Entropy analysis on pulsating Carreau-Yasuda nanofluid flow in a vertical channel with MHD and Soret effect: a Buongiorno model

The article examines the entropy generation resulting from the vertical channel flow of Carreau-Yasuda nanofluid experiencing pulsatile MHD effects. The influence of thermophoresis, Brownian motion, thermal radiation, heat source/sink, Joule heating, Soret effect and viscous dissipation were investigated using the Buongiorno concept. The incorporation of non-dimensional parameters enables the transformation of governing dimensional partial differential equations (PDEs) and boundary conditions into dimensionless nonlinear PDEs with suitable boundary conditions. The perturbation technique was then be applied to these equations, which resulted in a group of ordinary differential equations (ODEs). Subsequently, the approximate solutions of reduced ODEs were discovered by employing the 'bvp4c' algorithm in conjunction with the shooting strategy offered by MATLAB. The repercussions of several pertinent variables (Weissenberg number, Grashof number, thermal radiation, Hartmann number, thermophoresis, Brownian movement, Soret number, Schmidt number, and chemical reaction) have been meticulously investigated in relation to the controlling flow phenomena, with particular attention to the shear-thinning properties of blood. The results presented in this paper supports the premise that an apparent decline in the steady velocity profile coincides with growth in fluid parameters (n, d) and the Hartmann number. Conversely, a reversal trend was found in velocity when the range of Grashof number and Weissenberg number expands. The temperature rises with a bump in the Brownian motion variable, but an elevation in the parameter used for thermophoresis results in a drop in temperature. Temperature elevation has been observed upon expansion and reduction of heat source and the sink respectively. The concentration profile exhibits a noticeable decrease in trend as the range of thermophoresis and Soret parameters widens. Higher entropy production is the consequence of the Eckert number, Brownian motion, and the Weissenberg number. The Bejan number, on the other hand, demonstrates a contrasting pattern.