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.

Overheating is the major problem ofhermetic compressor due to extra amount of heat added from the motor windings to the shell. It reduces the mass flow rate of the system which results in reduced compressor volumetric efficiency and extremely high discharge temperature. The refrigerant injection is a technique to improve the system performance. This paper reviews the major research on refrigerant injection techniques in detail. The refrigerant injection technique divided into two categories, first is vapor injection and another is liquid injection. Flash tank and internal heat exchanger are two cycles for refrigerant injection. These two cycles are discussed in detail.

Piezoelectric materials appealing for use in smart structures as sensors and actuators instantaneously transform mechanical energy to electrical energy and contrariwise. They remember configurations and guarantee them when subject to stimulus, have superb electromechanical coupling characteristics and outstanding frequency response .Innumerous utilization of smart structures technology to diverse physical systems have progressed to actively control shape, aeroelastic stability, noise, damping, vibration and stress distribution. In this article the research activities of piezoelectric materials for smart structures is grouped into characterization, formulation, analysis, applications & debonding in aid in future research activities in any of the grouped class.

In present research, acoustic signals from gearbox of Massey Ferguson 285 are used for fault diagnosis of gears. Worn tooth face gear and broken tooth gear are studied as two common faults in gear-sets. Signal processing on acquired acoustic signals are done using wavelet transform. Decomposition is made using discrete wavelet transform (DWT) in four levels and using Db4 mother wavelet. Desired information from DWT decomposition is provided by applying some functions on DWT outputs. The investigated data set is fed into feed forward back-propagation neural network to classify the gears status. Two layer networks are trained and tested with separate data sets and using variable hidden layer neurons count. Results show that 100% performance is gained by a network with two neurons in hidden layer.

In this paper, a Hybrid approach has been developed by combining Taguchi Method, grey relational analysis method and fuzzy logic, to reap their advantages in the drilling process. Using hybrid approach a single hybrid grade is determined for multiple response characteristics. Drilling experiments has been performed on Al6061 material with coated and uncoated HSS tools under Minimum Quantity Lubrication (MQL) condition. The controllable parameters such as speed, feed, lubricant, tool material and point angle which influence the responses like power, temperature, Burr height, surface roughness are identified. The responses are analyzed using this hybrid approach and optimum controllable parameter combination is identified.

Thermal energy can be stored as latent heat in which energy is stored when a substance changes from one phase to another by either melting or freezing. Paraffin wax has been widely used for latent heat thermal energy storage system applications due to large latent heat and desirable thermal characteristics. Paraffin wax has lower heat transfer rates during melting/freezing processes due to its inherent low thermal conductivity. This paper reviews and summaries the recent experimental and theoretical works on the thermal conductivity enhancement of paraffin wax.

Investigation of the sandwich structures under bending has an important role to understanding the composite structures stability. Bending behavior of sandwich structures has a wide range of applications in science, engineering and technology. In this study the effects of core shape, cell wall height, wall thickness and skin thickness on critical bending load of honeycomb sandwich panels have been investigated. The other parameters of sandwich panel supposed constant during all analyses. The finite element simulation has been carried out with using of ABAQUS software and results were compared with experimental results. After that design of experiment based on Taguchi method has been carried out for understanding the effect of investigated parameters on maximizing the critical bending load. Eventually, the effect of parameters has been investigated with using of ANOVA.

Traditional Rapid Prototyping (RP) is referred to as layered manufacturing free form fabrication. It is used for the physical modelling of a new product design directly from CAD data without the use of any special tooling or significant process engineering. This reduces the lead time required to produce a prototype of product. This paper is related to designing and manufacturing of modified bench vise on rapid prototyping machining process. We have designed the conventional and modified bench vise in Pro-e CAD software and manufactured it on Dimension 1200esRPT machine and analysis is carried out in ANSYS CAE software.

Thermal designing of plate fin heat exchanger explains the heat transfer coefficient, hydraulic diameter, Colburn factor, friction factor, Reynolds number of plate fin heat exchanger. The present review explains the various correlations used in the thermal designing of plate fin heat exchanger. Colburn factor ,hydraulic diameter and Friction factor are the major parameters in the design correlations.

Compressor characteristics, being representations of the compressor pressure ratio as a function of gas flow through the compressor have been studied. Compressors are used in turbochargers to increase the pressure of air and also its density greater than ambient. Choosing the right compressor is very important in obtaining best power output of engine by turbocharging, so it is important to have compressor map for matching turbocharger with a particular engine. Compressor map is drawn by running compressor at varying speeds and mass flows. In this paper compressor characteristics were investigated through CFD analysis.