bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brayton Cycle Supercritical CO2 Power Block for Industrial Waste Heat Recovery
Authors: Sathish Sharath , Kumar Pramod , Nagarathinam Logesh , Swami Lokesh , Namburi Adi Narayana , Bandarupalli Venkata Subbarao , Gopi Pramod Chandra 
Published: January 2020

Abstract
The Brayton cycle based supercritical CO2 (sCO2) power plant is an emerging technology with benefits such as; higher cycle efficiency, smaller component sizes, reduced plant footprint, lower water usage, etc. There exists a high potential for its applicability in waste heat recovery cycles, either as bottoming cycles for gas turbines in a combined cycle or for industrial waste heat recovery in process industries such as iron & steel, cement, paper, glass, textile, fertilizer and food manufacturing. Conventionally steam Rankine cycle is employed for the gas turbine and industrial waste heat recovery applications. The waste heat recovery from a coke oven plant in an iron & steel industry is considered in this paper due to the high temperature of the waste heat and the technological expertise that exists in the author’s company, which has supplied over 50 steam turbines/ power blocks across India for various steel plants. An effective comparison between steam Rankine cycle and sCO2 Brayton cycle is attempted with the vast experience of steam power block technology and extending the high pressure-high temperature steam turbine design practices to the sCO2 turbine while also introducing the design of sCO2 compressor. The paper begins with an analysis of sCO2 cycles, their configurations for waste heat recovery and its comparison to a working steam cycle producing 15 MW net power in a coke oven plant. The sCO2 turbomachinery design follows from the boundary conditions imposed by the cycle and iterated with the cycle analysis for design point convergence. The design of waste heat recovery heat exchanger and other heat exchangers of the sCO2 cycle are not in the scope of this analysis. The design emphasis is on the sCO2 compressor and turbine that make up the power block. This paper highlights the design of a sCO2 compressor and turbine beginning from the specific speed-specific diameter (Ns-Ds) charts, followed by the meanline design. Subsequently, a detailed performance map is generated.
The relevance of this paper is underscored by the first of a kind design and comparative analysis of a Brayton sCO2 power block with a working Steam Power block for the waste heat recovery in the energy intensive iron and steel industry.
Conjugate Heat Transfer Analysis of a Small Annular Combustor With Centrifugal Fuel Injection System
Authors: Rana Rampada , Prajwal Alosri , Sivaramakrishna Gullapalli , Navindgi Raju Dharappa , Muthuveerappan Nagalingam 
Published: January 2020

Abstract
Over the years, the requirements of higher specific thrust and lower specific fuel consumption have been necessitating a continual increase in the maximum temperature and pressure in gas turbine engines. However, such an increase has a direct impact on the structural integrity of various modules of the engine; combustor being one of the severely affected modules. This makes the combustor designer’s task of achieving the targeted life of liner, the hottest component of combustor, a challenging one. Estimation of liner metal temperature, thereby arriving at the combustor life, is an essential part of the design process. In the present study, CHT analysis of a radial annular combustor has been carried out. RANS based analysis of a sector combustor with periodicity in flow and geometry has been performed at realistic engine operating conditions using ANSYS Fluent. Predicted liner metal temperatures have been compared with the measured data and a close agreement has been noted between them, the maximum variation being ± 10%.
Design and Development of Aeroderivative Gas Turbine Lifting and Handling Structures
Authors: Santhanagopalakrishnan Babu , Ghumre Milind , Kammalapalli Ramesh , Pittella Gianfranco 
Published: January 2020

