bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling the Transient Behavior of Combined Cycle Plants
Authors: Dechamps P. J. 
Published: February 2015

The last decade has seen remarkable improvement in industrial gas turbine unit size and performances. The coming years and decades hold the promise of even more progress in these fields.
Simultaneously, the fuel utilization achieved by combined cycles has been steadily increased, which is a combination of improvements both in the gas turbine technology and in the new combined cycle schemes with multiple pressure levels.
These combined cycles quite often have to operate on a load cycling duty or in the intermediate load range, so that not only the design point performances but even the off design are sufficient to ensure the plant profitability. Its transient behaviour, its ability to start quickly and reliably, are key parameters when selecting the plant.
This paper describes a method developed for the calculation of the transient performances of combined cycles, from no load situations, including cold conditions, to full load. The method is then applied and illustrated with a recently commissioned plant, for which some transient measurements are available.
Variations in the NOx Emission of Gas Turbines: Effects of Air Temperature, Air Humidity and Natural Gas Composition
Authors: Visser B. Martien , Bahlmann Fred C. 
Published: February 2015

The NOx emission, produced by gas turbines varies with ambient conditions and with fuel gas composition. Often, legislation requires that the NOx emissions of gas turbines has to be corrected to standard conditions. The EPA formula may be used for the correction for ambient temperature and humidity. In the Netherlands, the correction for fuel-gas composition is based on the observation that for natural gases, NOx emission varies linearly with the Lower Calorific Value (LCV).
It is concluded that both the EPA and LCV correction formulas are equivalent to the following relation between flame temperature and NOx emission: NOxa=NOxb*(1.0065)Ta−Tb where Ta and Tb represent characteristic flame temperatures under conditions a and b. In the paper, the utility of the EPA and the LCV correction formulas for gas turbines equipped with modem lean-premixed combustors is discussed.
Thermodynamical Optimization of a Combined Cycle Plant Performance
Authors: Sarabchi K. , Polley G. T. 
Published: February 2015

Computer modelling of Performance optimization was done to examine the effect of key operating variables like compressor pressure ratio, turbine inlet temperature, and recovery boiler pressure on performance parameters of a simple combined cycle and comparison was made to a simple gas turbine cycle. Both thermal efficiency and specific net work were examined as pressure ratio and recovery boiler pressure were varied for each turbine inlet temperature. Also careful consideration was given to admissible values of stack gas temperature, steam turbine outlet dryness fraction, and steam turbine outlet dryness fraction, and steam turbine inlet temperature.
Specifically, it was shown that when we treat a combined cycle as an integrated system, efficiency optimization entails a pressure ratio below that suitable for simple gas turbine plant.
Development of Silicon Nitride Rotors for Gas Turbine Applications
Authors: Yoshida Makoto , Tsuruzono Sazo , Ono Takashi , Gejima Hiroshi 
Published: February 2015

Kyocera is developing various ceramic parts for gas turbines under the government funded ceramic gas turbine development programs in Japan. Among the programs, Kyocera is contracted for the development components for CGT-302 and CGT-303 engines which are designed for 300kW output power generation. Of the various parts for gas turbines, we discuss developments and burst tests at room temperature of silicon nitride turbine rotors made by slip casting.
In particular, the result of burst tests of turbine rotors at room temperature is evaluated along with the strength prediction by a computer program (CARES) developed by NASA. Different types of turbine rotors were tested, and their burst speeds were well correlated to the strength predicted by computer analyses. This suggests that fracture stress of ceramic parts is well predicted from the material data.
Infrared Thermal Imaging System as a Diagnostic Tool for Gas Turbine Engine Faults
Authors: MacLeod J. D. , Steckhan P. , He D. 
Published: February 2015

