This paper presents the effects of aspect ratio $(0.1\le AR\le 0.7)$, Rayleigh number ( ${10}^2\le Ra\le {10}^6$) and inclination angle $0°\le \gamma \le 90°$ of the heated rectangular cylinder on heat transfer and fluid flow characteristics due to natural convection in air around heated rectangular cylinders of different sizes inside a cold square enclosure. Galerkin finite element method was adopted for the solution of the developed model. The walls of the enclosure were maintained at an isothermal cold temperature while the boundaries of the rectangular cylinder were kept at a constant hot temperature. The results are presented in the form of isothermal contours, stream functions, local and average Nusselt numbers. It has been found that for the range of aspect ratio and Rayleigh number considered, the rate of heat transfer increases with increasing aspect ratio and Rayleigh number. Furthermore, the orientation angle of the rectangular cylinder was found to generally augment heat transfer rate except at $AR$ value of $0.1$, where the average Nusselt number declines beyond $\gamma =45°$ for all the range of Rayleigh numbers considered. Results from the present study could be applied to nuclear reactor technology and cooling of electronic chips system optimisation.

The impacts of MHD and heat generation/absorption on lid‐driven convective fluid flow occasioned by a lid‐driven square enclosure housing an elliptic cylinder have been investigated numerically. The elliptic cylinder and the horizontal enclosure boundaries were insulated and the left vertical lid‐driven wall was experienced at a fixed hot temperature, and the right wall was exposed to a fixed cold temperature. COMSOL Multiphysics 5.6 software was used to resolve the nondimensional equations governing flow physics. A set of parameters, such as Hartmann number (), Reynolds number (), Grashof number (), heat generation‐absorption parameter (), and elliptical cylinder aspect ratio (AR) () have been investigated. The current study discovered that for low Reynolds number, the adiabatic cylinder AR of 2.0 provided the optimum heat transfer enhancement for the model investigated, also the impact of cylinder size diminishes beyond Gr = 10⁴. But for high Reynolds (Re = 1000), the size of the cylinder with AR = 3.0 offered the highest heat transfer augmentation. The clockwise flow circulation reduces because of an increase in AR, which hinders the flow circulation. In addition, heat absorption supports heat transfer augmentation while heat generation can suppress heat transfer improvement.

The primary heat source from the sunlight is solar energy (SE), which is used in photovoltaic (PV) panels, solar power plates, PV, streetlights, and solar-based hybrid nanocomposites. Currently, research is focused on analyzing and improving the efficiency of SE, particularly for powering aircraft, by combining solar power with nanotechnology advancements. As such, this study focuses on examining concentrated solar power and proposes a method to improve the performance of solar airplanes by employing nanotechnology. Furthermore, the work is based on the investigation of the flow rate, thermal distribution, and entropy generation of the magnetized tangent hyperbolic hybrid nanofluid (HNF) along the interior parabolic solar trough collector of an aircraft wing. This work utilizes similarity variables to simplify the partial derivative model into ordinary differential equations. These equations are then solved using the Galerkin weighted residual approach with the help of MATHEMATICA 11.3 software. From the obtained outcomes, it is reflected that the HNFs have high thermal conductivity than the NF. Intensification of Weissenberg number improves the performance of airplane wings subjected to heat transmission. Therefore, this research contributes to improved thermal management in advanced nanotechnology and solar aircraft.

This research was performed to optimize the performance characteristics of the Nigerian Jebba Hydropower Plant in order to enhance its generation of electricity. Pertinent hydropower data were hourly collected from the plant from 8:00 am to 5:00 pm between 2016 and 2018. The coefficient of determination obtained from the response surface methodology (RSM) showed that discharge, pressure drop, stator temperature and water pressure strongly influenced the generation of estimated power. Also, the contour and surface plots suggested that the discharge (D) 8200.00–8600.00 m³/s and pressure drop (Pd) ranging from 27.50–28.50 m gave the optimal power generation indicating that both factors must be kept high when the hydropower plant is in operation. The instability of power generation was attributed to the reduction in the net available head as turbine inlet decreased. The study, therefore, showed that net power output, speed of the turbine, and efficiency of the hydropower plant could be optimized with increase discharge and gross head. Predicted optimal values for discharge, pressure drop, stator temperature, and water pressure were 8783.3667 m³, 28.59 m, 58.00°C, and 31.00 N/m² respectively.