bluuebunny/crossref_metadata_2025_split huggingface dataset:
Benefits of Converting Utility Gas Turbines to Combined-Cycle Plants
Authors: Miliaras E. S. , Wilkinson P. 
Published: March 2015

A large number of simple cycle gas turbines (about 8% of the total current electric generating capacity) had been installed by utilities by the late 1970s. Because of the low efficiency of these, older simple cycle gas turbines (about 25% at full load, much worse at part load) and the reduced demand for electricity, little use is now made of these machines by most utilities.
The paper considers the specific and broader benefits of converting these older gas turbines to combined-cycle plants. The benefits include dramatic efficiency improvement at all loads, improved operating reliability, low cost additions to utility generating capacity, and the potential availability of significant new capacity in many regions of the country in a short time.
The combined cycles can also be operated instead of oil-fired and coal-fired cycling steam plants — at significantly lower startup-up costs in fuel and operating personnel, and with considerable reduction in the wear and tear of the steam plants from cycling thermal stresses.
When additional, new peaking capacity is needed, these older, converted gas turbines can be replaced with new, more efficient machines.
Development of a Low-NOx LBG Combustor for Coal Gasification Combined Cycle Power Generation Systems
Authors: Sato M. , Abe T. , Ninomiya T. , Nakata T. , Yoshine T. , Hasegawa H. 
Published: March 2015

From the view point of future coal utilization technology for the thermal power generation systems, the coal gasification combined cycle system has drawn special interest recently. In the coal gasification combined cycle power generation system, it is necessary to develop a high temperature gas turbine combustor using a low-BTU gas (LBG) which has high thermal efficiency and low emissions.
In Japan a development program of the coal gasification combined cycle power generation system has started in 1985 by the national government and Japanese electric companies. In this program, 1300°C class gas turbines will be developed. If the fuel gas cleaning system is a hot type, the coal gaseous fuel to be supplied to gas turbines will contain ammonia. Ammonia will be converted to nitric oxides in the combustion process in gas turbines. Therefore, low fuel-NOx combustion technology will be one of the most important research subjects.
This paper describes low fuel-NOx combustion technology for 1300°C class gas turbine combustors using coal gaseous low-BTU fuel as well as combustion characteristics and carbon monoxide emission characteristics.
Combustion tests were conducted using a full-scale combustor used for the 150 MW gas turbine at the atmospheric pressure. Furthermore, high pressure combustion tests were conducted using a half-scale combustor used for the 1 50 MW gas turbine.
A New Method for Optimizing Friction Damping in Randomly Excited Systems
Authors: Cameron T. M. , Griffin J. H. 
Published: March 2015

A method is developed that can be used to calculate the stationary response of randomly excited nonlinear systems. The method iterates to obtain the fast Fourier transform of the system response, returning to the time domain at each iteration to take advantage of the ease in evaluating nonlinearities there. The updated estimates of the nonlinear terms are transformed back into the frequency domain in order to continue iterating on the frequency spectrum of the staionary response.
This approach is used to calculate the response of a one degree of freedom system with friction damping that is subjected to random excitation. The one degree of freedom system provides a single mode approximation of systems (e.g. turbine blades) with friction damping. This study investigates various strategies that can be used to optimize the friction load so as to minimize the response of the system.
The Performance Prediction and Demonstration of a Centrifugal Compressor for the Multiple Purpose Small Power Unit (MPSPU)
Authors: Yoshinaka Tsukasa , Thompson R. G. , Létourneau Jean 
Published: March 2015

This paper describes an analytical procedure for the prediction of the design point performance of a small centrifugal compressor. Results of a subsequent performance demonstration are presented. The geometry of the compressor was derived from an existing stage used in the PW200 engine, but rematched to 6:1 pressure ratio.
Test data obtained from subsequent performance demonstration showed that the predicted performance had been achieved, but at 103% of design speed. A possible cause of this discrepancy is proposed.
Development of a Coal-Fueled Gas Turbine Slagging Combustor
Authors: Cowell L. H. , LeCren R. T. 
Published: March 2015

