bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Application of DLN Technology to the Tornado and Tempest Industrial Gas Turbines
Authors: Boyns Michael B. , Patel Rajeshri 
Published: December 2014

Dry low NOX combustion technology has been successfully applied to the EGT Tornado and Tempest industrial gas turbines. This lean-premix technology has been based on that being employed in the EGT Typhoon gas turbine, as reported by Norster & De Pietro (1996) but with a number of modifications to suit the individual engines.
The Tornado is a 6.1 MWe machine designed in the late 1970’s for power generation and mechanical drive applications. The worldwide emissions legislation of recent years has provided the requirement to reduce NOX emissions in the exhaust, both for new machines and for those already in operation. Hence a system suitable for retrofitting as well as new production was required. The Tornado utilises similar burners to the Typhoon but with different combustion chambers and a different centre casing from the standard Tornado. Due to the differing cycle conditions, a different reaction zone stoichiometry has been used. A short rig test program followed by engine testing have achieved NOX emissions at base load significantly lower than the initial program target of 42 ppmv and led to the program target being revised to 25 ppmv.
The Tempest, launched into the market in 1995 produces 7.49 MWe in single shaft configuration and is aimed at the electrical power generation market. To comply with current emissions legislation, a DLN system has been developed. The Tempest is a 25% scale up of the Typhoon but its mechanical design incorporates a simplified main and pilot burner arrangement and a fully fabricated combustor. At base load, the Tempest operates at a higher turbine entry temperature than the Typhoon but has been designed such that the equivalence ratio in the reaction zone is slightly lower. A comprehensive test programme has demonstrated hardware which significantly improves upon the target emissions limit of 25 ppmv NOX.
Combustion of Coal-Derived Fuel Gas in an Oxygen-Blown Pressurized Topping Combustor
Authors: Hoppesteyn Peter D. J. , Andries Jans , Hein Klaus R. G. 
Published: December 2014

Advanced integrated gasification combined cycle (IGCC) plants promise to be efficient and environmentally friendly systems to utilise solid fuels for the production of electricity and heat. An IGCC system consists of a gasifier, producing a low calorific value (LCV) fuel gas, and a gas turbine in which the LCV fuel gas is being combusted. At this time some demonstration IGCC plants have been commissioned in the United States and Europe. A sound understanding of the interaction between the gasifier and the gas turbine combustor is critical for successful operation of an IGCC system. Reliable theoretical and experimental information on the characteristics of the gas turbine as a whole and the combustor as such, leading to this information is needed prior to commercialisation of these IGCC systems. The combustion of natural gas in gas turbine combustors has been studied extensively. The combustion of coal-derived LCV fuel gas however has been studied in much less detail.
To obtain more fundamental data on the combustion of LCV fuel gas, a 1.5 MW pressurised fluidised bed gasifier (PFBG) with a separate pressurised topping combustor (PTC) has been designed, built and operated at Delft University of Technology (The Netherlands). The maximum system pressure is 10 bar. Experiments have been performed at 8 bar, using recirculated flue gas, steam and oxygen as gasifying agents. The produced LCV fuel gas is combusted in an oxygen blown PTC. In this way a flue gas with a high carbon dioxide concentration can be obtained from which the carbon dioxide can be removed more easily than from flue gases. A numerical model has been constructed to simulate the combustion of the LCV fuel gas in the PTC.
A detailed description of the test rig will be given. The first experimental results will be described and compared with simulation results obtained with the commercial Computational Fluid Dynamics code Fluent version 4.3. Finally the future work will be described.
Non Linear Behaviour of Oil Film Bearings and its Relevance in Force Identification Procedures
Authors: Bachschmid Nicolò , Dellupi Riccardo 
Published: December 2014

