Experimental and Pore-Scale Analysis of Flow and Thermal Fields in a Packed Bed Channel
Experimental and Pore-Scale Analysis of Flow and Thermal Fields in a Packed Bed Channel
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DOI：
10.1080/01457632.2021.1943846
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发表时间：
2021-01
影响因子：
2.3
通讯作者：
M. Khaljani;M. Nazari;M. Azarpeyvand;Y. Mahmoudi
中科院分区：
文献类型：
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作者：
M. Khaljani;M. Nazari;M. Azarpeyvand;Y. Mahmoudi
摘要本研究以实验与数值模拟相结合的方式，探讨了内生热填充床内的紊流对流换热与压降问题。主要目的是开发床和冷却剂之间的传热以及系统中的压降使用详细的实验和三维孔隙尺度数值模拟的相关性。所分析的系统是一个水平的圆形通道中填充不同的不锈钢球的直径为5.5毫米，6.5毫米，和7.5毫米。研究是在900-2600的范围内，不同的雷诺数（基于球体直径）的湍流状态。使用电磁感应加热方法加热球体。根据实验数据，建立了湍流压降和对流换热系数的经验关联式。孔隙尺度分析的结果显示了流场的复杂性，与入口速度相比，速度经历了相当大的增加，并且在球体之间的窄间隙中更加明显。数值模拟结果还表明，温度场和速度场是相互耦合的，非均匀速度场会导致填充床内空气和固体颗粒的温度分布不均匀。
Abstract The study investigates experimentally and numerically the problem of turbulent convective heat transfer and pressure drop in a packed bed with internal heat generation. The main objective is to develop correlations for the heat transfer between the bed and coolant as well as the pressure drop in the system using detailed experimental and 3-dimensional pore-scale numerical simulation. The system analyzed is a horizontal circular channel filled with different stainless steel spheres with diameters of 5.5 mm, 6.5 mm, and 7.5 mm. Dry air is used as working fluid. The study is performed for turbulent flow regimes with different Reynolds number (based on the spheres diameter) in the range of 900–2600. The spheres are heated using an electromagnetic induction heating method. Based on the experimental data, empirical correlations for turbulent pressure drop and convective heat transfer coefficient are developed. Results of pore-scale analysis show the complexity of the flow domain, which the velocity experiences a considerable increase compared to inlet velocity and is more evident in narrow gaps between spheres. Moreover, numerical results indicate the coupling of temperature and velocity fields, which a nonuniform velocity filed leads to nonuniform temperature distributions of air and solid spheres in the packed bed.