Abstract

A macrolayer formation model for predicting the critical heat flux (CHF) in saturated and subcooled pool boiling was proposed. The concept of this model was based on the bubble coalescence process, which was observed using a high-speed camera. In the present model, the thickness of the macrolayer was calculated assuming that the liquid volume remaining under the lower part of the bubble should contribute to the formation of the layer. A Poisson distribution was adopted for the distribution of nucleation sites. The predicted macrolayer thicknesses were used for the prediction of CHFs in saturated and subcooled pool boiling based on the macrolayer dryout model. This model reproduced the CHF values for pool boiling up to subcooling 40 K. The model concept was confirmed using a computational fluid dynamics code, where the assumption was that the liquid was captured and the macrolayer was formed at the coalescence of bubbles.

摘要

提出了预测饱和和过冷池沸腾临界热通量 (CHF) 的宏观层形成模型。该模型的概念基于气泡聚结过程，该过程使用高速相机进行观察。在本模型中，假设气泡下部剩余的液体体积应有助于层的形成，计算宏观层的厚度。成核位点的分布采用泊松分布。基于宏观层干涸模型，预测的宏观层厚度用于预测饱和和过冷池沸腾中的 CHF。该模型再现了池沸腾到过冷 40 K 时的 CHF 值。该模型概念已使用计算流体动力学代码得到确认，