Numerical simulation of the flow field and heat transfer inside the channel with different dimensions of spindle obstacles in the presence of power-law non-Newtonian fluids

In this article, the analysis of the flow field and forced convection heat transfer of non-Newtonian fluids inside the channel with spindle-shaped obstacles is discussed. At first, after checking the governing equations and the boundary conditions of the problem, the grid independency has been evaluated. Then, the results of the present study have been validated for two cases of the Newtonian and non-Newtonian fluids with previous similar works. The effects of various parameters such as the effect of the arrangement of spindle obstacles, the effect of the obstacles diameter and the effect of the obstacles length have been investigated. Also, the effect of different power indexes of non-Newtonian fluid and its effect on drag coefficient and Nusselt number have been investigated. By examining the results, it was found that for all the mentioned parameters, the staggered arrangement of the spindle obstacles had a higher heat transfer rate than the ordered arrangement. The results of this research revealed that with the increase in the diameter and length of the obstacles, the amount of heat transfer from the obstacles decreases. Also, by increasing the diameter of obstacles, the pressure and friction drag coefficients increases. Finally, by examining the behavior of the non-Newtonian fluid of the power-law model, it was found that with the increase of the power index, the Nusselt number decreased and for shear thinning non-Newtonian fluids (n<1) less friction and pressure drops were obtained.