Khaled Al-Farhany

The stability analysis of Marangoni magneto-convection (MMC) is investigated in a two-layer system consisting of an electrically conductive fluid-saturated porous layer overlain by an identical fluid layer, incorporating variable heat sources and a uniform magnetic field. The upper fluid surface is free, allowing surface-tension-driven convection, while the lower porous boundary is rigid. Two thermal boundary conditions are examined: (i) adiabatic–adiabatic (A–A) and (ii) adiabatic–isothermal (A–I). The governing equations are solved analytically using an exact method to obtain the thermal Marangoni number, an eigenvalue, as a function of depth ratio, Darcy number, Chandrasekhar number, internal Rayleigh numbers, wave number, and thermal diffusivity ratio. Graphical results show that the onset of MMC can be either advanced or delayed by appropriate choices of depth ratio and thermal boundary conditions. The novelty of the present work lies in deriving closed-form expressions for a composite fluid–porous system with simultaneous consideration of variable internal heat sources and magnetic effects under dual thermal boundary conditions, and demonstrating how depth ratio and thermal boundary conditions can be strategically tuned to either advance or delay the onset of instability.

The work aims to investigate the MHD Casson fluid flow over an exponentially long sheet via a thermally stratified permeable medium. All facets of chemical processes, Joule heating, and exponential heat sources are covered in this subject. By using the appropriate similarity conversions, the leading partial differential equations (PDEs) of the model are transformed into a set of nonlinear ordinary differential equations (ODEs). The description of the previous technique was made simpler by applying the Keller Box methodology. The results reveal that when the viscosity factor is increased, the velocity profile improves, but when the thermal profile improves, the opposite trending impact is evident. The temperature profile exhibits the opposite tendency, despite a decline in the number of observations of the Casson fluid constraint. Joule heating parameters allow for more precise measurements of the heat source's properties by raising the temperature. The concentration graph shows a reduction as the number of observations for the chemical reaction parameter increases. The validity of the problem is investigated by computing the Nusselt number for cumulative Prandtl number observations and comparing the results with the literature.

This paper investigates numerically the effect of MHD and entropy generation on double‐diffusive combined convection in an inclined enclosure filled with Si₂O/H₂O and heated fins. The geometry's base is connected to double fins with three locations in three cases. A range of variables has been considered, such as Reynolds, Richardson, Lewis, bouancy ratio, the volume fraction, Hartmann numbers, and the orientation of the enclosure, to investigate how these variables can affect the fluid flow and the mass and thermal transfer. The finite element method has been applied to solve these variables, and the main findings indicated that the value of average Nusselt and Sherwood numbers increases with the increase of volume fraction, Richardson, and Lewis numbers while decreasing with the increase of magnetic strength, Hartmann number. Where Nu_avg and Sh_avg increase to 65% and 19% when increasing Re from 40 to 180 while both values decrease to around 35% when increasing Haatmann number from 0 to 62. Moreover, increasing the volume concentration from 0 to 0.08 increases Nu_avg and Sh_avg to around 3% and 12% respectively. Furthermore, the average Sherwood number increases with the increase in inclination angle. In contrast, the average Nusselt decreases with the increase in the inclination angle, except for the right angle, which gives a higher value. Moreover, the total average entropy generation is reduced with the increase of the magnetohydrodynamic and buoyancy ratio while increasing with the rise of Reynolds, Richardson, Lewis, and the concentration of the nanoparticles. Also, the lowest values of entropy generation are generated in Case 3, while CaseI generates the highest values of entropy generation.

This study describes a computational model that simulates the behaviour of a solar-powered desalination system. The model incorporates photovoltaic/thermal (PVT) collectors and direct contact membrane distillation (DCMD). A novel DCMD unit model was established and verified using existing data from the literature and the model was incorporated into the TRNSYS library. The effect of feed water mass flow rate and temperature on production was investigated through a parametric analysis. The PVT-DCMD system was modeled, analyzed, and dynamically simulated for the month of June in Algeria using TRNSYS software. Results show that the PVT collector's outlet solar fluid temperature ranges from 20 °C to 85 °C, providing 5000 kJ/hr of useful energy for seawater desalination through a heat exchanger. Meanwhile, the auxiliary heater utilizes around 10,000 kJ/hr of solar energy. The simulation demonstrates the feasibility and effectiveness of using PVT collectors with a DCMD system for seawater desalination, achieving a distillate production rate of approximately 12 L/hr.m2 of membrane.

The main objective of this work is to investigate numerically double-diffusive mixed convection flow in a channel filled with a hybrid nanofluid of Cu-Al2O3 in a porous media. It is considered that the cavity's left wall is continuously heated. The fluid flow enters the channel at low concentration and temperature. This work has been looked into two cases: Case 1, where it is supposed that the left wall cavity has high concentrations, and Case 2, where it is expected that the right wall cavity has high concentrations. The cavity's remaining walls are impermeable and thermally insulated. Non-dimension governing equations are solved with the finite element method. Parameters effects of Reynolds number(10≤Re≤100), Richardson number (2≤Ri≤10), Darcy number (Da=10-2,10-4), Lewis number (1≤Le≤5), buoyancy ratio, N=1, the solid volume fraction (ϕ=0.02), and Prandtl number (Pr=6.2). The results show that increasing Reynolds, Richardson, and Darcy numbers increases the average Nusselt while it decreases by increasing Lewis number. In addition, Sherwood numbers increase with increasing Reynolds, Lewis, and Darcy numbers while they decrease with Richardson numbers for both cases. When the Reynolds number increases from 10 to 50 at (Da=10-4) and (Ri =10), the Nusselt number increases by 102%, while the Sherwood number decreases to 72%.

This work numerically explores the mixed convective heat transfer in an open square enclosure containing conducting fins fixed to the heated vertical wall. This kind of work with fins has enormous potential due to its applications in research, engineering, and current industries. Therefore, the current work is highly significant to understand the impact of mixed convection. The external flow enters from the hole in the bottom wall and leaves from the hole in the upper wall. The left vertical wall of the enclosure is heated isothermally, and the fins are attached to the heated walls at a uniform height. Both the upper and lower walls are adiabatic, whereas the right sidewall is at a lower temperature. The non‐dimensional transport equations are resolved by using the finite element method. The study is accomplished for the wide control variables range, such as Reynolds number (50 ≤ Re ≤ 200), Richardson's number (0.1 ≤ Ri ≤ 10), the length of the fins (L_f = 0.2, 0.4, and 0.6), the size of the outlet opening (W_out = 0.1, 0.2, and 0.3), and the gaps in between the outlet hole and left heated wall (S = 0, 0.45, and 0.9). The results show that the thermal performance of the open enclosure is meaningfully affected by the control parameters. The maximum and minimum heat transfer happens when the position of the outlet opening is at the left (S = 0) and right (S = 0.9), respectively. The heat transfer improves by raising the Ri and Re, whereas increasing the fin's length and distance between the outlet opening and left wall reduces heat transfer significantly. The rises 13% with a decrease in the fin's length from 0.6 to 0.2 at Re = 200, S = 0 due to the improvement of the convection on the heated wall. Also, increases by 15% when Ri increases from 1 to 9.