THERMAL SCIENCE

International Scientific Journal

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Numerical study of flow inhomogeneity and heat transfer enhancement in structured packed beds

ABSTRACT
Packed beds are widely used in engineering applications due to their high specific surface area and good heat transfer characteristics. A grille-sphere composite packed bed is proposed previously and has been proved to have higher overall heat transfer coefficient than the simple cubic packing structure. In the present paper, the flow inhomogeneities in both grille-sphere composite packed bed and the simple cubic packing are studied and the relationship between the flow inhomogeneity and the heat transfer characteristics is revealed by numerical simulations. The simulations are performed on ANSYS FLUENT software. The turbulence flow is modeled by the Renormalization Group k-ε model. Both dispersion of the velocity distribution and the residence time distribution are employed to assess the flow maldistribution. When inlet velocity equals 2.17 m/s, the variance of the residence time distribution of the composite packed bed is 5.91% smaller than that of the simple cubic packing while the Nusselt number is 10.64% higher. The results indicate that less flow maldistribution can lead to heat transfer enhancement.
KEYWORDS
PAPER SUBMITTED: 2020-03-23
PAPER REVISED: 2020-04-21
PAPER ACCEPTED: 2020-05-01
PUBLISHED ONLINE: 2020-09-26
DOI REFERENCE: https://doi.org/10.2298/TSCI200323274W
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