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

Mechanical

The ever increasing demand and depletion of fossil fuels along with environmental concern has prompted search for alternate fuels. The selection of optimum biodiesel with the appropriate blend for the IC engine plays a vital role in the energy sector. This paper describes the application of novel hybrid multi-criteria decision making (MCDM) technique to evaluate the optimum fish oil biodiesel blend. Fuzzy TOPSIS and fuzzy VIKOR are used to evaluate the best blend, where fuzzy is to determine the relative weights of the criteria, TOPSIS and VIKOR has been used for obtaining the final ranking of alternatives. A four stroke single cylinder, constant speed, direct injection with a rated output of 4.4 kW was used for exploratory analysis. The ranking performance of both the methods is also compared with each other and selected B40 is the best blend to operate the engine. The proposed MCDM models are simple, precise and efficient tool for the decision makers to identify the suitable blend among the alternatives. Copyright © 2020 Inderscience Enterprises Ltd.

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School of Mechanical Engineering

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International Journal of Oil, Gas and Coal Technology

Selection of optimum bio-diesel fuel blend using fuzzy TOPSIS and fuzzy VIKOR approaches

In the present study, numerical investigation is performed on a H-Darrieus wind turbine under turbulent flow conditions. The turbine contains 3 rotor foils, NACA-0012 with 0° angle of attack, placed at 120° apart from each other, with rotor casing close to the airfoil. The inlet is considered to be velocity inlet and outlet to be pressure outlet while the side walls are given symmetric boundary conditions, as the walls are considered to be infinity. The airfoils are rotating at 150 R.P.M. The meshing is done using Hexa-Dominant element to capture the flow very precisely and inflations are given wherever necessary. The problem is considered as two-dimensional, and the analysis of the model under the condition of turbulent flow is modeled using S.S.T-k-ω turbulence model. Simulation is performed using finite volume solver Ansys Fluent 2019-R2. The performance of the H-Darrieus wind turbine is analyzed, by varying the wind speed and turbine rotational speed. The further investigations are performed by comparing the flow characteristics between a stationary and rotating turbine. The results are analyzed by plotting the streamlines, velocity and pressure contours. The flow is analyzed at 6m/s, 8m/s, 10m/s as inlet freestream velocity and also by varying the rotor dimension, which was initially made as small as possible. The results indicate that the wind speed and rotational speed significantly influences the significant aero characteristics of the model of the wind turbine. The present results are validated and are in good accord with the benchmark results available in literature. © Published under licence by IOP Publishing Ltd.

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IOP Conference Series: Earth and Environmental Science

Numerical investigation of aerodynamic performance of a H-Darrieus wind turbine under turbulent flows

This paper presents the flow and heat transfer characteristics of melting behavior of phase change material (PCM) in the presence of nanoparticles. The melting process occurs in a concentric cylindrical enclosure filled with PCM (ice) and aluminum oxide (Al2O3) nanoparticles. The inner and outer walls of the concentric cylinder are considered as hot and cold walls and maintained at a constant wall temperature. The problem is modeled as unsteady, two-dimensional turbulent multiphase flow using the Eulerian multiphase model and SST k-ω turbulence model. The numerical simulation is performed using Ansys Fluent 19.2. The primary and secondary phases are specified with thermo-physical properties of ice and aluminum oxide. The transient melting behavior of PCM is investigated for different nanoparticle volume concentrations by varying the temperature difference between the hot and cold walls of concentric enclosure. The results are analyzed by plotting the streamline, velocity and temperature contours. The results indicate that the dispersion of aluminum oxide nanoparticles into phase change material increases the heat transfer rate and decreases the melting temperature of PCM. The results also indicate that the melting rate and thermal performance are significantly enhanced with increase in volume concentrations and temperature difference. © Published under licence by IOP Publishing Ltd.