With the cost of maintaining a fleet of gas turbine engines continuing to rise, there is a greater need to develop methods to diagnose engine deterioration and identify faulty engine components quickly and efficiently. The Structures, Materials and Propulsion Laboratory of the National Research Council of Canada (NRC) has established a program to develop and evaluate various diagnostic techniques. The effort is aimed at investigating the effects of typical in-service faults on engine performance characteristics. An important aspect of the engine test program is the evaluation of non-intrusive sensors to accurately measure gas turbine performance.
Using infrared thermography, the measurement of temperature is accomplished non-intrusively using the infrared radiation spectra. This instrumentation provides an indirect measurement of temperature and does not interfere with the flow field being measured. The temperature patterns can be used to determine engine health, and identify possible fault conditions within the hot section of the engine.
This paper describes the project objectives, the experimental installation, and the results of the performance evaluations. A description of the infrared thermography system, and the data reduction and analysis systems used to convert infrared light into temperature profile contours is given.
Wake Region Measurements of a Highly Three-Dimensional Nozzle Guide Vane Tested at DRA Pyestock Using Particle Image Velocimetry
Authors: Funes-Gallanzi M. , Bryanston-Cross P. J. , Chana K. S. 
Published: February 2015

The quantitative whole field flow visualization technique of PIV has over the last few years been successfully demonstrated for transonic flow applications. A series of such measurements has been made at DRA Pyestock. Several of the development stages critical to a full engine application of the work have now been achieved using the Isentropic Light Piston Cascade (ILPC) test facility operating with high inlet turbulence levels:
• A method of seeding the flow with 0.5μm diameter styrene particles has provided an even coverage of the flow field.
• A method of projecting a 1 mm thick high power Nd/YAG laser light sheet within the turbine stator cascade. This has enabled a complete instantaneous intra-blade velocity mapping of the flow field to be visualized, by a specially developed diffraction-limited optics arrangement.
• Software has been developed to automatically analyze the data. Due to the sparse nature of the data obtained, a spatial approach to the extraction of the velocity vector data was employed.
• Finally, a comparison of the experimental results with those obtained from a three-dimensional viscous flow program of Dawes; using the Baldwin-Lomax model for eddy viscosity and assuming fully turbulent flow.
The measurements provide an instantaneous quantitative whole field visualization of a high-speed unsteady region of flow in a highly three-dimensional nozzle guide vane; which has been successfully compared with a full viscous calculation. This work represents the first such measurements to be made in a full-size transonic annular cascade at engine representative conditions.
System Evaluation and LBTU Fuel Combustion Studies for IGCC Power Generation
Authors: Cook C. S. , Corman J. C. , Todd D. M. 
Published: February 2015

The integration of gas turbines and combined cycle systems with advances in coal gasification and gas stream cleanup systems will result in economically viable IGCC systems. Optimization of IGCC systems for both emission levels and cost of electricity is critical to achieving this goal.
A technical issue is the ability to use a wide range of coal and petroleum-based fuel gases in conventional gas turbine combustor hardware. In order to characterize the acceptability of these syngases for gas turbines, combustion studies were conducted with simulated coal gases using full scale advanced gas turbine (7F) combustor components. It was found that NOx emissions could be correlated as a simple function of stoichiometric flame temperature for a wide range of heating values while CO emissions were shown to depend primarily on the H2 content of the fuel below heating values of 130 Btu/scf (5125 kJ/NM3) and for H2/CO ratios less than unity. The test program further demonstrated the capability of advanced can-annular combustion systems to burn fuels from air-blown gasifiers with fuel lower heating values as low as 90 Btu/scf (3548 kJ/NM3) at 2300 F (1260 C) firing temperature.
In support of ongoing economic studies, numerous IGCC system evaluations have been conducted incorporating a majority of the commercial or near commercial coal gasification systems coupled with “F” series gas turbine combined cycles. Both oxygen and air-blown configurations have been studied, in some cases with high and low temperature gas cleaning systems. It has been shown that system studies must start with the characteristics and limitations of the gas turbine if output and operating economics are to be optimized throughout the range of ambient operating temperature and load variation.
Composite Filter System Development and Performance
Authors: Belcher M. 
Published: February 2015

