Impact of impulsive motion on the Eyring-Powell nanofluid flow across a rotating sphere in MHD convective regime: Entropy analysis

•Impact of impulsive motion and the nanofluid.•Magnetized field influence the flow characteristics.•Comparing the Eyring-Powell nanofluid with the Newtonian nanofluid.•Minimization of entropy generation.•Activation energy effects over a chemical reaction.•Diffusion of liquid hydrogen. The widespread use of non-Newtonian fluids with impulsive motion in engineering sheds light on this investigation. This study investigates the entropy optimization in the Eyring-Powell nanofluid flow over an impulsive rotating, moving sphere in an unsteady combined convection regime with the effect of magnetized field, activation energy, and liquid hydrogen diffusion. The angular velocity of the sphere and the free stream velocity combine to produce the impulsive motion seen here. The governing partial differential equations (PDEs) are formulated in dimensional form by incorporating the boundary layer approximation. After undergoing non-similar transformations, these PDEs are transformed into dimensionless nonlinear PDEs. Consequently, resulting equations are linearized using the Quasilinearization method. An implicit finite difference method is employed to discretize the linearized equations. The findings are depicted through graphs with a variety of profiles and gradients. The fluid velocity and surface friction tend to decrease for Eyring-Powell nanofluid than the primary Newtonian nanofluid. The energy transfer strength is cut down by approximately 11% for rising values of magnetic field characteristics. A small change in the Brownian diffusion characteristics reinforces the mass transfer strength by 11% approximately. The entropy generation is pronounced more for linear combined convection βt=0, whereas it is less for nonlinear combined convection βt≠0. Adopting nonlinear combined convection, a magnetic field over a moving sphere can reduce the entropy generation.