A slagging combustor for a coal-fueled gas turbine engine is being developed. The work to date has been accomplished using a bench-scale combustor with one-tenth the heat input required for the full-scale gas turbine unit. The combustor features a fuel-rich slagging primary zone with hot refractory walls. Both single and multiple primary air/fuel injectors have been tested. Aerodynamic jet impaction on a target at one end of the primary zone removes much of the slag. The jet impaction is the result of the single air/fuel injector flow for multiple injectors, the intersection of the multiple jets forms a central jet. There is an additional particulate rejection impact separator between the primary and secondary zones to remove the slag that escapes the primary zone. Secondary air is introduced via multiple jets that rapidly mix with the incoming gas from the particulate removal device, resulting in a minimal formation of thermal NOx and the completion of the combustion process.
Variables that have been evaluated include coal-water mixture properties such as top and mean particle size, viscosity, loading and ash fusion temperature, and primary zone parameters such as volume, cross-sectional area, loading, and equivalence ratio.
Combustor performance was compared with single or multiple fuel injectors, relating the combustor performance to the spray characteristics of the two injector configurations. Modifications of the single injector were evaluated with the goal of attaining at least the same atomization performance as the smaller injectors used in the multiple injector configuration.
Flow visualization, computer modelling, and cold-flow velocity traverses have been employed to aid the development program. The results of the subscale development are being used to design and develop the full-size combustor for integration with the engine.
Probabilistic Structural Analysis for Advanced Space Propulsion Systems
Authors: Cruse T. A. , Unruh J. F. , Wu Y.-T. , Harren S. V. 
Published: March 2015

The paper reports on recent extensions to ongoing research into probabilistic structural analysis modeling of advanced space propulsion system hardware. The advances concern probabilistic dynamic loading, and probabilistic nonlinear material behavior.
In both cases, the reported work represents a significant advance in the state-of-the-art for these topics. Random, or probabilistic loading is normally concerned with the loading described in power spectral density (PSD) terms. The current work describes a method for incorporating random PSD’s along with random material properties, damping, and structural geometry.
The probabilistic material response is concerned with the prediction of nonlinear stress-strain behavior for physical processes that can be linked to the original microstructure of the material. Such variables as grain size and orientation, grain boundary strength, etc. are treated as random, initial variables in generating stochastic stress-strain curves. The methodology is demonstrated for a creep simulation.
The General Electric LM5000 Marine Gas Turbine
Authors: Stancliff Robert C. 
Published: March 2015

The General Electric LM5000 Marine Gas Turbine (see figure 1) intended for application to commercial and naval ships requiring high power (50,000 BHP nominal), high thermal efficiency (38 percent), and compact, marinized and relatively light weight prime movers is described. Ship candidates include Fast Support Ships, Aircraft Carriers [in a Combined Nuclear and Gas Turbine (CONAG) propulsion system], Battleships and large surface effect ships.
The LM5000 marine gas turbine is a marinized version of the LM5000 industrial gas turbine which was derived in 1977 from the CF6-50 aircraft engine. The CF6-6 model of this family of aircraft engines was the parent of the over 648 GE LM2500 marine gas turbine now used on the ships of 18 navies, 32 ship programs and 247 ships of the world. Over 2100 of the CF6-50 mode] engines are used on over 600 of the McDonald Douglas DC-10, the Airbus A300 and the Boeing 747 aircraft.
Since reliability and durability are dependent upon engine family experience, the hardware commonality with the CF6-50 aircraft engine is described as well as the associated experience, performance, installation and maintainability features.
Mathematical Formulation of Blade Surfaces in Turbomachinery: Part I — Theoretical Surface Formulations
Authors: Rautenberg M. , Engeda A. , Wittekindt W. 
Published: March 2015

