Emerging Trends in Mechanical Engineering

With the advancement in the defence technologies of the military sector of the world, the chances of encountering life threats have also increased. Police personnel and the armed forces deal with such situations regularly during their duty. The most common of such situations is injuries and life threats due to small arms and light weapons. Thus, there is an emerging need for advancement in the study and manufacturing of bullet-resistant or bullet-proof materials to avoid the harms created by ballistic impacts of a projectile. This paper studies the effect of Young’s modulus of the material and thickness of the target plate on residual velocity of the projectile through finite filament modeling. Simulations were carried out to study the effect of adding graphene to silicon carbide matrix to the penetration of the projectile and to find out the minimum thickness of the composite plate required to resist the complete perforation of the projectile.

Artificial neural network (ANN) is used as an advanced technology for the prediction of the behaviour of mechanical systems. ANN research is focused on developing computational approaches to analyse the complex and time-consuming problems. The present paper shows the ANN predictions for maximum pressure of hole entry hybrid journal bearing for different values of non-dimensional load and speed parameters. The present ANN model is trained and tested in SciLab using literature data and found capable to show more accurate results. Feed forward back propagation algorithm is used in this ANN model to minimize the error and to update the weights. Sigmoid activation function is used for hidden layer neurons and output layer neuron. ANN is found as best predictor for journal bearing analysis.

The wind tunnel is proper functioning platform for accurate aerodynamic research which helps to provides adequate environment condition around scaled model to the compatible dimension. Wind tunnel data is part of design process that used to design their model. For correcting wind tunnel data of wall and mounting effects very careful techniques are used. But it shows limitation for linear flow approximation. This research paper proposed first part of the project i.e. design calculation and simulation i.e. flow in wind tunnel and checking incompressible flow in test section over an airfoil using CFD software. Test section design in rectangular shape for proposed wind tunnel. Contraction cone has contraction ratios 7 and cross section in rectangular shape. Diffuser design in conical shape with 5° diffusion angle and area ratio 1.33. The design philosophy is discussed along method for wind tunnel calculation is outlined. Using Computational fluid dynamics (CFD), design and simulation of flow parameter are investigated with systematic way in open loop wind tunnel. It shows good quality flow in test section as well as in entire wind tunnel. The proposed wind tunnel is conformed to design and can be used for different test in the field of aerodynamics. Wind tunnel design to achieve 40 m/s speed of air with expected low intensity turbulence level. Analysis of airfoil shows that good flow quality in test section. Lift and drag coefficient plotted against angle of attack.

In this study, finite element technique has been used to evaluate vertical and fore–aft seat to head transmissibility of human subject representing 95th percentile anthropometric data of Indian male population when exposed to whole body vibration. Human model has been subjected to three different back support postures (without back support, vertical back support and inclined back support) at acceleration magnitudes of 0.25, 0.5 and 1.0 m/s² rms. This study is focused in frequency range of 0.5–15 Hz as in this range many human organs such as heart, shoulder natural frequency lies, which causes general feeling of discomfort and motion sickness. Maximum transmissibility in vertical and fore–aft direction has been evaluated in frequency range between 4–7 Hz at acceleration of 0.25 m/s². Study shows that backrest support has more influence on fore-and-aft transmissibility than vertical transmissibility.

Three-dimensional scanning is increasingly used in numerous domains such as medicine, computer graphics, and architecture. The first three-dimensional scanning technology was evolved in the 1960s. There are an immense variety of methods to scan objects and their assortment depends primarily on the type of the object and its location. The objective of this study is to provide an overview of three-dimensional scanning technologies and methodologies which were projected in the existing industrial as well as scientific literature. All through the paper, basic physics of surface reflectivity and a variety of related techniques are reviewed, which consist, mainly, of laser scanning and photogrammetry, as well as the three-dimensional scanners, augmented with combinational and comparative studies. These studies are helpful for intending to make a clearer distinction on the relevance and reliability of the possible preferences.

Perforated bias flow liners are widely applied to mitigate combustion instabilities in afterburner of a jet engine. Combustion instabilities are the product of pressure pulsations caused due to thermoacoustic feedback between the heat release and acoustic waves inside a combustor, which may result in excessive wearing or even cracking of exposed components within the combustor. There is a grazing flow, which grazes the perforations while another is cooling or bias flow, which passes through the perforations of the liner. Damping of sound is a result of the interaction between sound wave and the joint grazing-bias flow. There are a number of parameters that affect the acoustic damping response of these liners. The variable parameters include porosity, diameter, bias flow, grazing flow and thickness. This study is concerned with the analytical predictions for the variable parameters. The analytical model used to predict the behaviour of the perforated liner is first validated with the experimental measurements. The experimental measurement used standard two-load method for the acoustic characterization of liners. The measurements and predictions are conducted in the environments with and without mean flow. Results of the parametric study provide a basis to design such liners and also provide insights into the effects of parameters on the absorption.

