bluuebunny/crossref_metadata_2025 huggingface dataset:
Reflections on Persimals
Authors: Schechtman Marya
Published: July 2014

Steven Luper offers richly‐textured arguments against the Embodied Part View developed by Jeff McMahan and offered as an answer to the “too many thinkers” problem. One of the major objections he raises is connected to McMahan's claim that the mind, and so the person, is to be identified with the part of the brain in which consciousness is directly realized. This view has the implausible consequence, Luper argues, that persons do not and cannot think or reason or have desires or interests. While this is indeed a worrisome consequence, it is not clear that McMahan is committed to the understanding of what constitutes “the part of the brain in which consciousness is directly realized” that Luper attributes to him. Making reference to McMahan's Theory of Time‐Relative Interests, I develop an alternate way of reading this phrase, one which avoids the difficulties Luper raises. I acknowledge that my understanding yields a view that, while formally consistent, is unattractive in a variety of ways. I suggest, however, that this should not be taken as a reason to favor animalism, since animalism has its own difficulties, which are not entirely unlike those faced by the Embodied Part View.
Brains, Neuroscience, and Animalism: On the Implications of Thinking Brains
Authors: Gillett Carl
Published: July 2014

The neuroscience revolution has led many scientists to posit “expansive” or “thinking” brains that instantiate rich psychological properties. As a result, some scientists now even claim you are identical to such a brain. However,EricOlson has offered new arguments that thinking brains cannot exist due to their intuitively “abominable” implications. After situating the commitment to thinking brains in the wider scientific discussions in which they are posited, I then critically assessOlson's arguments against such entities. Although highlighting an important insight, I show thatOlson's objections to the existence of thinking brains fail and that a wider discussion engaging our new empirical findings is actually required in order to resolve the deeper issues.
Conceptualization and Assessment of Multiple Forms of Social Withdrawal in Turkey
Authors: Bayram Özdemir Sevgi , Cheah Charissa S. L. , Coplan Robert J.
Published: July 2014

We examined the meaning, assessment, and implications of different forms of social withdrawal in Turkey across two studies. In study 1, semi‐structured interviews were conducted with children, mothers, and teachers to identify descriptors of social withdrawal. Shyness and unsociability were confirmed through content analyses, and regulated withdrawal, a new subtype characterized by overregulation of behaviors and suppression of own desires during social interactions, was revealed. Based on these findings, the child social preference scale, an established North American measure of social withdrawal, was revised. In study 2, a confirmatory factor analysis on a sample of 599 9–11‐year‐old children revealed three distinct forms of social withdrawal. Shyness was related to a wider range of child adjustment difficulties than unsociability and regulated withdrawal, although all forms of withdrawal were associated with child adjustment difficulties, providing support for the importance of children's active involvement in social relationships for their positive development and well‐being.
Malignant mesenchymoma with widespread metastasis including bone marrow involvement in a dog
Authors: Weishaar Kristen M. , Edmondson Elijah F. , Thamm Douglas H. , Olver Christine S.
Published: July 2014

A male castrated Golden Retriever was presented for evaluation of a large mass over the left shoulder extending to the lower part of the neck that had been present for an extended period of time, but had a recent history of rapid growth. Previous aspirates of the mass were consistent with a lipoma. The mass was surgically excised and was diagnosed as an extraskeletal osteosarcoma based on histopathology. After surgery, the dog was initiated on a chemotherapy protocol with carboplatin and metronomic cyclophosphamide. He became neutropenic, anemic, and thrombocytopenic 14 days after the carboplatin treatment was administered. The neutropenia resolved, but the anemia and thrombocytopenia progressed. A bone marrow aspirate revealed erythroid hypoplasia, myeloid hyperplasia with a predominance of early precursors, and a subset of cells that made up 20% of the total population that were reported as bizarre and unclassifiable. These cells were discrete in nature and were thought to be hematopoietic in origin. The dog was euthanized due to deterioration of the clinical condition. On postmortem examination, widespread metastasis involving the lungs, liver, kidney, heart, and bone marrow was found. Histopathology of the tumor lesions determined 2 distinct malignant populations of liposarcoma and osteosarcoma, consistent with malignant mesenchymoma. However, the possibility of 2 separate neoplastic processes cannot be definitively excluded. This is the first report of bone marrow metastasis of a malignant mesenchymoma in a dog.
Overview of Enhanced Continuum Theories for Thermal and Mechanical Responses of the Microsystems in the Fast-Transient Process
Authors: Voyiadjis George Z. , Faghihi Danial
Published: July 2014

