Coordination number and thermal conductivity predictions in hybrid-particle packed beds

Abstract

Particle packed beds find wide applications and existences in thermochemical heat storage, thermal insulation and 3D-printing, while their thermal conductance performance could importantly affect these applications. In this work, a coordination-number model for hybrid-particle packed beds was firstly established, and then the thermal conductivity model was further derived with statistical method by considering size distributions of particles in the bed. Comparisons between the model and available experiments turn out that the model could give sound predictions of coordination-number and thermal conductivities in both macro- and nano-particle packed beds. In nanoscale, influences of sizes of hybrid nanoparticles on thermal conductivity could be included by defining a special mean radius of particles, and a small mean radius of particles could cause a large space density of interparticle interfaces thus leasing to a small thermal conductivity. The model is expected to predict or understand the thermal conductivity of hybrid particle packed beds.