Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Department of Thermal and Energy Engineering

The fabrication method of composite materials has significant influence on the mechanical properties of the materials. Establishment of proper bonding, dispersion and diffusion of reinforcement in the matrix are identified as principal characteristics which need to be taken care during the manufacturing of metal matrix composites. The current work has highlighted the impact of metal (Al) mixed dual size particle reinforcements (Al2O3 (μm) &amp; Si3N4 (nm)) and the domination of silicon nitride nano particle in the composite system. The reinforcement powders were ball milled for 3 h. The matrix alloy used in this work was AA6061 which holds the applications in the construction of structures, aircraft and automobile bodies. The matrix alloy was melted and milled powders were added at 850 °C followed by stirring process. The tensile, Compression and Hardness tests were conducted to characterize the mechanical behavior of the prepared composites. The Optical Microscope and the Scanning Electron Microscopes were used to analyze the morphology of the as-cast and fractured surfaces. The composites of metal mixed reinforcements offered improved mechanical properties than the composites of unmixed reinforcement. Tensile characteristics [Ultimate Tensile Strength (72.3 MPa–153.2 MPa), yield strength (67 MPa–148 MPa), and ductility (2–8.3%)] were much influenced by pre mixed Si3N4 nano particles and its volume fraction in composites. The composites with dual reinforcement have shown superior tensile behavior than single reinforcement. The compression behavior [compression strength (253–361.74 MPa)] and hardness of the composites were dominated by single reinforcement with premixed Al2O3 particles. The dislocation density due to the presence of Si3N4 nano particle and proper bonding of hard Al2O3 particles in the matrix supported by Si3N4 nano particles were observed as strengthening mechanism in the composites with dual reinforcement. © 2017 Elsevier B.V.

World University root node

School of Mechanical Engineering

Vellore Campus

Journal of Alloys and Compounds

Influence of metal powder premixing on mechanical behavior of dual reinforcement (Al2O3 (μm)/Si3N4 (nm)) in AA6061 matrix

The knowledge of heat flux distribution on the receiver area is very important to improve the overall performance of the solar Concentrating Photovoltaic (CPV) system. In a CPV system, non-uniform flux distribution is one of the common issues. Non-uniform illumination of heat flux is mainly due to the limitations in the design of concentrator optics, slope error in the concentrator profile, tracking system error, misalignment of concentrator, and the efficiency of refractive lens/reflecting mirrors. The prediction of the heat flux distribution will play a vital role in the CPV system such as designing the receiver area, selection of the materials, thermal management and to estimate the power output. In this paper, an experimental work for in-situ prediction of heat flux distribution profile on a flat plate receiver is presented. Inverse heat transfer technique is adopted to predict the heat flux distribution. A Gaussian distribution is assumed to model the distribution of the heat flux. The forward problem is a 3-D steady state heat conduction equation subjected to convection and radiation heat loss boundary conditions. The forward problem is solved using Finite Element Method in Ansys APDL. The unknown parameters of the assumed heat flux distribution are then estimated by minimizing the sum of squared error between measured and simulated temperature distribution. A deterministic search technique, Levenberg-Marquardt algorithm is used to solve the inverse problem. The simulated temperature distribution with the predicted heat flux are in good agreement with the measured temperature with a maximum residue of ±5 °C. Also, the deviation between theoretical and predicted total solar energy is found to be <6%. © 2017 Elsevier Ltd

Solar Energy

In-situ prediction of focal flux distribution for concentrating photovoltaic (CPV) system using inverse heat transfer technique for effective design of receiver

Valve dynamics has great impact on the overall efficiency of a hermetic reciprocating compressor. Suction and discharge valves are responsible for the refrigerant flow rate throughout the vapour compression refrigeration system and the suction valve influences more than the discharge valve when efficiency is considered. The closing and opening of a suction valve affects many parameters such as effective flow and force area, backflow effect, fatigue, valve displacement etc., which directly affects the efficiency of the compressor. In the present work, a two-way Fluid Structure Interaction (FSI) simulation is carried out to study the influence of inlet pressure of refrigerant on suction valve dynamics of a hermetic compressor. For validation purpose a small experimental setup is made where air is taken as working fluid in place of refrigerant. In experimental studies, the deflection of the valve is measured by strain gauge which is connected to a wheat stone bridge in the laboratory. The inlet air is supplied from a compressor and its pressure is controlled by a pressure regulator. The numerical simulation is carried for the same experimental boundary conditions and the predicted deflection results for 0.5 bar is validated by a two-way Fluid Structure Interaction (FSI) methodology in ANSYS Workbench 16.0 which includes ANSYS Mechanical and ANSYS Fluent. The stresses are plotted in ANSYS Structural tool on the surface of suction valve and its corresponding deflection is obtained. Pressure contours on the surface of suction valve is plotted using ANSYS Fluent. Upon validation, the two way FSI simulation is extended to further investigate the influence of inlet pressure of air from 1.0 bar to 3.5 bar and the corresponding deflection of the suction valve is predicted. The current work may be used as benchmark for numerical studies of a hermetic compressor using two way FSI simulations.

