Abstract The effect of swirling intensity on the structure and heat transfer of a turbulent gas–droplet flow after a sudden pipe expansion has been numerically simulated. Air is used as the carrier phase, and water, ethanol, and acetone are used as the dispersed phase. The Eulerian approach is applied to simulate the dynamics and heat transfer in the dispersed phase. The gas phase is described by a system of Reynolds-averaged Navier-Stokes (RANS) equations, taking into account the effect of droplets on mean transport and turbulent characteristics in the carrier phase. Gas phase turbulence is predicted using the second-moment closure. A swirling droplet-laden flow is characterized by an increase in the number of small particles on the pipe axis due to their accumulation in the zone of flow recirculation and the action of the turbulent migration (turbophoresis) force. A rapid dispersion of fine droplets over the pipe cross-section is observed without swirling. With an increase in swirling intensity, a significant reduction in the length of the separation region occurs. The swirling of a two-phase flow with liquid droplets leads to an increase in the level of turbulence for all three types of liquid droplets investigated in this work due to their intensive evaporation. It is shown that the addition of droplets leads to a significant increase in heat transfer in comparison with a single-phase swirling flow. The greatest effect of flow swirling on heat transfer intensification in a two-phase gas-droplet flow is obtained for the droplets of ethanol and water and smallest effect is for the acetone droplets.

中文翻译：

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管道突然膨胀中旋流湍流液滴流动与传热的数值分析

摘要 数值模拟了旋流强度对突然扩管后湍流气体-液滴流结构和传热的影响。空气用作载相，水、乙醇和丙酮用作分散相。欧拉方法用于模拟分散相中的动力学和传热。气相由雷诺平均纳维-斯托克斯 (RANS) 方程系统描述，考虑到液滴对载体相中平均传输和湍流特性的影响。使用二阶矩闭合预测气相湍流。带液滴的涡流的特点是管轴上的小颗粒数量增加，这是由于它们在流动再循环区域中的积累和湍流迁移（涡轮电泳）力的作用。观察到细小液滴在管道横截面上快速分散而没有涡流。随着旋流强度的增加，分离区域的长度显着减少。由于其强烈蒸发，具有液滴的两相流的漩涡导致本工作中研究的所有三种类型的液滴的湍流水平增加。结果表明，与单相涡流相比，添加液滴会导致传热显着增加。