Print Email Facebook Twitter An experimental study of flow and heat transfer in a differentially side heated cavity filled with coarse porous media Title An experimental study of flow and heat transfer in a differentially side heated cavity filled with coarse porous media Author Ataei Dadavi, I. (TU Delft ChemE/Transport Phenomena) Rounaghi, Nima (Student TU Delft) Chakkingal, M. (TU Delft ChemE/Transport Phenomena) Kenjeres, S. (TU Delft ChemE/Transport Phenomena) Kleijn, C.R. (TU Delft ChemE/Transport Phenomena) Tummers, M.J. (TU Delft Fluid Mechanics) Date 2019 Abstract Flow and heat transfer in a differentially side heated cubic cavity filled with relatively large solid spheres forming a coarse porous medium have been studied experimentally. Nusselt numbers were measured for Rayleigh numbers between 1.9 × 107 and 1.7 × 109, solid-to-fluid conductivity ratios between 0.32 and 618, and for different sphere sizes (d/H = 0.065, 0.14, 0.20), and packing geometries. The heat transfer results indicate that the presence of a porous medium in the cavity decreases the heat transfer compared to the pure-fluid cavity unless the solid spheres are highly conductive. We present a new Nusselt number correlation for coarse porous media based on porous medium dimensionless numbers. Particle image velocimetry and liquid crystal thermography measurements were performed in a refractive index-matched porous medium to obtain pore-scale velocity and temperature fields. The results show that the layers of spheres adjacent to the hot/cold walls play the most prominent role in the heat transfer reduction by hindering the formation of high-velocity boundary layers along the hot/cold walls, causing a portion of the boundary layer fluid to divert away from these walls, thus changing the stratified temperature distribution to a tilted one which leads to a lower overall heat transfer. Subject Differentially heated cavityHeat transferNatural convectionPacked bedsPorous mediaRefractive index matching To reference this document use: http://resolver.tudelft.nl/uuid:69c161fd-3091-4adc-9ffe-f6807329bf56 DOI https://doi.org/10.1016/j.ijheatmasstransfer.2019.118591 ISSN 0017-9310 Source International Journal of Heat and Mass Transfer, 143 Part of collection Institutional Repository Document type journal article Rights © 2019 I. Ataei Dadavi, Nima Rounaghi, M. Chakkingal, S. Kenjeres, C.R. Kleijn, M.J. Tummers Files PDF 1_s2.0_S0017931019312955_main.pdf 3.54 MB Close viewer /islandora/object/uuid:69c161fd-3091-4adc-9ffe-f6807329bf56/datastream/OBJ/view