Thermal Analysis of Extended surfaces from the Heat sink of Different shape - A Brief Review

This paper introduces a brief review about the way of heat extraction enhancement from heat sink using fins of different types and different shapes and also with different shape of perforation. Extended surfaces from the base plate or heat sink is nothing but they are FINS. There are various types of fin exits. They are Rectangular, Square, Annular, Elliptical, Cylindrical or Pin fin which is utilized with different geometrical combinations. To achieve maximum temperature droop from the base surface or heat sink by using fins numerous trials are completed or being carried out for designing optimized Fin. The optimization of Fin can be achieved by increasing surface contact area with the atmospheric air. In these days there are numbers of experiment is done on fins like Solid fin, Porous fins and Solid fins with perforation, has also been brought off. The various design modifications which are implemented and studied analytically and experimentally by the researchers using ANSYS Work bench is been discussed in this review paper.

Study of the micro/nano-texture design to improve the friction properties of DLC thin films

In this study, a DLC pattern was fabricated through a photolithography process that constitutes a part of the semiconductor process, to investigate the frictional wear characteristics. The photolithography was used to produce negative patterns with a pattern width of 10 [Formula: see text]m or 20 [Formula: see text]m and a pattern depth of 500 nm on the DLC surface. The change in the coefficient of friction of the surface was investigated through a ball-on-disk tribology test on the fabricated micro/nano-sized DLC pattern. The DLC pattern fabricated by the photolithography process showed a superior coefficient of friction to that of the general DLC sample. These results show that the decrease in the surface friction coefficient of the patterned DLC thin film is due to the reduction in the surface contact area owing to the modification of the micro/nano-texture of the surface as well as the low friction characteristics of the DLC.

Influence of variable cutting surface contact area on the components of cutting forces and accuracy

The article discusses the process of diamond honing of conical holes. The purpose of the article is to identify the dependence of power in the process of cutting and the effect of changing the contact areas of the components of the cutting forces. The experiments were carried out on a developed installation to determine the cutting ability of diamond honing stones. Depen- dences of linear removal of steel 50 and steel 45 on the applied pressure have been established. Based on the data obtained, it can be concluded that if the value of the Py index goes beyond the limits of pure contact, then this leads to the seizure of surfaces and a deterioration in the quality of processing.

Studi Perbandingan Perilaku Dalam Reaktor Kolom Gelembung Secara Non-Katalitik Dengan Simulasi CFD Terhadap Kadar ME Biodiesel

Abstrak. Biodiesel dihasilkan melalui reaksi transesterifikasi atau reaksi esterifikasi asam lemak bebas dan tergantung dari kualitas minyak nabati yang digunakan sebagai bahan baku. Teknologi produksi biodiesel memiliki 2 metode yaitu metode katalis dan non katalis. Salah satu metoda produksi biodiesel tanpa katalis adalah metoda superheated methanol vapor (SMV). Namun metode inimenghasilkan kadar biodiesel yang rendah dari SNI. Salah satu cara untuk meningkatkan kadar biodiesel dengan meningkatkan luas kontak permukaan antara gelembung metanol dengan minyak. Hal ini dilakukan dengan memberikan perforated plate (obstacle) di dalam kolom reaktor. Perancangan desain obstacle sangat mempengaruhi luas kontak permukaan antara metanol uap dan minyak. Beberapa jenis obstacle yang dirancang di simulasikan dengan metode Computational Fluid Dynamics (CFD), karena CFD dapat menggambarkan distribusi gelembung di dalam kolom reaktor, sehingga pembuatan obstacle dapat lebih tepat dan memudahkan menganalisa perilaku gelembung di dalam kolom reaktor. Hasil simulasi di-dapatkan luas kontak permukaan yang tertinggi menunjukkan desain obstacle A-4 dengan nilai sebesar 0.013635 m2/det. Namun kadar metil ester pada obstacle tersebut masih rendah dibandingkan dengan SNI yaitu sebesar 67.73% (w/w). Untuk kadar metil ester yang mendekati SNI adalah obstacle D-4 yaitu 94.55 % (w/w).Comparative Study Of Behavior In Non-Catalytic Bullet Column Reactors With CFD Simulation on Content me biodieselAbstract. Biodiesel is produced through transesterification reaction triglycerides or esterification of free fatty acids depending on the FFA content of the feedstock. The reaction normally requires a catalyst, even though the non-catalytic reaction has attracted significant attention recently. One of the non-catalytic method by using superheated methanol vapor (SMV). However, this method still has a low reaction rate and thereby needs to be improved by increasing the surface contact area between methanol vapor and oil. In this study, the utilization of a perforated plate (obstacle) in the reactor column was studied using computational fluid dynamics (CFD). Several types of obstacles were designed and their influence on the reaction rate was evaluated through CFD simulation. The result shows that obstacle design A4 gave the highest contact surface (0.013635 m2/s), even though methyl ester concentration in the reaction product is still low (67.73 %w/w). For methyl esters which are close to SNI is design obstacle D-4, which is 94.55 %(w/w).

