Mechanical Engineering

The present work deals with experimental studies on heat transfer and flow characteristic for buoyancy induced flow through inclined tubes. The parameters varied during the experimentation are; tube inclination and heat supply. It was found that mass flow rate and heat transfer coefficient increases with increase in heat flux supplied. The flow rate decreases for increase in tube inclination.

In the present day scenario rapid product development (RPD) becomes essential for product manufacturers for their survival. However, success of RPD depends on advancement and effective utilization of many more available technologies. Now with the availability of Computer Aided Design (CAD) / Computer Aided Manufacturing (CAM) for RPD making the demands of the present day industry are taken care. The product development by CAD/CAM reduces the considerable time of equipment and is made with higher accuracy and repeat-ability resulting in faster development of products and less rejection in the long run this approach to product developing results in cost effectiveness. This paper reviews the technological advancements in CAD/CAM Systems. This paper also depicts the lead-time reduction in product development through modeling with CAD/CAM and application of reverse engineering, Rapid prototyping and CNC approach to RPD.

Agricultural Machinery is mostly used in off road i.e. in the field. In the field these machines perform different field operations like Ploughing, where the parts are subjected to stresses like tensile stress, compressive stress and shear stress thereby high wear due to heavy loads. The critical components in the agriculture machinery are either forged or fabricated out of medium carbon steel by unorganized sectors in India. As a result the users suffer on account of quality and short service life of these components. Recently Austempered Ductile Iron (ADI) has come up which has high strength, high wear resistance and less manufacturing cost. This material is now being widely used in production of critical agricultural machinery components for cost effectiveness uses. The paper described the Mechanical, Tribological properties of Austempered ductile iron and its application areas in agricultural machinery in India and abroad.

Heat exchanger is a necessary laboratory equipment in a thermo-fluid laboratory, and lack of this equipment makes learning ineffective. Hence, this study aims to design and construct a shell and tube heat exchanger for laboratory use. To achieve this aim, mechanical and thermal factors were considered. The thermal design was done using the Bell Delaware method. The heat exchanger was designed based on the assumption that there is no phase change, while water at a cold inlet temperature of 15 °C enters the heat exchanger through the tube and hot water at 100 °C enters the heat exchanger through the shell. Results show that the geometry of the heat exchanger favours turbulent flow which enhances heat transfer. This causes a heat load of 107.973 kW to be transferred from the hot fluid to the cold fluid through the tube wall when hot fluid of 0.5 kg/sec flows at a velocity of 0.3 m/s and cold fluid of 2.58 kg/sec flows with a velocity of 1 m/sec. This heat transfer caused the cold fluid temperature to increase by 10 °C as it exits the tube, while the temperature of the hot fluid fell to 45 °C as it exits the shell. The pressure drops in both the shell and tubes were within the allowable range, and hence, accepted. With the overall heat coefficient at 134.23 W/m2K and the efficiency of the system at 73.3%, the study is said to have achieved its objective.

It has been found that the solar tree produces more energy than a conventional flat rooftop arrangement of solar PV system or modules. The solar energy converts the sunlight energy directly into electrical energy by making use of photo -voltaic or concentrated solar power. The energy demand is increasing with each period, as a result the grid electric supply unit prices are also increasing day by day. For example, with the supply of oil the quantity of oil is decreasing and the prices are increasing. Similarly in case of coal which is abundantly for the production of electricity is available for few more hundred years. So in order to fulfill the increasing demand of energy we must have some alternative sources of nonconventional sources of energy. The energy from the sun is the best alternative among all the renewable sources of energies. It is available free of cost, inexhaustible, non-polluting, eco-friendly and continuously. The main drawback of solar panels is the land requirement for the installation of solar panels. The developed solar artifact requires only 1% of the land compared to the flat rooftop to produce same amount of energy. A single converting cell or more generally known as a photo voltaic cell, but a combination of cells in series or parallel designed to increase the power output is called solar module or solar array. In this article the load capacity or energy requirement of a small house in India is estimated to 1.74kWhr/day [6]. All the calculations are done considering solar radiation data at Durgapur, West Bengal. As per experimentation it is found that tracking system can be easily employed in solar artifact, hence its performance will be better than flat solar PV system. The solar cells are mounted in a phyllotaxy pattern to avoid any obstruction from the others. Keywords: Solar artifact, phyllotaxy pattern, PV system, Solar module, manual tracking.

