bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Assessment of Fiber Reinforced Ceramics for Combustor Walls
Authors: Filsinger D. , Münz S. , Schulz A. , Wittig S. , Andrees G. 
Published: December 2014

Experimental and theoretical work concerning the application of ceramic components in small high temperature gas turbines has been performed for several years. The significance of some non-oxide ceramic materials for gas turbines in particular is based on their excellent high temperature properties. The application of ceramic materials allows an increase of the turbine inlet temperature resulting in higher efficiencies and a reduction of pollution emissions.
The inherent brittleness of monolithic ceramic materials can be virtually reduced by reinforcement with ceramic fibers leading to a quasi-ductile behavior. Unfortunately, some problems arise due to oxidation of these composite materials in the presence of hot gas flow containing oxygen.
At the Motoren- und Turbinen Union, München GmbH, comprehensive investigations including strength, oxidation, and thermal shock tests of several materials that seemed to be appropriate for combustor liner applications were undertaken. As a result, C/C, SiC/SiC, and two C/SiC-composites coated with SiC, as oxidation protection, were chosen for examination in a gas turbine combustion chamber.
To prove the suitability of these materials under real engine conditions, the fiber reinforced flame tubes were installed in a small gas turbine operating under varying conditions. The loading of the flame tubes was characterized by wall temperature measurements.
The materials showed different oxidation behavior when exposed to the hot gas flow. Inspection of the C/SiC-composites revealed debonding of the coatings. The C/C- and the SiC/SiC-materials withstood the tests with a maximum cumulated test duration of 90 hours without damage.
Development and Investigation of Ceramic Parts for Gas-Turbine Engines
Authors: Nozhnitsky Youry A. , Fedina Youlia A. , Rekin Anatoly D. , Petrov Nickolai I. 
Published: December 2014

For years of time there have been conducted the investigations of gas-turbine engine parts made of carbon-carbon and ceramic materials.
This paper presents mainly the results of works done to create engine components of ceramic materials. There are given the investigation results on development of equipment and methods intended for use in determining the characteristics of heat-resistant non-metallic materials under ultra high temperature conditions. The unique tooling is developed to be used for conducting mechanical tests in different conditions (vacuum, protective medium, air) at temperatures up to 2200°C. There are considered three possible fields of application of ceramic materials, that are, turbine (1), combustion chamber and other stator components operating at high temperatures (2), bearings (3). Different ceramic elements are designed and manufactured, their structural strength is investigated in the laboratory faculties and also as part of engine gas generators.
The Design Modifications of the EGT Tornado Industrial Gas Turbine to Incorporate a Dry Low Emissions Combustion System
Authors: Gallimore Stephen , Vickers R. Michael , Boyns Michael B. 
Published: December 2014

The Tornado gas turbine was designed at a time when emissions legislation was minimal and was developed through the eighties to accept water or steam injection for NOX reduction. In recent years it has become necessary to develop dry methods of emissions reduction for new engine sales and to enable existing operators to retrofit their engines when legislation demands.
The compact design of the Tornado’s centre section did not lend itself to a simple combustor changeout. The lean pre-mix dry low emissions (DLE) system developed for the Typhoon gas turbine required additional combustor length for CO burnout and could not be fitted into the existing casings of the Tornado engine. The challenge was therefore to redesign the centre section to enable the DLE system to be fitted without compromising the design of the compressor, HP turbine and gas generator rotor.
This paper describes the methodology used and the design of the engine centre section together with the results of design and performance validation undertaken including emissions measurements.
Film-Cooling From Holes With Expanded Exits: A Comparison of Computational Results With Experiments
Authors: Giebert D. , Gritsch M. , Schulz A. , Wittig S. 
Published: December 2014

A 3D Navier-Stokes code, together with the standard k-ϵ model with wall function approach, was used to investigate the flowfield in the vicinity of three different single scaled-up film-cooling holes. The hole geometries include a cylindrical hole, a hole with laterally expanded exit, and a hole with forward-laterally expanded exit.
Comparisons of numerical results with detailed flowfield measurements of mean velocity and turbulent quantities are presented for a blowing ratio and density ratio of unity. Additionally, experimental data for different blowing ratios and a density ratio of about two are taken to perform validation of the code for adiabatic film-cooling effectiveness prediction.
Results show that for both the round and the expanded hole geometries the code is able to capture all dominating flow structures of this jet in crossflow problem. However, discrepancies are found when comparing the flowfield inside the hole and at the hole exit. In particular, jet location at the hole exit differs significantly from measurement for the expanded hole geometries. For the adiabatic film-cooling effectiveness, it is shown that for round and expanded hole exits the intensity of the shear regions and the source of turbulence, respectively, have a strong influence on the predictive capability of the numerical code.
Adiabatic Wall Effectiveness Measurements of Film-Cooling Holes With Expanded Exits
Authors: Gritsch M. , Schulz A. , Wittig S. 
Published: December 2014

