Mechanical Engineering

The study focused on the modelling of a candle flame using CFD modelling technique. Governing equation which formed the basis of a CFD modelling using SolidWorks flow simulation was developed, and the simulation result was compared with an existing experimental result. Modelling results show that the heat flux is maximum at the wick base and minimum at a distance of 0.1m from the wick tip, where it maintains averagely a constant value of 55.23kW/m2. This implies that the heat flux generated by a typical candle is large enough to ignite secondary objects such as wood materials located even 100 mm above the wick of the candle as they are capable of auto-ignition at heat flux above 40kW/m2. However, nearby objects that are not directly over the candle base can also be ignited, but must be located much closer for ignition to occur.

This paper presents the characterization of solid state sintering schedule for near-net shaping of warm formed metal powder compacts. Iron ASC 100.29 powder was used as main powder constituent during this investigation.  The feedstock was prepared by mechanically mixed iron powder with 0.4 wt% zinc stearate as admixed lubricant. The powder mass was then formed as solid cylinder at 180ºC.  The defect-free green compacts were sintered in an argon gas fired furnace at different sintering schedule. The sintered products were characterized through dimensional measurement, and mechanical testing. The results revealed that sintering schedule plays an important role in manufacturing near-net shape yet high strength components.

In this paper experimental investigation has been carried out on kevlar/glass angle ply hybrid composites to characterize interlaminar shear strength. With the aim of determining the influence that the structure, a reinforcement type and a sort of resin exert upon the interlaminar strength. Hybrid composites are considered materials of great potential for engineering applications. One advantage of hybrid composite materials for the designer is that the properties of a composite can be controlled to a considerable extent by the choice of fibers and matrix and by adjusting the orientation of the fiber. The scope for this tailoring of the properties of the material is much greater, however, when different kinds of fiber orientations are incorporated in the same resin matrix. Three orientations viz 0?/90?, ±45?and 60?/30? were considered for studies. Mechanical properties such as interlaminar strength, interlaminar stiffness, & peak load of the hybrid composites were determined as per ASTM standards. Vacuum bagging technique was adopted for the fabrication of hybrid specimens. It was observed that orientation at 0?/90?showed significant increase in ILSS properties as compared to other orientation.

A numerical study is presented on the effects of chemical reaction and magnetic field on the unsteady free convection flow, heat and mass transfer characteristics in a viscous, incompressible and electrically conducting fluid past an exponentially accelerated vertical plate embedded in a porous medium by taking into account the heat due to viscous dissipation. The problem is governed by coupled non-linear partial differential equations. The dimensionless equations of the problem have been solved numerically by the implicit finite difference method of Crank – Nicolson’s type. The effects of governing parameters on the flow variables are discussed quantitatively with the aid of graphs for the flow field, temperature field, concentration field, skin-friction, Nusselt number and Sherwood number. It is found that under the influence of chemical reaction, the flow velocity as well as concentration distributions reduce, while the velocity reduces as porous medium increases. Viscous dissipation parameter leads to increase the temperature.

The paper presents a new approach to the classification of rolling element bearing faults by implementing Artificial Neural Network. Diagnostics of rolling element bearing faults actually represents the problem of pattern classification and recognition, where the key step is feature extraction from the vibration signal. Characterization of each recorded vibration signal is performed by a combination of signal's time-varying statistical parameters and characteristic rolling element bearing fault frequency components obtained through the frequency spectrum analysis method. The experimental data is collected for four bearings at three different speeds. The sensor is located at three different positions for each bearing. Both time domain and frequency domain signals were measured. Thus the data was three time spectrums and three frequency spectrums for each speed for a bearing. The entire data set comprised of 72 (6 x 3 x 4) data. The time domain signal was comprised of 8192 samples and extracting these features from a huge data set was difficult. To overcome this difficulty the 8192 samples were split into 32 bins each containing 256 samples. The entire process of splitting and evaluating the seven features was coded in MATLAB. From these seven features the most suitable features for explaining the intensity of the defect is discussed.

The concept of CNC (Computer Numerical Control) in machine tool evolved at the Massachusetts Institute of Technology (MIT), USA between the year 1947 to 1952 for the manufacture of complex & accurate helicopter blades. Since then, this technology has been applied to many different types of machines & machine tools. Now a days the CNC machines have found adoption of by many industries. They have become virtually indispensible in many manufacturing industries because of their many advantages and easy management & reliability. In the face of stiff competition, higher cost of labour & higher rejection of parts, CNC machines proved to be a boon for any manufacturing industry, be it a metal cutting industry, metal forming industry & any other manufacturing industry. Now a days no industrialist can think of putting up an industry without CNC machines, such are their importance & advantages. Talking of Cellular Manufacturing Systems, where a cell of machine tools & other facilities like job movement arrangement etc are created to process a machine part or component from the input of raw material to the finished part. One cannot think of designing such a cell without any CNC machine . CNC machines are part & parcel of Cellular Manufacturing Systems. Rather, they form the backbone of Cellular Manufacturing Sytems.