The recently growing demand for production and applications of microscale devices and systems has motivated research on the behavior of small volume materials. The computational models have become one of great interests in order to advance the manufacturing of microdevices and to reduce the time to insert new product in applications. Among the various numerical and computational techniques, still the approaches in the context of continuum theories are more preferable due to their minimum computational cost to simulation on realistic time and material structures. This paper reviews the methods to address the thermal and mechanical responses of microsystems. The focus is on the recent developments on the enhanced continuum theories to address the phenomena such as size and boundary effects as well as microscale heat transfer. The thermodynamic consistency of the theories is discussed and microstructural mechanisms are taken into account as physical justification of the framework. The presented constitutive model is calibrated using an extensive set of microscale experimental measurements of thin metal films over a wide range of size and temperature of the samples. An energy based approach is presented to extract the first estimate of the interface model parameters from results of nanoindentation test.
Revisiting the Inhibition of Vanadium-Induced Hot Corrosion in Gas Turbines
Authors: Rocca Emmanuel , Steinmetz Pierre , Moliere Michel
Published: July 2014

Since the 70’s, nothing substantially new has been published in the Gas Turbine Community about the hot corrosion by vanadium and its inhibition, after the “inhibition orthodoxy” based on the formation of magnesium vanadate, was established. However, the experience acquired since the late 80’s with Heavy Duty Gas Turbines burning ash-forming fuels in Southern China, shows that the combustion of very contaminated fuels does not entail corrosion nor abundant ash-deposit on gas turbines buckets. Analyses of deposits collected from gas turbines fired with these crude oils showed that the ash-deposit contains a large amount of nickel.

These new facts led to revisit the role played by nickel and envisage its possible inhibiting action against the vanadium-induced hot corrosion. A thorough review of the literature on the vanadium-induced corrosion have been carried out, and the study of the nickel effects with respect to magnesium effects on the ash deposit have been performed

Results show that nickel presents an interesting way to substitute magnesium for the inhibition of vanadium-induced hot corrosion. The advantages of nickel with respect to magnesium are to be efficient at a low Ni/V ratio, to produce less abundant, less adherent ash and to act, to some extent, as a self-cleaning agent for the blades of the turbine.
Materials Compatibility With Pyrolysis Biofuel
Authors: Kirk D. W. , Li Z. R. , Fuleki D. , Patnaik P. C.
Published: July 2014

The conversion of biomass such as wood and wood byproducts via pyrolysis into a liquid fuel is important in maximizing the use of material resources and in providing alternative and renewable sources of energy. Pyrolysis oils (or biofuels) have good combustion characteristics but are compositionally different from conventional diesel fuels. This difference requires that materials in contact with the biofuel be tested for compatibility. Three types of biofuels were tested for compatibility with a variety of polymeric materials and metal alloys. The test temperatures were set at 80°C to represent aggressive field usage conditions. The tests were conducted using coupons, which were fully immersed in the fluid for periods up to 15 days.

These tests revealed that the metals 304L stainless steel, 316L stainless steel, 430 stainless steel and 20M04 stainless steels had corrosion rates of less than 0.007 mm/y and are suitable for use with the oils tested. A non-traditional low chromium alloy steel, MASH, was also examined and was found to be highly susceptible to all fuels at the high temperature tested and corroded at rates up to 3.7 mm/y. At room temperature, the alloy showed good resistance with a corrosion rate less than <0.009 mm/y.

The polymeric materials showed a wide range of properties in the oils tested. Non-elastomers such as polytetrafluoroethylene, polypropylene and high-density polyethylene in general showed little swelling or staining in the oils. The elastomeric materials were much more susceptible to swelling, weight gain and change of surface properties. The attack on elastomeric materials was quite rapid with significant volume expansion seen within 24 hours. Viton, Buna-N and EPDM had volume changes up to 100% during a 10-day test and were not considered suitable seal materials for these oils.

Multiple day tests for the low alloy steel at 80°C revealed that the corrosion attack was linear in nature leaving a corrosion scale, which slowed but did not prevent further attack. Details of the material degradation will be discussed.
Effects of Fuel Composition on Flammability Limit of a Lean Premixed Combustor
Authors: Wicksall Donald M. , Agrawal Ajay K.
Published: July 2014

Fuel flexibility is desired in advanced power generating gas turbines operating in the lean premixed combustion mode. In this study, experiments were performed in a lean premixed, swirl-stabilized combustor operated at atmospheric pressure to quantify how adding liquid petroleum gas (LPG), hydrogen, oxygen, nitrogen, and carbon dioxide to natural gas (NG) affected the flame stability. The flame extinction characteristics were obtained for NG fuel mixtures with up to 40% by volume of the indicated gases. The combustion air was supplied at room temperature and the fuel-air mixture was fully premixed before reaching the combustor. The total fuel-air flow rate was varied by a factor of two to achieve a range of aerodynamic conditions. Results demonstrate that additions of hydrogen and oxygen to NG extended the stable operating range of the combustor. Addition of LPG to NG had a slightly adverse effect while the non-reactive species in the NG did not affect the lean flammability limit.
A Novel Correction Technique for Simple Gas Turbine Parameters
Authors: Assadi Mohsen , Mesbahi Ehsan , Torisson Tord , Lindquist Torbjörn , Arriagada Jaime , Olausson Pernilla
Published: July 2014

