The effects of Lorentz force and inclined angle on time-dependent free-convective thermal-material transport by micropolar binary mixture of fluid passing a continuous permeable surface have been analyzed in this article. Using the local similarity transformation, the governing partial differential equations have been converted into ordinary differential equations. The shooting technique was then employed to solve non-dimensional ordinary differential equations with boundary conditions using the "MATLAB ODE45" software. The effects of emerging Lorentz force (M) and inclined angle (γ) on the fluid velocity, concentration, temperature, and microrotation have been investigated within the boundary layer. Other non-dimensional parameters in this study, such as Schmidt number, suction parameter, and Prandtl number are kept fixed at Sc = 0.22, c = 0.5, and Pr = 0.71, respectively. The numerically simulated result shows that the velocity falls for uplifting values of the inclined angle and Lorentz force. The skin friction coefficient decreases by 49%, and 20% due to increasing the values of inclined angle (00-600), and Lorentz force (1.0 - 4.0), respectively. The surface couple stress is found to be increased about 24%, and 44% with the upturning values of M (1.0 - 4.0), and γ (00-600), respectively. Through this research, the behavior of the fluid flow has been explored.

Climate change and the exhaustion of conventional energy sources with the growing demand for energy have caused concern among researchers all over the world. Renewable energy sources are a long-term alternative to our reliance on fossil fuels and reduce carbon emissions. Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy, and solar architecture. Photovoltaic thermal (PVT) is a hybrid system, which includes both thermal and electrical energy generations. A 3D solar photovoltaic and thermal hybrid system is considered in this study where the encloser of the heat exchanger is fabricated from corrosion resistive stainless-steel sheet, and uncovered surfaces to the air of the heat exchanger are insulated using the glass wool. The fins manual air circulation and the channels are made of aluminium. The top side of the fins is bended and tightly attached to the lower back floor of the solar PV panel, wherein heat switch from the PV panel to the fins happens via the conduction technique. The equations of the heat transfer for PV layers such as for glass, cell, fins, heat exchangers, and laminar flow equation for the fluid domain are solved numerically applying the finite element method (FEM). Temperatures of air at the inlet-outlet and solar cell of the PVT system, are obtained for the variation of solar irradiance from 200 to 400 W/m2 using the weather situation of Bangladesh. Finally, the overall efficiency is calculated under different weather conditions in Bangladesh. The numerical results depict that the new layout of the heat exchanger efficiently transfers heat to the circulating air and the overall efficiency of the PVT is greater at the lowest solar irradiance of 200 W/m2.

The slip flow and thermal transfer inside the boundary layer are extremely significant for various problems in aerodynamics, wing stall, skin friction drag on an entity, high-level velocity aircraft, etc. The current research investigated the effect of the slip factor and shape factor on the axisymmetric bullet-shaped object by taking the viscous dissipation parameter and location parameter. The analysis is conducted for both fixed and moving bullet-shaped objects due to thinner and thicker surfaces. The governing equations are transformed into a system of ordinary differential equations using suitable local axisymmetric similarity transformations and solved by applying the spectral quasi-linearization method. A new correlation analysis is made for velocity and temperature gradients. It is observed that the boundary layer structure has no defined shape due to a thicker bullet-shaped object instead it forms a steep angle with the axis which is contradictory to the formation of the boundary layer. A negative correlation is observed for the parameters M, Ec, Q*, and s but a positive correlation is observed for the parameters such as Pr, P, λ, and ε. The surface thickness and stretching ratio significantly affect the fluid flow and heat transfer processes. It is also noticed that the thinner bullet-shaped object performs as a better cooling conductor compared to a thicker one. The skin friction is reduced in the case of a thinner bullet-shaped object compared to a thicker one. The present analysis reveals that the heat transfer rate and the friction factor may be helpful in industrial sectors for controlling the cooling rate and quality of the final product. This research brings forward to increase in the rate of heat transfer inside the boundary layer region. The result may help to design the various types of moving objects in the automobile engineering sector when the objects pass through the fluid.

We investigate the unsteady laminar convective magnetohydrodynamic nanofluids flow in a square cavity driven by an exothermic chemical reaction. Because exothermic chemical reactions are intrinsic in nanofluidic flow applications, we consider this exothermic chemical reaction in the analysis, which is governed by Arrhenius kinetics energy. A water-based nanofluid containing iron oxide (Fe3O4) nanoparticles is employed in the simulation. The square cavity is accurately propounded by a combination of suitable heating and flow conditions. The left vertical wall of the enclosure is considered a higher unevenly heated wall, the right vertical wall of the domain is considered a relatively cool constant temperature, and the upper and lower walls are considered insulating walls. Each wall assumes a no-slip condition. The nanofluid governing equations are transformed into the non-dimensional set of equations using similarity analysis and then modified into finite element equations. Galerkin's method in finite element analysis is used to obtain the results of the problem. The results show that the Rayleigh number, the Frank-Kamenetsky number, and the nanosolid volume ratio all have significant effects on the convective flow regime, and the average Nusselt number increases with these parameters. Due to the greater value of the Rayleigh number (Ra = 106), the average Nusselt number increased to 75.92%, and heat generation due to a strongly exothermic reaction (higher Frank-Kamenetskii number) can blow up the bounded solution. The water-Fe3O4 nanofluid achieves a greater rate of heat transfer (maximum 22.65%) than that of the base fluid.

Interruption of continuous process and decreasing flow rate over time are very common challenges in peristaltic flow. This research takes an initiative to restrain the thermal and fluid flow rate over time by unsteady finite element analysis of Casson fluid flow through a two-dimensional peristaltic duct. The time-dependent flow equation exists in conjugate forced convection and the energy equation consists of radiative heat flux and entropy reduction. The top and bottom walls of the peristaltic duct are considered as contact with air. A circular bolus is set up in the middle of the duct. Four types of Casson fluids like slurry, silicone oil, apple juice, and blood are used as working fluids. The finite element method of Galerkin's residual technique is applied to solve the leading second ordered non-linear partial differential equations with proper border conditions. The effects of pertinent parameters on entropy reduction and thermal transport are analyzed. Results are displayed qualitatively in terms of streamlines, vortex field, and heatline contours as well as quantitatively in the form of average temperature, mean thermal, viscous, and total entropy. The obtained numerical results show that thermal performance and entropy reduction are significantly influenced by forced convection, atmospheric characteristics, internal thermal radiation, and Casson fluids. Approximately 6.99% and 72.13% increment of temperature and flow irreversibility are found for shear stress variation of Casson fluid from thickening to thinning. Decreasing thermal performance of 18.71% and increasing energy loss of 38.07% are noticed within the variation of Casson fluids (slurry, silicone oil, apple juice, and blood). About 14.05% enhancement of thermal transport and 64.91% reduction of total entropy are observed due to increasing internal thermal radiation from 0.5 to 2. The numerical results from this research represent a better thermal and fluid flow rate over time compared to the experimental/existing methodology/numerical research. The obtained flow and thermal transport phenomena expose many attention-grabbing performances which deserve additional investigation on Casson fluid characteristics particularly the continuation of flow rate. A fine approach to the biological peristaltic system is offered by the results.