This paper presents detailed measurements of the film-cooling effectiveness for three single, scaled-up film-cooling hole geometries. The hole geometries investigated include a cylindrical hole and two holes with a diffuser shaped exit portion (i.e. a fanshaped and a laidback fanshaped hole). The flow conditions considered are the crossflow Mach number at the hole entrance side (up to 0.6), the crossflow Mach number at the hole exit side (up to 1.2), and the blowing ratio (up to 2). The coolant-to-mainflow temperature ratio is kept constant at 0.54. The measurements are performed by means of an infrared camera system which provides a two-dimensional distribution of the film-cooling effectiveness in the nearfield of the cooling hole down to x/D = 10.
As compared to the cylindrical hole, both expanded holes show significantly improved thermal protection of the surface downstream of the ejection location, particularly at high blowing ratios. The laidback fanshaped hole provides a better lateral spreading of the ejected coolant than the fanshaped hole which leads to higher laterally averaged film-cooling effectiveness. Coolant passage crossflow Mach number and orientation strongly affect the flowfield of the jet being ejected from the hole and, therefore, have an important impact on film-cooling performance.
Discharge Coefficient Measurements of Film-Cooling Holes With Expanded Exits
Authors: Gritsch M. , Schulz A. , Wittig S. 
Published: December 2014

This paper presents the discharge coefficients of three film-cooling hole geometries tested over a wide range of flow conditions. The hole geometries include a cylindrical hole and two holes with a diffuser shaped exit portion (i.e. a fanshaped and a laidback fanshaped hole). The flow conditions considered were the crossflow Mach number at the hole entrance side (up to 0.6), the crossflow Mach number at the hole exit side (up to 1.2), and the pressure ratio across the hole (up to 2).
The results show that the discharge coefficient for all geometries tested strongly depends on the flow conditions (crossflows at hole inlet and exit, and pressure ratio). The discharge coefficient of both expanded holes was found to be higher than of the cylindrical hole, particularly at low pressure ratios and with a hole entrance side crossflow applied. The effect of the additional layback on the discharge coefficient is negligible.
A Small Gas Turbine Plant for Cogeneration of Electricity, Thermal and Cooling Thermal Energy With an Absorption Unit
Authors: De Lucia Maurizio , Lanfranchi Carlo , Matucci Antonio 
Published: December 2014

A cogeneration plant with a small gas turbine was installed in a pharmaceutical factory and instrumented for acquiring all the values necessary to appraise both its energetic and cost advantages. The plant was designed and built as a demonstrative project under a program for energy use improvement in industry, partially financed by the European Union.
The system comprises as its main components: 1) a gas turbine cogeneration plant for production of power and thermal energy under the form of hot water, superheated water, and steam; 2) a two-stage absorption unit, fueled by the steam produced in the cogeneration plant, for production of cooling thermal energy.
The plant was provided with an automatized control system for the acquisition of plant operating parameters. The large amount of data thus provided made it possible to compare the new plant, under actual operating conditions, with the previously existing cooling power station with compression units, and with a traditional power plant.
This comparative analysis was based on measurements of the plant operating parameters over nine months, and made it possible to compare actual plant performance with that expected and ISO values. The analysis results reveal that gas turbine performance is greatly affected by part-load as well as ambient temperature conditions. Two-stage absorber performance, moreover, turned out to decrease sharply and more than expected in off-design operating conditions.
Comparison of Industrial Gas Turbine Transient Responses Performed by Different Dynamic Models
Authors: Peretto A. , Spina P. R. 
Published: December 2014

In this paper, the transient responses of different dynamic models of a generator drive single shaft gas turbine working in parallel with electrical mains, have been analyzed.
The time variations of the main thermodynamic and performance parameters are obtained by varying the fuel valve position, for an assigned IGV angle, and by varying the IGV angle for an assigned fuel valve position.
The influence of the dynamic phenomena due to the working gas mass contained in the gas turbine component volumes, of the metal mass thermal inertia and of the heat transfers, are taken separately into account. The dynamic balance of rotating masses is not instead considered, since the single shaft gas turbine works in parallel with electrical mains.
The developed analysis has shown the negligible influence of the phenomena due to the working gas mass contained in the gas turbine component volumes and a more significative effect of the metal mass inertia and of the heat transfers on the transient response. In particular, this influence is significative only for gas turbine and compressor outlet temperatures.
The influence on the gas turbine transient behaviour of the control system that uses the gas turbine outlet temperature in feedback has been also evaluated.
Gas Turbine Exhaust Emissions Monitoring Using Non-Intrusive Infrared Spectroscopy
Authors: Hilton Moira , Lettington Alan H. , Wilson Chris W. 
Published: December 2014