This paper justifies recent trends in the mathematical definition of blade surfaces of impellers and rotors. The authors introduce a simple and efficient surface definition method, which is highly suited for numerical manufacture. Examples of a centrifugal compressor impeller, a mixed flow pump impeller and a gas turbine blade manufactured using the method are also presented.
In this first part the theoretical approach and the mathematical derivations of the authors STRAIGHT-LINE-SURFACE structure method is introduced.
Steam Injecting a Mature Gas Turbine in a Modern Cogeneration Plant
Authors: Kaempffer L. , Williams K. 
Published: March 2015

Factors such as low capital cost, good match of power and heat requirements, and proven reliability, can sometimes lead an end user into purchasing mature gas turbines for use in a modern cogeneration plant.
Invariably, older gas turbines were not specifically designed for low NOx emissions and steam injection.
This paper presents what the author(s) believe to be the simplest method of modifying an existing fuel system design to provide the best NOx reduction possible using steam injection, without significantly increasing carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions. Results of emissions tests are presented, along with a discussion on the projected limits for NOx control attainable using this new system.
Also presented, is an idea for improving cogeneration efficiency and capability, by placing the turbine cooling air cooler in the steam generation circuit.
A Comparison Between Engine Test Results and Design Predictions of Turbine Blade Cooling Performance
Authors: Hannis J. M. , Smith M. K. D. 
Published: March 2015

Significant differences exist between the behaviour of cooled turbine blades under engine conditions and their behaviour as predicted in design calculations.
This paper presents a comparison between engine test data, static cascade rig data, and design predictions. Wherever possible, the reasons for the differences are identified and cross referenced to recently reported research work. In some cases hard supportive evidence for phenomena observed on research rigs has been obtained from engine tests.
The data is presented for two subsonic aerofoil designs with several different cooling configurations.
Gas Turbine Exhaust Expansion Joints, Diverter and Damper Designs for the New Generation of Higher Temperature, High Efficiency Gas Turbines
Authors: Bachmann Lothar , Koch W. Fred 
Published: March 2015

The purpose of this paper is to update the industry on the evolutionary steps that have been taken to address higher requirements imposed on the new generation combined cycle gas turbine exhaust ducting expansion joints, diverter and damper systems. Since the more challenging applications are in the larger systems, we shall concentrate on sizes from nine (9) square meters up to forty (40) square meters in ducting cross sections. (Reference: General Electric Frame 5 through Frame 9 sizes.)
Severe problems encountered in gas turbine applications for the subject equipment are mostly traceable to stress buckling caused by differential expansion of components, improper insulation, unsuitable or incompatible mechanical design of features, components or materials, or poor workmanship.
Conventional power plant expansion joints or dampers are designed for entirely different operating conditions and should not be applied in gas turbine applications. The sharp transients during gas turbine start-up as well as the very high temperature and high mass-flow operation conditions require specific designs for gas turbine application.
The Evolution of Marine Gas Turbine Controls
Authors: Sylvestre R. A. , Dupuis R. J. 
Published: March 2015

The background and evolution of gas turbine fuel controls is examined in this paper from a Naval perspective.
The initial application of aero-derivative gas turbines to Navy ships utilized the engine’s existing aircraft fuel controls which were coupled to the ship’s hydro-pneumatic machinery control system. These engines were adapted to naval requirements by including engine specific functions.
The evolution of naval gas turbine controllers first to analog electronic, and more recently to distributed digital controls, has increased the system complexity and added a number of levels of machinery protection. The design of a specific electronic control module is used to illustrate the current state of the technology.
The paper concludes with a discussion of the further need to address the issues of fuel handling, metering and control in Navy ships with particular emphasis on integration in the marine environment.
Physical Aspects of Deposition From Coal Water Fuels Under Gas Turbine Conditions
Authors: Wenglarz Richard A. , Fox Ralph G. 
Published: March 2015

