Magnetohydrodynamic flow of Williamson fluid in a microchannel for both horizontal and inclined loci with wall shear properties

This study reports the flow of Williamson fluid in a microchannel, considering the effect of thermal radiation, heat source, slip regime, and convective boundary. The physical phenomenon is demonstrated by employing the Williamson model. The mathematical expressions are made dimensionless by using nondimensional quantities. The numerical approach called Runge–Kutta–Fehlberg scheme is hired to get the solution. The upshots of the pertinent flow parameter on physical features are visualized through graphs. It is established that the augmentation of Nusselt number has been achieved by increasing Weissenberg number and Reynolds number. In addition to this, it is emphasized that the reduction in the wall velocity gradient is obtained for a higher Weissenberg number.     

Magnetohydrodynamics Eyring-Powell fluid in a vertical porous microchannel with convective boundary condition subjected to entropy generation

This investigation is concentrated on the second law analysis of a magnetohydrodynamics Eyring-Powell fluid in a vertical microporous channel with the convective boundary conditions under the impacts of heat generation, viscous dissipation, exponential space, temperature dependence, and Joule heating. The reduced form of the governing equations is obtained with the aid of applying nondimensional variables and is resolved using Runge-Kutta-Fehlberg's fourth fifth-order method. The various relevant parameters that affect the heat transfer and entropy have been discussed in detail through graphs. It is found that the impacts of suction/injection, viscous dissipation, and convective conditions are important and the thermal performance can be improved with these factors. The generation of entropy boosts up with the impacts of radiation, space/temperature-dependent, and Biot number and slows down with Eyring-Powel parameters. Furthermore, the heat transfer rate amplifies with the magnetic number and the drag force intensifies with the Brinkman parameters. The comparison of results has been performed and it provides an excellent agreement.     

Investigation of irreversibilities in a microchannel by differing viscosity,including buoyancy forces and suction/injection

Single-phase Poiseuille flow considering oxides of copper-water nanoliquid in the upright microchannel with uneven viscosity causes the production of inbuilt irreversibility in the system. This is reported in the present investigation involving the buoyancy force with suction/injection at the walls by taking into account different shapes of nanoparticles. The equations so obtained being highly nonlinear is attempted to solve via Runge–Kutta–Fehlberg shooting scheme. Flow and heat transmission characteristics are explored by considering the nanoparticle's shape. The result exemplifies that the viscosity variation parameter escalates the flow profile as well as temperature profile. The thermal radiation and Biot number boost the let go of thermal energy, which leads to system cooling. The temperature profile for nanoparticle shape factor upholds the fact that temperature is high for lamina-shaped nanoparticles and least for spherical-shaped nanoparticles. Also, the Biot number, radiation parameter, and nanoparticle volume fraction serve in lowering the entropy, which augments the exergetic effectiveness of the system.     

Analysis of multilayer convective flow of a hybrid nanofluid in porous medium sandwiched between the layers of nanofluid

AgBr acts as a good sensitizer for titanium oxide, hence TiO₂–AgBr nanoparticles exhibit high photocatalytic activity which helps decompose methyl orange under visible light irradiation. Methyl orange is a chemical compound that is hard to degrade and has high stability. It is photoreactive and can capture photons from the sun and is highly used as a light harvester in solar cells, hence, it is used in solar applications. In view of this, the present article deals with the analysis of heat transfer in a multilayer flow of two immiscible nanofluids in a vertical channel that finds application in the fields of solar reactors, electronic cooling, and so on. The mathematical model involving the effect of thermal radiation and the presence of heat source is in the form of a system of ordinary differential equations. This system of equations is simplified using the differential transform method-Padé approximant and the resulting equations are solved algebraically. It is observed that the temperature of the coolant does not reach its saturation point faster due to the presence of different base fluids that differ in their thermal conductivity. This helps in maintaining the optimum temperature of the system.     

Numerical illustrations of 3D tangent hyperbolic liquid flow past a bidirectional moving sheet with convective heat transfer at the boundary

Convective heat transfer plays a central role in the numerous industrial devices because it perturbs the mechanical behavior of a system along with its thermodynamics. Keeping such applications in mind, analysis of heat transportation in three‐dimensional tangent hyperbolic fluid flow is investigated here. Convective heat transportation at the boundaries is considered. Rosseland's approximation has been used for the radiation effects. Closed form analytical solutions for the governing equations are difficult to obtain even after the use of similarity transformations. Therefore, the numerical solutions are presented through the Runge‐Kutta‐Fehlberg forth‐fifth method. Graphical analysis of the numerical results has been carried out. Roles of sundry constraints on flow are studied. It is also noted that the rates of heat transportation and skin‐friction are higher in the presence of convective heat transfer near the boundary.     

Analysis of a fully wetted moving fin with temperature‐dependent internal heat generation using the finite element method

The temperature field of a moving longitudinal porous fin with varying internal heat generation with respect to temperature has been studied under natural radiation and convection effects. The Darcy model was implemented for the analysis and the parameters, whose effect on the thermal process were grouped and nondimensionalized. By using the finite element method, the obtained highly nonlinear second order ordinary differential equations were numerically solved. The relevant parameters were studied by means of graphs and subsequently their importance in the rate of heat transfer was interpreted.     

Transient thermal investigation of a fully wet porous convective–radiative rough cylindrical pin fin

The microelectromechanical systems technologies frequently produce rough surfaces, and the repercussion of roughness on the thermal performance is more prominent in structures of smaller dimensions. In this regard, the present article intends to examine the unsteady thermal behavior of a fully wet, porous, and rough micropin-fin structure under convective–radiative conditions. Here, a pin fin of a cylindrical profile has been chosen. The problem is modeled by incorporating the roughness parameters in the perimeter and cross-sectional area of the pin fin. Further, the study of the porous structure has been carried out by implementing the Darcy model. The resulting partial differential equation is nonlinear and of the second order which has been solved by employing the finite difference method. The impact of the roughness parameter, wet porous parameter, dimensionless time, convective parameter, base radius-to-length ratio, radiative parameter, thermal conductivity parameter, power index, and ambient temperature on the thermal performance and efficiency of rough micropin-fin structures has been established graphically. According to the findings, for $0.15\%$ rise in roughness, the rough micropin fin has $12\%$ more thermal drop rate and $13\%$ less efficiency than the smooth one. Further, the work is beneficial in the field of microelectronics, especially in the design of micropin-fin structures.