bluuebunny/crossref_metadata_2025_split huggingface dataset:
CFD Based Taguchi Optimization of the Performance of a Gas Turbine Combustor
Authors: Pandey Mukund Kumar , Sivaramakrishna G. , Navindgi R. D. , Muthuveerappan N. 
Published: January 2020

Abstract
Achieving minimum pressure loss and exit temperature pattern factors are the two important, but conflicting performance goals of a gas turbine combustor. In this study, Taguchi method was used to design CFD (Computational Fluid Dynamics) analysis based experiments in order to arrive at optimized liner hole sizes (primary and dilution) of an annular gas turbine combustor. The CFD experiments were steady & three-dimensional Reynolds Averaged Navier-Stokes (RANS) based analyses performed on a 20-degree sector combustor model. Nine CFD analyses were performed as per the Taguchi L-9 orthogonal array, based on which, an optimal hole configuration was arrived. An additional CFD run was carried out to verify the predicted result. The optimized hole size combination reduces the Circumferential Pattern Factor (CPF) by 28% and pressure loss by 0.06% (difference between absolute values of percentage pressure losses) in comparison to the baseline configuration.
Parametric Analysis and Performance Evaluation of 2D Scramjet Inlet
Authors: Kane Aniruddha Ajay , Peetala Ravi K. 
Published: January 2020

Abstract
The air breathing propulsion system used for hypersonic vehicle cruising is a scramjet. Inlet design is one of the important step in overall design of scramjet. The initial steps in the inlet design process consist of identification of shock angles, shock hitting points and there after evaluation of performance parameters using inviscid flow consideration at a given Mach number called design Mach number. During the flight, the vehicle operates on the off-design conditions. The current study focusses on the effect of these off-design conditions such as variation of freestream Mach number, angle of attack, total temperature on the flow field and performance parameters using inviscid flow assumption. The performance parameters considered in the present study are total pressure recovery, static pressure ratio, static temperature ratio, kinetic energy efficiency, adiabatic compression efficiency, non-dimensional entropy increase.
Case Study of a Gas Turbine Chronic Failure at Saudi Arabia
Authors: AlKhudhayr Abdullah N. , AlAdel Abdulrahman M. 
Published: January 2020

Abstract
A gas turbine is a reliable type of rotating equipment, utilized in various applications. It is well known in power generation and aviation. In the oil and gas industry, gas turbines are utilized in locations with limited electrical power or a high power driven load requirement, such as offshore or a high-rated power 20MW compressor.
Five gas turbines are used as mechanical drive equipment. After a few years of operation, the gas turbines were experiencing high operating temperatures in bearings, turbine compartments, high spread temperature, and the presence of smoke in the exhaust. During a major overhaul of the turbines, oil was found to have accumulated internally in the wrapper casing, along with damage to several internal combustion components. In one case, the exhaust casing experienced severe damage with deformation. This paper presents a case study of a gas turbine failure and its contributors. The paper explains the mitigated solution to overcome the challenges related to the gas turbine operation, maintenance, and machine design.
Sealing in Fabricated Shrouds of Aero-Derivative Power Turbine for Marine and Industrial Applications
Authors: Katti Srinidhi , Colantoni Simone , Tripoli Girolamo 
Published: January 2020

Abstract
Gas Turbine shroud is a static component, which forms the outer flow path surface and sealing clearances to turbine blade tip. It also protects the casing from hot gases ingestion and radiation. Shrouds are segmented circumferentially to accommodate the large thermal gradients. The sealing between adjacent segments and the hook clearances play an important role in controlling hot gas ingestion and loss of efficiency. Heavy duty engine shrouds are typically bulky and machined from either forged ring or investment casting. They have tight tolerance-controlled hooks and hence controlled clearances with casing. It incorporates intersegment seals to control leakages between adjacent segments. On the other hand, Aero-derivative shrouds are typically thin and sheet metal fabricated. Tight tolerance control is not possible in sheet metal hooks and use of intersegment seal is also not feasible in these thin structures. Hence both the design features and approach to address sealing criteria will be different. In this article, it presents the challenges like manufacturing constraints and life requirements and the optimization study that was performed to meet the sealing criteria considering these challenges.
Exergy Analysis of a Combined Gas Turbine and Organic Rankine Cycle Based Power and Absorption Cooling Systems
Authors: Nondy Joy , Gogoi Tapan Kr. 
Published: January 2020

