Thermal mixing performances of shear-thinning non-Newtonian fluids inside Two-Layer Crossing Channels Micromixer using entropy generation method: Comparative study

Abstract

In this work, a numerical comparative study is carried out to investigate a laminar steady flow behavior of shear-thinning non-Newtonian fluids in three chaotic geometries: Two-Layer Crossing Channel Micromixer, C-shaped channel and serpentine channel. The process is validated for non-Newtonian flow in a complex geometry which heated by a constant flux. Secondary flow structures are formed in the chosen geometries enhance significantly the fluid dynamic performances. To characterize this performance Poincaré map method is presented for different geometries with various cases of fluid power-law index. Thermal mixing behavior with two different inlet temperatures of shear-thinning fluids in the considered geometries is performed. For various cases of fluid power-law indexes, the TLCCM displayed thermal mixing degree enhancement of 42–84% relative to the thermal mixing degree in both C-shaped and serpentine channels. The second law of thermodynamics is controlled in terms of entropy generation due to the thermal and hydrodynamic process, as a function of low rates of generalized Reynolds number and power-law index, under the effects chaotic advection. Thereby, the TLCCM configuration exhibited very important enhancement of mixing degree than that obtained in other considered geometries, with minimization of friction and thermal irreversibilities.