Today, the use of composites has received widespread attention due to their special properties that cannot be found in alloys. Kevlar-Epoxy composite is one of the most widely used materials. In this paper, we analyze the heat transfer in Rectangular fin and present an exact, Differential Transform Method and FEM solution for steady-state conduction heat transfer in Rectangular composite laminates. The differential Transformation Method (DTM), is applied for predicting the temperature distribution in a Rectangular composite fin. Laminate with fiber orientations of 0° is considered for the analysis. By validating the results in one composite layer, the temperature changes and heat flux in several composite layers were finally simulated in ABAQUS software and the effect of the number of composite layers and time on these parameters have been investigated. The selected composite fin’s material is Kevlar-epoxy. The results show that the exact solution and DTM predict the same trend compared to the FEM result and are very accurate and there is a good match between FEM results with DTM method and the exact solution. The thermo-geometric fin parameter (µ), the number of composite layers, and time have a significant effect on temperature distribution and heat flux. By increasing of thermo-geometric fin parameter (µ), heat flux and dimensionless variable for temperature distribution increase. When the number of layers increases, the dimensionless variable for temperature distribution and heat flux decrease along the fin. With increasing time, the temperature distribution and heat flux become more uniform and the ratio of heat flux changes decreases along the fin.

For desalinating seawater and brackish water, a basic and inexpensive device known as a solar still is used. The limited amount of freshwater output that can be obtained from a solar still is its primary flaw, which limits its global use and applicability. The improvement of a solar still's freshwater output is the main goal of this research. Two identical single slope solar stills are created for this purpose, and one of them is changed by adding Rectangular aluminium fins and a bamboo cotton wick to the still basin. This modified still is called. The other still that hasn't been altered is known as a standard still. In this experimental study, Kurukshetra, India (29.96°N, 76.87°E) weather conditions are used to evaluate both stills. At varying water depths of 1 cm, 2 cm, and 3 cm, the performance of the modified still and the conventional still are concurrently compared. According to experimentation's findings, 1 cm of water depth is where both stills' daily productivity and optimum water temperature are attained. The daily productivity of the solar still improved by about 19% when bamboo cotton wick was spread over the Rectangular fins in the still basin.

This work focused on the geometric assessment by the lens of the Constructal Design of a Rectangular fin placed at different surfaces and positions of lid-driven cavities under laminar forced convection. This study aims to maximize the Nusselt number (NuH) from the isothermal fin for Reynolds numbers (ReH) ranging from 10 to 1000 and a fixed Prandtl equal to 0.71. The fin was placed at the lower, upstream, and downstream cavity surfaces in five positions (S* = 0.1; 0.3; 0.5; 0.7; 0.9). The domain presents two constraints: the cavity area and the ratio fin area to cavity area kept constant for all cases (φ = 0.05). The degrees of freedom explored to maximize the Nusselt number were the ratio between the height and length of the fin (H1/L1) and the fin position along each cavity surface. The results indicated that the fin geometry and positions significantly affected the Nusselt number. The highest Nusselt number was achieved for the fin positioned on the downstream cavity surface with H1/L1 = 2.0 and S* = 0.9, improving the Nusselt number by 63.1% and 5.8% compared to the optimal shapes in the lower and upstream cavity surfaces.

Conventional Wrap-Around fins (WAF) have unique aerodynamic characteristics, such as changing the roll moment direction with increasing Mach number and the nonlinearity of the aerodynamic coefficients. The placement of Wrap-Around fins against each other eliminates their aberrant and non-linear aerodynamic characteristics and provides the condition with a less complicated guidance system. In this research, the effects of curvature of Opposite Wrap-Around fins (OWAF) on the aerodynamic performance of the projectile has been investigated. This investigation has been done numerically, and the results were compared with the wind-tunnel accessible test data, which have good accuracy. The simulation has been carried out at a Mach number of 1.5 and an angle of attack of  0 and 5 degrees, assuming a turbulent compressible flow; the physics of the flow around the fins has been investigated. The results showed that increasing fins curvature increases lift and drag coefficients by 7% and pitch moment up to 20%. Also, the fin curvature eliminate flow separation in junction of fin leading edge and body.