Abstract
In this paper, a combined power and cooling system is thermodynamically analyzed. The system consists of a natural gas-fired gas turbine (GT) plant integrated with a heat recovery steam generator (HRSG), two steam turbines (STs), one organic Rankine cycle (ORC) and two absorption cooling systems (ACSs). With certain given input parameters, the GT plant produces net power of 36.06 MW, the two STs contribute 17.07 MW while from the ORC, 7.18 MW of net power was obtained. From the steam-operated ACS-I, a net 10.36 MW of cooing could be produced. Again, from the GT exhaust operated ACS-II, it was possible to generate additional 3.37 MW of cooling. From exergy analysis, it was found that the total irreversibility was the highest in the GT cycle with a net contribution of 180.412 MW followed by 4.178 MW from the HRSG, 3.561 MW from the ORC, 1.743 MW from ACS-I, 1.186 MW from ST-I, 0.812 MW from ACS-II, 0.175 MW from ST-II. The exergy efficiencies of the GT cycle, ORC, ACS-I and ACS-II were found 22.00%, 65.48%, 18.95% and 14.4% respectively. Regarding the power and cooling output, it can be concluded that these results are specific to the selected operating parameters. Further investigation is required, where, other similar configurations may be considered to make a final comment on the suitability of the proposed configuration from energy output and economic point of view.
Online Automatic Degradation Diagnosis of Gas Turbine Bearings Based on Unsupervised Machine Learning
Authors: Kakati Pallabi , Dandotiya Devendra , Savanur Rajendrakumar 
Published: January 2020

Abstract
The bearing prognostic analysis plays a critical role in improving the reliability of any rotational engine. In data-driven methods, used in such bearing prognosis, real time bearing vibrational data can be acquired from a set of sensors. In literature, many supervised learning techniques have been proposed to analyze this data. However, the labelled training data required for such a supervised technique is not always available in real life. Therefore, in this work, an unsupervised learning technique based on adaptive resonance theory 2 (ART2) has been used for bearing vibrational signal analysis. The benefit of this method is that no separate training is required for the prognosis purpose. The gas turbine is studied in this work is a GE MS 3002 used in natural gas transportation in Algeria. This method is used to study the bearing vibrational signal emitted at the high-pressure turbine side. The use of online method helps us updating the model, as new observations are available. This method also offers better performance under noisy environment.
Advanced Models for Fatigue Life Estimation of Combustor Components for Gas Turbine Application
Authors: Sivarama Iyer Dileep , Chandran Pillai Nikhil 
Published: January 2020

Abstract
Modern day combustors operate at very high temperatures which are close to combustor material softening temperatures. At the same time, to meet stringent emission legislations there is a strong drive to improve upon the rich burn combustor technology or shift to advanced lean burn combustor technologies. One of the key driver to improve emission is to save the cooling air budget and use the saved air for primary combustion but this approach would require more advanced and efficient cooling techniques. Fan shaped effusion cooling technology is a very promising technique as it offers high film cooling effectiveness. However, complex cooling features associated with this technology can lead to higher stress concertation and localized triaxial stress state. This stressstrain field in combination with a typical gas turbine engine operating cycle makes such effusion holes highly vulnerable to the thermo-mechanical fatigue failure. Hence to ensure the safety and reliability of combustor liners with such innovative features, it is essential to have thorough understanding of the stress-strain field in the vicinity and accurate prediction of life to first crack. The biggest challenge the designers and engineers face while predicting the initiation life of a structure is selecting the appropriate fatigue damage model for an application. This is due to following reasons: (a) The scatter in fatigue life predicted using different models and experimental values are very huge (b) There is no general universal method which can predict the multiaxial fatigue life accurately for all the materials and loading conditions (c) No general consensus exits among the researchers on which model have to be used for a particular application, material, loading and geometry (d) Application level studies are seldom available on this subject, most of the studies are restricted to laboratory level specimens with very limited implications to industry. Ideally, the fatigue damage model which has to be used for a particular application has to be validated through experiments. To meet this objective, several test specimens featuring novel fan shaped hole geometries were mass-produced using state of the art laser drilling technology. All these specimens were subjected to strain controlled isothermal low cycle fatigue test and the cycles to crack initiation was monitored using potential drop method. Six different multiaxial fatigue damage models (which can be used in low cycle fatigue regime) viz. Walker model, Smith Watson and Topper model (SWT), Fatemi Socie model (FS), Wang and Brown model (WB), Shang model (SW) and Xu model were selected and the life estimated by these models were compared with the experimental values. From the study it is observed that Xu model in which the damage parameter is built using the concept of shear strain energy looks most promising for this application.
Estimation of the Hydraulic Losses in the Inlet Shaft of a Land-Based Gas Turbine
Authors: Baturin Oleg V. , Kolmakova Daria A. , Krivtsov Alexander V. , Popov Grigorii M. , Volkov Andrei A. 
Published: January 2020