Infrared (IR) spectra of the exhaust emissions from a static gas turbine engine have been studied using Fourier Transform (FT) spectroscopic techniques. Passive detection of the infrared emission from remote (range ∼ 3 m) hot exhaust gases was obtained non-intrusively using a high spectral resolution (0.25 cm−1) FTIR spectrometer. Remote gas temperatures were determined from their emission spectra using the total radiant flux method or by analysis of rotational line structure. The HITRAN database of atmospheric species was used to model the emission from gas mixtures at the relevant temperatures.
The spatial distribution of molecular species across a section transverse to the exhaust plume −10 cm downstream of the jet pipe nozzle was studied using a tomographic reconstruction procedure. Spectra of the infrared emission from the plume were taken along a number of transverse lines of sight from the centreline of the engine outwards. A mathematical matrix inversion technique was applied to reconstruct the molecular concentrations of CO and CO2 in concentric regions about the centreline.
Quantitative measurements of the molecular species concentrations determined non-intrusively were compared with results from conventional extractive sampling techniques.
A Test Facility for the Measurement of Torques at the Shaft to Seal Interface in Brush Seals
Authors: Wood P. E. , Jones T. V. 
Published: December 2014

An important factor in the performance of brush seals for a wide range of gas turbine applications is the rate of wear at the seal to shaft interface, which is dependant on the contact pressure that exists between the bristles and rubbing surface. This is dependent on a variety of effects. Principally these are; the aerodynamic forces bending the bristles onto the rubbing surface; frictional effects within the bristle pack, and at the backing ring, that arise with the application of pressure differential; geometrical changes due to centrifugal and thermal growths and transient differential movements of the rotor that develop in flight manoeuvres.
In order to investigate the effect of these phenomena on contact pressure, a test facility has been devised in which the torque exerted by a brush seal on a rotating shaft is used as an indirect measurement of contact pressure. This has necessitated the design of a test facility in which all system torques can be fully calibrated. Consequently, a pressure balanced design has been adopted, in which applied seal differential and pressure levels have a minimal effect on axial loads at the rotor bearing assembly. The primary method of torque measurement is the instantaneous deceleration of the rotor. Thus measurements over a wide speed range are acquired with high frequency instrumentation. The means whereby small parasitic torques are evaluated and corrected is given. Results demonstrating the dependence of contact pressure on seal differential and pressure levels are presented.
Effects of Rotation on Blade Surface Heat Transfer: An Experimental Investigation
Authors: Moss Roger W. , Ainsworth Roger W. , Garside Tom 
Published: December 2014

Measurements of turbine blade surface heat transfer in a transient rotor facility are compared with predictions and equivalent cascade data. The rotating measurements involved both forwards and reverse rotation (wake free) experiments.
The use of thin-film gauges in the Oxford Rotor Facility provides both time-mean heat transfer levels and the unsteady time history. The time-mean level is not significantly affected by turbulence in the wake; this contrasts with the cascade response to freestream turbulence and simulated wake passing.
Heat transfer predictions show the extent to which such phenomena are successfully modelled by a time-steady code. The accurate prediction of transition is seen to be crucial if useful predictions are to be obtained.
Improved Reliability of Bladed Disks due to Friction Dampers
Authors: Sextro Walter , Popp Karl , Wolter Ivo 
Published: December 2014

Friction dampers are installed underneath the blade platforms to improve the reliability. Because of centrifugal forces the dampers are pressed onto the platforms. Due to dry friction and the relative motion between blades and dampers, energy is dissipated, which results in a reduction of blade vibration amplitudes.
The geometry of the contact is in many cases like a Hertzian line contact. A three-dimensional motion of the blades results in a two-dimensional motion of one contact line of the friction dampers in the contact plane. An experiment with one friction damper between two blades is used to verify the two-dimensional contact model including microslip.
By optimizing the friction dampers masses, the best damping effects are obtained.
Finally, different methods are shown to calculate the envelope of a three-dimensional response of a detuned bladed disk assembly (V84.3-4th-stage turbine blade) with friction dampers.
Non-Contact Vibration Measurements of Mistuned Coupled Blades
Authors: Schaber Ulrich 
Published: December 2014