In this research, in order to investigate the effect of the piezoelectric patch which is used as a sensor or actuator in rotating flexible structures such as a helicopter blade, the free vibrations of the rotating Rectangular sheet with and without the piezoelectric patch have been presented. First-order shear deformation theory is considered for plate displacement and piezoelectric field. Considering the effect of Coriolis acceleration, centrifugal acceleration and centrifugal in-plane forces, the equations of motion are derived from Hamilton's principle and the electromechanical couple equation is obtained from Maxwell's equation. For piezoelectric, two electrical conditions, open circuit and closed circuit, which are used in sensors and actuators, respectively, have been considered. The equations are discretized with the help of the numerical method of generalized differential squares and the matrices of inertia mass, eccentricity, Coriolis and stiffness matrix are obtained. Natural frequency values for beam and rotating plate have been compared in Abaqus software. Also, the values obtained from the numerical solution in MATLAB have been verified with articles and ABAQUS, which have high accuracy. The effect of parameters such as hub radius, rotation speed, sheet thickness, aspect ratio, piezoelectric patch thickness and applied voltage on the natural frequency of the system has also been investigated.

Applying heat sinks as extended surfaces plays a significant role in cooling various industrial equipment. This study investigates the impact of heat transfer parameters of fins, such as practical geometry, wall heat flux, coolant velocity, and the angle at which the coolant flow interacts with the fin. The geometry of the fins includes Rectangular and triangular shapes, with a heat flux range of approximately 4. 6-18. 5 kW/m2, coolant velocities ranging from 1-2 m/s, and angles of 0º, 45º, and 90º between the fin position and cooling flow direction. Aluminum, known for its high conductivity, was chosen as the material for the fin structure, with air serving as the primary cooling flow. The study found that triangular fins exhibited a higher convective heat transfer rate than Rectangular fins, approximately 47. 4% higher on average across all conditions. However, Rectangular fins dissipated heat from the wall more effectively. Pressure drop was assessed by comparing cooling flow velocities associated with each fin in various positions. Results revealed that the sharp tip of triangular fins reduced the vorticity effect, increased average flow velocity, and decreased pressure drop. Additionally, Rectangular fins were approximately 10. 4% more efficient on average than triangular fins. The study also concluded that the impact angle had a negligible effect on the efficiency of both Rectangular and triangular fins.

Abstract In this paper, multi-objective optimization (MOO) of heat transfer and flow field in interrupted micro channel heat sinks (MCHS) with Rectangular fins using in computer chips is performed using Computational Fluid Dynamics (CFD) techniques and Nondominated Sorting Genetic Algorithms (NSGA II). At first, fluid flow is solved numerically in 100 various interrupted MCHS with Rectangular fins using CFD techniques. Finally, the CFD data will be used for Pareto based multi-objective optimization of fluid flow in MCHS with Rectangular fins using NSGA II algorithm. In the MOO process there are three geometrical parameters and the conflicting objective functions are to simultaneously maximize the amount of heat transfer and minimize the pressure drop. It is shown that the achieved Pareto solution includes important design information on fluid flow in MCHS with Rectangular fins.

Experiments were conducted to investigate forced convective cooling performance of an air cooled parallel plate fin heat sink with and without circular pin fins between the plate fins. The original parallel plate heat sink was fabricated consist of 9 parallel plates of length 53 mm with cross-sectional area of 1.4 mm in width by 20 mm height for each plate. The second heat sink has the same geometry of original one but with some circular pins between the plate fins. Thermal and hydrodynamics performances of the heat sinks have been assessed from the results obtained for the pressure drop, thermal resistance and overall performance with the free stream air velocity ranging from 4.7 to 12.5 m/s. Results show that the free stream air velocity has a significant effect on the thermal and hydrodynamics performance of the system. With increasing free stream velocity, the heat transfer coefficient increases and consequently the thermal resistance decreases while pressure drop increases due to higher inertial of fluid at higher velocities. Furthermore, at the same free stream air velocity the thermal resistance for the heat sink with circular pin is about 37.7% lower than that of the original heat sink.

In this study, the cooling process of a laptop processor is investigated and simulated. The geometry in question consists of a heat pipe and a heat sink with fins, and the cooling process is simulated in the ANSYS Fluent software. Using the simulation results, the effect of six different geometries for the aluminum heat sink fins on the cooling rate and temperature of the laptop processor is investigated. The geometries evaluated include Rectangular, triangular, wavy, Rectangular with holes, Rectangular with pins, and Rectangular with appendages. Air passes over the fins at a speed of 1 m/s and the air flow is considered turbulent. For all geometries under study, it is assumed that a heat flux of 70 kW/m2 is transferred from the heat pipe to the top of the heat sink. The results show that using the wavy fin geometry leads to increased heat transfer from the top surface of the heatsink, resulting in a reduction in the processor surface temperature (up to 63 °C). Also, using triangular fins leads to a temperature of 149 °C on the processor surface, which is inappropriate and can cause damage to it