Modelling of free bubble growth with Interface Capturing Computational Fluid Dynamics
Modelling of free bubble growth with Interface Capturing Computational Fluid Dynamics
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DOI：
10.1007/s42757-022-0139-5
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发表时间：
2022-09-12
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影响因子：
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通讯作者：
Issa, Raad I.
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文献类型：
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作者：
Giustini, Giovanni;Issa, Raad I.
本文提出了一个扩展的液体池中的静止和上升的蒸汽气泡的生长模拟使用界面捕获计算流体动力学（CFD）方法，再加上一种方法，用于模拟在汽液界面的界面传质。该模型使机械预测的汽液界面处的相变的局部速率，并适用于涉及具有大密度比的两相混合物的实际情况。模拟方法是基于流体体积（VOF）表示的流量，其中发生传质的界面区域隐含地识别相指标，在这种情况下，液体的体积分数，它从属于“散装”液体的值到散装蒸汽的值。这里提出的新方法已经实现了使用有限体积框架和解决方案的方法典型的“工业”CFD实践嵌入在OpenFOAM CFD工具箱。通过与零重力下球形气泡生长和正常重力下上升气泡生长的实验观察结果进行比较，验证了模拟结果。由于密度比大，存在强烈的界面蒸发和向上的气泡上升运动，验证案例代表了对界面捕获方法的严格测试。模拟结果与文献中可用的测量值的一致性表明，本文详述的方法适用于模拟由真实的流体中的相变驱动的气泡生长。
This paper presents simulations of the growth of stationary and rising vapour bubbles in an extend pool of liquid using an Interface Capturing Computational Fluid Dynamics (CFD) methodology coupled with a method for simulating interfacial mass transfer at the vapour-liquid interface. The model enables mechanistic prediction of the local rate of phase change at the vapour-liquid interface and is applicable to realistic cases involving two-phase mixtures with large density ratios. The simulation methodology is based on the Volume of Fluid (VOF) representation of the flow, whereby an interfacial region in which mass transfer occurs is implicitly identified by a phase indicator, in this case the volume fraction of liquid, which varies from the value pertaining to the "bulk" liquid to the value of the bulk vapour. The novel methodology proposed here has been implemented using the Finite Volume framework and solution methods typical of "industrial" CFD practice embedded in the OpenFOAM CFD toolbox. Simulations are validated via comparison against experimental observations of spherical bubble growth in zero gravity and of the growth of a rising bubble in normal gravity. The validation cases represent a severe test for Interface Capturing methodologies due to large density ratios, the presence of strong interfacial evaporation and upward bubble rise motion. Agreement of simulation results with measurements available in the literature demonstrates that the methodology detailed herein is applicable to modelling bubble growth driven by phase-change in real fluids.