The need for eco friendly alternatives to conventional cutting fluids arises because usage of conventional cutting fluids poses threat to ecology and health of workers. The present work focuses on performance of nano solid lubricant suspensions in vegetable oils in turning of AISI1040 steel in minimum quantity lubrication(MQL). Soyabean, canola and coconut oils are taken as base lubricants with suspensions of 100nm sized boric acid particles. These particles are characterized by X-Ray Diffraction (XRD) and particle size analyzer to confirm their purity and particle size. Variation of basic properties like thermal conductivity, specific heat and heat transfer coefficient are evaluated from empirical relations, to check the viability of nano lubricants in machining. Variation of cutting tool temperatures, average tool flank wear and surface roughness of the machined surface with cutting speed and feed are studied with the prepared nano lubricants. Results are encouraging and coconut oil seems to be more advantageous compared to other vegetable oils.

This paper presents the failure analysis of the turbine blade of a gas turbine engine 9E GE type, installed in a certain type of simple systems consisting of the gas turbine driving an electrical power generator. A non-linear finite element method was utilised to determine the stress state of the blade segment under operating conditions. High stress zones were found at the region of the lower fir-tree slot, where the failure occurred. A computation was also performed with excessive rotational speed. Attention of this study is devoted to the mechanisms of damage of the turbine blade and also the critical high stress areas.

Glass fiber reinforced polymer composites are finding its increased applications in variety of engineering applications such as aerospace, automobile, electronics and other industries. The main objective of this study is to optimize the process parameters with multiple machinability characteristics. The performance characteristics considered were surface roughness (Ra), Cutting force (Fz) and cutting power (P). Optimal combination of process parameters can then be determined by Taguchi method using the grey relational grade as performance index. The process parameters considered were cutting speed, feed, depth of cut and fiber orientation angle (work piece). Experiments are planned according to Taguchi’s L25 orthogonal array in the design of experiments and were carried out on an all geared lathe using carbide (K20) cutting tool insert. The experimental results reveal that the feed is the most significant process parameter on the multiple machinability characteristics, this proposed method can be effectively used to improve the machining characteristics of GFRP composites.

Friction Stir Welding, a relatively new welding process, was developed in 1991 at The Welding Institute near Cambridge, England. In this process parts are mated together, rigidly fixtured, and joined in solid-state by forcing a rotating tool into the joint, and traversing that tool along the joint. This process creates weldments with properties comparable to the base metal and in most cases superior to traditional fusion welding techniques. During the Friction Stir Welding (FSW) process, the forging forces under the tool plastically deform the material, “stirring” the material around the tool pin and against the tool shoulder, thus joining the mated parts together. This process induces large shear forces in the plastically deforming material, raising the temperature of the material to approximately 80% of the melting temperature. The FSW process parameters such as tool rotational speed, welding speed, axial force, etc. play a major role in deciding the weld quality. In present investigation, the effect of processing parameters on mechanical properties of AA6082-O joints produced by friction stir welding was analyzed. Different welded specimens were produced by varying rotating speeds of the tool as 900 & 1200 rpm and by varying welding speeds as 50 & 63 mm/min. The FSW joints mechanical properties of the material such as yield strength, tensile strength and percentage of elongation were evaluated by means of tensile tests.

The aim of this study was to establish the relationship between the Stature and Popliteal Height Sitting, PHS. 161 male occupational bus drivers were randomly selected for anthropometric characterization of Stature and PHS using standard measuring equipment. The data were analyzed using SPSS 16.0 and Design-Expert 6.0.8. Then regression model was used to estimate PHS. The model shows that there is a linear relationship between the Stature and PHS with coefficient of determination (R2) of 0.8258 (p < 0.0001). The model mitigates time required for gathering anthropometric data. Designers would find this as a huge working tool for adequate productions.