The main differences in the calculated behaviour of an unbalanced rotor on two-lobe oil film bearings, in terms of mean statical position, 1 × rev. and 2 × rev. components in steady-state conditions, between the results obtained by means of the linearized and the non linear oil film models are shown.
The errors introduced by the linearized model are not negligible and can affect significantly the accuracy of results of numerical simulations. This may be unacceptable if one uses the measured vibrations in the bearings for identifying the exciting forces on the rotor in a model based diagnostic approach.
Therefore a method is presented which utilises the linear model of the rotor and the non linear oil-film forces in the identification procedure.
Development of a Dry Low-NOx Combustor for the VT100 Automotive Gas Turbine
Authors: Johansson Patrik 
Published: December 2014

The design and development of a pilot assisted dry low-NOx LPP (Lean Premix Prevaporized) combustor for the VT100 turbogenerator is described. The combustor was designed for and tested on ethanol, a renewable biofuel chosen to minimize the contribution to atmospheric CO2.
Engine specifications for pressure drop, operability and emissions have been met. The combustor has successfully demonstrated ultra low NOx and CO emissions below 10 and 20 ppmv respectively at the best engine conditions.
The rig testing was performed at reduced inlet temperatures and the fuel flow was scaled to achieve main combustion zone flame temperatures as in the engine. The results show good agreement for NOx vs. flame temperature between the rig and engine tests.
The dry low-NOx combustor for the VT100 turbogenerator meets the emission specification and gives the hybrid propulsion system the potential of meeting the foreseen (2010) NOx emission targets for urban delivery vehicles of 1 g/kWhe compared to today’s 7 g/kWhe.
Rotor Design in Industrial Gas Turbines
Authors: Florjancic Stefan S. , Pross Jörg , Eschbach Urban 
Published: December 2014

The various design aspects of an industrial gas turbine rotor need special attention to ensure safe and reliable operation of the entire machine. The rotor has to fulfill the following main criteria and tasks: carry the blading, transmit the torque, define the aerodynamic channel geometry, guide the cooling air, provide sealing and bearing surfaces, and exhibit acceptable rotordynamic behavior. Additional criteria linked to the rotor design can be established, i.e., ease of manufacture and assembly, maintainability (where needed), transient blading tip clearances, rotational inertia, balance of axial thrust, and safety against fault conditions (blade loss, short circuit, hot-gas ingestion, etc.) with possibilities for subsequent repair. Industrial practice shows that there are several design approaches possible.
This paper describes the general requirements and how to assess the strength and the dynamic behavior under transient and steady state conditions. Additionally, the individual existing main design principles, i.e., stacked discs with individual centering and tie rod types, and monolithic or welded integral rotor design, are compared. Differences in levels of loading and in the dynamic behavior are outlined. Finally, an assessment of the individual rotor designs under fault conditions is given, and critical areas of the component under such conditions are discussed.
On-Site Liquid Gas Turbine Fuel Analysis for Trace Metal Contamination
Authors: Lukas M. , Anderson D. P. 
Published: December 2014

Contamination levels of liquid fuel entering the combustor of a gas turbine must be low to avoid high temperature corrosion and fuel system fouling. Accordingly, each of the major industrial gas turbine manufacturers has strict contamination limits which must be met in order to comply with the warranty of the turbine. The responsibility to assure compliance lies with the owner of the power plant and can only be guaranteed with on-site fuel analysis for contaminants and ash-forming metals.
This paper discusses the various fuel analysis techniques available to the gas turbine user. It will review each technique’s ability to meet the need for fast and precise on-site analytical data. It will be demonstrated that the rotating disc electrode (RDE) atomic emission technique is the preferred analytical method for on-site fuel analysis. Actual field experience will be used to illustrate and discuss compromises that may be necessary to meet the objectives of the gas turbine user, fuel treatment supplier and turbine manufacturer.
The Computation of Adjacent Blade-Row Effects in a 1.5 Stage Axial Flow Turbine
Authors: Emunds Rolf , Jennions Ian K. , Bohn Dieter , Gier Jochen 
Published: December 2014

