulations of the bubble detachment process under an electric field are carried out to investigate the enhanced mechanism of pin electrode on minichannel flow boiling.

中文翻译：

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针电极对垂直微通道内流动沸腾传热和气泡动力学行为的影响

电流体动力学可以显着改善流动沸腾传热。然而，针电极配置尚未得到全面研究。本研究探讨了针电极形成的非均匀电场中垂直微通道的流动沸腾性能。研究了电场下针电极间距和阵列区域对流型和传热的影响。通过使用可视化技术捕获和分析气泡流、段塞流和受限气泡流的流动模式。结果表明，在电场作用下，气泡体积减小，数量增加。此外，电场减轻了气泡聚结并延迟了流型转变。电场增强比高达1.64。这些测试的电极配置的增强效果与气泡的长径比有关。在目前的实验条件下，当平均长径比超过3.12时，电场增强效果开始减弱。在理论方面，我们对不同电极布置下气泡的脱离行为进行了数值模拟。此外，还对电场下气泡脱离过程进行了模拟，研究了针电极对微通道流动沸腾的增强机理。