Deposition, erosion, and corrosion (DEC) experiments were conducted using three coal-water fuels (CWF) in a staged subscale turbine combustor operated at conditions of a recuperated turbine. This rich-quench-lean (RQL) combustor appears promising for reducing NOx levels to acceptable levels for future turbines operating with CWF. Specimens were exposed in two test sections to the combustion products from the RQL combustor. The gas and most surface temperatures in the first and second test sections represented temperatures in the first stators and rotors, respectively, of a recuperated turbine. The test results indicate deposition is affected substantially by gas temperature, surface temperature, and unburned carbon due to incomplete combustion.
The high rates of deposition observed at first stator conditions showed the need for additional tests to identify CWF coals with lower deposition tendencies and to explore deposition control measures such as hot gas cleanup.
A Secondary Flow Calculation Method for One Stage Axial Transonic Flow Compressors, Including Shock-Secondary Flow Interaction
Authors: Kaldellis J. , Douvikas D. , Falchetti F. , Papailiou K. D. 
Published: March 2015

A secondary flow calculation method is presented, which makes use of the meridional vorticity transport equation. Circumferentially mean flow quantities are calculated using an inverse procedure.
The method makes use of the mean kinetic energy integral equation and calculates simultaneously hub and tip secondary flow development. Emphasis is placed upon the use of a coherent two-zone model and particular care is taken in order to describe adequately the flow inside an unbounded (external), semi-bounded (annulus) and fully-bounded (bladed) space. Along with the velocity field, the losses, the defect forces and the corresponding additional work realized inside the viscous wall shear layer are calculated for stationary and rotating flow.
An approximate model for the interaction of the viscous shear layers and the external flow is used, which takes into account the meridional and the peripheral blockage. When shock waves are present in the external flow, an approximate interaction model is used, additionally, which calculates the static pressure field resulting from the interaction of the shock wave and the corresponding wall shear layer.
The method has been applied to two one stage transonic flow compressors and the results of the comparison between theory and experiment are presented and discussed.
Numerical Simulation of the Two Dimensional Viscous Compressible Flow in Blade Cascades Using a Solution Adaptive Unstructured Mesh
Authors: Sidén Gunnar L. D. , Dawes William N. , Albråten Per J. 
Published: March 2015

An explicit finite element procedure has been coupled with an automatic mesh generation procedure for mesh adaptive steady state simulations of two-dimensional viscous compressible flows in cascades. Turbulence is modelled by a two-layer algebraic eddy viscosity model. Results show good behavior in comparison with measurements and results of a conventional H-mesh viscous flow solver. Computed loss approaches measured loss as the mesh is refined.
Currently, the unstructured solver suffers in efficiency terms because the automatic mesh generator tends to produce inefficient equilateral triangles in the regions of shock waves and boundary layers where stretched elements would be more appropriate. This means that, at least for the Navier-Stokes equations, the unstructured approach is not yet competitive with conventional structured techniques. Nevertheless, this will change once the key advantages of geometric flexibility and user independent solutions force rapid development.
A Small Air Turbine Power Plant Fired With Coal in an Atmospheric Fluid Bed
Authors: Foster-Pegg R. W. 
Published: March 2015

An efficient, indirectly heated, steam-injected air turbine power or cogeneration plant, fired with coal in an atmospheric fluid bed, is described. The plant, described in the paper, will meet all environmental standards and will generate about 35 MW.
The plant offers a high power to steam ratio without requiring a condensing steam turbine and can operate efficiently without any export steam. Eliminating a condensing steam turbine, cooling tower, etc., reduces the capital cost and produces a low $/kw installation. If necessary, most of the water injected into the air turbine can be recovered from the exhaust air and reused.
All the equipment for the plant is commercially available.
Solution of Combustor Noise in a Coal Gasification Cogeneration Application of 100 MW-Class Combustion Turbines
Authors: Scalzo A. J. , Sharkey W. T. , Emmerling W. C. 
Published: March 2015