Gas turbine operation in urban environments creates new challenges in inlet filtration. The particulate concentration could be light, but significant quantities of the particles are sub-micron in size. Additionally, the presence of hydrocarbons can cause problems with air filter performance, both through short life and turbine fouling.
A new filter system for these environments is described. Development objectives for the medias and filter systems are discussed, test and evaluation procedures are defined, and the performance of the resulting product is documented.
Observations of Flame Behavior From a Practical Fuel Injector Using Gaseous Fuel in a Technology Combustor
Authors: Hedman Paul O. , Sturgess Geoffrey J. , Warren David L. , Goss Larry P. , Shouse Dale T. 
Published: February 2015

This paper presents results from an Air Force program being conducted by researchers at Brigham Young University (BYU) Wright-Patterson Air Force Base (WPAFB), and Pratt and Whitney Aircraft Co (P&W). This study is part of a comprehensive effort being supported by the Aero Propulsion and Power Laboratory at Wright-Patterson Air Force Base, and Pratt and Whitney Aircraft, Inc. in which simple and complex diffusion flames are being studied to better understand the fundamentals of gas turbine combustion near lean blowout. The program’s long term goal is to improve the design methodology of gas turbine combustors.
This paper focuses on four areas of investigation: 1) digitized images from still film photographs to document the observed flame structures as fuel equivalence ratio was varied, 2) sets of LDA data to quantify the velocity flow fields existing in the burner, 3) CARS measurements of gas temperature to determine the temperature field in the combustion zone, and to evaluate the magnitude of peak temperature, and 4) two-dimensional images of OH radical concentrations using PLIF to document the instantaneous location of the flame reaction zones.
The Flight Testing of Natural and Hybrid Laminar Flow Nacelles
Authors: Barry Brian , Parke Simon J. , Bown Nicholas W. , Riedel Hansgeorg , Sitzmann Martin 
Published: February 2015

The achievement of large areas of laminar flow over aircraft engine nacelles offers significant savings in aircraft fuel consumption. Based upon current engine configurations nett sfc benefits of up to 2% are possible. In addition the engine nacelle is ideally suited to the early inclusion of laminar flow technology, being relatively self contained with the possibility of application to existing airframes.
In September 1992 a European Consortium managed by Rolls-Royce including MTU and DLR began flight testing of a natural laminar flow nacelle. This programme was later extended by R-R and DLR to flight test a hybrid laminar flow nacelle featuring boundary layer suction and insect contamination protection.
The tests evaluated the effects of flight and engine environment, boundary layer transition phenomena, suction system operation and insect contamination avoidance strategies.
This paper describes the global conclusions from these flight tests which are a significant milestone leading to the future application of laminar flow technology to engine nacelles.
Advanced Turbine Systems Program Requirements and an Approach to Implementation
Authors: Ali Sy A. , Webb Holmes A. 
Published: February 2015

The U.S. Department of Energy (DOE) is sponsoring a program to conduct design and development, leading to full scale demonstration of advanced gas turbine systems. The Advanced Turbine Systems (ATS) program is jointly administered by the DOE Office of Fossil Energy (DOE/FE) and the Office of Energy Efficiency and Renewable Energy (DOE/EE). The program will demonstrate commercial prototypes of both utility- and industrial-scale ATS by the year 2000.
The ATS program objectives are: system efficiency 60 percent (lower heating value [LHV]) or greater for utility-scale systems, and an equivalent 15 percent improvement for industrial systems; environmental superiority without the use of post combustion emissions controls; busbar energy costs 10 percent lower than current systems; adaptability to coal or biomass firing; and reliability, availability and maintainability equivalent to current advanced turbine systems.
A competitive procurement process is being used for the selection of contractors to develop and demonstrate full scale systems. System studies were completed by six U.S. turbine manufacturers, and awards were announced in August 1993 for “concept development.” This paper describes one implementation approach to achieve the DOE/ATS targets.
High Temperature Demonstration Unit for a 1500°C Class Gas Turbine
Authors: Sato M. , Matsuzakl H. , Yamaura T. , Aoki S. , Suanaga K. , Ito E. , Tomita Y. 
Published: February 2015