Abstract
The paper presents the results of numerical simulation of air flow through a modernized variant of the inlet filter unit (IFU) of the gas compressor unit GPA-Ts-16. A feature of the IFU design is that to reduce the load on the filter unit, it is proposed to be as compact as possible, which determines its complex shape.
The goal of the study is to study the hydraulic losses and to develop the measures to reduce them, since it is found that every 100 Pa of losses in the inlet unit increases the consumption of fuel gas by 2.5 kg/h or reduces the engine power by 10.5 kW.
Calculations of hydraulic losses in IFU are carried out for cases of absence or presence of wind with a velocity from 0 to 35 m/s, blowing from 5 main directions (0°, 45°, 90°, 135°, 180°). Studies are also carried out on the effect of the weather shield shape, presence of baffles under it, and the rack in the shaft on the hydraulic losses.
As a result of the research, recommendations are provided for designing (changing the shape) of the inlet filter unit that eventually allow to propose a design that will reduce the hydraulic losses in IFU by 15% relative to the originally suggested variant.
The Concept of a Multi-Level Optimization Model of the Centrifugal Compressor Workflow
Authors: Popov Grigorii M. , Egorov Igor , Marchukov Evgenii , Volkov Andrei A. , Baturin Oleg V. 
Published: January 2020

Abstract
The paper presents the main ideas of the virtual test bench concept for rapid obtaining of the reliable characteristics of compressors based on a multi-level mathematical model with a two-step identification using data obtained from mathematical models with a high order of accuracy. One of the possible identification algorithms and the results of its successful testing are given on the example of a centrifugal compressor stage developed and tested at NASA.
A Comprehensive Analysis of the Fiber Laser Application in Cleaning Process of Corrosion Layers for Iron-Based Samples
Authors: Shelar Mayur , Bawankar Kaushik , Madake Shailesh , Dhamangaonkar P. R. 
Published: January 2020

Abstract
This paper describes the comprehensive review of the gradual layer removal of reactive corrosion products from Iron sample to establish the methodology for less intrusive and exacting laser cleaning approach. Effects of laser radiation on substrate, factors affecting the efficiency of graffiti removal and laser parameters such as wavelength, focal length, pulse duration effect, speed, power constant, line space and laser pattern are investigated. Nano-second pulse fiber laser, operating in the near-IR at a wavelength of 1064 nm and power capacity of 30W was used in the study. The laser system was coupled via computer with EzCAD 2.9.9 UNI, a vector graphic editor, with a CAD-like capability that enables users to perform rapid, precise and complex surface scanning treatments in a repeatable way. A series of laser cleaning studies has been performed on corroded iron reference samples along with analyzing the effects of various parameter changes on the corroded surface using Alicona 3-D surface analyzer. Chemical composition, microscopic analysis and oxide content test for the various layers of sample is been determined with SEM. The results obtained from various tests are providing reliable base to understand laser cleaning mechanism and their effect on different laser characteristics.
Effect of Guide Vane Fillets on Wave Energy Harvesting Impulse Turbine
Authors: Maurya Gautam , Das Tapas K. , Dudhgaonkar P. V. , Samad Abdus 
Published: January 2020