Abstract
Gas turbines Lifting devices (such as lifting lugs, eye bolts, trunnions, are provided on large stationary gas turbine parts as an aid in manufacturing, assembly, transport, shipping, test, installation, repair, and serviceability. Trunnions are used to lift the entire turbine including the base during assembly, transportation and installation Similarly, lugs are used to lift major components such as stator tube casings and subassemblies. In some circumstances there are geometric, fatigue, or assembly constraints that make the use of lugs problematic. In these circumstances, other approved lifting devices such as eye bolts, swivel hoist rings, and shackles may be used. Other devices may also be used for parts smaller than stator tube casings.
This paper presents the design and development of the Aeroderivative gas turbine lifting and support lug features which are used for lifting, handling and transportation of the full gas turbine. It describes the challenges encountered during development of LPT lifting lugs to meet product requirements. The effects of full engine deformations due to support legs under worst case conditions of full engine handling are presented here. The benefits resulted due change in lug position are explained which is leveraged for the final production design. It also talks about the various design options considered to reduce stresses and simplify the lugs manufacturing.
A Numerical Study on the Effect of Unbalance and Misalignment Fault Parameters in a Rigid Rotor Levitated by Active Magnetic Bearings
Authors: Kumar Prabhat , Tiwari Rajiv 
Published: January 2020

Abstract
This paper focusses on analysing the vibration behaviour of a rigid rotor levitated by active magnetic bearings (AMB) under the influence of unbalance and misalignment parameters. Unbalance in rotor and misalignment between rotor and both supported AMBs are key fault parameters in the rotor system. To demonstrate this dynamic analysis, an unbalanced rigid rotor with a disc at the middle levitated by two misaligned active magnetic bearings has been mathematically modelled. One of the novel concepts is also described as how the force due to active magnetic bearings on the rigid rotor is modified when the rotor is parallel misaligned with AMBs. With inclusion of inertia force, unbalance force and force due to misaligned AMBs, the equations of motion of the rigid rotor system are derived and converted into dimensionless form in terms of various non-dimensional system and fault parameters. Numerical simulations have been performed to yield the dimensionless rotor displacement and controlling current responses at AMBs. The prime intention of the present paper is to study the effect on the displacement response of the rigid rotor system and the current consumption of AMBs for different ranges of disc eccentricities and rotor-AMB misalignments.
Computational Analysis on the Use of Various Nimonic Alloys As Gas Turbine Blade Materials
Authors: Subbarao Rayapati , Mahato Nityanando 
Published: January 2020

Abstract
Blade failure is triggering more problems to the gas turbine engines, while being used in airline and jet engines. In this paper, causes of blade failure with respect to various Nimonic alloys is investigated by performing structural and thermal analyses. Using Ansys, both these analyses on turbine blade are carried out, which is utilized for determining equivalent stresses, deformation and thermal stresses by applying different turbine inlet temperatures and pressures. Turbine blade model is prepared using Solid Works. The computational model is then imported to Ansys workbench. Before importing to the solver, the domain is meshed and boundary conditions are applied. Properties like coefficient of thermal expansion and thermal conductivity are given as material conditions. Ambient temperature, rotational speed, inlet pressure and temperature are considered as boundary conditions. For various configurations and alloy materials, deformation, strain and thermal stresses are plotted and analyzed. After thorough investigation, the turbine blade failure region is identified and the trend is compared for different input temperatures and pressures. At the root of the blade, the stresses and strains are found to be more. Of all the materials considered, Nimonic-90 has less deformation and thermal stresses. Nimonic-80A has more equivalent stress, strain and deformation. Out of the other two materials, Nimonic-263 is showing favourable properties than Nimonic-105. However, the values of stresses and strains are comparable. Thus the present work is beneficial in identifying suitable Nimonic alloy as gas turbine blade material in order to avoid the frequent turbine blade failures.
Analysis of Static and Dynamic Performance Parameters of Two-Lobe Journal Bearing Operating With Non-Newtonian Lubricant
Authors: Kumar Ashutosh , Kakoty Sashindra Kumar 
Published: January 2020

Abstract
Static and dynamic performance parameters of two-lobe journal bearing, working with non-Newtonian lubricant has been obtained. Krieger-Dougherty model is used to obtain the effective viscosity of nano-lubricant for a given concentration of solid-particle in base lubricant. Modified Reynolds equation is solved to obtain bearing performance parameters for couple stress model and variable viscosity model. Dynamic coefficients are also determined for various couple stress parameter. Results reveal a noticeable increase in flow co-efficient and load carrying capacity while there is a decrease in friction variable. It also reveals a significant betterment in dynamic co-efficient of bearing.
Experimental and Numerical Assessment of Cross Flow Vertical Axis Wind Turbine
Authors: Seralathan Sivamani , Thomai Micha Premkumar , Jayakumar Rian Leevinson , Lokesh Reddy Basireddy Venkata , Venkatesan Hariram 
Published: January 2020

