Convective heat transfer coefficient for a rod-like particle in a uniform flow

Abstract

Rod-like particles are widely encountered in the industry, e.g., the biomass utilization, and it always involves the heat transfer in a forced flow. However, works about the convective heat transfer, i.e., the Nusselt number, for rod-like particles are rare. Motivated by this fact, this work is therefore devoted to investigating the heat transfer behaviors of rod-like particles in a forced flow and to developing a Nusselt number relation. To do so, a hot stationary rod-like particle that is passed by the cold continuous fluid flows is simulated by three-dimensional IBM-LBM (Immersed Boundary Method – Lattice Boltzmann Method). Abundant results have been obtained and are available for elucidating the influences of pertinent parameters, including the Reynolds number (Re), particle aspect ratio (AR) and particle orientation (α), in the range of parameters: 1 ≤ Re ≤ 1500, 1 ≤ AR ≤ 5 and 0° ≤ α ≤ 90°. The simulation results indicate that changing the Reynolds number, particle aspect ratio and orientation will significantly affect the heat transfer between the fluid phase and rod-like particle. Moreover, how the particle shape and orientation impact the heat transfer is concerned with the Reynolds number. At last, based on the obtained data, a correlation for averaged Nusselt number that considers the effects of Re, AR and α is proposed. This correlation holds promising prediction accuracy and can be enclosed in the multiphase modeling, e.g., the Eulerian-Lagrangian coupling calculation, involving the convective heat transfer of rod-like particles.