In today’s fast-paced generation, the need of the hour is to develop a technology that can make day-to-day mundane activities obsolete and replace them with a much more convenient and versatile solution. One of such mundane activities is the operation of household switchboards. This project provides the luxury of comfort while “jockeying the sockets of one’s household.” The world is facing the problem of overcharging, wherein a lot of phone companies are investing billions to solve it by modernizing phones/chargers, while our solution is to modernize the sockets instead. In the current work, basic networking and communication have been used. Base framework for developing technology that can solve many of our day-to-day problems is developed. One of the primary aims of the current work is to eliminate the physical requirement of the user at the time of switching on or off devices plugged on to switchboards. This will not only be a luxury for the buyers but also to the world as it cuts on electronic waste and saves electricity. Finally, a product is designed and developed to be used remotely to switch on or off (timer enabled) the power supply of devices at the convenience of the user.

A scaled version of a gantry robot to cover an envelope of 300 × 300 × 150 mm is designed to establish the accuracy of end positions prior to the manufacturing of any industrial gantry robot. A desk top 3D printer is suitably modified for the fabrication of robot, and measured translational motions are compared with prediction following well-known D-H parameter. A good agreement on the end positions between the test and prediction are illustrated. Arduino code employed to control the real-time execution of the gantry robot movement in a semi-automatic mode is provided for the designer.

A circular interpolation algorithm used to determine the parameters of separate circular paths was used to generate round shapes on a computer-controlled numeric (CNC) turning machine. It is suggested that this calculation should be included in the CNC lathes’ resident software program. This would decrease the amount of blocks of data required for part of the program. In a single block, a complete circular interpolation cycle for the number of passes could be specified. The suggested algorithm is optimized for minimal machining time and enhanced surface roughness. The programming of the new interpolation scheme, using circular and linear segments, must be applied to the specific part.

It is challenging for a designer/engineer to presume the adopted posture of a rider on a motorcycle during the 2D sketching at the conceptual phase of the design. Current techniques followed for predicting rider’s posture include superimposing 2D manikin on the sketch of the motorcycle. To facilitate the designer/engineer, apart from demonstrating a method for classifying motorcycles, the current research proposes ‘rider triangle’ (connecting three points located at the handlebar, seat, and footrest) based alternative posture determination technique for a standard motorcycle without the direct involvement of 2D manikin. The proposed method deploys regression models to predict absolute angles of six body joints, namely trunk, thigh, leg, foot, arm, and forearm. The regression models were validated with negligible (below 10%) errors compared with the posture of real human rider from 2D image analyses. Although there are various limitations of this technique, it is capable of giving rough estimates of aforesaid six body joint angles for the rider of average body dimensions.

In this paper, the performance of the evaporative cooler was analysed when coupled with the silica gel. A bed of silica gel is fabricated and attached with the three sides of the evaporative cooler. The performance of system was tested at different flow rates with and without the use of silica gel. Therefore, it was observed that the performance of the system was reliable with the use of silica gel. However, the system is not run continuously because the silica gel gets saturated after 15–20 min. After saturation, there is a need of replacement of the silica bed with regenerated silica gel, which makes it complicated. Hence, in future the silica bed should be replaced by the desiccant bed for continuous operation of the system.

Controlling air pollution is important for healthy well-being of humans and nature as a whole. The presence of particulate matter in air is a serious matter of concern as it causes several health hazards. One of the most cost effective and efficient methods to separate particulate matter is by using cyclone separator. Cyclone separator is a device without any moving parts having tangential inlet velocity of gas stream transformed into a compact vortex or spiral flow downward between walls of gas discharge outlet and body of cyclone. The centrifugal force resulted by vortex or spiral creation leads to coarse particulate separation of particulate matter (24–30 μm) from the polluted air. This paper presents the design of a 2D-2D cyclone separator using Lapple mathematical model. Tangential inlet velocity and barrel diameter of cyclone separator are some of the important factors which collection efficiency depends on. Optimum barrel diameter and inlet velocity for highest collection efficiency were found by numerical analysis using Lapple model, in which former parameter was made fixed and latter changed and vice versa. The iteration was further carried out on four particles of different densities like manure dust, Arizona test dust, fly ash, and micro-alumina. Collection efficiencies of cyclone separator were determined for the selected particles above mentioned. It was observed that the collection efficiency reached a maximum after a size range (24–40 μm) of particles. The theoretical results obtained were verified with the results obtained in CFD.

