Numerical investigation into flow and mixed convective heat transfer of non-Newtonian impinging slot jets

Mixed convection heat transfer of non-Newtonian impinging slot jets was investigated numerically in this study. The simulation was performed using a temperature-dependent power-law viscosity model. The results showed that, for high Richardson numbers, a recirculation zone was created in the vicinity of impingement wall which prevents the jet stream from penetration into near wall region and decreases the Nusselt number around the stagnation point. The effects of jet-to-plate spacing, inlet Peclet number, and jet inlet width on the flow structure and heat transfer characteristics of impinging jet were studied using the numerical results. By decreasing jet-to-plate spacing and jet inlet width and increasing inlet Peclet number, the flow reversal in the vicinity of heated wall disappeared, and the local Nusselt number increased as a result of deeper penetration of jet stream into the near wall region. Furthermore, the results indicate that the maximum local and average Nusselt numbers belong to the shear-thinning jets with minimum inlet width and minimum jet-to-plate spacing. (C) 2018 Sharif University of Technology. All rights reserved.