Thermal Features of mixed convection from an inline periodic array of circular cylinders in non-Newtonian power-law fluids

Abstract

Mixed convection heat transport from multi-cylinders finds numerous applications in chemical, petroleum, and food industries. This study presents the mixed convection characteristics of an inline array of heated circular cylinders in non-Newtonian power-law fluids for the following governing parameters: fluid volume fractions; 0.70≤ φ f ≤0.99, power-law index; 0.4≤ n ≤ 1.8, Reynolds number; 1≤ Re D ≤40, Prandtl number; 1≤ Pr D ≤50 and Richardson number; 0≤ Ri D ≤2. Mathematical model equations are solved using the Finite Volume Method within the framework of Boussinesq approximations. Thermal features are explored using isotherms, local and averaged Nusselt numbers. Qualitatively, isotherms display a complex relationship with the governing parameters. Local and average Nusselt numbers improve with increasing Reynolds, Prandtl and Richardson numbers, shear-thinning natures. An opposite nature is noted for shear-thickening fluids. Nusselt numbers were further improved with increased fluids volume fractions contrary to decrease in forced convections cases. At maximum Reynolds, Prandtl and Richardson numbers, Nusselt number increased by 30.53% and 13.11% for shear-thinning (n = 0.4) fluids, respectively for φ f = 0.70 and 0.99. An unsteady nature was also found in shear-thinning regions at larger volume fractions. Lastly, statistical analysis is presented for the average Nusselt numbers to depict additional physical insights of the numerical outcomes.