Tohoku Electric Power Co., Inc. and Mitsubishi Heavy Industries, Ltd. have begun a joint development program on key technologies for a next generation gas turbine which aims for a combined cycle efficiency over 55%. Under the program, advanced cooling technologies, better heat resistant materials and thy low NOx (DLN) combustion technologies are being developed. For verifying high temperature technologies, turbine testing is going to be performed using the HTDU (High Temperature Demonstration Unit) at Takasago Machinery Works, Mitsubishi Heavy Industries, Ltd.
This paper describes the general description of the HTDU facility and plans for testing a turbine at a firing temperature of 1500°C.
The Simulation Methods in the Rotor-Machinery Diagnostics
Authors: Kicinski Jan , Drozdowski Robert 
Published: February 2015

The paper presents some examples of simulation research carried out in view of large turbomachinery diagnostics. On the basis of computer simulations of some typical damages, such as “unbalanced” and hydrodynamic instability, it was possible to obtain the trajectories of the journal and the disc centre, as well as the amplitudes and the phase angles.
The paper refers to an example of two-point-supported rotor modelled using the Finite Element Method. The calculations were made on the basis of the complex elastodia-thermic model of the hydrodynamic slide bearing and also on the non-linear analysis of the system motion equations. The non-linear analysis made it possible to generate a characteristic vibration spectrum for every diagnostic relation. It refers especially to the computer simulations of the oil whirls and the oil whip, carried out for the various conditions of the rotor-machinery operation.
An Assessment of the Thermodynamic Performance of Mixed Gas-Steam Cycles: Part A — Intercooled and Steam-Injected Cycles
Authors: Macchi Ennio , Consonni Stefano , Lozza Giovanni , Chiesa Paolo 
Published: February 2015

This paper discusses the thermodynamics of power cycles where steam or water are mixed with air (or combustion gases) to improve the performance of stationary gas turbine cycles fired on clean fuels. In particular, we consider cycles based on modified versions of modern, high-performance, high-efficiency aero-derivative engines.
The paper is divided into two parts. After a brief description of the calculation method, in Part A we review the implications of intercooling and analyze cycles with steam injection (STIG and ISTIG). In Part B we examine cycles with water injection (RWI and HAT).
Due to lower coolant temperatures, intercooling enables to reduce turbine cooling flows and/or to increase the turbine inlet temperature. Results show that this can provide significant power and efficiency improvements for both simple cycle and combined cycle systems based on aero-engines; systems based on heavy-duty machines also experience power output augmentation, but almost no efficiency improvement.
Mainly due to the irreversibilities of steam/air mixing, intercooled steam injected cycles cannot achieve efficiencies beyond the 52–53% range even at turbine inlet temperatures of 1500°C. On the other hand, by accomplishing more reversible water-air mixing, the cycles analyzed in Part B can reach efficiencies comparable (RWI cycles) or even superior (HAT cycles) to those of conventional “unmixed” combined cycles.
Unsteady Boundary Layers on a Flat Plate Disturbed by Periodic Wakes: Part II — Measurements of Unsteady Boundary Layers and Discussion
Authors: Funazaki K. 
Published: February 2015

As the second part of the study, detailed hot-wire anemometry measurements of wake-affected boundary layers on the flat plate are made. These measurements are organized in order, first, to check the standpoint of the modeling of the wake-induced transition proposed in Part I, and second, to observe wake-boundary layer interaction in detail from a viewpoint of direct and indirect effect of the wake passage upon turbulent spot generation within the boundary layer, as described by Walker (1993).
The validity of the presumed state of the wake-affected boundary layer in the distance-time domain, which constitutes the basis of the transition model, is confirmed to great extent. However, it is also found that the criterion for the onset of the wake-induced transition adopted in Part I should be reconsidered. Some successful attempts are therefore made to specify the transition onset.
Measurement of Tip-Clearance Flow in a Multi-Stage, Axial Flow Compressor
Authors: Foley Andrew C. , Ivey Paul C. 
Published: February 2015