The field conversion of two W501D5 combustion turbines to burn medium BTU fuel gas supplied by a DOW Chemical coal gasification process at Plaquemine, Louisiana resulted in excessive 105 Hz airborne sound and a corresponding unacceptable non-synchronous engine vibration when burning natural gas. A joint Westinghouse and DOW Chemical corrective action program is described including field tests.
Test results indicated that the combustion noise phenomenon was related to the strength of the primary air scoop recirculation pattern and its compatibility with the fuel and steam momentum vectors. A design was selected that eliminated the non-synchronous combustion noise generated vibration and reduced the 100 Hz third-octave noise from 115 db to 97 db, an intensity reduction of 64 to 1.
Explosions in Gas Turbine Lube Oil Reservoir Result in Installation of Dry Gas Seal System
Authors: Ferrill Lawrence R. , Ronsky N. Daryl , Harris Tim A. 
Published: March 2015

Mechanical dry gas seal systems were retrofitted into two centrifugal natural gas compressors which are located offshore in the Norwegian sector of the North Sea.
The project was initiated after a fire and several gas explosions had occurred in the gas turbine lube oil reservoir. These incidents were a result of gas leaking from the compressor’s seal oil system and then migrating via the lube oil lines into the reservoir.
The dry gas seal systems have eliminated gas leakage into the turbine lube oil reservoir, eliminating the hazard of gas explosion. The retrofits have also provided additional benefits including reductions in space and weight, reduced power usage, reduced maintenance, and elimination of seal oil consumption which had been up to 440 gal./day (2000 liters/day).
Industrial Centrifugal Compressors: The Influence of the Impeller Diffusion on the Stage Performance
Authors: Lüdtke Klaus 
Published: March 2015

The meridional convergence of an unshrouded inducer type impeller with 30° backward leaning blades was modified by reducing the exit width by 22%. The vaneless diffuser was changed accordingly, whereas the impeller eye opening was kept constant. Performance curves show that the lower diffusion leads to enhanced surge limit, lower head at increased efficiency. Choke point remains unchanged and the extension of the rotating stall range is reduced. The range of tip speed Machnumbers tested was 0.6 to 1.17.
Test value analysis, broken down into components, is based on the two-zone model impeller exit evaluation procedure detecting clearly the causes of performance map changes.
Braze Repair of MA754 Aero Gas Turbine Engine Nozzles
Authors: Elder J. E. , Thamburaj R. , Patnaik P. C. 
Published: March 2015

MA754, an oxide-dispersion strengthened nickel-base superalloy, is the vane material being used in the High Pressure Turbine (HPT) Nozzle of the F404-400 turbofan engine. Thermal fatigue cracks are known to develop in the nozzle vanes during service and the component replacement costs can, in general, be very high. Attempts to demonstrate the feasiblity for braze repair of MA754 have thus far yielded little success.
An experimental program aimed at developing a braze repair procedure for healing cracks in MA754 HPT nozzles is described. Thirteen different braze compositions, using two different brazing times and gap widths, are evaluated. Experimental results are described detailing the microstructure, degree of oxide agglomeration and porosity in the region of the brazed joints. The feasibility of applying a braze repair procedure to the nozzle component is discussed.
Experimental Investigations of Pressure Drop in the Combustion Chamber of Gas Turbine
Authors: Dzida Marek , Kosowski Krzysztof 
Published: March 2015

In bibliography we can find many methods of determining pressure drop in the combustion chambers of gas turbines, but there is only very few data of experimental results.
This article presents the experimental investigations of pressure drop in the combustion chamber over a wide range of part-load performances (from minimal power up to take-off power). Our research was carried out on an aircraft gas turbine of small output. The experimental results have proved that relative pressure drop changes with respect to fuel flow over the whole range of operating conditions. The results were then compared with theoretical methods.
Experimental Evaluation of a Liquid-Fueled, Lean-Premixed Gas Turbine Combustor
Authors: Smith K. O. , Cowell L. H. 
Published: March 2015

Rig testing of a lean-premixed, liquid-fueled corabustor was conducted to establish the feasibility of achieving ultra-low NOx emissions at typical gas turbine operating conditions. Two different filming fuel injector concepts were evaluated.
The majority of combustor testing was conducted using No. 2 diesel. The test results showed 12 and 20 ppm NOx at 6 and 9 atm, respectively. Corresponding CO levels were 50 ppm in both cases.