A review of correlations to model the packing structure and effective thermal conductivity in packed beds of mono-sized spherical particles

Radiation represents an important contribution to the heat transfer through a packed bed. The packing structure is important in the determination of the radiation heat transfer, but this aspect is not explicit in most of the mathematical models proposed in the literature. Here, a new numerical approach is proposed to calculate the radiation heat transfer in such a bed from its structure using the Voronoi network model. On this basis, the effective thermal conductivity (ETC) is evaluated by taking into account the effects of the radiation heat transfer and conduction through neighbor particles and stagnant fluid. The validity of this approach is verified by comparing the calculated and measured ETCs under different conditions. This approach is used to investigate the effects of variables such as particle thermal conductivity, emissivity and size, and bed temperature as well. The relative contributions of different heat transfer mechanisms are analyzed. It is shown that there is a similarity in the probabil...

Particle Scale Evaluation of the Effective Thermal Conductivity from the Structure of a Packed Bed: Radiation Heat Transfer

The development of Module In-vessel degraded severe accident Analysis Code MIDAC and the relevant research for CPR1000 during the station blackout scenario

The effective thermal conductivity of high temperature particulate beds—II. Model predictions and the implication of the experimental values

Heat transfer—a review of 1976 literature

The radiative heat transfer, in a bed of negligible interparticle axial heat conduction, was measured by means of an original developed apparatus. The measurements were taken over a temperature range of 350 K to 930 K, in a bed packed with spherical particles of negligible heat resistance. The experimental results support a previously published (and here improved) theory, which was developed for the calculation of radiative heat transfer in terms of the radiative properties and the geometry of the packing material. The results are valid for particles of high heat conductivity.

G. Kasparek

Papers

Radiative heat transfer in packed beds of spheres with negligible heat resistance