Wang Ziqi, Mathai Varghese, Sun Chao
Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, 100084, Beijing, China.
School of Engineering, Brown University, Providence, RI, 02912, USA.
Nat Commun. 2019 Jul 26;10(1):3333. doi: 10.1038/s41467-019-11221-w.
Turbulence is known for its ability to vigorously mix fluid and transport heat. Despite over a century of research for enhancing heat transport, few have exceeded the inherent limits posed by turbulent-mixing. Here we have conceptualized a kind of "active particle" turbulence, which far exceeds the limits of classical thermal turbulence. By adding a minute concentration (ϕ ∼ 1%) of a heavy liquid (hydrofluoroether) to a water-based turbulent convection system, a remarkably efficient biphasic dynamics is born, which supersedes turbulent heat transport by up to 500%. The system operates on a self-sustained dynamically equilibrated cycle of a "catalyst-like" species, and exploits several heat-carrier agents including pseudo-turbulence, latent heat and bidirectional wake capture. We find that the heat transfer enhancement is dominated by the kinematics of the active elements and their induced-agitation. The present finding opens the door towards the establishment of tunable, ultra-high efficiency heat transfer/mixing systems.
湍流以其强烈混合流体和传输热量的能力而闻名。尽管经过了一个多世纪提高热传输的研究,但很少有研究能超越湍流混合所带来的固有极限。在此,我们构想了一种“活性粒子”湍流,其远远超越了经典热湍流的极限。通过向水基湍流对流系统中添加微量浓度(ϕ ∼ 1%)的重液(氢氟醚),一种显著高效的双相动力学应运而生,其热传输效率比湍流热传输高出多达500%。该系统在一种“类催化剂”物质的自持动态平衡循环上运行,并利用了包括伪湍流、潜热和双向尾流捕获在内的多种热载体介质。我们发现,传热增强主要由活性元素的运动学及其诱导的搅动所主导。这一发现为建立可调谐的超高效率传热/混合系统打开了大门。