Numerical analysis of effects of fins and conductive walls on heat transfer in side heated cavities — Onset of three-Dimensional phenomena in natural convection

In the present study, we analyse individual and combined effects of conductive horizontal walls and conductive fins on the natural convection of air in side heated cavities (SHC). The flow and heat transfer are studied for Rayleigh numbers in the range of 10⁴−−10⁹: Direct Numerical Simulation (DNS) is conducted for the...

Thermal and hydrodynamic phenomena in the stagnation zone—impact of the inlet turbulence characteristics on the numerical analyses

One of the methods of heat transfer enhancement is utilization of the turbulent impinging jets, which were recently applied, for example, in the heat exchangers. Their positive impact on the heat transfer performance was proven, but many questions related to the origin of this impact are still unanswered. In general, the wall-jet interaction...

Curved surface minijet impingement phenomena analysed with ζ-f turbulence model

The jet impingement phenomenon plays an important role among the heat transfer intensification methods. Very often its application and analyses refer to simple flat surfaces, while there is a lack of information in the literature for cases addressing curved surfaces. In the present work, the single jet impingement on the non-flat (concave and...

On the daytime micro-climatic conditions inside an idealized 2D urban canyon

This study investigated the surface temperature, air temperature and mean radiant temperature inside an idealized 2D street geometry during daytime. The goal was to unravel the relative impact of radiative transfer, heat conduction and ventilation to the urban heat budget. A building-resolving simulation model has been used, which represents...

Numerical and experimental analysis of a planar jet with heated co-flow at medium and low Prandtl-number values

In the present work, we combine experiments and numerical simulations of a planar jet with heated co-flow with medium (air) and low-Prandtl (He-Xe gas mixture) fluids. Jets are recognized as representative test cases to be investigated in large components of pool-type liquid metal-cooled nuclear systems, like the Multi-purpose hYbrid Research...

Experiments on mixed convection in a vented differentially side-heated cavity filled with a coarse porous medium

This paper reports on an experimental study of mixed convection flow and heat transfer in a vented, differentially side-heated cubical cavity filled with a porous medium consisting of relatively large solid low-conductivity spheres. Rayleigh numbers and Reynolds numbers are varied over the ranges 6 × 10⁶ &lt; Ra &lt; 7 × 10<sup>7<...

Numerical analysis of natural convection in a differentially heated packed bed with non-uniform wall temperature

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...

Inversion of flow and heat transfer of the paramagnetic fluid in a differentially heated cube

The present study addresses the detailed numerical analysis of the flow and heat transfer of a paramagnetic fluid inside a differentially heated cubical box and subjected to a strong non-uniform magnetic field. Two different heating scenarios are considered regarding an initial thermal stratification: unstable (heated from the bottom) and...

Flow and heat transfer measurements in natural convection in coarse-grained porous media

This paper reports on an experimental study of natural convection in an enclosure that is heated at the bottom and cooled at the top, filled with a packed bed of relatively large solid spheres. Nusselt numbers were measured for various sphere conductivities, spheres sizes and sphere packings for Rayleigh numbers varying between 10⁷...

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

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...

Energy spectra and turbulence generation in the wake of magnetic obstacles

Numerical simulations and analysis of flow and heat transfer of an electrically conducting fluid past magnetic obstacles are reported. We studied the channel flow configuration with electrically and thermally insulated horizontal walls containing a single or multiple (two or three) magnetic dipoles. Different values of the interactive parameter...

Large eddy simulations of targeted electromagnetic control of buoyancy-driven turbulent flow in a slender enclosure

We conducted a large eddy simulation (LES) of a locally applied electromagnetic control of turbulent thermal convection of an electrically conductive fluid (electrolyte solution) inside of a slender enclosure. Generic configurations, consisting of two or three magnets of opposite polarities located below the lower wall, and two oppositely...

Large–eddy simulations of wall heat transfer and coherent structures in mixed convection over a wavy wall

In this numerical study the mixed convective flow of water over a heated wavy surface over a range of Reynolds and Richardson numbers, including transitional and turbulent flow regimes (20 ? Re ? 2000 and 0.5 ? Ri ? 5000) is investigated. A dynamic Large Eddy Simulation (LES) approach is applied where the thermal buoyancy effects are represented...