Abstract
Due to increase in energy demand along with environmental awareness, the attention is shifting towards renewable energy sources. A wind turbine developed from Banki water turbine is used in this study as it starts at low-wind speeds and has high starting torque. Experimental investigations are carried out on a test rig equipped with open jet wind tunnel with wind velocity varying from 7 to 11 m/s. Later, 3D steady-state numerical analyses are performed using ANSYS CFX for better understanding of the flow physics of cross flow VAWT. The experimental investigations revealed that cross flow VAWT has a good self-starting ability at relatively low-wind speeds. A peak power coefficient (Cp, max) value of 0.059 is observed for the tip speed ratio (λ) of 0.30. As the tip speed ratio is raised further, the Cp value is observed to decrease gradually. The numerical simulations reveal the reason for the drop in Cp value. This is due to lessening of positive interaction between the flow and cross flow VAWT blades at higher λ due to vortex formation. The torque coefficient is found to decrease almost linearly from a peak value of around 0.49 at λ = 0 to a value of 0 around λ = 0.60. Polar plot between angle and torque shows that torque output of the turbine is nearly same in all directions which reinforce the potency of cross flow VAWT to be omni-directional as it produces the same performance regardless of wind directions.
Acoustic Investigation on Unmanned Aerial Vehicle’s Rotor Using CFD-MRF Approach
Authors: Murugesan Ramesh , Raja Vijayanandh 
Published: January 2020

Abstract
Future developments have been indicated for further research and development in the Aeroacoustics of the components of Unmanned Aerial Vehicles (UAVs). In which the implementation of multi-rotor UAVs in the complex applications is quite high but it has the drawback of high drive-line noise levels, which is one of the prime radar detectability factors. As a result, an idea is emerged to design and test the quite UAV, in which the noise from propellers plays a major role. in order to the successful completion of the design study, a complete is conducted, in which the design parameters and various noise reduction methodologies in the rotating components have been noted and included in the final design. To minimize the noise signature issue in UAV, the idea finalized that to minimize the decibel of small Unmanned Aircraft System (UAS) propellers via leading-edge modifications. A computer-aided design of base propeller and three different versions propeller with leading-edge modifications are generated with the help of CATIA for Computational Fluid Dynamics (CFD) simulations. Comparative noise variation simulations between the existing and the propellers with modification are performed, in which dynamic conditions play a predominant to initiate the analysis and thereby the analyses are carried out with the help of ANSYS Workbench Fluent 16.2. Especially, to make an acceptable solution, the Moving Reference Frame (MRF) approach is used in order to capture the propeller rotation in an effective manner. Finally, a propeller with airfoil cut at the leading edge has induced the low noise.
Influence of Lewis Number on Heat Release Rate in Premixed Syngas Flames
Authors: Bhide Kedar G. , Sreedhara Sheshadri 
Published: January 2020

Abstract
Syngas is an attractive alternative to currently popular hydrocarbon fuels due to its ability to be synthesized from multiple sources and lower carbon content. Direct Numerical Simulation (DNS) studies on premixed and non-premixed syngas flames have recently received attention. In this light, DNS of turbulent premixed syngas has been performed. Influence of turbulence and differential diffusion effects on chemical pathways of fuels like Hydrogen and methane has been studied in the past. Similar study on syngas flame has not been reported in the literature. Two cases with variation in the intensity of turbulence have been reported in this study. Effect of differential diffusion and turbulence on heat release rate and fuel consumption rate has been discussed. The behavior of heat release rate and fuel consumption rate was largely similar between laminar and turbulent flames considered in this study. Influence of species Lewis number was found to be more pronounced than that of turbulence.
Simulation of Laser Cutting on Functionally Graded Material Used in Aviation Industry
Authors: Nath Subha , Das Apurba , Inaba Kazuaki , Karmakar Amit 
Published: January 2020

