Investigation of heat transfer in spacer-filled channels by experiments and direct numerical simulations
Investigation of heat transfer in spacer-filled channels by experiments and direct numerical simulations
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DOI：
10.1016/j.ijheatmasstransfer.2015.11.034
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发表时间：
2016-02-01
影响因子：
5.2
通讯作者：
Ciofalo, M.
中科院分区：
文献类型：
--
作者：
Tamburini, A.;Renda, M.;Ciofalo, M.
流场和传热传质现象的分析对于优化设计各种膜基工艺的间隔填充通道几何形状具有重要意义。本文采用实验和计算流体力学（CFD）相结合的方法，对膜蒸馏中常用的间隔器填充通道模型进行了研究。实验依靠基于热致变色液晶（TLC）和数字图像处理的非侵入式技术，并提供热活动壁面上对流换热系数的局部分布。CFD依赖于所研究的雷诺数范围低端的稳态（层流）模拟和该范围高端的直接数值模拟。后者是一个对实际应用有很大实际兴趣的领域，其中流动是混沌的，但不是完全湍流的，稳态模拟和湍流模型的使用都不能提供令人满意的预测。结果报告和讨论了一个特定的间隔器几何形状（重叠的正交圆柱细丝）和不同的间隔器方向相对于主流。据作者所知，这是第一次对间隔器填充通道的局部热或传质计算结果进行实验验证的研究。(C) 2015 Elsevier Ltd.版权所有。
The analysis of flow fields and heat or mass transfer phenomena is of great importance in the optimum design of spacer-filled channel geometries for a variety of membrane-based processes. In the present work, models of spacer-filled channels often adopted in Membrane Distillation are simultaneously investigated by experiments and Computational Fluid Dynamics (CFD). Experiments rely on a non-intrusive technique, based on the use of Thermochromic Liquid Crystals (TLC) and digital image processing, and provide the local distribution of the convective heat transfer coefficient on a thermally active wall. CFD relies on steady-state (laminar flow) simulations in the lower end of the Reynolds number range investigated and on direct numerical simulations in the upper end of this range. This latter is a region of great practical interest for real applications, in which the flow is chaotic but not fully turbulent, and neither steady-state simulations nor the use of turbulence models would provide satisfactory predictions. Results are reported and discussed for a specific spacer geometry (overlapped orthogonal cylindrical filaments) and different spacer orientations with respect to the main flow. To the authors' knowledge, this is the first study in which an experimental validation of computational results concerning local heat or mass transfer is performed for spacer-filled channels. (C) 2015 Elsevier Ltd. All rights reserved.