bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermodynamic Analysis and Performance Enhancement of Air and CO2 Based Compressed Gas Storage Systems
Authors: Dahiya Abhishek , Bhattacharya Jishnu , Banker Nitin D. 
Published: January 2020

Abstract
Due to the depletion of fossil fuels and their adverse effects on the environment, there is a need of hour to shift towards the renewable energy resources. However, the most promising renewable resources such as wind power and solar power are intermittent in nature. Thus, a sustainable shift requires economical and efficient energy storage systems. Use of batteries is the widely accepted storage systems for such resources and significant research work has been carried out in last few decades to improve the cycle life of batteries but they are still unsuitable for large scale systems and disposal of discarded batteries is also a major environmental concern. In view of this, researchers found compressed gas energy storage (CGES) system as one of the potential alternatives to store renewable energy at large spatial and temporal scales. The current study provides a comparison between air and carbon dioxide (CO2) based CGES systems from a thermodynamic standpoint. In an effort of improving efficiency of system, it is proposed to supply additional heat via renewable resource to CO2 based system before the expansion of gas in the turbine. The performance comparison of six different systems has been carried out using first and second law efficiencies.
Effect of Partial Texture on the Hydrodynamic Performance of Meso Scale Air Bearings for Mesoscale Turbo-Machines
Authors: Hingawe Nilesh , Bhore Skylab 
Published: January 2020

Abstract
In this paper, the hydrodynamic performance of surface textured meso scale air bearing is evaluated. The effect of texture position is investigated for circular shaped texture. Partially textured zones are modeled along the circumferential direction of the bearing. For this, numerical simulation is carried out using COMSOL Multiphysics 5.2 software. The compressible Reynolds equation is solved using the finite element method for a thin film model. In comparison with plane bearing, the significant improvement in load capacity is observed for textured bearing. Full texturing has obtained 12.80% more load capacity than the plane bearing. Among different partial texture positions, the convergent zone (0°–180°) showed the most promising result. It has obtained 14.02% and 1.25% more load capacity than the plane and fully textured bearings. Moreover, the texture position in the bearing is found to be sensitive. However, surface texture at the outlet of active pressure zone is found to be ineffective for improving load capacity of the bearing.
Numerical Simulation and Experimental Validation of Frequency Based Fault Detection and Localization in a Planetary Gearbox Under Dynamic Condition
Authors: Venkataram Nithin , K. Bhagavan Harish , Cadambi Rahul M. , R. Rao Arun 
Published: January 2020

Abstract
The planetary gearbox is often susceptible to faults under dynamic condition. Most of the literature assumes that gearboxes are free from defects. But in real-time working condition these assumptions are not accurate. Therefore the challenge lies in identifying and localizing a fault in planetary gearbox under dynamic condition. In this paper, the focus is on modelling and simulation of a fault in a planetary gearbox and validate the same with experimental tests. A planetary gearbox is modelled as per DIN standard and simulated for time and frequency domain signals. On comparing a fault free and fault induced frequency domain signals, a small peaks are observed on either side of the mesh frequencies, indicating the presence of a fault in the planetary gearbox. These peaks around the mesh frequencies are used to localize the fault in a planetary gearbox. Simulation results are validated with the experimental test results of the planetary gearbox under dynamic conditions. Similar trend is observed in simulation and experimental results.
On Effect of the Flare Angle on the Behaviour of the Flow Field of Twin-Radial Swirlers/High Shear Injector
Authors: Kumar Sonu , Chaudhuri Swetaprovo , Basu Saptarshi 
Published: January 2020

Abstract
The swirl flow in gas turbine combustor plays a major role in flame stabilisation and performance of engine. Since the swirl flow is very complex and boundary sensitive phenomena, it is difficult to interpret it properly. High shear injector is being used now a days in modern gas turbine combustor to generate the swirl flow and achieve better fuel atomisation in the combustion chamber. High shear injector accommodates a series of swirlers (primary and secondary) with a diverging flare at the exit and fuel nozzle mounted at the centre of the swirler.
In the present study it is tried to understand the influence of the flare angle on the non-reactive flow behaviour of the swirling spray flow-field generated through counter-rotating high shear injector. To perceive the influence of flare angle on the flow topology of the spray flow-field generated by a high shear injector, seven different flare half angles (β): 40°, 45°, 50°, 55°, 60°, 65° and 70° respectively were selected as a geometrical parameter to conduct the experiments. High-Speed Particle Image Velocimetry (HSPIV) technique was employed to perceive the topological structure of the spray flow field, mean and instantaneous behaviour of the velocity fields respectively. For all the cases mass flow of air and liquid (water) were kept constant. It was observed that with change in flare angle the size of the CTRZ, mean velocity and turbulent behaviour were also changing. Here the size of CTRZ is represented in terms of nondimensional radial width (W/Df) and height (H/Df) of the recirculation zone. The experiment was conducted without flare, initially and then subsequently with flares. It was found that both the radial width and the height of the recirculation zone were smallest for without flare case. With increase in flare angle the radial width and height of the CTRZ increases initially up to 60° flare angle and afterward decreased. The experiments made clear that flare angle has strong effect on the spray flow-field.
Application of Data Analytics in Gas Turbine Engines
Authors: Taluru Danteswara Rao , Allabanda Rajendra Prasad Uppara 
Published: January 2020