Generally medicines must be stored and handled in accordance with the manufacturer’s guidelines in order to maintain the quality of the product. Storage outside the recommended temperature range can result in chemical and physical changes to the product which may lead to a loss of efficacy and may cause harm to the patients. In order to maintain such recommended temperatures we generally use vapour compression refrigeration systems. The main drawback is emission of CFC compounds (refrigerants) like R22 upon leakage which could produce harmful effects on environment like ozone depletion. This work aims at developing alternate system for producing refrigeration effect called Thermo Electric Refrigeration. Thermoelectric cooling devices utilize the Peltier effect, whereby the passage of a direct electric current through the junction of two dissimilar conducting materials causes the junction to either cool down (absorbing heat) or warm up (rejecting heat), depending on the direction of the current. Finally using this thermoelectric principle a cold storage is fabricated for preserving the medicines and tested. The minimum cooling temperatures obtained are 10°C at 36°C ambient temperature in 210 minutes that is 3 hours 30 minutes.

Metal-joining plays an important role in the industry and virtually all servicing and manufacturing concerns, directly and indirectly, benefit from it. However, not all kinds of joining processes are suitable for thin metals and light works due to the sensitivity of light metals to heavy heat, rapid corrosion of most metals at high temperatures and very high quantities of heat energy needed to fuse parts. It has been observed that the heat energy required to melt and establish continuity across parts is even higher with welding and brazing-which utilize fillers of high tensile strengths and melting points-such as iron (0.8% steel-800 MNM-e 1535oc), copper (210 MNM-z 10-83oc) and silver (125MNM-e 961oc). In this study, therefore the cold-brazing Joining technique which does not utilize heat in its operation, was studied using experimental designs. Light copper wires of about 0.01mm diameter, zinc electrode and concentrated zinc tetraoxosulphate (vi) solution (Zn2So4) were used and, results from the investigation and calculations show that thin metals and light parts can be easily joined using cold-Brazing joining technique with energy consumption for depositing a zinc filler of 1kg using high temperature process and the same amount of zinc filler using cold-Bracing, in the ratio of 71:269 KJ. Thus, it is certain that other electrolytically depositable metals with higher tensile strengths and melting points than silver-solders and brass, such as copper, can be used with this technique. And if fully made better, the present innovation will not only rival, but surpass most joining methods.

In metalworking, rolling is a metal forming process in which metal stock is passed through a pair of rolls. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is termed as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is termed as cold rolling. In terms of usage, hot rolling processes more tonnage than any other manufacturing process, and cold rolling processes the most tonnage out of all cold working processes. This article describes the use of advanced tubing inspection NDT methods for boiler and heat exchanger equipment in the petrochemical industry to supplement major turnaround inspections. The methods presented include remote field eddy current, magnetic flux leakage, internal rotary inspection system and eddy current.

The thermal performance of tractor radiator is improved with Cu/water when compared with CuO/water nanofluids as workings fluid. The nanomaterial plays a vital role for past two decades in the research areas like thermal management and material science. Miniaturization and increased operating speeds of heat exchangers warranted the need for new and innovative cooling concepts for better performance. The nano materials and its suspension in fluids as particles have been the subject of intensive study worldwide recently since pioneering researchers recently discovered the anomalous thermal behavior of these fluids. For heavy vehicles the engine cooling is an important factor for their performance in the intended application. Here the tractor engine radiator cooling is enhanced by nanofluid mechanism of heat transfer for its improved performance in agricultural work. If the tractor engine cooling is enhanced then using this farm equipment more agricultural field can be ploughed which can be utilized for cultivation within a short period of time. Heat transfer in automobile is achieved through radiators. In this research work an experimental and numerical investigation for the improved heat transfer characteristics of a radiator using Cu/water and CuO/water nanofluid for 0.025, 0.05 and 0.075% volume fraction is done with inlet temp of 50 - 60°C under the turbulent flow regime (8000 ? Re ? 25000). The overall heat transfer coefficient decreases with increase in nanofluid inlet temperature of 50 - 60°C. The experimental results of the heat transfer using the Cu metal particles of nanofluid is compared with Oxide and the numerical values which shows an increase in heat transfer coefficient. The results in this work suggest that the best heat transfer enhancement can be obtained compared with the base fluid and oxide form by using a system with Cu/water nanofluid-cooled radiators. The nanofluids showed better heat transfer characteristics as a new alternative coolant for the radiator.