A new correlation for heat transfer in particle-fluid beds.

• Lattice Boltzmann simulations have been conducted to study the heat transfer in particle-fluid beds. • The effects of flow condition, material properties and bed structure on the heat transfer are quantified. • The underliying mechanisms are analysed in terms of spatial and statitiscal distributions of relevant transport properties. • New correlation is formulated to describe, more accurately and generally, the heat transfer in particle-fluid beds. Non-isothermal fluid flows through packed beds are common in many industries. Such a system is very complicated because heat transfer is associated with the interaction between fluid and particles. Our current understanding of the phenomenon is still limited. For example, the effect of the Prandtl number on thermal flow and the significant inconsistency between experimental data and predictions at a low Peclet number remain unclear. To overcome these problems, this paper presents a comprehensive study of this system on a sub-particle scale. This is done by conducting about five hundred Lattice Boltzmann simulations under different conditions, covering a wide range of Reynolds number (Re), Prandtl number (Pr), and bed porosity (ε). The results show that the effects of Re, Pr , and ε on the thermal behavior of fluid flows are strong, varying significantly with the flow condition and fluid/bed properties. Based on the simulation data, a new correlation to calculate the heat transfer coefficient is established and validated against the experimental data in the literature. This correlation is more accurate and general than those reported in the past and is recommended for simulations of non-isothermal fluid-particle flows in the future. [Display omitted] [ABSTRACT FROM AUTHOR]