Faculty Publications
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Item Highway mounted horizontal axial flow turbines for wind energy harvesting from cruising vehicles(American Society of Mechanical Engineers (ASME) infocentral@asme.org, 2016) Hegde, S.S.; Thamban, A.; Bhai, S.P.M.; Ahmed, A.; Upadhyay, M.; Joishy, A.; Mahalingam, A.Renewable energy technologies are a growing subject of concern these days. Wind energy is one among the renewable energy sources which has been implemented in a large scale for energy production. A large amount of capital has been invested in this field to harness energy and power homes. Wind energy from highways is usually unused and can provide a considerable amount of wind energy to drive a turbine due to high vehicle traffic and the speed of the vehicles. Extensive research on wind patterns is required to determine the average velocity of the wind created by oncoming vehicles. The objective of this work is to design and analyze a horizontal axis wind turbine to capture wind energy from moving vehicles on the highway. A computational fluid dynamics approach is used to solve this problem. The major innovation in this paper is that wind energy is being harvested in a very unique manner and also turbine power calculations have been done to quantify the amount of energy being harvested. Although a few of the literatures have discussed similar ideas power quantification has never been done. Also the entire mechanism has been simulated in MATLAB to find out the number of cars required to charge a battery which is very unique to this paper. Power calculations have been done for the turbine and validated against theoretical calculations which were done using the concept of velocity triangles. The idea is to have a separate mounting for cars and heavy vehicles which can be realized by having separate lanes on highways. The analysis will be done for vehicles moving in a range of speeds on the highway. The wind turbines will be placed on overhead shafts (the height of which is be determined suitably) thereby capturing the wind generated as a result of pressure difference. The mounts can also be used as signboards for vehicles moving on the highway and hence serve a dual purpose. In addition, extensive structural and fatigue analysis will be done for the turbines and the mounting structures in order to determine a suitable material for the turbine as well as the mounts to withstand the forces generated. Using all of the collected energy, existing amenities such as street lights on the medians can be powered by these wind turbines. Thus the main objective of this work is to complement the conventional electrical energy used for powering amenities along highways by a renewable source of energy (wind power) thereby leading to the concept of sustainable highways. © © 2016 by ASME.Item Chassis mounted single stage impulse turbine for wind energy harvesting on a cruising transport vehicle(Institute of Electrical and Electronics Engineers Inc., 2016) Hegde, S.S.; Thamban, A.; Ahmed, A.; Arun, M.Fossil fuels have been a means of energy source since a long time, and have tended to the needs of the large global population. These conventional sources are bound to deplete in the near future and hence there is a need for producing energy from renewable energy sources like solar, wind, geothermal, tidal etc. Technologies involving renewable energy are a growing subject of concern. The problem is the excessive pollution caused by conventional sources of energy and their impact on the environment. In particular, one of the main sources of pollution is harmful gases emitting out of automobiles. Wind energy is one among the renewable energy sources which is implemented in large scale energy production. A large amount of research has been done in this field to harness energy and power houses and other amenities are nearby wind farms. The purpose of this study is to consider the use of wind energy along with conventional energy sources to power automobiles. Specifically the concept of an impulse turbine mounted on the chassis of a typical vehicle structure is considered. Computational Fluid Dynamics (CFD) is used to validate the concept and also come up with a design that maximizes energy generation by such turbines. © 2015 IEEE.Item Energy Harvesting from Vortex Induced Vibrations Using Vented Cylinders Mounted on Light Rail Locomotive(IEEE Computer Society help@computer.org, 2016) Kumar, K.R.; Morab, S.; Shekar, S.; Mahalingam, A.Majority of the population is dependent on the fossil fuels which are the conventional sources of the energy. Since fossil fuels are non-renewable they are bound to deplete in the near future. Leading edge research on the renewable sources of energy like wind energy, solar energy etc. Is a growing concern which has to replace the conventional energy sources to prevent environmental pollution and global warming. Wind energy is one among the renewable energy which is used for large scale power production using turbines, wind mills and power houses. Harvesting energy from vibrations caused because of alternative vortex shedding due to fluidic flow over a bluff body is under progressive research. The purpose of this study is to harvest wind energy from cross flow vibrations using vented cylinders mounted on the chassis