Detailed measurements using pneumatic probe traverses, blade static pressure tappings and laser anemometry are made in the third stage of a large scale, low speed, four stage, axial flow, research compressor.
Inlet conditions show well ordered ‘two dimensional’ flow from approximately 40 to 85% annulus span. Outside of this region, reduced total pressure due to upstream leakage losses aod endwall effects results in high incidence to the following blade row. As a result, peak suction surface static pressure moves forward along the blade chord for both the huh and tip of stators and rotors. At the blade tip however, the peak suction pressure is maintained with chord due to radial flow on the suction surface being entrained into the tip leakage jet. The extent of rotor chord for which this ‘entrainment’ occurs increases with increasing rotor tip clearance gap. The leakage jet from both stators and rotors is seen to ‘roll up’ into a vortex downstream of their respective blade rows.
An Engineering Calculation Method for Multi-Component Stagnant Droplet Evaporation With Finite Diffusivity
Authors: Chin J. S. 
Published: February 2015

A practical engineering calculation method has been formulated for commercial multicomponent fuel stagnant droplet evaporation with variable finite mass and thermal diffusivity. Instead of solving the transient liquid phase mass and heat transfer partial differential equation set, a totally different approach is used. With zero or infinite mass diffusion resistance in liquid phase, it is possible to obtain vapor pressure and vapor molecular mass based on the distillation curve of these turbine fuels. It is determined that Peclet number (Pef) is a suitable parameter to represent the mass diffusion resistance in liquid phase. The vapor pressure and vapor molecular mass at constant finite Pef is expressed as a function of finite Pef, vapor pressure, and molecular mass at zero Pef and infinite Pef. At any time step, with variable finite Pef, the above equation is still valid, and PFsPef=∞, PFsPef=0, MfvPef=∞, MfvPef=0 are calculated from PFsPef≡∞, PFsPef≡0, MfvPef≡∞, MfvPef≡0, thus PFs and Mfv can be determined in a global way which eventually is based on the distillation curve of fuel.
The explicit solution of transient heat transfer equation is used to have droplet surface temperature and droplet average temperature as a function of surface Nusselt number and non-dimensional time. The effect of varying com position of multi-component fuel evaporation is taken into account by expressing the properties as a function of molecular mass, acentric factor, critical temperature, and critical pressure. A specific calculation method is developed for liquid fuel diffusion coefficient, also special care is taken to calculate the binary diffusion coefficient of fuel vapor-air in gaseous phase. The effect of Stefan flow and natural convection has been included. The predictions from the present evaporation model for different turbine fuels under very wide temperature ranges have been compared with experimental data with good agreement.
Process Studies as Applied to Ceramic Gas Turbine Engine Low-Emission Double-Zone Micro-Diffusion Combustion Chamber
Authors: Sudarev A. V. , Zakharov Y. I. , Vlnogradov E. D. , Butovsky L. S. , Ranovskaya E. A. G. 
Published: February 2015

Initial results of the first step (at Pa = 0.11–0.12 MPa) of an experimental investigation of the basic parameters of full-scale, micro-flame double-zone combustors with flame tubes are presented. This combustion chamber is developed for a 2.5 MW advanced ceramic gas turbine unit. (Sudarev, et al., 1991). This engine, when working at the design operation conditions, has an efficiency range of 41–46%, which is a function of using either intecooling or a heat regeneration scheme. The efficiency is the result of increasing the gas temperature to a maximum turbine inlet temperature of 1250°C and a 2.5 MW pressure ratio of 29. With such high initial parameters of the working media, the problem of nitrogen oxide emissions reduction assumes paramount importance.
The objective of the paper is to develop a combustor which would ensure NOx emissions at the design conditions not above 75 mg/Nm3 (at 15% 02) due to application of a double-stage working process of pre-mixture firing. Specific features of fuel burn-up, formation of pollutants at combustion, dependencies of combustor characteristics and upgraded algorithm of combustor loading are also shown.