Data normalization for gas turbines is necessary for comparison of test data collected at various environmental conditions. The normalization procedure is regulated by the ISO-standard. In this study, a single Artificial Neural Network is used to model the performance of a simple gas turbine (VT600) using measured data at various environmental and operational conditions. Consequently, engine performance maps covering a wide range of operational and environmental conditions have been generated. Comparison of the normalized/experimental data, results provided by thermodynamic models using heat and mass balance programs and results generated by the Artificial Neural Network (ANN) model shows a high level of consistency. The study presented here was performed as a pilot study, to investigate the applicability of an ANN model for data normalization applied to an Evaporative Gas Turbine (EvGT), since the ISO-standard normalization procedure is not applicable to the EvGT plant. Results of this work show that Artificial Neural Networks are powerful tools for performance prediction as well as generation of accurate power plant model of an specific simple gas turbine, and that data normalization can easily and accurately be carried out by using these performance maps.
A Parametric Investigation of the Diagnostic Ability of Probabilistic Neural Networks on Turbofan Engines
Authors: Romessis C. , Stamatis A. , Mathioudakis K.
Published: July 2014

Fault identification through the use of Artificial Neural Networks has become very popular recently. Probabilistic Neural Networks (PNN) is one of the architectures, which have mostly been investigated for gas turbine diagnostics. In this paper, the influence of parameters related to the structure and training on the diagnostic performance of a probabilistic Neural Network (PNN), is investigated. In particular, the parametric investigation examines the effect of the training set on the diagnostic performance of a PNN. The effect of noise level was also examined and found to be important. Another parameter examined is the severity of a fault, which was found to affect seriously the performance of the diagnostic PNN. Other parameters also examined are the effect of the operating conditions as well as the considered output parameters of the network. Guidelines useful for setting up this type of network, are derived.
Data Rectification and Detection of Trend Shifts in Jet Engine Gas Path Measurements Using Median Filters and Fuzzy Logic
Authors: Ganguli Ranjan
Published: July 2014

Filtering methods are explored for removing noise from data while preserving sharp edges that many indicate a trend shift in gas turbine measurements. Linear filters are found to be have problems with removing noise while preserving features in the signal. The nonlinear hybrid median filter is found to accurately reproduce the root signal from noisy data. Simulated faulty data and fault free gas path measurement data are passed through median filters and health residuals for the data set are created. The health residual is a scalar norm of the gas path measurement deltas and is used to partition the faulty engine from the healthy engine using fuzzy sets. The fuzzy detection system is developed and tested with noisy data and with filtered data. It is found from tests with simulated fault free and faulty data that fuzzy trend shift detection based on filtered data is very accurate with no false alarms and negligible missed alarms.
Simulation of the WR-21 Advanced Cycle Engine
Authors: Biraud Benoit , Despierre Arnaud , Gayraud Stephane
Published: July 2014

Representative simulation of gas turbine operation has to be performed by engine manufacturers during engine development programs for a number of reasons, including technical risk mitigation, safety analysis and cycle optimisation.

Minimisation of Specific Fuel Consumption (SFC) is the main challenge faced by the WR-21 engine, an intercooled and recuperated gas turbine which is at the forefront of future naval propulsion systems. Steady state simulation tools need to be developed to accurately predict engine performance under any set of environmental conditions. The methodology used involves an integrated “analysis-synthesis” simulation technique where extensive test data analysis is built into a full thermodynamic model of the engine.

Simulation of the gas turbine behaviour under transient conditions is also required to ensure maximum operability through optimised control, and gas turbine stability under any circumstances. For the WR-21 engine this simulation capability has been developed in both Real Time (RT) and Non-Real Time (NRT) modes. This process is particularly challenging for such an advanced cycle gas turbine where the number of components, and their thermodynamic interaction, is far greater than for a simple cycle prime mover.

This paper examines how these challenges have been successfully overcome by the WR-21 project. It describes the tools and techniques that have been developed in the project, and exemplifies their application through demonstration of significant technical achievements.

It also expands on the strategic issue of model flexibility and connectivity, and elaborates on future developments in simulation techniques, that will drive the naval gas turbine industry towards continual process improvement, ever closer to its customers.
Code-in-the-Loop Simulation for Embedded Software Development
Authors: Jaw Link C. , Wu Dong N.
Published: July 2014

Control or monitoring logic development typically follows the process of model building, analysis, design, and (nonlinear) simulation. After the logic is verified in computer simulation, the corresponding embedded control or monitoring code is generated and downloaded to the controller’s microprocessor. Then a hardware-in-the-loop (HITL) simulation is conducted to verify the logic and the controller interface. Although this process is well established, the requirements for real-time simulation and hardware/software integration often pose a high risk in the embedded software development process. This risk can be mitigated by the code-in-the-loop (CITL) simulation methodology presented in this paper.