Thermal performance of nanoparticle enhanced phase change material in a concentric cylindrical enclosure

Hydrogen gas has proven to be an ideal green fuel. Its use is limited at present due to inefficient and harmful methods of production like steam-methane reformation and coal gasification. Systems that utilize hydrogen as a fuel can be considered practical only with the development of better, cost-efficient methods of its production. This study focuses on efficient mass production of bio-hydrogen (and bio-ethanol as a byproduct) for commercial utilization with a theoretical multiple reactor system. The process involves culturing of modified photosynthetic algae (such as Chlamydomonas reinhardtii) in bioreactors for bio hydrogen production. This process produces some waste algal cells. These can be sent to subsequent reactors for production of bio-ethanol by fermentation. Also, the waste algal cells need to undergo pyrolysis before the fermentation. Hydrogen is produced in this process too. All these factors put together improve the overall yield of the complete process and reduce its cost substantially. Though the model is theoretical, it can be adapted for commercial production of hydrogen. The hydrogen can, in turn, be used as fuel for powering fuel cells which have zero emission and hence, are environment-friendly. © Published under licence by IOP Publishing Ltd.

Multiple Reactor System for Biohydrogen and Bioethanol Production

Cars kept in open have the tendency to attain temperatures far higher than the one prevailing in the surroundings. This condition is especially severe during summer months, and can cause a lot of discomfort to passengers, who re-occupy the car after parking it in the open for a while. Employing a Phase Change Material (PCM) can be a possible solution to control the car cabin temperature to a certain extent. This paper is focused on experimental and numerical study on employing a suitable PCM to control the car cabin temperature. Four different locations inside the car cabin namely roof, head, bottom and feet were selected for monitoring the temperature using temperature sensors. The effect of 90 minutes of exposure to the solar load is simulated by employing the Surface to Surface (S2S) radiation model available in ANSYS FLUENT 18.2. Experimental and numerical results conveyed the reduction in cabin average air temperature by ∼ 8°C after Placing the phase change material inside the four wheeler cabin. Comparison of Numerical and experimental results was carried out and the absolute average deviation in temperature predicted by S2S model from the experimental data is 9.93 %. © Published under licence by IOP Publishing Ltd.

Experimental and Numerical Investigation of Car Cabin Temperature under Solar Load Condition using Phase Change Materials

Clean burning nature and renewability of hydrogen makes it viable and alternative/supplementary fuel for utilization in IC engine. In the past two decades, researchers have gained interest in using hydrogen in Internal combustion (IC) engines. Electrolysis is the widely used technique for production of hydrogen. The effect on emission parameters of using hydrogen and HHO gas in a dual fuel engine at idling condition was focused in this research work. HHO gas was synthesized from stored cylinders of hydrogen &amp; oxygen in 2:1 ratio. The mixture of H2 and O2 are produced in stoichiometric ratio similar to electrolysis of water. Effect of introduction of hydrogen gas and stimulated HHO gas on emission characters such as unburnt hydrocarbon (UHC), carbon dioxide (CO2), oxides of nitrogen (NOx) and smoke of the engine were noted at idling condition (1700 rpm). Engine was supplied with 6, 12, 18, 24, 30, 36 LPM of hydrogen and 9, 18, 27, 36, 45, 54 LPM of HHO gas where the composition of mixture was maintained in the ratio of 2:1 and energy supplied by Hydrogen and HHO gas remains same. Introduction of hydrogen and HHO gas has reduced the total diesel fuel consumption and formation of CO2 at all operating condition than neat diesel operation. There was slight increase in UHC emission with hydrogen and by substituting HHO gas the UHC emission was reduced. © Published under licence by IOP Publishing Ltd.

Emission Characteristic of a Dual fuel Compression Ignition Engine Operating on Diesel + Hydrogen &amp; Diesel + HHO gas with same Energy Share at Idling Condition

