An experimental study of flow and heat transfer in a differentially side heated cavity filled with coarse porous media

Iman Ataei-Dadavi, Nima Rounaghi, Manu Chakkingal, Sasa Kenjeres, Chris R. Kleijn, Mark J. Tummers

Research output: Contribution to journalArticleScientificpeer-review

11 Citations (Scopus)
115 Downloads (Pure)

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.

Original languageEnglish
Article number118591
Number of pages11
JournalInternational Journal of Heat and Mass Transfer
Volume143
DOIs
Publication statusPublished - 2019

Keywords

  • Differentially heated cavity
  • Heat transfer
  • Natural convection
  • Packed beds
  • Porous media
  • Refractive index matching

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