Numerical Investigation of Thermal Performance in Cross Flow Around Square Array of Circular Cylinders

Abstract

Flow over square array of circular cylinders was studied for various Reynolds numbers i.e. 40, 50, 100, 150 and 200 by varying different Prandtl number i.e. 0.7, 1, 7, 10 and 20. Flow and Thermal analyses were done on square array of cylin- ders having length between centres of two cylinders to diameter ratio (L/D) 1.25. Effect of asymmetric arrangement of cylinders in domain and change of boundary conditions were also analysed. The analyses were done by solving two dimensional continuity, unsteady incompressible Navier-stokes and energy equation using Fluent (version 6.2.16.). The effect of surface heating of cylinder, change in Reynolds num- ber on wake formation and vortex generation, change in Reynold number, change in asymmetricity of cylinders and change in Prandlt number on average Nusselt num- ber was numerically studied. The validations was done for average Nusselt number on single cylinder at Re = 150 and Re = 200 and results were compared and found in good agreement with referred experimental and numerical work. It was found that qualitatively with increase in Prandtl number, temperature variation decreased around cylinders for constant value of Reynold number and quantitatively, with in- crease in 5 unit & 10 unit asymmetricity of cylinders, increase in average Nusselt no. were 4.69% and 7.17% respectively. Similarly average Nusselt number was 18 to 25% higher in case of UHF boundary Condition compare to CWT boundary condi- tion for symmetric domain. The Correlation was also presented for average Nusselt number as function of Reynold number and Prandtl number in case of symmetric and asymmetric domain of cylinder array.