Abstract
In recent years, Aerospace technology has seen a paradigm shift towards Data analytics. Design, manufacturing, aftermarket and operations found importance of data analytics in reducing cost. Manufactures are developing Data Analytic based tools which help in optimizing their processes and reduce lead time. Engine, aircraft manufactures along with airliners are working together to improve customer experience. This paper, covers topics related to engine manufactures point of view. Engine manufactures can apply data analytics in concept initiation, concept optimization, preliminary, detailed and validation phases. Manufactures can optimize supply chain management using data analytics. Major gas turbine manufactures are persistent to enhance intelligence in aerospace product life cycle. Data analytics in aerospace engineering also helps in making predictions based upon descriptive patterns from huge data. Since, the aircraft industry is expecting a seven-fold increase in air traffic by 2050. The future demand of aircraft engine production would drive industries to adopt to big data in helping decision making and dynamic production capabilities. This paper helps in identifying different data analytics application in gas turbine product life cycle. Specifically in aero thermal discipline, which would help in increasing efficiency, optimizing design and result in reducing cost. This paper takes the reader through the application of gas turbine as a systematic and concise article. The future scope of the paper would include a test case explaining the application more in detail using data analytics.
Labyrinth Seal With Variable Height Teeth Tips for Efficient Leakage Control
Authors: Chougule Hasham , Naik Abhay , Qizar Mohd. 
Published: January 2020

Abstract
A modification of a conventional straight tooth labyrinth seal with variable tooth height is proposed. The baseline and modified labyrinth seal teeth with solid land are examined by three-dimensional CFD numerical modeling of the flow field and evaluated for predicting the leakage through the seal during the engine operation. Stocker’s [1] static labyrinth seal experimental data is used to validate the CFD methodology used in this paper. The baseline and the proposed modified design [2] — “Labyrinth seal with variable tooth heights” are numerically studied with solid lands and evaluated to measure the reduction in leakages. The objective of this study is to provide an improved sealing effectiveness by restricting the leakage flow and controlling the seal leakage during the operation of the engine. In this study, a conventional straight-through four-tooth labyrinth seal with solid land is used as the baseline model. It is first evaluated at different unworn constant radial gaps — between the teeth tips and solid land. In the proposed modification, the height of the intermediate teeth of the baseline four-tooth are varied. The teeth heights are designed in such a way that intermediate longer teeth form a very small or tighter radial gap at start of operation. The shorter ones are designed based on the expected wear groove/rub depth considered by the seal designer.
Results indicate that the proposed modification — Variable height teeth tips, reduce the seal leakage by over 50% compared to the baseline. The advantage of this modified design over a baseline seal is that at unworn or worn conditions, the teeth tips always forms a considerable tighter radial gap when compared with baseline seal. The achieved sealing is such that during engine operation of the seal, even if the seal gets worn, the overall leakage is significantly reduced.
Dynamic Parameters Estimation and Fault Identification From Random Response of Rolling Element Bearing in a Rotor Bearing System
Authors: Kumar Pankaj , Narayanan S. , Gupta Sayan 
Published: January 2020

Abstract
This paper presents a procedure for determination of dynamic properties of rolling element bearing by using the vibration signals picked up at the bearing caps. The rotor-bearing assembly is idealized as Duffing oscillator and random vibration signals modelled as exponentially correlated (Ornstein-Uhlenbeck) colored noise. Expressing the excitation as a first order filtered white noise enables the direct formulation of the 3D-Fokker Planck (FP) equation for system response through the Markov vector approach. Closed form solution of the stationary FP equation is derived. Subsequently the response statistics of experimentally obtained random vibration signal are processed through the closed form solution of the FP equation as the inverse process of parameters estimation from the measured response. Further, the dynamic behavior of rigid rotor-bearing system is investigated under combined excitation of white noise and harmonic forces arising due to rotor unbalance force. The effect of system nonlinearities, stiffness, damping and unbalanced excitation force on the dynamic response are investigated using the bifurcation plot. For assessment of structural degradation of bearings, a novel entropy based approach is developed. Experimental studies on roller bearing are carried out to demonstrate the effectiveness of the proposed approach.
Energy and Exergy Analysis of a Gas Turbine Power Plant Integrated With Vapor Adsorption Refrigeration System
Authors: Agarwal Sanchit , Gupta Darshika , Dandotiya Devendra , Banker Nitin D. 
Published: January 2020

