Effect of Reynolds number and porosity on heat transfer across triangular periodic array of cylindersDOI: 10.1615/IHMTC-2019.1140 Mohd. Asif AbstraktThe forced convection heat transfer for the flow of an incompressible, steady and Newtonian fluid across a triangular array of periodic cylinders has been studied. The interactions between the cylinders modelled as a unit cell with periodic and symmetric boundary conditions and the governing equations (flow and energy) have been solved numerically using a finite volume based methodology. The present study analysed the dependence of characteristics such as isotherms, local Nusselt number and average Nusselt number and others for the following parameters: fluid volume fraction φ_{f} ranged from 0.7 to 0.99, and Reynolds number Re ranged from 10 to 50 for water as a working fluid. Figure 1 shows the computational domain obtained by approximating a unit cell from the infinite number of cylinders in the array, such that if one joins the centres of three cylinders they form an equilateral triangle; L is the centre to centre distance between cylinders in the array and D is the diameter of the cylinders. This study shows that at high values of Re, the emergence of carbuncle or thermal spike on isotherm near the surface of the cylinders is observed where the value of local Nusselt number is low. The heat transfer improves and average Nusselt number increases with increase in Re. However, the heat transfer decreases as we increase the porosity/free volume fraction. The maximum value of local Nusselt number is not appearing at the front stagnation point as opposed to the case of a single cylinder. |
Archive |