of the train. In this study usage of vented cylinders over a normal baseline cylinder is of major concern to enhance vortex shedding and to extract maximum amount of energy considering a typical single carriage of a train. Using Computational fluid dynamics, Strouhal number is calculated which is validated and further designing a system for harvesting energy from vibrations. © 2016 IEEE.Item Numerical Analysis of Wall Shear Stress Parameters of Newtonian Pulsatile Blood Flow Through Coronary Artery and Correlation to Atherosclerosis(Springer Science and Business Media Deutschland GmbH, 2020) Buradi, A.; Mahalingam, A.The formation of atherosclerosis mainly depends on local hemodynamic blood flow parameters. The spatial and temporal variation of hemodynamic blood flow parameter is considered as an important factor for atherogenesis. The laminar, Newtonian pulsatile blood flow is considered for hemodynamic analysis of the idealized non-stenosis human coronary artery. To model and study the relationship between relative residence time (RRT), time-averaged wall shear stress (WSS) vector (TAWSSV), oscillatory shear index (OSI), and time-averaged WSS (TAWSS) the computational fluid dynamics technique are used. The study shows that higher OSI values are predicted at lower TAWSS and TAWSSV. At the low TAWSS areas the RRT attains a higher value, the region with high RRT correlates with atherosclerotic lesions on the artery wall. The local differences between RRT, OSI, and WSS magnitude may help to find predominantly where the atherosclerotic lesion progresses and develops at specific locations of the artery. © 2020, Springer Nature Singapore Pte Ltd.Item CFD investigation of unsteady three-dimensional savonius hydrokinetic turbine in irrigation channel with varying positions for hydro power application(American Institute of Physics Inc., 2021) Shashikumar, S.; Hindasageri, V.; Madav, M.Savonius turbines are a drag driven device, and it has high starting torque. It is a vertical axis turbine and installed in small irrigation channels to utilize the hydrokinetic energy available. Since the density of water is more and the flow of water in the channel is constrained to one direction is the advantage for a vertical axis turbine as it reduces the yaw control mechanism. In the present work, a three-dimensional conventional Savonius turbine modeled and meshed in ANSYS Fluent and unsteady transient simulations are carried out using a sliding mesh technique. The computational simulations were carried out at three different positions to analyze the effect of placing a turbine blade in the high depth of water using a conventional Savonius turbine blade with an aspect ratio of 0.7 and 0.0 overlap ratio. The turbulence model used for CFD simulation is the k-ω SST model, and the results found that the maximum coefficient of torque and coefficient of power of 0.22 and 0.17 at a tip speed ratio of 0.7 and 0.9 respectively. © 2021 Author(s).Item Use of a CFD code in the investigation of cross corrugated heat transfer surfaces(2010) Ashok Babu, T.P.A.; Shekoor, T.M.The variation of main geometric details of cross corrugated surfaces (i.e. aspect ratio and angle of corrugation) makes it increasingly difficult to have a general design method. In the absence of adequate 'database' covering all possible configurations, it is nearly impossible to predict the highly effective configuration. Thus CFD simulation is effective, as it allows computation for various geometries, and study of the effect of various design configurations on heat transfer and flow characteristics. The present paper discusses the use of a CFD code to select the cross corrugated heat transfer surface (CC surface) with minimum core volume of a recuperator matrix. Due to difficulties Induced by geometry and computational time, simple model is used as a first step. The SS T turbulence model was preferred over other flow models for simulations. This simple model, comprised of three corrugated plates having their crest nearly in contact, with hot and cold fluids flow alternately through passage created between the plates. Some selected cross corrugated heat transfer surfaces are used for the analysis. The results for the simplified model, presented in terms of outlet temperatures, heat transfer coefficients and skin friction coefficients, is encouraging to undertake extensive work in CFD simulation and create more 'database' on various configurations. Design calculations of a recuperator matrix for a 10 kW micro turbine have been carried out for the selected surfaces. The relation between the minimum core volume of the matrix from design calculation and average skin friction coefficient from CFD analysis is established to use CFD analysis for selection of heat transfer surfaces with minimum recuperator matrix core volume. The analysis is carried out with air and nitrogen as heat transfer fluids.Item Transient analysis of subcritical/supercritical carbon dioxide based natural circulation loops with end heat exchangers: Numerical studies(Elsevier Ltd, 2014) Yadav, A.K.; Ram Gopal, M.; Bhattacharyya, S.Transient analysis of carbon dioxide based natural circulation loop (NCL) with end heat exchangers has been carried out. Subcritical and supercritical phases of CO2 are considered with operating pressures in the range