CFD ANALYSIS OF FLOW AND HEAT TRANSFER AROUND A TRAPEZOIDAL CYLINDER

Abstract

Effects of blockage ratio on the two-dimensional laminar flow and heat transfer around a heated tapered trapezoidal cylinder are investigated numerically in the confined steady state regime (Reynolds number, Re = 1 — 40, blockage ratio = 0.125 — 0.5 and Prandtl number, Pr = 0.71). The engineering flow and heat transfer parameters like individual and overall drag coefficients, local and average Nusselt numbers, etc. are calculated for the above range of conditions. The onset of flow separation exits between Re = 4 — 5 for the blockage ratio of 0.125 and between Re = 5 — 6 for the blockage ratios of 0.25 and 0.5. The wake/recirculation length increases as the Reynolds number increases for the constant value of the blockage ratio; however, the wake length decreases as value of the blockage ratio increases. The drag coefficients decrease with increasing value of the Reynolds number; however, drag values increase with blockage ratio in the steady flow regime. The average Nusselt number increases with increasing value of the Reynolds number. Simple correlations of wake length, drag and average cylinder Nusselt number are also obtained in the steady regime.