Transient Analysis of the Interactions Between a Heat Transferring, Radial Stagnation Flow, and a Rotating Cylinder-Magnetohydrodynamic and Nonuniform Transpiration Effects

Abstract

This paper aims at providing further understanding on the fluid flow and heat transfer processes in unsteady rotating systems with mass transpiration. Such systems can be found in chemical separators, hydraulic systems, and printing devices. To this end, an unsteady viscous flow in the vicinity of an unaxisymmetric stagnation-point on a rotating cylinder is examined. The nonuniform transpiration and a transverse magnetic field are further considered. The angular speed of the cylinder and the thermal boundary conditions are expressed by time-dependent functions. A reduction of the Navier–Stokes and energy equations is obtained through using appropriate similarity transformations. The semisimilar solution of the Navier–Stokes equations and energy equation are developed numerically using an implicit finite difference scheme. Pertinent parameters including the Reynolds number and magnetic parameter and transpiration function are subsequently varied systematically. It is shown that the transpiration function can significantly affect the thermal and hydrodynamic behaviors of the system. In keeping with the findings in other areas of magnetohydrodynamics (MHD), the results show that the applied magnetic field has modest effects on the Nusselt number. However, it is demonstrated that the magnetic effects can significantly increase the imposed shear stress on the surface of the rotating cylinder.

Combined heat and mass transfer and thermodynamic irreversibilities in the stagnation-point flow of Casson rheological fluid over a cylinder with catalytic reactions and inside a porous medium under local thermal nonequilibrium

“…Furthermore, Eq. 9 indicates that the viscous flow solution approaches, in a manner analogous to the Hiemenz flow, the potential flow solution as → ∞ [26,27,30,31,34]. This can be verified by starting from the continuity equation in the following, − 1 ( ) = Constant = 2 ̅ and integrating in the and directions with boundary conditions, = 0 when = 0 and = − 0 ( ) when = .…”

“…Therefore, if the applied shear stress is less than the yield stress, the non-Newtonian fluid behaves like a solid, whereas if it is greater then it starts to move. A two-dimensional Darcy-Brinkman model of transport of momentum [5,[25][26][27][28][29][30][31] together with the two-equation model of the transport of thermal energy in porous media [32,33] are used in this work. The governing equations and boundary conditions, in the cylindrical coordinate system shown in Fig.…”

Spectral approach to study the entropy generation of radiative mixed convective couple stress fluid flow over a permeable stretching cylinder

“…Relevant articles can be found in literature. [13][14][15][16][17][18][19][20][21][22][23] Thermal radiative effect on the flow characteristics as well as heat transfer provides an important character in physics or particularly in space technology. The MHD flow with radiation has gained a huge significance in electrical power generation, astrophysical issue, solar power equipments, designing space vehicles or manufacturing other industrial equipments.…”