Abstract
In the step towards the utilization of waste energy of Gas Turbine (GT) power plant exhaust gas, researchers have imposed adsorption refrigeration system over the absorption refrigeration due to several positive advantages. In the reported work, the system was analyzed based on first law efficiency. However, combining heat and work together for an evaluating system using first law efficiency would not provide a true picture of the performance of the system, whereas second law efficiency shows various irreversibilities associated with each component of the system and helpful in obtaining the optimum conversion of energy. In view of this, the presented paper studies performance analysis of GT power plant incorporated with the adsorption refrigeration system. Based on the parameters such as energy and exergetic efficiencies, cooling to power ratio and exergetic specific fuel consumption are considered for the system performance evaluation.
A Study of Flow Behaviour in Radial and Mixed Flow Turbines With Variable Nozzle Vanes for a Turbocharger
Authors: Kannan Ramesh , Prasad Bhamidi , Koppa Sridhara 
Published: January 2020

Abstract
A mixed flow turbine with variable nozzle vanes is developed along with its radial counterpart for the wheel size of about 30 mm, suitable for turbocharger of 1.5 lit. engine capacity. In order to understand the flow behaviour inside the turbines, computational fluid dynamics studies are conducted for both the radial and mixed flow turbines. Flow through the turbine stage is discussed with velocity distribution in the meridional plane. In addition, the loss coefficients for the nozzle vanes and turbine wheel are estimated. At nozzle vanes opening of 50% mass flow parameter and for the turbine expansion ratio of 1.5, the flow velocities at the exit of the nozzle vanes are found to be about 120 to 170 m/s for the radial flow turbine and 150 to 180 m/s for the mixed flow turbine. Higher level of uniformity in flow is also observed for mixed flow turbine stage compared to the radial. The maximum Mach number is observed on the middle of the turbine wheel, and the same is less than unity for both the turbines. Both the nozzle and rotor loss coefficients for mixed flow turbine are lower than the values observed for the radial flow by about 6% and 15% respectively.
Effect of Various Trench Designs on Axial Compressor Blade Tip Aerodynamics
Authors: Ashok Ashwin , Sidhartha Patur Ananth Vijay , Sivadasan Shine 
Published: January 2020

Abstract
Tip clearance of axial compressor blades allows leakage of the flow, generates significant losses and reduces the compressor efficiency. The present paper aims to discuss the axial compressor tip aerodynamics for various configurations of tip gap with trench. The various configurations are obtained by varying the clearance, trench depth, step geometry and casing contouring. In this paper the axial compressor aerodynamics for various configurations of tip gap with trench have been studied. The leakage flow structure, vorticity features and entropy generations are analyzed using RANS based CFD. The linear compressor cascade comprises of NACA 651810 blade with clearance height varied from 0.5% to 2% blade span. Trail of the tip leakage vortex and the horseshoe vortex on the blade suction side are clearly seen for the geometries with and without casing treatments near the stalling point. Since the trench side walls are similar to forward/backing steps, a step vortex is observed near the leading edge as well as trailing edge of the blade and is not seen for the geometry without the casing treatment. Even though the size of the tip leakage vortex seams to be reduces by providing a trench to the casing wall over the blade, the presence of additional vortices like the step vortex leads to comparatively higher flow losses. An increase in overall total pressure loss due to the application of casing treatment is observed. However an increase in stall margin for the geometries with casing is noted.
Simulation of CO Emission in Primary and Secondary Zone of a Small Gas Turbine Combustion Chamber Using CFD and Reactors Network
Authors: Zubrilin Ivan A. , Gurakov Nikita I. , Semenikhin Alexander S. , Kolomzarov Oleg V. , Matveev Sergey G. , Anisimov Vladislav M. 
Published: January 2020

Abstract
In this paper the influence of various parameters of the primary and secondary zones of a small-sized combustion chamber on its environmental characteristics was studied. The study of the environmental characteristics of the combustion chamber was carried out in two ways. The first method consisted of two steps. The first step was a 3D simulation of combustion processes using FGM combustion model. The second step was based on results of the first step using reactors network implemented in the ANSYS Fluent 18.2 software. The construction of the reactors network in this approach occurred automatically according to a temperature and mixture fraction. The number of reactors in the result was about 500. The second method was a simple model of a reactors network in which the primary zone was simulated by a perfectly stirred reactor, and the secondary zone was a plug flow reactor. Methane was used as a fuel. The influence of the residence time of the mixture and fuel-air equivalence ratio in each zone on the emission of CO and NOx at the combustion chamber exit was studied. The residence time and fuel-air equivalence ratio for the first method were changed using the design parameters of the combustion chamber. For a simple reactors network, these parameters are set as input data, so this method can be used at the preliminary design stage. As a result of the work, a method was obtained that allows to find the parameters of the primary and secondary zones of the combustion chamber in order to minimize pollutant emissions at the preliminary design stage.
Investigation of a Variable Geometry Turbine Nozzle for Diesel Engine Turbochargers
Authors: Srivastava Anuj , Kumar Kuldeep , Banda Ganesh 
Published: January 2020