Modern vehicles are the major source of air pollution and diesel engines are the at most pollutant with emission of NOx ranging from 500 to 1000 ppm. NOx is the most harmful pollutant amongst various other emission such as HC, CO₂, CO, PM and soot. In this research work, an experimental investigation has been performed on a single cylinder direct injection compression engine with power capacity 3.5 KW. A surge tank set-up has been developed through which cooled EGR will be utilised for reducing the NO. The results of the engine performance and emission have been investigated at different loading conditions with EGR ranging from 10% to 20%. From the experimental analysis, it has been found out that with 20%, EGR the NO emission level has been reduced by 72% that is from 290 ppm to 83 ppm on full loading conditions.

Lift generated on ground vehicles moving at high speeds has always been a major concern for aerodynamicists and designers. A proven way out is to use passive lift mitigating strategies for generating additional downforce on the vehicle for regaining the loss of stability. A rear wing helps in rectifying such trouble of handling cars at high speeds by generating negative downward force which improves overall stability of the vehicle. A new dual wing spoiler is designed for the mentioned purpose in this work. The spoiler is fitted on a generic ground vehicle having slant edge angle of 35°. Innovative swan neck linkage has been used to connect the rear wing with the vehicle. Numerical investigations have been performed on symmetric models of the vehicle with and without the new wing at different length-based Reynold’s numbers ranging from 1.98 × 10⁶ to 4.76 × 10⁶ using two-equation realizable k-ε eddy-viscosity turbulence model. The observed data showcased an increment of 20% in drag coefficient on the entire vehicle. At the same time, it was found that there is a drastic decrement in lift coefficient in comparison to the baseline values of the vehicle, albeit it showed a minor increase with increase in Reynold’s number.

This project involves the study of the outlet water temperature, Nusselt number, heat transfer coefficient and efficiency of a flat plate collector–solar water heater having a straight riser and header set-up. Records of mass flow rate were maintained and its effects on the outlet temperature of the water and the thermal efficiency were observed. ANSYS Fluent was employed for predicting the Nusselt number, heat transfer coefficient, outlet temperature of water and efficiency using the experimental values of solar radiation, ambient temperature and the temperature of the water at the inlet. It was found that the thermal efficiency of the solar water heater increases with mass flow rate of water to achieve a long and stabilized efficiency curve. Nusselt number shows gradual increase with the increasing mass flow rate. The results were validated by the experimental results obtained from the experimental set-up situated on the roof of Mechanical Engineering Department.

In this paper, fouling’s effect on performance of a vapour compression refrigeration system is evaluated by changing evaporator and condenser conductances individually, and simultaneously between 0 to 50% and also by variation in T_in,cond (i.e. coolant inlet temperature of condenser at 35, 37.5 and 40 ℃), for refrigerants HFC134a, HFO1234yf and HFO1234ze, while keeping the T_in,evap (i.e. evaporator air inlet temperature at 0 ℃) and constant \({\upeta }_{{{\text{cp}},{\text{isn}}}}\) (efficiency of compressor, i.e. 65%). A simulation programming is done on EES for computing the results. It is observed that the decrease in COP is more when conductances vary simultaneously in comparison with evaporator and condenser conductances that are varied individually, although fouling of condenser has larger effect on W_cp%, as it increases up to 9.12 and 7.41 for refrigerants HFO1234yf and HFO1234ze, whereas for refrigerant HFC134a, its value increases up to 7.38 with varied coolant inlet temperature of condenser (T_in,cond). It is observed that the second-law efficiency (ƞ_II) is decreased and HFC134a can be replaced by refrigerants HFO1234yf and HFO1234ze.

Perforated liners are used to suppress the thermoacoustic instabilities in jet engines. These are perforated cylindrical sheets traversed by bias flow and grazed by grazing flow through the orifices. In this paper, time-domain numerical studies have been conducted to simulate the interaction between sound and joint grazing-bias flow. Effect of propagation of the sound wave is modeled by giving perturbation to the mean flow. For this purpose, sinusoidal perturbation of desired frequency is added to the mean flow by means of user-defined function (UDF) which constitutes mean and perturbation components of the velocity. Turbulence models mainly standard k-ɛ, SST k-ɷ, and scale-adaptive simulation (SAS) are compared by assessing their ability to capture the key flow features of these interactions. Velocity power difference for with and without perturbation cases are analyzed. The velocity power difference spectra indicate a relationship between the perturbation energy/acoustic energy loss and creation of additional turbulent fluctuation components. The present results thus support the theory of vortex–sound interaction and subsequent dissipation of sound. On comparison, it is observed that for a transient numerical study of these interactions, the SAS turbulence model is the best among all the models considered.