Abstract
Oscillating water columns (OWC) are widely used devices for the extraction of wave energy through self -rectifying impulse air turbines. To improve the performance of any turbo-machinery, guide vanes (GV) play an essential role in deciding turbine characteristics in terms of efficiency and torque. The concept of filleting is used in the GVs of bidirectional impulse turbine (BDI) with five different types of GV fillets for different radii, and the performance was analyzed. The numerical simulation was done using the commercial code ANSYS CFX 16.2, which solves the three-dimensional Reynolds-Averaged Navier-Stokes equation by finite volume explicit Runge-Kutta scheme with the k-ω SST closure model. There is a close agreement between the experimental and the numerical model. The detailed flow physics of filleted GVs have been included in the present work, and it was found that the efficiency increases at higher flow coefficients.
Studies on the Characteristics of Three-Inline Non-Premixed Turbulent Oxy-Methane Flame Jets
Authors: Jana Tamal , Kaushik Mrinal 
Published: January 2020

Abstract
In the present study, the characteristics of three-inline non-premixed Oxy-Methane turbulent flame jets, with Methane jet at the center and two Oxygen jets on either side, are computationally investigated. For all the jets, the velocity is varied from 10.13 m/s to 108 m/s. It is found that, in the presence of central jet, the mixing of lateral jets are delayed further downstream. In contrast, the central jet diffuses at a faster rate. At far-field locations, all the jets merge with each other and form a single jet, which can be seen from the uniformity of the radial velocity distribution. The turbulent intensity is found to be more at the jet periphery, where jets interact with the surrounding fluid. The temperature of the flame is found to be higher at the periphery of the methane and the oxygen jets, due to the existence of most appropriate equivalence ratio. Also, the flame lift-off height is found to be increasing with the jet velocity. The concentration of methane is reduced along the streamwise direction due to the penetration of combustion products towards the jet centerline.
Leakage and Windage Heating in Stepped Labyrinth Seals
Authors: Nayak Kali Charan , Kandaswamy Nomesh P. , Faheemulla Syed 
Published: January 2020

Abstract
Stepped labyrinth seals are used in multiple locations in the gas turbine with the intent to reduced leakage compared to straight labyrinth seals. However the selection of geometric factors in stepped labyrinth seals is critical to allow lower leakage in its operating envelope. Particularly the step height and axial position during the running condition play a vital role. The influence of these factors on the leakage, swirl development and windage heating in stepped labyrinth seal has not been thoroughly investigated in the previously published work. This paper focuses to study above effects with numerical simulations in a smooth four-fin stepped labyrinth seal. Specifically, a 2D axi-symmetric computational fluid dynamics (CFD) model is developed utilizing commercial finite volume-based software incorporating the standard k-ε turbulence model. Using this model, a broad parametric study is conducted by varying step height, axial position of the knife from the step, radial clearance and pressure ratio for a four-teeth stepped labyrinth seal. It has been observed that the seal leakage reduces with increase in step height to pitch ratio up to 0.35 and with further increase it tails off. The axial position of the tooth has strong influence on the flow structure and swirl development in the seal pocket.
Towards Visualisation of Capacity, Bearing Thrust Load and Reaction Variation With Aerofoil Skew in a Gas Turbine
Authors: Srinivasan Karthik , Bhaumik Soumyik K. , Valliappan Lakshmanan 
Published: January 2020

