On critical heat flux and its evaporation momentum and hydrodynamic limits
On critical heat flux and its evaporation momentum and hydrodynamic limits
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DOI：
10.1016/j.ijheatmasstransfer.2022.123837
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发表时间：
2023-04
影响因子：
5.2
通讯作者：
Suhas Rao Tamvada;Daniel Attinger;S. Moghaddam
中科院分区：
文献类型：
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作者：
Suhas Rao Tamvada;Daniel Attinger;S. Moghaddam
从被加热的表面到周围沸腾液体的热传递的上限，自从Nukiyama（1934）发现这个极限以来，一直是许多研究的主题。控制这一现象的基本物理原理，通常被称为临界热通量（CHF）极限，已经被广泛争论了近一个世纪。出现了两种流行的假设，包括流体动力不稳定性和蒸发动量阈值，分别由Kutateladze（1948）和Steinchen和Sefiane（1996）提出。Zuber（1959）和Kandlikar（2001）基于这些假设建立了相关性，预测了大致相似的CHF值，即铜表面上1atm水的CHF值为~ 100 W/cm2。在这里，我们展示了在不同尺寸的平面加热器表面上对具有广泛热物理性质的液体进行的实验和分析研究（以稳定流动流体动力学），结果表明蒸发动量极限（CHFEM）大约是Zuber极限（CHFZuber）的4倍。我们表明，chfem只能在表面以上的液体和蒸汽的流体动力学稳定时观察到，描绘了一个由表面-流体界面的力平衡而不是远离表面的液体和蒸汽界面的不稳定性控制的最终极限。我们发现，对于所有测试的流体、饱和温度和加热器几何形状，CHF/ chfemm在0.2到1之间变化，代表了48种情况。
The upper limit of heat transfer from a heated surface to a surrounding boiling liquid has been the subject of numerous studies ever since Nukiyama (1934) discovered this limit. The underlying physics governing this phenomenon, universally known as the critical heat flux (CHF) limit, has been extensively debated for nearly a century. Two prevailing hypotheses have emerged including hydrodynamic instability and evaporation momentum force thresholds proposed by Kutateladze (1948) and Steinchen and Sefiane (1996), respectively. Zuber (1959) and Kandlikar (2001) developed correlations based on these hypotheses that predict roughly similar CHF values i.e., ∼100 W/cm2for water at 1 atm on a copper surface. Here, we present experimental and analytical studies conducted on liquids with a wide range of thermophysical properties on planar heater surfaces of different size (to stabilize the flow hydrodynamics) that show the evaporation momentum limit (CHFEM) is roughly 4 times the Zuber's limit (CHFZuber). We show that CHFEMcan only be observed when hydrodynamics of liquid and vapor above the surface is stabilized, delineating an ultimate limit governed by a force balance at the surface-fluid interface rather than the instability of liquid and vapor interface away from the surface. We find that CHF/CHFEMvaries from 0.2 to 1 for all fluids, saturation temperatures, and heater geometries tested, representing 48 conditions.