This CITL simulation methodology has been applied to a software update of the full-authority digital engine control (FADEC) unit for the Honeywell (formerly AlliedSignal) Universal Jet Air Starter Unit (UNIJASU), which is a gas turbine engine packaged as an auxiliary power unit to jump start aircraft engines on the ground. The CITL simulation, although non-real time, successfully predicted the effects of several control logic options and facilitated the implementation of software update. Hence we recommend that the CITL simulation be incorporated in the embedded control software development process to shorten software update time. We further recommend that CITL be a necessary step in the process if HITL simulation is not feasible.
Modal Analysis of Annular Combustors: Effect of Burner Impedance
Authors: Krebs Werner , Walz Günther , Flohr Patrick , Hoffmann Stefan
Published: July 2014

For the development of modern Low-NOx gas turbine combustors featuring high power densities due to their compact design a detailed knowledge about thermoacoustically induced combustion oscillations is required. In order to design passive and active means to suppress thermoacoustic oscillations and to extend the stable operation range of the gas turbine an investigation of the acoustic eigenmodes of the combustor already in the design phase is necessary. In a combined experimental and computational project, tools to determine the mode shapes of a gas turbine combustor have been developed. The mode shapes of an annular combustor of the 3A series have been identified under operating conditions in the test bed of Berlin by cross correlating pressure signals mounted on twelve different azimuthal locations. These data have been used in order to validate the new numerical steady state response method. It has been found that taking into account appropriate acoustic boundary conditions at the burner outlet the numerical predictions are in good agreement with the measurements.
Performance of a Dry Low-NOx Gas Turbine Combustor Designed With a New Fuel Supply Concept
Authors: Wakabayashi Tsutomu , Ito Seiichi , Koga Shonosuke , Ippommatsu Masamichi , Moriya Koji , Shimodaira Kazuo , Kurosawa Yoji , Suzuki Kazuo
Published: July 2014

This paper describes the performance of a dry low-NOx gas turbine combustor designed with a new fuel supply concept. This concept uses automatic fuel distribution achieved by an interaction between the fuel jet and the airflow. At high loads, most of the fuel is supplied to the lean premixed combustion region for low-NOx, while at low loads, it is supplied to the pilot combustion region for stable combustion.

A numerical simulation was carried out to estimate the equivalence ratio in the fuel supply unit. Next, through the pressurized combustion experiments on the combustor with this fuel supply unit using natural gas as fuel, it was confirmed that NOx emissions were reduced and stable combustion was achieved over a wide equivalence ratio range.
Autoignition Characteristics of Gaseous Fuels at Representative Gas Turbine Conditions
Authors: Goy C. J. , Moran A. J. , Thomas G. O.
Published: July 2014

The autoignition properties of gas turbine fuels have been studied for many years and by numerous researchers. The advent of ultra low emission industrial gas turbines using lean premixed technologies has given rise to premixer designs with longer residence times. This, in conjunction with the ever-increasing pressure ratios of aeroderivative machines, leads to the potential for autoignition within premix ducts, and has therefore renewed the interest in this field. Although much has been published, data in the region of interest to high pressure ratio gas turbines is extremely sparse. Similarly, modelled autoignition delay times are not very accurate, as most reaction mechanisms were not generated to cover this range of conditions. Hence the uncertainties of autoignition delay times at gas turbine conditions are significant, thereby either imposing over-stringent design limitations or introducing risks of ignition occurrence in the early design process.

A series of experiments have been carried out for methane and simulated natural gas fuels in the region of interest, using shock tubes as the test vehicle. The experimental technique was chosen to isolate only the chemical kinetic component of the autoignition delay time, without any additional delays due to mixing and heating of the test gases. Predictive correlations and a chemical kinetic model (the GRI mechanism) have also been used to predict autoignition delay times at the same conditions. The correlation between experiment and prediction has been shown to be poor at representative temperatures. This paper discusses some of the possible explanations for this poor agreement.
Commissioning of a Test Rig for Auto-Ignition Delay Time Measurements on Kerosene Based Fuel Paper
Authors: Cheung W. S. , Tilston J. R.
Published: July 2014

A thorough understanding of the auto-ignition process is critical to the success of lean premixed prevapourised (LPP) combustors for future ultra-low NOx emissions gas turbines. A considerable amount of work has been done in the past on auto-ignition delay time (ADT) measurements for various aviation fuels and hydrocarbons. However, little was known about the influence of various possible fuel additives on ADT. A test rig was designed and built by DERA specifically for ADT measurements. It consisted of an injector housing and an instrumented duct where the ignition location could be monitored by fibre optic sensors. It was intended to acquire ADT measurements at 875K, 16bar and 40m/s of mean flow. The test rig and instrumentation were commissioned in January and February 2000. However, instrumentation inside the injector housing was damaged soon after the initial hot run as a result of overheating. Attempts were made to repair the damaged components and to identify the cause of overheating. Unfortunately, the damage to the components was extensive and the cause of overheating could not be diagnosed. In view of the technical risks involved, it was decided to stop further testing with this rig. Although ADT measurements could not be undertaken as planned, useful operating experience was gained from the tests conducted.
Prediction of Premixed Laminar Flame Structure and Burning Velocity of Aviation Fuel-Air Mixtures
Authors: Kyne A. G. , Patterson P. M. , Pourkashanian M. , Wilson C. W. , Williams A.
Published: July 2014

