On the accuracy of Eulerian-Lagrangian CFD simulations for spray evaporation in turbulent flow

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL International Journal of Thermal Sciences Pub Date : 2024-10-30 DOI:10.1016/j.ijthermalsci.2024.109461

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Abstract

CFD simulation of droplet evaporation in turbulent flows is challenging as the accuracy and reliability of the results strongly depend on the available sub-models and their modeling parameters. This study presents a systematic sensitivity analysis focused on the impact of the most widely used discrete random walk (DRW) model, the constant time scale coefficient (C_L), the turbulence model, and the drag coefficient model. CFD simulations with the Eulerian-Lagrangian approach are employed. The analysis is based on grid-sensitivity analysis and validation with measurements of spray evaporation in a heated turbulent airflow. The results show that using the DRW model leads to a good agreement between the CFD results and the experimental data of droplet size and droplet mean velocity, attributed to the turbulent fluctuations inducing droplet dispersion. The best performance is observed for the standard k-ε turbulence model with C_L = 0.30 and 0.45. This is mainly attributed to the reasonable interaction time between droplets and turbulent eddies at these C_L values. The three drag coefficient models (i.e., Spherical, Ischii-Zuber, and Grace) lead to similar results due to the low droplet Reynolds number.

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论欧拉-拉格朗日 CFD 模拟湍流中喷雾蒸发的精度

湍流中液滴蒸发的 CFD 模拟极具挑战性，因为结果的准确性和可靠性在很大程度上取决于可用的子模型及其建模参数。本研究针对最广泛使用的离散随机漫步（DRW）模型、恒定时间尺度系数（CL）、湍流模型和阻力系数模型的影响进行了系统的敏感性分析。采用欧拉-拉格朗日方法进行 CFD 模拟。分析基于网格敏感性分析以及加热湍流气流中喷雾蒸发测量的验证。结果表明，使用 DRW 模型可使 CFD 结果与液滴大小和液滴平均速度的实验数据保持良好的一致性，这归因于湍流波动诱导了液滴的分散。CL = 0.30 和 0.45 的标准 k-ε 湍流模型的性能最佳。这主要是因为在这些 CL 值下，液滴与湍流涡旋之间的相互作用时间比较合理。由于液滴雷诺数较低，三种阻力系数模型（即球形模型、Ischii-Zuber 模型和 Grace 模型）的结果相似。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.