Numerical simulation of convective heat transfer between air flow and ceramic foams to optimise volumetric solar air receiver performances
Numerical simulation of convective heat transfer between air flow and ceramic foams to optimise volumetric solar air receiver performances
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DOI：
10.1016/j.ijheatmasstransfer.2010.11.037
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发表时间：
2011-03
影响因子：
5.2
通讯作者：
Zhiyong Wu;C. Caliot;G. Flamant;Zhifeng Wang
中科院分区：
文献类型：
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作者：
Zhiyong Wu;C. Caliot;G. Flamant;Zhifeng Wang
多孔陶瓷泡沫用于在太阳能热回收系统中实现高性能。了解气流和陶瓷泡沫之间的对流传热在优化容积式空气接收器时非常重要。在这项工作中，对流传热进行了数值研究。本方法的目的是计算空气流和多孔陶瓷泡沫之间的局部对流换热系数。为此，解决了多孔泡沫陶瓷内部的能量平衡和流动问题。此外，考虑了多孔陶瓷泡沫的详细几何形状。泡沫陶瓷由理想化的堆积的十四面体结构表示。数值模拟基于三维雷诺平均Navier-Stokes（RANS）方程。以孔隙率、流速和泡孔平均尺寸为参数，对换热系数进行了敏感性研究。基于数值模拟结果，建立了泡沫陶瓷与空气间局部对流换热系数的关联式。由此产生的相关性涵盖了广泛的孔隙率，速度，细胞大小和温度。将关联结果与文献中的实验数据进行了比较，结果吻合较好。该相关性旨在用于容积式太阳能空气接收器的设计。
Porous ceramic foams are used to achieve high performance in solar heat recovery systems. Understanding the convective heat transfer between the air flow and the ceramic foam is of great importance when optimising the volumetric air receiver. In this work, the convective heat transfer was numerically studied. The present approach was designed to compute the local convective heat transfer coefficient between the air flow and a porous ceramic foam. For that purpose, the energy balance and the flow inside the porous ceramic foam were solved. In addition, a detailed geometry of the porous ceramic foam was considered. The ceramic foams were represented by idealised packed tetrakaidecahedron structures. The numerical simulations were based on the three dimensional Reynolds-averaged Navier–Stokes (RANS) equations. A sensitivity study on the heat transfer coefficient was conducted with the porosity, velocity and mean cell size as parameters. Based on the numerical simulation results, a correlation for the volumetric local convective heat transfer coefficient between air and ceramic foams was developed. The resulting correlation covers a wide range of porosities, velocities, cell sizes and temperatures. The correlation results were compared with experimental data from the literature, and the comparison shows good agreement. The correlation is intended to be used in the design of volumetric solar air receivers.