Abstract
Functionally graded materials (FGMs) are widely used in engineering applications for the advantages offered by the properties of materials in combination. It is a special type of composite material which is inhomogeneous (micro-scopically). Laser cutting offers advantages while cutting these materials compared to traditional cutting methods. The objective of this work is to investigate numerically the effect of process parameters such as laser power and scanning speed on kerf width, depth of cut and thermal stress. Gaussian heat source, representing the laser beam, is applied along a straight line path through the middle of the work piece. The FGM considered in this work material mainly consists of a FGM made of nickel and stainless steel (AISI 304). The work piece is assumed to be symmetric. In this simulation finite element software COMSOL MULTIPHYSICS is used to simulate the thermo-mechanical model. The model is meshed with nonuniform pattern tri-angular mesh. It is observed from the results of numerical simulation that with the increase of laser power the width and depth of the cut has increased. The cut has a very narrow kerf width with increasing scanning speed leading to considerable saving in material. The variation in thermal stress is observed on the material with the considered parameters.
Effect of Laser Energy Density on Bulk Properties of SS 316L Structures Built by Laser Additive Manufacturing Using Powder Bed Fusion
Authors: Nayak Saurav K. , Mishra Sanjay K. , Paul Christ P. , Jinoop Arackal N. , Yadav Sunil , Bindra Kushvinder S. 
Published: January 2020

Abstract
Laser Additive Manufacturing using Powder Bed Fusion (LAM-PBF) is one of the revolutionary technologies playing a key role in fourth industrial revolution for redefining manufacturing from mass production to mass customization. To upkeep the pace, Raja Ramanna Centre for Advanced Technology (RRCAT) has indigenously developed an LAM-PBF system and it is being used for process and component development for various engineering applications. This paper reports a parametric investigation to evaluate the influence of process parameters on the sample properties and to develop the process window for fabricating complex shaped engineering components. In the present work, an experimental investigation is carried out to investigate the effect of Laser Energy density (LED) on the porosity, microstructure and mechanical properties of SS 316L bulk structures fabricated by LAM-PBF system. LED is a combined parameter simultaneously considering the effect of Laser Power (P), Scan Speed (v), hatch spacing (h) and layer thickness (t). The effect of three LED values such as 83.33 J/mm3, 253.97 J/mm3 and 476.19 J/mm3 is investigated in the present work by building cuboidal samples at a layer thickness of 75 microns. Porosity is estimated using area fraction method in optical microscopy and it is found that the minimum porosity of 0.14 % and pore area of 1.28 mm2 are observed at 253.97 J/mm3. Maximum porosity of 18.85 % is observed at 83 J/mm3 due to incomplete fusion defects. However, porosity observed at 475 J/mm3 is 6.56 % with average pore size of 17.8 mm2. Microstructural studies show primarily columnar growth in all the samples with fine dendrites. The dendrite size is observed to be 3.2 μm, 2.4 μm and 1.46 μm at 83.33 J/mm3, 253.97 J/mm3 and 476.19 J/mm3 respectively. Micro-hardness and single cycle automatic ball indentation studies are found to be in agreement with dendritic size, with lower hardness at larger dendrite size. X-Ray Diffraction (XRD) studies indicate similar peaks at all the conditions, with slight peak shift observed with increase in LED primarily due to higher amount of residual stress. Thus, it can be inferred that LED of 253.97 J/mm3 is suitable for fabricating engineering components due to combination of lower porosity and fine dendritic structure.
Dynamic Characterization of an Additive Manufactured Turbine Wheel of Turbocharger
Authors: Selvam R. Panneer , Duraiselvam Muthukannan , Barad Sanjay G. , Kumar Dilip 
Published: January 2020

Abstract
Experimental Modal Analysis (EMA) is a conventional technique for establishing the modal parameters of the components. The modal parameters are the dynamic characteristics viz. frequency, mode shapes and damping that are used for assessing and validating the design predictions through correlation studies.
For this task EMA technique is adopted to assess the dynamic characteristics of an additive manufactured (AM) turbine wheel of a turbocharger. Correlation studies are undertaken to validate the theoretical model developed. These Correlation studies ensured that there is no major deviations to proceed for high speed spin testing of this turbine wheel in simulated environment. The possible interference or resonances in the operating range are identified for safe operation of the test rotor.
Investigation on Flow Characteristics and Performance of a Vertical Axis Wind Turbine With Deflector Plates
Authors: Karthik Selva Kumar K. , Kulkarni Vinayak , Sahoo Niranjan 
Published: January 2020

