Natural convection flows around submerged heated cylinders have gained attention in recent years due to their use in many engineering applications such as flow around tubes and rods (as in nuclear reactors and spent fuel cooling ponds). The purpose of this paper is to establish the modelling strategy for simulating natural convection heat transfer and flow around vertically positioned cylinders submerged in a water tank heated with a constant heat flux. The simulations were conducted for cylinders having different diameters which varied from 10 mm to 165 mm. The problem involved flow transition from laminar to turbulent within the boundary layer as the maximum Rayleigh number based on the cylinder length reached a magnitude of the order of 1014. The outcomes of these calculations were validated against published experimental data. The comparisons were made in terms of heat transfer coefficient and Rayleigh number which showed good agreement between predictions and experimental results. The predicted results showed sensitivity to various eddy viscosity models and the final results were obtained with SST model. Another important point that emerged from the study was that the specification of a suitable evaporation boundary condition at the top (water) surface was very critical. The treatment of evaporation from the top surface is discussed in detail which was also successfully incorporated in the methodology. We believe that the results obtained from our study will be useful for modelling flow in situations where a large number of heated cylinders are involved.
|Publication status||Published - 7 Sep 2015|
|Event||UK Heat Transfer Conference - Edinburgh University|
Duration: 7 Sep 2015 → …
|Conference||UK Heat Transfer Conference|
|Period||7/09/15 → …|