This paper deals with the numerical simulation of flow through a 1.5 stage axial flow turbine. The 3-row configuration has been experimentally investigated at the University of Aachen where measurements behind the first vane, the first stage and the full configuration were taken. These measurements allow single blade row computations, to the measured boundary conditions taken from complete engine experiments, or full multistage simulations. The results are openly available inside the framework of ERCOFTAC 1996.
There are two separate but interrelated parts to the paper. Firstly, two significantly different Navier-Stokes codes are used to predict the flow around the first vane and the first rotor, both running in isolation. This is used to engender confidence in the code that is subsequently used to model the multiple bladerow tests, the other code is currently only suitable for a single blade row. Secondly, the 1.5 stage results are compared to the experimental data and promote discussion of surrounding blade row effects on multistage solutions.
Research and Development of 300kW Class Ceramic Gas Turbine Project in Japan
Authors: Arakawa Hironori , Suzuki Takayuki , Saito Kazufumi , Tamura Shigeru , Kishi Shinsuke 
Published: December 2014

The ceramic gas turbine (CGT) engine can achieve higher thermal efficiency, lower pollutant emissions, and has a wider fuel tolerance compared to conventional gasoline and diesel engines. Accordingly, research and development of a 300kW class ceramic gas turbine has been performed in Japan as a national project since FY 1988, under the Agency of Industrial Science and Technology (AIST), which is an agency of the Ministry of International Trade and Industry (MITI). The final target of the project is to achieve 42% thermal efficiency at a Turbine Inlet Temperature (TIT) of 1350°C.
At present, two different types of ceramic gas turbines (CGT 301 and CGT 302) are under development and operating tests of prototype engines are being carried out. The CGT 301 features removable ceramic blades joined to a metal rotor disk. This 37 blade hybrid rotor of the high pressure stage was hot spin tested at a TIT of 1350°C and the burst of the blades did not occur at the rated speed. A thermal efficiency of 26.4% was achieved at a TIT 1200°C during the first year of prototype operation. Improvement in component parts is ongoing and as a result, improvements in thermal efficiency are forthcoming.
The CGT 302 features a lean premixed low-NOx combustor having a primary diffusion burner, a set of main pre-mixed burners, single fuel injector, and air bypass to control combustion. This combustor showed a lower pressure loss and NOx emissions of 5ppm (O2 = 16%), which is less than the allowable value of 70ppm. Recent operating tests of this engine showed a maximum output power and thermal efficiency of 228kW and 36%, respectively, as of November 1996.
For both the CGT 301 and CGT 302, more focused research on CGT materials and components, as well as operating tests at 1350°C TIT, are being carried out in order to reach the final target values.
Entropy Generation in a 2-D Cascade at Different Angles of Attack: A Numerical Study
Authors: Natalini Gianni , Sciubba Enrico 
Published: December 2014

This paper presents the results of an entropy generation calculation made on a representative gas turbine rotor blade; in particular, the numerical study has dealt with the different flowfields which are encountered when the angle of attack is varied in a two-dimensional cascade on axial, internally cooled gas turbine rotor.
The analysis takes into consideration a two-dimensional cascade at medium Reynolds number (Rechord = 225000), sub-sonic Mach number (Main = 0.27), and steady state. The full Navier-Stokes equations of motion for a turbulent compressible viscous flow, together with the appropriate energy equation, are solved via a standard finite elements code with a k-ε closure, so that complete velocity- and temperature fields are obtained (including boundary-layer effects, via proper wall functions). These fields are then used to compute the entropy generation rates corresponding to the viscous- (Ṡv) and thermal (Ṡr) dissipation.
Several configurations have been numerically tested, the reference one being at design conditions, and the remaining being obtained from it by varying the angle of attack α (defined as the angle, measured ccw, between the relative velocity vector W1 and the tangent to the blade chord at impingement point), to simulate volume flowrate variations.
A commercial finite-element code (FIDAP, by FDI Inc.) has been modified to allow for the calculation of the local values of the entropy generation rates, the thermal- and viscous portions of which have been computed separately.
The results at design point are shown to agree well with the available cascade performance data.
The entropy generations rates are then used to compute the so-called entropy loss coefficient (a better name for which would be that of irreversibility coefficient, ζ, defined as:ζ=T0Δsh1s-h2iwhere T0 is the reference ambient temperature, Δs is the total local entropy generation rate (sum of the viscous- and thermal components), and h1i and h2i are the stagnation enthalpy upstream of the rotor and the ideal exit enthalpy respectively.
The results are shown under the form of cp - and ζ graphs computed for different angles of attack α (from −4.4 to +7.6 degrees), and are representative of realistic situations which could arise in actual gas turbine rotors. The loss coefficient ζ is shown to attain a minimum value at design point.
Integral values for the entropy generation rates are also computed, and total entropy losses are thus computed for the various configurations. Maps of the viscous- and thermal entropy generation rates are shown for each angle of attack, where of interest.
Engine Representative Discharge Coefficients Measured in an Annular Nozzle Guide Vane Cascade
Authors: Rowbury D. A. , Oldfield M. L. G. , Lock G. D. 
Published: December 2014