Abstract
In this article, a 3D computational study has been performed to understand the flow phenomenon over the vertical axis wind turbine with a three-bladed NACA0021. The rotary motion of the VAWT simulated with sliding mesh techniques with reference to the SST-Kω turbulence model using the CFD software. The observed results were found to be having a significant improvement in the enhancement of the power output. Also, the investigation was move forwarded to understand the flow characteristics of the VAWT with the presence of deflector plates in different orientation at the upstream conditions. The present of deflector plates creates an augmented flow phenomenon which creates an accelerated flow at the near wake region, causing a significant improvement in the coefficient of power of the wind turbine.
Metaheuristic Optimization of Dual-Element Vertical Axis Wind Turbine Using Genetic Algorithm
Authors: Kumar Sushrut , Gupta Priyam , Singh Raj Kumar 
Published: January 2020

Abstract
This paper presents a framework for the optimization of Dual-Element Vertical Axis Wind Turbine (VAWT) Blade configurations for improvement in power generation. Multi-element nature of the turbine was specifically chosen as this configuration offers better-attached flow over a conventional single element H-type turbine. The framework was based on a genetic evolutionary algorithm which is a metaheuristic optimization technique based on the principle of survival of the fittest. The class of genetic algorithm used was Invasive Weed Optimization. The geometry of the turbine consists of a rotor with three sets of dual-element airfoil oriented symmetrically. Effective chord length and relative chord angle were taken as modifying parameters for generating new configurations. The fitness of each individual was evaluated by performing two-dimensional Computational Fluid Dynamics Simulations. OpenFOAM was used for performing numerical simulations. Qualitative data of torque, pressure, velocity, and turbulence kinetic energy of best configuration is shown. A considerable increase in torque in the final geometry. The model was found ideal for optimizing multi-element VAWT configuration.
Lean Blowout Phenomena and Prior Detection of Lean Blowout in a Premixed Model Annular Combustor
Authors: Bhattacharya Arijit , Gupta Bikash , Hansda Satyajit , Haque Zohadul , Kumar Ashish , Mishra Manohar Kumar , De Somnath , Mukhopadhyay Achintya , Sen Swarnendu 
Published: January 2020

Abstract
Strict emission norms in the last few decades have paved the path for adaptation of new low NoX emission alternatives to power generation and aircraft propulsion. Lean combustion is a very promising and practicable technology for reducing NOX reduction and also have very high fuel efficiency. However, lean combustion technology suffers from inherent combustion instabilities that are manifested under different conditions, most importantly, thermoacoustic instability and lean blowout. Lean blowout occurs when a gas turbine combustor operating close to lean limit, for lowest NoX emission, faces abrupt changes in fuel homogeneity, quality or flow rate. While many work have been done in thermo-acoustic instability and flame propagation in annular combustors, studies in lean blowout in annular combustors are very limited. The lean limit of combustors are not fixed and is dependent on fuel characteristics and operating condition including environmental effects. So accurate online prediction of lean limit is very important to keep the combustors operating safely near lean limit. Recent works have demonstrated that single burner combustors leave out a significant amounts of physics including interaction of flames from different burners prior to blowout.
In this work, a stepped down swirl and bluff body stabilized annular combustor in CB configuration (having chamber and burner), is used as experimental test rig having 4 number of identical burners. Video and heat release data are taken at different conditions as lean blowout is approached. Frequent attachment and reattachment of the flames prior to lift off was seen. As lean blowout is approached, inherent subtle differences in the different burners get amplified when flame becomes sufficiently weak and flame symmetry is broken. As air fuel mixture is made gradually leaner, one by one the flames from different burners elongates although remains partially attached to burner. Further lowering the equivalence ratio results in lift off and merging of the flame fronts of different burners. Three pixel averaged color ratios are extracted from still camera RGB images as flame stability indicators which are, red by blue, red by green and blue by green. The parameters show marked change at the point of lift off as well as at the lean blowout point.