Analysis of entropy generation in tri-hybrid nanofluid flow towards a spinning disk under the influence of hall effect and variable viscosity

The flow of a viscous fluid over a rotating frame is a characteristic phenomenon observed in numerous manufacturing processes, especially in structures featuring rotating disks. This paper examines the combined effects of Hall effect, thermal radiation and variable viscosity on the unsteady flow near a stagnation point over a rotating disk. The study examines the flow in two scenarios: tri-hybrid nanofluid flow and mono-nanofluid flow. Through suitable similarity transformations, the PDEs governing the flow problem are transformed into ODEs, which are then solved numerically using the “bvp4c” function in MATLAB. A validation of numerical code is done by a comparison with results from existing literature. The influence of key parameters on flow characteristics and the heat transfer rate are illustrated graphically. Subsequently, an advanced artificial neural network (ANN) is employed to predict the Nusselt number. The heat transfer rate exhibited by the THNF is marginally superior to that observed in the NF. The rate of entropy generation in the region near the disk is marginally greater for the THNF than for the NF. The HT rate values predicted by neural network show good accuracy which was assessed by mean squared error and regression coefficient. The findings of this study will benefit various fields involving rotating disk systems like brakes, gears, flywheels, gas turbine engines, geothermal extraction, rotor-stator systems, computer devices, etc.