This paper discusses measurements of the discharge coefficients of gas turbine nozzle guide vane film cooling holes under fully engine representative conditions. These unique experiments were carried out in a large scale annular blowdown cascade which models the three-dimensional external, flow patterns found in modern aero-engines, including all secondary flow phenomena. Furthermore, the coolant system design allows the coolant-to-mainstream density ratio and blowing parameter to be matched to engine values, although they can be independently varied.
The results confirm that the discharge coefficients of film cooling holes are significantly altered by external crossflow. The discharge coefficient is usually reduced by external crossflow, but under certain external flow conditions it can be increased over the non-crossflow case. This previously unhightighted phenomenon has been termed ‘the crossover effect’, and, although an initially surprising result, is of importance to aero-engine designers as taking account of it should lead to improved predictions of coolant consumption. As a consequence, more uniform blade cooling should be achieved and, in turn, the attainment of greater component durability will be possible.
Three Dimensional Unsteady Pressure Measurements for an Oscillating Turbine Blade
Authors: Bell D. L. , He L. 
Published: December 2014

A complete set of unsteady blade surface pressure measurements is presented for a single turbine blade oscillating in a three dimensional bending mode. Results are provided for five spanwise sections at 10%, 30%, 50%, 70% and 90% of span. Steady blade pressure measurements and five-hole probe traverses at the inlet and exit planes of the test section, are also included.
The test facility operates at low speed and the working section consists of a single turbine blade mounted in a profiled duct. A rigid blade with constant section was used, and a three dimensional bending mode realised by hinging the blade at root and driving the tip section. The low speed and scale of the test facility allowed low oscillation frequencies (5 to 20 Hz) to be employed, in order to match realistic reduced frequencies. This enabled the unsteady blade surface pressure response to be recorded with externally mounted pressure transducers. The validity of this technique is examined. Results from the test facility demonstrate a noticeable three dimensional behaviour of the unsteady flow.
The Design of Fabricated Ducts to Avoid Gas Induced High Cycle Fatigue
Authors: Eaton R. , Platt J. , Gallimore S. 
Published: December 2014

The design and fatigue life analysis of many fabricated sheet metal components which operate in a hot gas path environment is made uncertain by the difficulty in predicting the gas dynamic forces to which the component will be subjected. This is particularly true for ducts which are exposed to minimal static loading such as inter-turbine ducts, which have little pressure drop across them but are subjected to highly non-uniform flow from the upstream turbine exit. Finite element analysis and static testing has revealed — that certain modal frequencies respond much more significantly than others and where these coincide with gas dynamic frequencies a resonance is set up and rapid and catastrophic failure will occur.
Through a combination of analysis and engine testing it has been possible to identify the damaging gas dynamics and modal frequencies. This has enabled rules to be developed which assist in the design of such ducts to avoid high cycle fatigue failure.
This paper describes the development of the design process and by means of a typical example shows its application and effect on the design of an inter-turbine duct.
The Maximum Transient Resonance Response of Rotating Blades With Regard to Centrifugal Force and Non-Linear Damping Effects
Authors: Irretier Horst D. 
Published: December 2014