The aim of this research was to study the influence of the composition of saturated fatty acids of biodiesel on the performance, emissions and characteristics of combustion in an engine with compression ignition. An increase in saturated fatty acids may eliminate biodiesel deficiencies. Various 55% mixtures of saturated fatty acids with diesel fuel were studied and compared. Five different combinations of blend were prepared using the following esters such as Palm oil methyl ester (POME), Coconut oil methyl ester (COME), Neem oil methyl ester (NOME), Mahua oil methyl ester (MOME), Jatropha oil methyl ester (JOME) and Pongamia oil methyl ester (PONOME). All five combinations (BD1-BD5) were tested and compared for physicochemical characteristics such as density, viscosity, iodine number, saponification number, energy consumption, thermal efficiency, exhaust gas temperature, toxic gas emissions. Five blended combinations showed viscosity around 5.13 to 5.56 centistokes. The Cetane number of the five blends were in the range of 52-56. The heating value of the five combinations was in the range of 38.92 to 40.65 MJ/kg. Iodine values were found to be in the range of 50-73. The brake thermal efficiency percentage were in the range of 27.15-27.4. All five blends found to emits less amount of Greenhouse gases. The results of the research state that all five combinations of biodiesel are unique, and they show very good performance properties as fuel along with less discharges toxic emissions. © 2019 Elsevier Ltd. All rights reserved.

Materials Today: Proceedings

Influence of saturated fatty acid material composition in biodiesel on its performance in internal combustion engines

The programmable logic controller (PLC) based and magnetic tape guided automatic guided vehicles were designed and implemented in a production environment where significant material handling is involved. The work is focused on transporting the components of transmission plant of a small car from the machining line (consisting of multitude of machine tools) to the assembly line. The new automated material handling system was designed to replace the existing manual material handling system. The PLC controller deals with the movement of the vehicle in forward and reverse path with the use of four different sensors. Magnetic tape-based guiding lines that are relatively inexpensive, and less-complex are implemented for the movement of automated guided vehicle (AGV) in a specified path. Infrared sensor system is integrated to the AGV for effective obstacle detection during the material movement. Auto-charging of the batteries of the AGV without needing them to halt specifically for charging is implemented. The results showed that lithium-ion batteries are more suitable compared to the led-acid batteries for the present type of AGVs and their charging strategy. The overall AGV system showed promise and proved to be more productive and reliable compared to the previously existing manual material handling system. Copyright © 2020 Inderscience Enterprises Ltd.

International Journal of Mechatronics and Automation

Productivity enhancement by using programmable logic controller-based automated guided vehicles for material handling

Dry machining is undesirable for machining of good surface quality products, because the thermal properties of a material may contribute to a reduction of tool life when machining difficult to cut materials. Likewise, the conventional lubrication through a jet or flood cooling is not economical or eco-friendly and increases the environmental burden. Owing to the above facts it becomes necessary to implement Minimum Quantity Lubrication (MQL) in end milling process. In this study, a numerical analysis has been carried out to investigate the impact of compressed air pressure and the oil flow rate on Sauter mean diameter of MQL spray and on tool temperature. Sauter Mean Diameter (SMD) of MQL spray and temperature distribution in the end milling tool are calculated for three different air pressure (2, 3, and 4bar) and oil flow rate (100, 150, and 200ml/hr). ANSYS Fluent software is used for the analysis with discrete phase model (DPM) for predicting the spray particle size. From the analysis, SMD and tool temperature are found to decrease with increase in air pressure for constant oil flow rate whereas there is no considerable change in SMD as the flow rate of oil is changed beyond 150ml/h. This study has been used for selecting the optimum air pressure and flow rate of the oil for efficient lubrication and cooling in MQL aided machining. © 2020 Elsevier Ltd. All rights reserved.

Numerical analysis of the effect of air pressure and oil flow rate on droplet size and tool temperature in MQL machining

Titanium and their alloys are widely investigated material in the field of biomedical for their high extensive properties in biomedical applications. In this work, the synthesis of titanium oxide (TiO2) nanotubes by electrochemical anodization with the influence of different electrolyte were performed. Structure, surface, mechanical and chemical properties of TiO2 nanotubes coated materials were investigated with a high range of measurement techniques. The HR-SEM analysis notifies that various levels of water and hydrofluoric acid (HF) delivers different lengths and diameters of nanotubes. Nanoindentation analysis shows the mechanical behavior of the nanotubes coated material. Corrosion analysis informs that the maximum length of nanotubes provides that maximum corrosion resistance. The application of biomedical improved in mechanical and chemical properties by the coating of TiO2 nanotubes. © 2020 Elsevier Ltd. All rights reserved.