Print Email Facebook Twitter Numerical analysis of natural convection in a differentially heated packed bed with non-uniform wall temperature Title Numerical analysis of natural convection in a differentially heated packed bed with non-uniform wall temperature Author Chakkingal, M. (TU Delft ChemE/Transport Phenomena) Kenjeres, S. (TU Delft ChemE/Transport Phenomena) Ataei Dadavi, I. (TU Delft ChemE/Transport Phenomena) Tummers, M.J. (TU Delft Fluid Mechanics) Kleijn, C.R. (TU Delft ChemE/Transport Phenomena) Date 2020 Abstract We report numerical simulations of natural convection and conjugate heat transfer in a differentially heated cubical cavity packed with relatively large hydrogel beads (d/L=0.2) in a Simple Cubic Packing configuration. We study the influence of a spatially non-uniform, sinusoidally varying, wall temperature on the local flow and heat transfer, for a solid-to-fluid conductivity ratio of 1, a fluid Prandtl number of 5.4, and fluid Rayleigh numbers between 105 and 107. We present local and overall flow and heat transfer results for both sphere packed and water-only filled cavities, when subjected to variations of the wall temperature at various combinations of the amplitude and characteristic phase angle of the imposed wall temperature variations. It is found that imposing a sinusoidal spatial variation in the wall temperature may significantly alter the local flow and heat transfer, and consequently the overall heat transfer. At identical average temperature difference, applying a spatial variation in wall temperature at well-chosen phase angle can lead to significant heat transfer enhancement when compared to applying uniform wall temperatures. However, this is achieved at the cost of increased entropy generation. Subject Entropy generationLocal flow and heat transferNatural convectionNon-uniform wall temperatureOpenFOAMPorous-mediaSide heated cavitySteady-state To reference this document use: http://resolver.tudelft.nl/uuid:d5f9322c-bce6-4047-a588-db928fb2304e DOI https://doi.org/10.1016/j.ijheatmasstransfer.2019.119168 ISSN 0017-9310 Source International Journal of Heat and Mass Transfer, 149 Part of collection Institutional Repository Document type journal article Rights © 2020 M. Chakkingal, S. Kenjeres, I. Ataei Dadavi, M.J. Tummers, C.R. Kleijn Files PDF 1_s2.0_S0017931019352974_main.pdf 4.29 MB Close viewer /islandora/object/uuid:d5f9322c-bce6-4047-a588-db928fb2304e/datastream/OBJ/view