The structure of a rich burner stabilised kerosene/O2/N2 flame is predicted using a detailed chemical kinetic mechanism where the kerosene is represented by a mixture of n-decane and toluene. The chemical reaction mechanism, consisting of 440 reactions between 84 species, is capable of predicting the experimentally determined flame structure of Douté et al. (1995) with good success using the measured temperature profile as input. Sensitivity and reaction rate analyses are carried out to identify the most significant reactions and based on this the reaction mechanism was reduced to one with only 165 reactions without any loss of accuracy. Burning velocities of kerosene-air mixtures were also determined over an extensive range of equivalence ratios at atmospheric pressure. The initial temperature of the mixture was also varied and burning velocities were found to increase with increasing temperature. Burning velocities calculated using both the detailed and reduced mechanisms were essentially identical.
Primary Jet Characteristics Within an Isothermal Gas Turbine Combustor
Authors: Carrotte J. F. , Griffiths J. P. , Spencer A.
Published: July 2014

A detailed experimental investigation has been undertaken into the isothermal flow field within a modern gas turbine annular combustor. In this paper data is presented which demonstrates the strong coupling that exists between the flow conditions within each feed annulus, that surround the flame tube, and the jets formed within the flame tube by the primary and secondary ports. The initial pitch angle of the jets, port discharge coefficient and the jets axial and radial momentum were influenced by well known bulk property variations, but also by less well known local conditions feeding the port. Furthermore, this strong coupling meant that differences were apparent in the initial conditions of each jet due to local variations in the feed annulus velocity profile. In most cases these differences, between opposing jets, affected the location of their impingement point and the fluid trajectory after impingement. However, for the primary jets in line with the fuel injector a dramatically increased sensitivity to feed conditions was displayed, caused by the low pressure associated with the swirling injector flow. This caused the jets to be deflected in opposite directions with no impingement. Numerical predictions were also used to demonstrate the coupling between the jets and the internal pressure field within the flame tube. Furthermore, the experimental data has implications as to how, in general, such numerical predictions should be conducted if the interactions between the flame tubes external and internal flow fields are to be accurately captured.
Scaling From Atmospheric Pressure Rig to Full-Scale Pressure for the Emission Measurements From a Gas Turbine Combustor
Authors: Martelli F. , Riccio G. , Benelli G. , Cecchini D. , Carrai L.
Published: July 2014

Investigating the pressure scalability of pollutant emissions from a heavy-duty diffusion flame type, natural gas fuelled gas turbine combustor a two steps approach is presented in the current paper. First a theoretical viewpoint is established using similitude theory to characterize the operation conditions chosen for atmospheric tests in relation to the real gas turbine pressurized conditions. Then the corresponding experimental tests are presented for the full-scale gas turbine combustor in the original version both under atmospheric and pressurized gas turbine conditions at the ENEL test facilities.

The results from the theoretical study indicate, that similitude cannot be maintained rigorously between the atmospheric and pressurized tests. However the experimentally determined NOx-emissions obtained under the reduced similarity test conditions provide a pressure scaling relation that can be maintained between the original and the retrofitted version of the combustor.
Carbon Deposits in Gas Turbine Injectors
Authors: Tidjani N. , Martin G. H. , Ropital F. , Grienche G. , Verdier H.
Published: July 2014

The formation of carbon deposits in gas turbines is a recurring problem to which a lot of important work has been dedicated. These deposits cause a lot of problems and have a direct impact on the performance of gas turbines both from an environmental point of view and on the energetic efficiency and on hot parts life. In the combustion chambers of gas turbines, two different types of deposits may appear, one inside the fuel injectors and the other in the flame tube. The understanding of the formation of these deposits as well as their characterization is of up most importance for the design of the combustion chambers of gas turbines.

The study presented in this paper summarizes the recent work carried out in IFP (Institut Français du Pétrole) on the formation of these deposits on the materials currently used in the design of the combustion chambers and injectors of gas turbines. A micro-pilot thermogravimetric unit operating at cracking temperatures to the order of 900°C allows us to define the parameters influencing the formation of these deposits. Thus, the influence of the nature of the material, of the composition of the charge and of the operating conditions (temperature, flow rate,…) on the formation of the deposits and their morphology was shown. This work was carried out by testing a turbine injector during several hours on a test bench reproducing the working conditions of medium power industrial gas turbine. Different physico-chemical characteristics of common turbine fuels have been tested in an inert atmosphere. The characterization of the deposits (obtained with an electronic microscope), shows their morphology, as well as their elementary composition.

For different fuels and various operating conditions, this work allows also to compare different types of materials used in the construction of gas turbines.
Coke Removal in Fuel-Cooled Thermal Management Systems
Authors: Huang He , Spadaccini Louis J.
Published: July 2014

The extent to which the benefits of hydrocarbon fuel cooling technology can be realized depends on our ability to manage coke deposits. The coke deposits, which may form in heat exchangers, reactors and on inside surfaces of fuel system components, degrade heat transfer, catalyst activity, and fuel flow characteristics and can lead to system failure. Therefore, in situ regeneration of fouled surfaces was investigated as a practical approach for reducing the impact of coke formation on aircraft thermal management systems.

