Experimental analysis of forced convective heat transfer in novel structured packed beds of particles

摘要

Followed by the numerical study of Yang et al. (2010), the macroscopic hydrodynamic and heat transger characteristics in some novel structured packed beds are experimentally studied in this paper, where thepackings of ellipsoidal or non-uniform spherical particles are investigated for the first time with experiments and some important results are obtained. For present experiments, the interstitial heat transfer coefficient in the packed bed is determined using an inverse method of transient single-blow technique. The effects of packing form and particle shape are carefully investigated and the experi-mental and mumerical results (Yang et al., 2010) are also compared in detail. Firstly, it is discovered that, the computational method reported by Yang et al. (2010)might be appropriate for heat transfer predictions in strured packings, while it might underestimate the friction factors, expecially when the porosity is relatively low. Ssecondly, it is found that, the traditional ergun's and wakao's equations might overpreimental modified correlations are obtained. Furthermore, it is also revealed that, both the effects of packing form and particle shape are significant to the macroscopic hydrodynamic and heat transfer characteristics in structured packed beds. With proper selection of packing form, such as simple cubic packing (SC) and particle shape, such as ellipsoidal particle, the pressure drops in the structured packed beds can be greatly reduced and the overall heat transfer performances will be improved. These experimental results would be reliable and useful for the optimum design in industry applications.