International Journal of Pure and Applied Mathematics

Two-way Fluid Structure Interaction (FSI) Analysis on the Suction Valve Dynamics of a Hermetic Reciprocating Compressor

The conjugate heat transfer due to oblique impingement of two-dimensional, steady state, incompressible, turbulent slot jet on a uniformly heated flat plate has been studied in the present work. The standard high Reynolds number two-equation k - ϵ eddy viscosity model has been used for numerical simulation. The Reynolds number based on the hydraulic diameter of nozzle exit and turbulent intensity maintained at 9, 900 and 2% respectively. The angle of inclination 30°, 45°, 60° and, 75° degrees are considered for the numerical study. A uniform temperature higher than the jet exit temperature is provided to the bottom surface of the plate. The flow field have been studied using the contour plots of pressure and velocity in the fluid domain. The influence of inclination on the distribution of the local Nusselt number over the surface of impingement have been presented. It is found that the angle of impingement influences the flow field and heat transfer characteristics more in the downhill direction of the stagnation zone compared to the uphill direction. © 2018 Author(s).

VIT Unitversity

AIP Conference Proceedings

Numerical analysis of conjugate heat transfer due to oblique impingement of turbulent slot jet onto a flat plate

Laser welding process is employed in the manufacturing of critical components where the final assembly units necessitate strict tolerances like low distortions and residual stresses. Laser beam welding offers several advantages like low heat input, very narrow heat affected zone, low residual stresses, low distortions and good mechanical joint properties in the weld joints when compared to the conventional techniques like Tungsten Inert Gas Arc welding processes. However, the implementation of laser beam welding holds certain challenges like process parameters optimization, experimental set-up and handling and expensive costs. In order to minimize the complex experimental process, simulation techniques using Finite Element Methods (FEM) are employed in order to estimate the heat input and weld process optimization prior to the experiments. This greatly helps in the optimization and estimation of the incurred stresses and distortions with the adapted weld process with known input weld process parameters. The present work reports the Gaussian heat source model for the laser welding of Inconel 625 Alloy plates. The developed moving heat source model is presented and demonstrated with the thermal profiles in terms of the thermal histogram, temperature profiles in the joint cross sections through welded region, interface across the joints.

Fulltext

International Journal of Engineering & Technology

Thermal Analysis Simulation for Laser Butt Welding of Inconel625 Using FEA

In the present scenario, world energy consumption is increasing rapidly every year because of the increasing trend of modernization and industrialization. Crude oil is the major source for producing energy, results in the degradation of the environment due to fossil fuel combustion. Moreover, the combustion products like carbon di-oxide (CO2), sulphur di-oxide (SO2), and nitrogen oxide (NOX) causes global warming.Crude oil depletes every year, to satisfy the energy demands, the crude oil is imported. The environmental problems caused by the indiscriminate use and scarcity of petroleum are the major factor to explore renewable energy resources. The idea of vegetable oil as a fuel to run diesel engines has been on the world stage over a century ago. Vegetable oil is an alternative fuel as a source of energy has been receiving great attention among the researchers because of its renewability, biodegradability, non-toxic and better quality of exhaust gas emissions.A lot of edible and inedible vegetable oils which canbe exploited for substitute fuel as diesel fuel, i.e., jatropha, karanja, rubber seed, cottonseed, palm oil, sun flower oil, rape seed oiland neemoils etc., has been selected and discussed the performance, combustion and emission characteristics of diesel engine under the variousworking conditions. © 2018, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.

Indian Journal of Chemical Technology

A review on performance, emission and combustion characteristics of a diesel engine fuelled with various vegetable oil

Department of Information Security

School of Computer Science and Engineering

Cognitive Computing for Big Data Systems Over IoT Lecture Notes on Data Engineering and Communications Technologies

Recent Trends in Deep Learning with Applications

Research Journal of Pharmacy and Technology

Phytochemical analysis and antioxidant activity of chloroform extract of Cassis alata

The purpose of the present work is to understand the evolution of residual stresses in weldments. The study made to weld the multipass dissimilar of Nickel-based superalloy Inconel 625 and stainless steel 316L using Continuous Current Gas Tungsten Arc Welding (CCGTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) process employing ERNiCrMo-3 and ERNiCr-3 fillers. The L4 orthogonal array was used in the present experimentation process. Analysis of Variance (ANOVA) is applied for the optimization and to identify the critical parameters. In welding process, the size of the lattice size will be stressed due to welding parameters; the lattice dimension is measured by non-destructive technique X-Ray diffraction to investigate residual stress in the weldment in the lateral surface of the plate. X-Ray Radiography test has evaluated the quality of welds. The results show that root gap is a critical parameter and filler wire and weld processes are not critical.

Materials Research

Effect of Residual Stresses of GTA Welding for Dissimilar Materials

The present study investigates the dissimilar weld joints between AISI 316L and Duplex 2205 stainless steel. The joints were fabricated with the Pulsed current gas tungsten arc welding with ER316L and ER309L filler wire. The weld joints were subjected to metallurgical and mechanical characterization. The macro examination and optical microstructure examination were carried out to see the defect in the weld joints and structural changes in the fusion zone. The results show that the defect free welding was achieved in the both the filler wire. The optical microstructure shows the ferritic structure in both filler wire. The strength of the weld joints was tested with the tensile test. The results indicate the fracture occurred in the base metal in both cases. © Published under licence by IOP Publishing Ltd.