Thermogravimetric analysis (TGA) was used to evaluate various surface regeneration techniques (such as carbon burnoff in air or oxygen and carbon gasification using CO2 or steam) and to compile a database for kinetics analysis. The most practical technique for in situ surface regeneration of heat exchangers and reactors is the carbon burnoff method. Although the burnoff method is simple and cost-effective, care must be taken to control strong exothermic reactions. For this reason, a kinetics model and a computer simulation have been developed to guide the selection of the key operating variables (i.e., temperature, pressure, and time) for the in situ regeneration method. A surface regeneration simulator was constructed and used to assess the effectiveness of the in situ regeneration techniques and validate the kinetics model. Use of the computer simulation tool in a real application to specify the conditions for removing coke deposits from a fouled heat-exchanger/reactor panel from a scramjet test engine is discussed in the paper.
Redesign of N2 Injection System for Gas Turbines in Integrated Gasification Combined Cycle Applications
Authors: Arar Malath I.
Published: July 2014

Gas Turbines (GT) applied to integrated gasification combined cycle (IGCC) power plants utilizing Nitrogen injection to reduce emission and increase power output. This redesign process reduced the customer’s equipment and the operational cost for GT’s with Nitrogen injection. This project focused on reducing nitrogen supply pressure required by the GT. Customer’s cost of electricity (COE) is reduced, translating to additional potential revenue of $3.0MM over the life of the plant. This has been achieved through six sigma methodology of design optimization of the Nitrogen injection manifold, reduced combustion chamber pressure entry loss and optimizing the control system. Statistical analysis combined with various engineering tools was used to optimize, validate and verify the new design. The new design is applicable to all GT frame sizes. It also, can be applied as an upgrade to existing units.
Tempest Dual Fuel DLE Development and Commercial Operating Experience and Ultra Low NOx Gas Operation
Authors: Cramb D. J. , McMillan R.
Published: July 2014

Following on from the experience gained on the Typhoon generator set, ALSTOM Power’s generic dual fuel Dry Low Emissions (DLE) combustion system has been successfully developed for operation on the Tempest generator set. The first engine fitted with the full DLE dual fuel system entered service in October 2000.

NOx emissions levels of less than 30vppm at 15% O2 have been demonstrated on distillate fuel. Low levels of combustion dynamics and pilot burner tip temperatures have been demonstarted on both fuels as well as gas fuel emission levels remaining less than 20vppm at 15% O2, the same as the gas only DLE version.

This paper describes the development of the dual fuel DLE system on the Tempest at ALSTOM’s test facilities in Lincoln, England as well as the commercial operating experience gained to date on both the full dual fuel DLE and liquid standby DLE systems. The commercial operating experience will cover areas such as operating concept, liquid starting reliability, and site issues encountered.

The lead Tempest gas only DLE units have successfully completed 22000 hours operation without any issues and will be discussed in the paper.
The Performance of the Low NOx Aero Gas Turbine Combustor Under High Pressure
Authors: Ikezaki Takashi , Hosoi Jun , Toh Hidemi , Fujimori Toshiro , Murayama Motohide , Saito Tsukasa
Published: July 2014

We have developed a new fuel staged combustor, which consists of diffusion flame pilot burners and lean premixing prevaporizing main burners and is therefore called a multiple fuel nozzle type low NOx gas turbine combustor. The goal for NOx reductions was set to 70 to 80% compared with conventional gas turbine combustors. Combustion tests for a section of the annular combustor have been performed for pressures P3 up to 2.9Mpa and temperatures T3 up to 823K with kerosene. As the results, even under high pressure and temperature condition, stable combustion without the problem of auto-ignition or flashback could be achieved. NOx emission index is 13 [g/kg,fuel] which is equivalent to more than 70% NOx reduction. The liner wall temperature is lower than the durability limit. The dependency of NOx emissions on pressure and temperature for this combustor are reported.
Improvement in the Design of Helium Turbine for the HTGR-GT Power Plant
Authors: Muto Yasushi , Ishiyama Shintaro , Inomata Asako , Kishibe Tadaharu , Minatsuki Isao , Matsumoto Iwao , Levet Francois
Published: July 2014

This paper describes the conceptual design of a 600MW HTGR-GT power plant which has been completed in the framework of the HTGR-GT feasibility study project. The project is assigned to JAERI by the Science and Technology Agency in Japan. The inlet and outlet gas temperatures in the reactor are 460°C and 850°C, respectively. Helium gas pressure is 6MPa. The gas turbine system type is intercooled recuperative direct cycle. Designs of helium turbine, LP and HP compressors and generator are presented. Efforts have been focussed on reducing their dimensions and weight in the preliminary design to facilitate the mechanical design of the rotor and also reduce the size of power conversion vessel. Rotor dynamics behavior and maintenance procedures of the horizontal single-shaft configuration adopted are explained.
Steam–Gas Condensing Turbine System for Power and Heat Generation
Authors: Chodkiewicz Ryszard , Porochnicki Jerzy , Kaczan Bazyli
Published: July 2014