of 50-100 bar for an operating temperature range of 323 K to 363 K. Studies are carried out for various loop tilt angles, different initial conditions, and different water mass flow rates. Results: are obtained for various inlet temperatures of water in the hot heat exchanger while keeping the inlet temperature of cooling water in the cold heat exchanger fixed. Effect of tilting the loop in XY and YZ planes on transient as well as steady state behaviour of loop are also studied. Validation of simulation results against experimental and numerical results reported in the literature in terms of modified Grashof number (Grm) and Reynolds number (Re) show good agreement. © 2014 Elsevier Ltd. All rights reserved.Item Effect of preheated mixture on heat transfer characteristics of impinging methane-air premixed flame jet(Elsevier Ltd, 2015) Tajik, A.R.; Kuntikana, P.; Prabhu, S.V.; Hindasageri, V.Energy from spent flame or other low grade energy can be used to increase the temperature of the air before mixing with fuel. This would improve the heat transfer characteristics of the impinging flame jet. The studies on impinging flame jets reported in the literature are based on the fuel-air mixture at ambient temperature. In the present work, the inlet air for mixture is heated by an electrical heater. The heat flux distribution is estimated using an inverse heat conduction (IHCP) technique. The Nusselt number (Nu) and effectiveness (?) distributions are obtained by estimating the adiabatic wall temperature (Taw) by the analytical-numerical method. A circular burner of 13.5 mm is used for impingement on quartz plate of 3 mm thickness. Reynolds number (Re) varying from 500 to 2000 for the non-dimensional burner tip to impingement plate spacing (Z/d) of 2-6 and stoichiometric condition (Ø = 1.0) is considered for varying preheated condition. The effect of equivalence ratio is studied for Ø = 0.75 to 1.5 for Re = 1000 and Z/d = 4. By increase in preheat temperature, the stagnation point heat flux increases from 20% to 50% unless the inner premixed zone touches the impingement plate. CFD simulations are carried out in FLUENT software to explain the distribution of heat flux. © 2015 Elsevier Ltd. All rights reserved.Item Coupled computational fluid dynamics-discrete element method simulations of a pilot-scale batch crystallizer(American Chemical Society service@acs.org, 2015) Ali, B.; Börner, M.; Peglow, M.; Janiga, G.; Seidel-Morgenstern, A.; Thévenin, D.Computational fluid dynamics (CFD) coupled with the discrete element method (DEM) has been used to investigate numerically crystal dynamics in an existing pilot-scale batch crystallizer. The CFD-DEM combination provides a detailed description of crystal dynamics considering a four-way coupling. In a previous analysis,1 CFD had been coupled with a discrete phase model (DPM) using a simple one-way coupling. The corresponding predictions are then compared with those obtained through four-way coupling considering KH2PO4 crystals in water. From the CFD-DEM simulation, it is possible to investigate quantitatively the driving force controlling crystal growth and the interaction of crystals with reactor walls, baffles, and impellers. This delivers essential data for process improvement. Different seeding procedures were also compared. The seed crystals have been injected either within the complete liquid volume or, as in the experiments, through a funnel. By varying the most important crystallization process parameters, we found optimal conditions for a liquid phase volume in the crystallizer of 24 L, for injection through a funnel above the baffle, and for an initial seed crystal size of 0.5 mm. © 2014 American Chemical Society.Item The effect of cordierite/Pt catalyst on the NOx reduction in a diesel and Jatropha bio-diesel operated single cylinder engine(Elsevier Ltd, 2015) Kumar, A.P.M.; Sreekumar, J.S.; Mohanan, P.Bio-diesel is an alternative energy resource, which can be successfully used in diesel engines. One major disadvantage of using bio-diesel is the higher emission of NOx. Hence some after treatment devices have to be adopted to reduce NOx in order to meet the stringent limits on emission standards. In the current research work honeycomb structured circular Cordierite/Pt SCR catalyst is used as an aftertreatment device. Studies revealed that SCR (Selective catalytic reduction) catalyst exhibits better performance at a higher temperature range (>500 °C), which can be successfully used in Trucks and Buses. But many catalysts failed to exhibit better performance at a lower temperature range varies from 180 to 400 °C, which makes these catalysts unsuitable to use with light and medium duty vehicles. The main objective of this study is to assess the suitability of Cordierite/Pt catalyst for light and medium duty vehicles and study the effect of SCR catalyst on bio-diesel blends in order to reduce NOx in a single cylinder diesel engine. The experimental work has been carried out using diesel and bio-diesel as a fuel and the NOx reduction is tabulated. The results are validated with CFD code AVL FIRE. The ammonia flow rate has been varied from 0.2 to 0.8 kg/h. It has been found that among all the blends B15 has shown maximum NOx conversion of 60% and NH3 conversion of 34%. © 2015 Elsevier Ltd. All rights reserved.