Dispersion technology on mechanical properties of carbon nanomaterials reinforced epoxy nanocomposites

Graphene nanoplatelets (GNPs) are platelet-liked graphite nanocrystals with multigraphene layers. In general, a high contact area between polymer and nanofiller maximizes stress transfer from the polymer matrix to nanofillers. Therefore, GNPs can be expected to exhibit better reinforcement than CNTs in polymer composites, because of their ultrahigh aspect ratio (600–10,000) and higher surface constant area. The GNPs planar structure provides a 2D path for phonon transport, and the ultrahigh surface area allows a large surface contact area with polymer resulting in the enhancement of the composite thermal conductivity. In this study, simple and efficient planetary mixing methods were used to enable the GNPs to disperse uniformly throughout the epoxy solution (i.e. 0, 0.1, 0.25, 0.5, 0.75, and 1.0 wt%) and then to prepare GNPs/epoxy nanocomposites. Mechanical properties of the nanocomposite, including ultimate tensile, flexural strength and flexural modulus, were investigated. Finally, the fracture surface of the specimen was investigated using scanning electron microscopy (SEM) to determine the dispersion of the GNPs in the composites.

A novel initiative on vertical-axis underwater turbine suitable for low underwater current velocities

The present paper discusses efforts made to reinvent the use of the vertical-axis turbine for use in locations of low underwater current velocities. The present work targets the low flow current of the sub-Saharan ocean system, which has an underwater current record of around 0.3 m/s and a sea state that is mild, benign and with little or no local storms. The present initiative is achieved through a combination of ducting techniques to increase velocity of flow, and the utilisation of a large surface contact area exposed to flowing water per unit of time. Torque estimations are made using three methods: first principle, SolidWorks computational fluid dynamics (CFD) software and physical measurement. The lowest power coefficient for the tested model is computed from SolidWorks CFD software as 0.70. Existing state-of-the-art underwater current power technologies are reviewed and the present initiative described. A future for ocean water current technology in sub-Saharan Africa is also proposed.

Forms of possible delamination of the liner in a metal composite high pressure vessel

The paper offers a calculation scheme of delaminating occurring in complex metal composite pressure vessels. The calculation is carried out in LS-DYNA software in dynamic formulation using 3D-finite-element discretization of the SHELL- and SOLID-types. Technological deviations have been introduced into the computational scheme, in which a unilateral constraint on the surface contact area is also taken into consideration. The analysis of delaminating is carried out by example of a vessel with a carbon-plastic shell and an aluminium liner in the process of thermal treatment of the vessel. It is shown that at certain heating temperatures of the vessel, liner delamination from the rigid composite shell may occure. Delamination is due to local buckling of the metal thin-walled liner occurring in the areas of technological deviations. Delamination has the form of folds (internal deflection), which in the form are subdivided into annular and radial folds on the bottoms and into the contour (turning into longitudinal) folds on the cylindrical part of the liner. Temporal process of wrinkling on the liner surface during heat treatment of the vessel is shown (video).

Skeleton Runner Roughness and Surface Contact Area Influence on Sliding Ability: Field Experiments

Scientists and sport athletes are constantly seeking for the methods which could improve surface sliding ability on ice. Modifications of contact area and surface roughness are relatively easy but not yet fully understood methods for sliding ability improvements. This research contains information of how one can perform on-field experiments with skeleton sleigh to determine the influence of surface contact area and roughness on sliding ability. Two types of surface roughness i.e. polished (3000 grain sandpaper) and scratched (600 grain sandpaper) are compared using three different contact areas. Obtained data showed that rougher surfaces tend to slide faster if contact area is larger but the effect reverses if contact area is reduced.