Effects of non-newtonian hybrid nanofluid heat transfer and entropy generation over a horizontal shrinking surface

The heat transport and entropy generation of Magnetohydrodynamic (MHD) non-Newtonian Powell-Eyring hybrid nanofluid near the stagnation point over a horizontal shrinking surface is examined using Tiwari and Das model, with graphene oxide (GO) as the main nanomaterial. Three problems of boundary layer flow are assessed, where GO is combined with iron dioxide (Fe2O4) and ethylene glycol (C2H6O2), molybdenum disulfide (MoS2) and glycerine (C3H8O3), and lastly molybdenum disulfide (MoS2) and ethylene glycol (C2H6O2). The first, second, and third problems study Joule heating, slips, and radiation effects, respectively. The mathematical modelling for each problem consists of continuity, momentum, and energy equations in partial differential equations (PDEs). Using suitable similarity transformations, the PDEs are then reduced to ordinary differential equations (ODEs). The ODEs are solved numerically by utilizing the bvp4c, a built-in solver in MATLAB software. The numerical results are illustrated in the form of figures and tables, where they display the velocity profile, temperature profile, skin friction, Nusselt number and entropy generation. The numerical results presented are gained by varying the value of several governing variables such as magnetic field, radiation, rapidity slip, thermal slip, heat source, viscous dissipation, Joule heating, Biot number and suction. The findings obtained reveal that the augmentation of GO concentration ameliorates the temperature of the fluid while depleting the rapidity of fluid, rate of heat transport and production of entropy. The amplification of thermal radiation intensifies the temperature of the liquid and plunges the formation of entropy. The solutions for the shrinking surface are found to be non-unique or known as dual solutions. Stability analysis is conducted by introducing disturbance to check the steadiness of both solutions. The stability analysis showed that the upper branch solution fulfils the characteristics of a stable solution. Hence, the lower branch solution is regarded as an unsteady solution.