Turbulent Flow and Heat Transfer Characteristics of Non-Newtonian Impinging Jets on a Flat Plate

Abstract

In the present work, a numerical analysis of non-Newtonian impinging jets on a flat plate subjected to a constant heat flux is carried out under turbulent flow conditions. By employing the power-law constitutive model to describe the jet’s non-Newtonian behavior, simulations have been performed for two (2D) and three-dimensional (3D) jet flow conditions. For turbulence simulation, SST- $$k\omega$$ turbulence model has been used coupled with continuity and energy equations. Dimensional results have been obtained by varying the inflow conditions 0.5–1.4 m/s and at a constant heat flux of 5000 W/m2. To instill the influences of shear thinning, Newtonian, and shear-thickening fluids, the range of power-law indices (n) is varied from 0.6 to 1.6. The results of the simulations infer that the pseudoplastics fluids are more efficient than Newtonian and dilatant fluids. Increasing power law shows efficacy of the fluids to cool the surface decreases as is observed by the average values of the Nusselt number on the target. It is found that there is a small difference in the final average temperature of the plate after cooling with different fluids, but that owes it to the small heat flux used in the present analysis. It is observed that the higher the velocity of the jet, the better is the cooling. Finally, the energy-saving capabilities of the jets are characterized by altering the rheological characteristics of the jets.