Abstract
High power demand, emission regulations, high efficient design are the prime requirement for the design of turbochargers. VGT (variable geometry turbocharging) is most widely used and explored compared to other available options to deal with today’s market. VGT turbochargers offers several potential benefits when compared to fixed geometry turbochargers, like increased transient response, wide operating range, improved torque characteristics, boost pressure recovery and better fuel economy. In this paper performance variation of compressor and turbine viz, — Pressure ratio, mass flow, and efficiency, and throat area are optimized to reach to the operating point of the engine. Different vane angles (0, +4°, +7°, +10° & +15°) are studied to understand the variation of transient turbine response. Authors also discussed the mechanical conceptualization of the VANT (Variable area nozzle) in thought of having great impact on the performance.
Liquid Atomization in a High-Speed Slinger Atomizer
Authors: Chakraborty Arnab , Sahu Srikrishna 
Published: January 2020

Abstract
The present research aims to investigate the liquid atomization process in a slinger atomizer test rig that houses a high-speed motor which allows high rotational speed of the slinger disc. Instead of delivering the liquid directly on the slinger disc, which is commonly reported in the literature, a stationary manifold was designed that receives the liquid from the pump and supply multiple liquid jets that impinge on the rotating slinger disc. The liquid jet breakup process was visualized using front light illumination technique. All experiments were performed using water as the working fluid and under atmospheric conditions. Four different water flow rates, ranging from 0.2 lpm up to 0.8 lpm were considered. The rotational speed of the slinger was varied from 5000 rpm up to 30000 rpm, which has been rarely reported in the past. The paper reports a comprehensive study on the differences in the liquid breakup modes due to higher liquid flow rate for the same rotational speed and vice-versa. Mostly the liquid was found to attach to the side of the slinger holes that is opposite to the direction of rotation indicating the strong influence of Coriolis forces on the liquid flow within the slinger and hence the atomization process. The droplet size in the spray was measured using the Interferometric Laser Imaging for Droplet Sizing (ILIDS) technique.
Experimental Study of Flow Field Effect on Spray and Flame Structure in Swirl Stabilized Combustor
Authors: Murugan Raju , Sellan Dhanalakshmi , Kolhe Pankaj S. 
Published: January 2020

Abstract
The spatial distribution of spray plays a key role in liquid fuel combustion, which dictates the local mixture fraction and the flame temperature distribution in gas turbine engines. The swirling flow creates further decomposition of the spray droplets in liquid fuel gas turbine engine, which increases the surface area of the droplets. Turbulent mixing due to the swirling flow is essential for preheating of unburned products and flame holding in the combustor. A lab-scale swirl stabilized liquid fuel combustor was designed and fabricated with the geometric swirl number (SN) of 1. Combustor flow geometry involves internal spray from flow blurring twin-fluid atomizer, surrounded by swirling airflow which is confined with co-flow air to provide full optical access. At constant spray operating conditions, the swirl Reynolds number (Re) is increased whereas co-flow velocity was maintained constant at 0.4 m/s. An experimental study was carried out to understand the effect of Reynolds number on the aerodynamic structure of airflow, the spatial distribution of spray structure and kerosene flame structures using Particle Image Velocimetry (PIV) and direct imaging. The experimental results show that the flow structure and spray spreads radially with the increase in swirl Reynolds number and the corresponding core spray height decreases, which were evident from flame images.
Enclosure Phenomenon in Varying Forced Flow Convection
Authors: Bhatia Ribhu , Supriya Dash Sambit , Malhotra Vinayak 
Published: January 2020

Abstract
Systematic experimentation was carried out on forced convection heat transfer apparatus under varying non-linear flow conditions to understand the energy transfer as heat, with the purpose of enhancing performance of numerous engineering applications.
Plate orientations, types of enclosures (solid, meshed, perforated), flow velocity variations etc. are taken as governing parameters to effect convective heat transfer phenomenon which is perceived as deviations in value of heat transfer coefficient. RV zonal system is utilized to simplify the fundamental understanding of heat transfer coefficient variation with surface orientation under varying flow field. The objectives of this work are as follows:
1) To establish relative effectiveness of forced convective heat transfer under varying flow field.
2) To investigate the implications of varying shapes and sizes of perforations on confined forced convective heat transfer.
To understand the controlling mechanism and role of key controlling parameters.