This study deals with new internal combustion turbine power systems in which a steam-gas mixture is the working medium. Heat is delivered to the system by injecting gaseous fuel and steam into the combustion chamber. Unlike in STIG systems, the fluid expansion in the turbine is much deeper (much below the atmospheric pressure) and the exhaust gas is cooled in a heat exchanger-condenser in such a manner that a significant amount of water can be recovered. The non-condensing gases (CO2 + N2 + rest of O2) from the exhaust fluid are compressed, after additional cooling, and discharged into the atmosphere.

If a cheap or waste fuel is available, the steam to be injected into the combustor can be produced in a waste fuel-burning boiler or in conventional coal boiler. In this case the heat exchanger between the turbine and condenser can deliver significant amounts of useful (process or district) heat or / and preheated feedwater for the boiler.

The efficiency analysis of this new energy system shows a growth by more than 10 percent points in comparison with the conventional STIG engine, at the same pressure ratio and turbine inlet temperature.
The Impact of Thermodynamic Properties of Air-Water Vapor Mixtures on Design of Evaporative Gas Turbine Cycles
Authors: Dalili Farnosh , Andrén Martin , Yan Jinyue , Westermark Mats
Published: July 2014

Reliable thermodynamic property data for air-water vapor mixtures are lacking for the design of evaporative gas turbine cycles (EvGT). Due to high working pressures and temperatures of gas turbines, considerable error would occur when applying the ideal models instead of the real gas mixture models.

This paper presents an extensive literature study regarding models for computing thermodynamic property data of gas mixtures. The Hyland and Wexler model is found to be the best available despite the limited temperature range. However, experimental data are needed to verify the extrapolation.

Furthermore, this paper evaluates the impact of thermodynamic properties of air-water vapor mixtures on the design of EvGT cycles. A suggested EvGT configuration, with results based on ideal gas mixture model and steam tables, is selected as a reference. The real properties of the working fluid mixture are recalculated by the means of the Hyland and Wexler model and applied in the cycle calculation. The results based on real data are compared to those based on ideal.

The results show that the real gas model predicts higher saturation humidity at a given temperature. The higher volatility of water improves the humidification performance. In the case studied here, the flue gas temperature is lowered by about 3°C and the cycle efficiency is improved only marginally. The real gas model predicts higher heat duty for superheating of moist air by about 10 percent, or 2 MW.

Finally, it can be concluded that thermodynamic property data mainly affect component sizing, especially the humid air superheater and to some extent the boiler.
Design Study of Part Flow Evaporative Gas Turbine Cycles: Performance and Equipment Sizing: Part 1 — Aeroderivative Core
Authors: Ågren Niklas D. , Westermark Mats O. J.
Published: July 2014

The evaporative gas turbine cycle is a new high efficiency power cycle that has reached the pilot testing stage. This paper presents calculation results of a new humidification strategy based on part flow humidification. This strategy involves using only a fraction of the compressed air for humidification. Thermodynamically, it can be shown that not all the air needs to be passed through the humidification system to attain the intrinsic good flue gas heat recovery of an EvGT cycle. The system presented also includes live steam production and superheating by heat from the hottest flue gas region. The humidifier only uses the lower temperature levels flue gas heat, where it is best suited. The analyzed system is based on data for the aeroderivative Rolls Royce Trent as a gas turbine core. Part 2 of this 2-part paper presents the results based on data for the industrial gas turbine ABB GTX100.

Simulation results include electric efficiency and other process datas as functions of degree of part flow. A detailed model of the humidifier is also used and described, which produces sizing results both for column height and diameter.

Full flow humidification generates an electric efficiency of 51.5% (simple cycle 41%). The efficiency increases when the humidification air flow is reduced, to reach a maximum of 52.9% when air flow to the humidification amounts to around 12% of the intake air to the compressor. At the same time, total heat exchanger area is reduced by 50% and humidifier volume by 36% compared to full flow humidification. This calls for a recommendation not to use all the compressed air for humidification.
Design Study of Part Flow Evaporative Gas Turbine Cycles: Performance and Equipment Sizing: Part 2 — Industrial Core
Authors: Ågren Niklas D. , Westermark Mats O. J.
Published: July 2014

This is part two of a 2-part paper and presents calculation results of a part flow EvGT cycle based on gas turbine data for the ABB GTX100 (modified for intercooling). The evaporative gas turbine cycle is a new high efficiency cycle that has reached the pilot testing stage. This paper presents calculation results of a new humidification strategy based on part flow humidification. This strategy involves using only a fraction of the compressed air for humidification. Thermodynamically, it can be shown that not all the air needs to be passed through the humidification system to attain the intrinsic good flue gas heat recovery of an EvGT cycle. The presented system also includes live steam production and superheating, by heat from the hottest flue gas region, for injection. The humidifier then only uses the lower temperature levels, where it is best suited. The analyzed system is based on data for the ABB GTX100.gas turbine in intercooled mode. Part 1 of this 2-part paper presents the results based on data for the aeroderovative Rolls Royce Trent.