Abstract
The requirements in the design of aerofoils for gas turbines are not limited to only meeting the aerothermal performance. A typical scenario for a turbine is to understand the impact of aerofoil skew on capacity, reaction and bearing thrust load. A means to achieve the target capacity could be by skewing the aerofoil. This, however, changes the stage reaction which in turn impacts the bearing thrust load. In the case of a multi stage turbine, the work split between the stages impacts the ratio of pressure drops and hence the contribution of the individual aerofoil rows to the overall capacity and bearing thrust load variation. This paper deals with a generic approach to visualise the variation of capacity and bearing thrust load with aerofoil skew for a stage of interest along with the Constraints that could be potentially imposed on the stage.
This methodology provides a useful mapping between parameters which are directly under the aerodynamicist’s control (i.e. aerofoil skew) to module- and system-level behaviours (i.e. capacity, bearing thrust load). It thereby allows informed choices to be made throughout the design process which deliver the turbine aerodynamic performance targets whilst respecting wider system-level constraints. Suitable optimisation within this design space will yield a design that is fundamentally robust to small deviations in skew angle. Additionally, qualitative variation of the gas path static pressure and reaction based on aerofoil skews are explained pictorially to facilitate the understanding.
Comparison of Showerhead Jet Impingement Configurations on Leading Edge of a Gas Turbine Blade
Authors: Singh Alankrita , Prasad B. V. S. S. S. 
Published: January 2020

Abstract
Anemometry measurements are made on three novel, equilaterally staggered showerhead cooling configurations of jet impingement, for the leading edge of a gas turbine blade. In all the configurations, there are five jet impingement tubes in the form of a showerhead, wherein the central jet is circular and the remaining four neighboring jets have either circular or ±45° chamfer at one of its end. Flow characteristics of these jet configurations are analyzed by determining the mean velocity and the turbulent intensity of jets. The differences in the flow characteristics of these arrangements occur due to the changes in jet velocity profile and jet-to-jet interactions. The turbulent intensity is primarily responsible for augmentation in heat transfer of the test section. The uniform cooling of test section is represented by an “uniformity index” a high value of which is desirable for material durability. The Nusselt number is correlated with Reynolds number and turbulent intensity for all the three configurations.
Experimental Analysis of Vortex Induced Vibration in the Bladeless Small Wind Turbine
Authors: Thomai Micha Premkumar , Kharsati Lasoodawanki , Rama Samy Nakandhrakumar , Sivamani Seralathan , Venkatesan Hariram 
Published: January 2020

Abstract
Vortex-induced vibration is one of the predominant fundamental concepts for forced oscillation which attracts considerable practical engineering application for energy conversion. In this work, an oscillation of a mast arising as a result of wind force is utilized for energy conversion. The paradigm for energy conversion from vortex-induced vibration in the mast is the bladeless wind turbine. It consists of a rigid mass known as a mast, fixed in the spring of stiffness (k) and allowed to oscillate along the direction of the flow. In this work, four different types of mast have been fabricated and tested. The first is uniform tapered hollow conical mast (MAST1), the cross-section of the second is uniform tapered plus symbol (MAST2), the third is uniform tapered inversed plus symbol (MAST3) and the fourth is uniform tapered simple rectangular cross-section (MAST4). All the masts were fabricated using fiber carbon. The experiments were conducted in a versatile small wind turbine testing facility of Hindustan Institute of Technology and Science, Chennai. This test facility contained an open jet wind tunnel with variable frequency drive and other measuring instruments. The vibration sensor was located in the mast where it experienced a large oscillation in a free stream. In this experiment, an increase in wind velocity led to a terrible change in the amplitude of vibration. A vigorous oscillation was experienced in this mast at this critical frequency, when the natural frequency of the mast was synchronized with the frequency of the vortex shedding and the frequency of the oscillation of the mast. The total force in this oscillation was a summation of the body force due to the mass of the mast and vorticity force that is mainly which was the result of the shedding of the vortices. In this work, extensive studies have been carried out for Reynolds number ranging from 2.5 × 105 to 5.0 × 105. The mast length to diameter ratio of 13 was exposed to various speeds of wind and response was measured. The occurrence of the maximum oscillation in a simple rectangular mast was seen where vortex shedding due to the bluff body was large for constant mass and spring stiffness. The frequency of the oscillation at maximum amplitude of the rectangular cross-section mast was equal to the natural frequency, due to vortices shedding at critical velocity. This demonstrated the appropriateness of the simple rectangular cross-section for harnessing the low rated wind energy and its suitability for renewable energy conversion in the small bladeless wind turbine.