Direct numerical simulation of fluid-particle heat transfer in fixed random arrays of non-spherical particles

Direct numerical simulations are conducted to characterize the fluid-particle heat transfer coefficient in fixed random arrays of non-spherical particles. The objective of this study is to examine the applicability of well-known heat transfer correlations, that are proposed for spherical particles, to systems with nonspherical particles. In this study the spherocylinders are used to pack the beds and the non-isothermal flows are simulated by employing the Immersed Boundary Method (IBM). The simulations are performed for different solids volume fractions and particle sizes and low to moderate Reynolds numbers. Using the detailed heat flow pattern, the average heat transfer coefficient is calculated for the different operating conditions. The numerical results show that the heat-transfer correlation of spherical particles can be applied to all test beds of spherocylinders by choosing a proper effective diameter. Our results reveal that the diameter of a spherocylinder is the proper effective diameter for characterizing particle-fluid heat transfer