Abstract A mechanistic model that includes the effect of the bubble coalescence on nucleate pool boiling heat transfer is developed through experimental and theoretical investigations. Transient temperature and heat flux distributions on the boiling surface are obtained using a high-speed infrared imaging technique. According to the temperature and heat flux distributions, the boiling surface is classified into three regions: natural convection, quenching, and evaporation regions. By observing how the heat flux on each region and the corresponding area fraction change as the bubble coalescence occurs, the effect of the bubble coalescence on nucleate pool boiling is investigated. It is found that the bubble coalescence does not affect the heat fluxes on the three regions but affects the area fractions: As the bubble coalescence occurs, the rates of increase in quenching and evaporation area fractions with respect to the wall superheat decrease, while the natural convection area fraction remains the same. By accounting for the effect of the bubble coalescence on quenching and evaporation area fractions, a new correlation of the boiling heat flux is developed and presented. To validate the proposed model, boiling curves for saturated water and FC-72 are reproduced and compared to experimental data. The most distinguishing feature of the model is that it accurately predicts the rate of change of the heat flux with respect to the wall superheat as well as the location of the inflection point at which the slope of the boiling curve begins to decrease. As a result, the error between the reproduced boiling curve and experimental data is reduced by 94% compared to the previous model, which does not include the effect of the bubble coalescence for both water and FC-72.

中文翻译：

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包括气泡合并对面积分数的影响的核池沸腾机理模型

摘要 通过实验和理论研究，建立了包括气泡聚结对核池沸腾传热影响的机理模型。沸腾表面的瞬态温度和热通量分布是使用高速红外成像技术获得的。根据温度和热通量分布，沸腾表面分为三个区域：自然对流区、淬火区和蒸发区。通过观察气泡聚结发生时各区域的热通量和相应的面积分数如何变化，研究了气泡聚结对核池沸腾的影响。发现气泡合并不影响三个区域的热通量，但影响面积分数：随着气泡合并的发生，淬火和蒸发面积分数相对于壁面过热度的增加率降低，而自然对流面积分数保持不变。通过考虑气泡聚结对淬火和蒸发面积分数的影响，开发并呈现了沸腾热通量的新关联。为了验证所提出的模型，再现了饱和水和 FC-72 的沸腾曲线并与实验数据进行了比较。该模型最显着的特点是它准确地预测了热通量相对于壁面过热度的变化率以及沸腾曲线斜率开始减小的拐点位置。结果，与之前的模型相比，再现的沸腾曲线与实验数据之间的误差减少了 94%，