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. The simulation was performed using a temperature dependent powerlaw viscosity model. The results showed that for high Richardson numbers, a recirculation zone is 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 the 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 was disappeared and the local Nusselt number increases as a result of deeper penetration of jet stream the near wall region. Furthermore, the results indicated that the maximum local and average Nusselt numbers belong to the shear-thinning jets with minimum inlet width and the minimum jettoplate spacing.