During the operation process in many types of fluid flow machines the rotating blades pass through various resonances e.g. during run-up or run-down or other transient conditions. Therefore, for the high cycle fatigue problem of the blades it might be important to consider the transient vibratory response of the blades during these passages through resonance and to get knowledge about the occuring maximum vibratory stresses.
In the paper, approximate formulas are presented which allow the estimation of the maximum transient response of the blades. Thereby, the influence of the change of the natural frequencies due to the increasing or decreasing centrifugal force field during the run-up or run-down, respectively, is taken into consideration. Basically, the approximate formulas are based on a linear change of the natural frequencies versus time and on a linear viscous type of damping. Extensions to account for parabolic changes which are more realistic for centrifugal effects and for non-linear damping models e.g. friction damping or turbulence damping are discussed.
Design of a Semiclosed Cycle Gas Turbine With Carbon Dioxide-Argon as Working Fluid
Authors: Ulizar Inaki , Pilidis Pericles 
Published: December 2014

The main performance features of a semiclosed cycle gas turbine with carbon dioxide-argon working fluid are described here. This machine is designed to employ coal synthetic gas fuel and to produce no emissions.
The present paper outlines three tasks carried out. Firstly the selection of main engine variables, mainly pressure and temperature ratios. Then a sizing exercise is carried out where many details of its physical appearance are outlined. Finally the off-design performance of the engine is predicted.
This two spool gas turbine is purpose built for the working fluid, so its physical characteristics reflect this requirement. The cycle is designed with a turbine entry temperature of 1650 K and the optimum pressure ratio is found to be around 60. Two major alternatives are examined, the simple and the precooled cycle.
A large amount of nitrogen is produced by the air separation plant associated with this gas turbine and the coal gasifier. An investigation has been made on how to use this nitrogen to improve the performance of the engine by precooling the compressor, cooling the turbine nozzle guide vanes and using it to cool the delivery of the low pressure compressor.
The efficiencies of the whole plant have been computed, taking into account the energy requirements of the gasifier and the need to dispose of the excess carbon dioxide. Hence the overall efficiencies indicated here are of the order of 40 percent. This is a low efficiency by current standards, but the fuel employed is coal and no emissions are produced.
The GE Rich-Quench-Lean Gas Turbine Combustor
Authors: Feitelberg Alan S. , Lacey Michael A. 
Published: December 2014

The General Electric Company has developed and successfully tested a full-scale, ‘F’ class (2550°F combustor exit temperature), rich-quench-lean (RQL) gas turbine combustor, designated RQL2, for low heating value (LHV) fuel and integrated gasification combined cycle applications. Although the primary objective of this effort was to develop an RQL combustor with lower conversion of fuel bound nitrogen to NOx than a conventional gas turbine combustor, the RQL2 design can be readily adapted to natural gas and liquid fuel combustion.
RQL2 is the culmination of a 5 year research and development effort that began with natural gas tests of a 2″ diameter perforated plate combustor and included LHV fuel tests of RQL1, a reduced scale (6″ diameter) gas turbine combustor. The RQL2 combustor includes a 14″ diameter converging rich stage liner, an impingement cooled 7″ diameter radially-stratified-quench stage, and a backward facing step at the entrance to a 10″ diameter film cooled lean stage. The rich stage combustor liner has a novel double-walled structure with narrow circumferential cooling channels to maintain metal wall temperatures within design limits. Provisions were made to allow independent control of the air supplied to the rich and quench/lean stages.
RQL2 has been fired for almost 100 hours with LHV fuel supplied by a pilot scale coal gasification and high temperature desulfurization system. At the optimum rich stage equivalence ratio NOx emissions were about 50 ppmv (on a dry, 15% O2 basis), more than a factor of 3 lower than expected from a conventional diffusion flame combustor burning the same fuel. With 4600 ppmv NH3 in the LHV fuel, this corresponds to a conversion of NH3 to NOx of about 5%. As conditions were shifted away from the optimum, RQL2 NOx emissions gradually increased until they were comparable to a standard combustor. A chemical kinetic model of RQL2, constructed from a series of ideal chemical reactors, matched the measured NOx emissions fairly well. The CO emissions were between 5 and 30 ppmv (on a dry, 15% O2 basis) under all conditions.