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.

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.

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.