Abstract A semi-mechanistic critical heat flux (CHF) model has been developed based on own experimental data. It is the first model, which can predict a spatial variation of the local CHF along a 10° inclined flat surface facing downward. To model the slug flow within the two-phase boundary layer, the present work modified several fundamental variables of the original Cheung and Haddad's model and they are critical void fraction, shear stress, and newly introduced momentum loss terms responsible for pressure drop via drag force exerted on the vapor slug and acceleration of the entrained liquid to the boundary layer flow. The present model predicted that the local CHF varied spatially along the heater surface, and the CHF variation could be divided into two regions. The first region is the buoyancy dominant region, in which the local CHF increases rapidly along the heater surface from the beginning point. In the second region called momentum loss dominant region, the local CHF gradually decreases as the position is down further. Interestingly, the current model showed that the very upstream region over the inclined heater surface is mostly susceptible to occurrence of boiling crisis, whose results could be supported by the Sulatskii et al.'s work.

中文翻译：

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沿略微倾斜向下表面的局部临界热通量空间变化的半机械预测

摘要 基于自己的实验数据开发了半机械临界热通量（CHF）模型。它是第一个模型，可以预测局部 CHF 沿朝下倾斜 10° 的平面的空间变化。为了模拟两相边界层内的段塞流，目前的工作修改了原始 Cheung 和 Haddad 模型的几个基本变量，它们是临界空隙率、剪应力和新引入的动量损失项，负责通过阻力引起的压降施加于蒸汽段塞和夹带液体加速到边界层流。本模型预测局部 CHF 沿加热器表面在空间上变化，并且 CHF 变化可分为两个区域。第一个区域是浮力优势区域，其中局部 CHF 从起点沿加热器表面迅速增加。在称为动量损失主导区域的第二个区域中，随着头寸进一步下跌，当地瑞士法郎逐渐减少。有趣的是，当前模型显示倾斜加热器表面上的非常上游区域最容易发生沸腾危机，其结果可以得到 Sulatskii 等人的工作的支持。