Experimental and Pore-scale Analysis of Flow and Thermal Fields in a Packed Bed Channel

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 analysed 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 non-uniform velocity filed leads to non-uniform temperature distributions of air and solid spheres in the packed bed.