Simulation results include electric efficiency and other process data as function of degree of part flow. A detailed model of the humidifier is used, which produces sizing results both for column height and diameter. Paper 1 includes detailed description of the modelling.

For the GTX100-system, full flow humidification generates an electric efficiency of 52.6% (simple cycle 36.2%). The efficiency is virtually unaffected if the air portion to humidification is cut to 60% of accessible compressor air (represents 48% of compressor intake). If 30% of air from the compressor after cooling bleed (24% of intake)is led to the humidifier, the efficiency is reduced to 52.2%. On the other hand is the total heat exchanger area reduced by 20% and column volume by 50%. This calls for a recommendation not to use all the compressed air for humidification. It is recommended to use 15-30% of compressor intake air. The exact economic optimum depends on local fuel prices, CO2-taxes, interest rates et c.
Mainstream Aerodynamic Effects due to Wheelspace Coolant Injection in a High-Pressure Turbine Stage: Part I — Aerodynamic Measurements in the Stationary Frame
Authors: McLean Christopher , Camci Cengiz , Glezer Boris
Published: July 2014

The relative aerodynamic and performance effects associated with rotor – NGV gap coolant injections were investigated in the Axial Flow Turbine Research Facility (AFTRF) of The Pennsylvania State University. This study quantifies the effects of the coolant injection on the aerodynamic performance of the turbine for radial cooling, impingement cooling in the wheelspace cavity and root injection. Overall, it was found that even a small quantity (1%) of cooling air can have significant effects on the performance character and exit conditions of the high pressure stage. Parameters such as the total-to-total efficiency, total pressure loss coefficient, and three-dimensional velocity field show local changes in excess of 5%, 2%, and 15% respectively. It is clear that the cooling air disturbs the inlet end-wall boundary layer to the rotor and modifies secondary flow development thereby resulting in large changes in turbine exit conditions.
Mainstream Aerodynamic Effects due to Wheelspace Coolant Injection in a High-Pressure Turbine Stage: Part II — Aerodynamic Measurements in the Rotational Frame
Authors: McLean Christopher , Camci Cengiz , Glezer Boris
Published: July 2014

The current paper deals with the aerodynamic measurements in the rotational frame of reference of the Axial Flow Turbine Research Facility (AFTRF) at the Pennsylvania State University. Stationary frame measurements of “Mainstream Aerodynamic Effects Due to Wheelspace Coolant Injection in a High Pressure Turbine Stage” were presented in part-I of this paper. The relative aerodynamic effects associated with rotor – nozzle guide vane (NGV) gap coolant injections were investigated in the rotating frame. Three-dimensional velocity vectors including exit flow angles were measured at the rotor exit. This study quantifies the secondary effects of the coolant injection on the aerodynamic and performance character of the stage main stream flow for root injection, radial cooling and impingement cooling. Current measurements show that even a small quantity (1%) of cooling air can have significant effects on the performance and exit conditions of the high pressure turbine stage. Parameters such as the total pressure coefficient, wake width, and three-dimensional velocity field show significant local changes. It is clear that the cooling air disturbs the inlet end-wall boundary layer to the rotor and modifies secondary flow development thereby resulting in large changes in turbine exit conditions. Effects are the strongest from the hub to midspan. Negligible effect of the cooling flow can be seen in the tip region.
Heat/Mass Transfer Measurement Within a Film Cooling Hole of Square and Rectangular Cross Sections
Authors: Cho Hyung Hee , Kang Seung Goo , Rhee Dong Ho
Published: July 2014

An experimental study has been conducted to investigate the heat/mass transfer characteristics within film cooling holes of square and rectangular cross-section. The experiments for this study have been performed using a naphthalene sublimation method, and the flow field has been analyzed by numerical calculation using a commercial code (FLUENT). The rectangular cross-section has the aspect ratio of 2 and the same hydraulic diameter as the square cross-section. A duct flow enters into a film cooling hole in a cross-direction. For the film cooling hole with square cross-section, it is observed that the reattachment of separated flow and the vortices within the hole enhance considerably the heat/mass transfer around the hole entrance region. The heat/mass transfer on the leading edge side of hole exit region increases as the blowing rates decrease because the mainflow induces a secondary vortex. Heat/mass transfer patterns within the film cooling hole are changed slightly with the various Reynolds numbers. For the film cooling hole with rectangular cross-section, overall heat/mass transfer characteristics are similar with those for the square cross-section. However, heat/mass transfer on the leading edge side of hole entrance region has two peak regions due to split flow reattachment, and heat/mass transfer on the leading edge side of hole exit region is less sensitive to the blowing ratios than the square cross-section case.