Mechanisms of thermal nanofluids on enhanced critical heat flux (CHF)
Mechanisms of thermal nanofluids on enhanced critical heat flux (CHF)
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DOI：
10.1016/j.ijheatmasstransfer.2008.01.034
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发表时间：
2008-09
影响因子：
5.2
通讯作者：
D. Wen
中科院分区：
文献类型：
--
作者：
D. Wen
自从大约十年前发现了热纳米流体的增强导热系数以来，对其的研究取得了迅速的进展。热纳米流体在池沸腾条件下能显著提高临界热流密度(CHF)，这不能用传统的纯流体理论解释。本文提出了另一种机制，即纳米颗粒在半月面中的限制产生的长程结构分离压力，并研究了它在高热流密度条件下的作用。将结构分离压力引入四区干片模型，建立了计算纳米颗粒存在下的平衡弯月面形状的解析模型。结果表明，结构分离压力能显著提高流体的润湿性，抑制干斑的形成。本文还讨论了增强充血性心力衰竭的其他可能机制，并推荐了解决剩余问题的未来研究。
Research on thermal nanofluids has progressed rapidly since their enhanced thermal conductivities were identified about a decade ago. Thermal nanofluids have been observed to increase the critical heat flux (CHF) remarkably under pool-boiling conditions, which could not be explained by conventional theories developed for pure fluids. This paper proposes an alternative mechanism, the long-range structural disjoining pressure arising from the confinement of nanoparticles in a meniscus, and investigates its role under high heat flux conditions. The structural disjoining pressure is incorporated into a four-zoned dry patch model and an analytical model is established to calculate the equilibrium meniscus shape in the presence of nanoparticles. The results show that the structural disjoining pressure can significantly increase the wettability of the fluids and inhibit the dry patch development. Other possible mechanisms on the enhanced CHF are discussed and future studies to resolve remaining issues are recommended.