In an agitated vessel for finding heat transfer coefficient, few factors play important role. For properly mixing of different fluids, the method of forced convection is used with the help of agitators. For studying the role of agitator diameter and Nusselt Number, calculations of heat transfer were performed with three different agitators of different diameters. It was observed that the diameter of agitator, D_a predicts the effect in Reynolds number, an approach has been done for fining the connection between the agitator diameter and Nusselt Number. A link between (N_uj/N″_Pra^1/3 N″_Rea^2/3) vs D_a/D_T and (N_uoc/N″_Pra^1/3 N″_Rea^2/3) vs D_a/D_c in which data of three fluids (1, 2 and 4% CMC-A solutions) have been plotted. Almost negligible effect of D_a/D_T is noticed maybe because of very short variation of D_a/D_T ratio considered in the current work. Nevertheless, an average line between data points gives the implication of D_a/D_T and D_a/D_c equal to 0.1. A comparison has been done between the experimental and calculated Nusselt numbers with standard deviation found to be 8.03%.

Biodiesel has been attracting scientist for near about a century, and new revolutionary research and technical improvement had taken place in this field. But the basic problem of cost involved in using the biodiesel in engine in place of conventional diesel fuel is lying as such till date. In the present research work, it was tried to eliminate this problem by using non-edible oils with natural sourced catalyst optimizing certain set of parameters of best biodiesel performance. The biodiesel was produced from castor oil from highmedia and neem oil secured form S.K. Bioenergy Pune and Paritosh Herbals Ltd., Dehradun, Uttarakhand. A new method of preparation of nano-catalyst lithium-doped CaO obtained from Musa balbisiana root has been suggested and used to prepare biodiesel. The characteristics of biodiesel produced were tested according to ASTM standards. Different blends of the biodiesel are produced using castor oil, neem oil and conventional diesel oil. The engine characteristics running on blended fuel were tested on a C.I. Engine. The trials were performed on a four-stroke diesel engine operated utilizing various mixes of oil. Engine speed and load are considered as the parameters of interest. The result is the optimized running condition at which the engine will give best BSFC and least pollutants in emission.

Most of the fixed pitched wind turbines, which are used for the small-scale power generation, typically, are operated at low Reynolds numbers where the aerodynamic performance of an airfoil can change considerably with Reynolds number. So that the study of aerodynamics performance of airfoil at various low Reynolds number is much important. In this paper, such an attempt has been made through simulating the selected airfoils, says National Renewable Energy Laboratory (NREL) S823 and DU 06-W-200, using QBlade open-source software. QBlade software habits the double multiple stream tube (DMS) algorithms for evaluating the performance of vertical axis wind turbines (VAWTs) blade element method (BEM) for the evaluation of horizontal axis wind turbines (HAWTs). The viscous-inviscid coupled panel process code XFOIL is integrated within the graphical user interface (GUI) of QBlade for the calculation of lift and drag coefficient of an airfoil at any angle of attack (AoA). The simulation is carried out at various Reynolds numbers in the range of 1 × 10⁵ to 3 × 10⁵ for both selected airfoil and compared to each other. The results show that for every applied Reynolds number, S823 airfoil obtains higher lift coefficient up to 10° AoA after that DU 06-W-200 airfoil exhibits higher values and also the same pattern followed for lift-to-drag ratio. Finally, the simulation results are compared with the identified experimental data for validation purpose, and that displays good agreement between the QBlade simulation result and experimental data.

The wind tunnel is proper functioning platform for accurate aerodynamic research which helps to provides adequate environment condition around scaled model to the compatible dimension. Wind tunnel data is part of design process that used to design their model. For correcting wind tunnel data of wall and mounting effects, very careful techniques are used. But it shows limitation for linear flow approximation. This research paper proposed first part of the project, i.e., design calculation and simulation, i.e., flow in wind tunnel and checking incompressible flow in test section over an airfoil using CFD software. Test section has 0.3 * 0.3 m² cross-sectional area with 0.5 m length design for proposed wind tunnel. Contraction cone has contraction ratios 7 and cross-sectional area 0.7 * 0.7 m² in rectangular shape. Diffuser outer diameter is 0.4 m and length is 1.5 m and diffusion angle 5°. The design philosophy is discussed along method for wind tunnel calculation is outlined. Simulation of wind tunnel using CFD shows no separation of flow along wind tunnel at 25 m\s speed of air. The proposed wind tunnel is conformed to design and can be used for different test in the field of aerodynamics. Wind tunnel design to achieve 40 speed of air with expected low intensity turbulence level. It has available for education and researching in area such as low speed aerodynamics and fundamental research in fluid mechanics.

In this study, exergy analysis of Sahyadry Sugar Factory (Steam power plant) located in a karad, Maharashtra, has been done. The data is collected from power plant and each component present in a power plant has been analyzed separately based on exergy. In this analysis, it is observed that the maximum amount of exergy destructed in boiler; nearly, 199.29 MW exergy is destructed within a boiler which is 89.4% of fuel exergy input. The second source of major exergy destruction is condenser where 9.88 MW exergy is destructed which is 4.4% of fuel exergy input. The exergetic efficiency of each component and whole cycle has been calculated. The exergetic efficiency of power plant is 7.3% which is very less.