Most of the turbomachine manufacturers are using a non-contact measurement system to measure blade vibration by two probes located in the casing radially outside a blade row. All blades of a row can be observed by this system, therefore it may be considered to be an ideal solution for measuring the vibration response of mistuned blades which have quite different vibration levels from blade to blade in resonance conditions.
By a simple calculation model a non-contact blade vibration measurement was simulated. It was found that for mistuned coupled blades the non-contact measurement results show some deviations from the actual vibration amplitudes. Different mistuning conditions have been investigated by a parameter study to estimate the inherent measurement error of the non-contact principle. Measurements at a circumferentially coupled gas turbine blading performed by a non-contact system and by strain gauges did also show deviations in the results obtained by the two measurement methods.
Allison Advanced Turbine Systems (ATS) Engine Cycle
Authors: Halsey Jack E. , Warns Richard J. , Weisbrod William D. 
Published: December 2014

An advanced, simple cycle, gas turbine engine under development will offer revolutionary improvements in simple cycle efficiency, emissions, and the cost of electricity. Overall thermal efficiencies from 38 to 40+% are projected over a 4 to 14 megawatt (MW) power range through the application of industry leading aerodynamics, turbine cooling, and material/manufacturing technologies. This family of engines will be identified as the Allison Model 701-K series. Aggressive compressor pressure ratios and firing temperatures equal to the most advanced, commercially available aero engines, will be used to reach this level of performance. This cycle efficiency is complemented by revolutionary advancements in dry low emission combustion technology that support the demands of future emission regulations.
The initial engine design and development effort is being accomplished under a cooperative agreement between the U.S. Department of Energy (DOE), Allison Engine Company, and multiple industry partners. This paper outlines the path to selecting the ATS engine cycle and general arrangement, the types of technologies required, and their application to the engine. An overview of the engine development program, including component rig and engine tests, and program status are presented. Program plans to evolve the ATS into a family of advanced industrial engines are also outlined.
High Temperature Proximity Measurement in Aero and Industrial Turbomachinery
Authors: Sheard A. G. , O’Donnell S. G. , Stringfellow J. F. 
Published: December 2014

The measurement of disc and shaft displacement has been performed for many years as part of the development, commissioning and monitoring of all classes of turbomachinery. This measurement has traditionally been performed using sensors that can not operate above the curie point of rare earth magnets.
In this paper a programme of work is described that was undertaken to develop a measurement system that could make a measurement of target proximity in a high temperature environment. The specific objectives were firstly to make possible the measurement of turbine disc axial movement and shaft motion in the engine core, close to the combustion chamber or turbine; and secondly to make possible the measurement of tip clearance over shrouded turbine rotors.
Transient Performance Analysis of a Two Spool Turbofan for Lifing and Handling Purposes
Authors: Kotsiopoulos Petros , Pilidis Pericles , Adamopoulos Dimitrios 
Published: December 2014

The handling of a gas turbine and its life usage are closely related. As the handling capability required from an engine increases so does the life consumption. Faster transients and response require higher temperature levels, this reduces component lives. The phenomenon investigated here is thermal fatigue and the main focus is in the hot section of the engine, specifically the turbine blades.
To make a quantitative assessment of the reduction of life due to the requirement of a faster transient response a simulation code of a two spool turbofan engine has been developed. It has a routine that estimates the High Pressure Turbine blade metal temperature. This temperature has been used to estimate the reduction of life loss when fast shaft accelerations are required.
The main conclusion of this work is that, as expected, fast transients consume life faster. The present investigations suggest a quantitative level of thermal life reduction of approximately twenty five to thirty percent when comparing a fast acceleration of two to three seconds with a slower one of eight to ten seconds.
Development in the Full Assembly Test Rig of the 100kW Automotive Ceramic Gas Turbine
Authors: Nakazawa Norio , Ogita Hiroshi , Takahashi Masayuki , Kawaguchi Yoshihiro 
Published: December 2014

“Development of 100kW Automotive Ceramic Gas Turbine (CGT)” is a seven-year program started in fiscal 1990. Subsidized by the Agency of Natural Resources and Energy, the Ministry of International Trade and Industry, this program is being carried forward by the Petroleum Energy Center (PEC) and is aimed at the following goals;
- Maximum Output Power: 100kW
- Maximum Thermal Efficiency: 40% [Turbine Inlet Gas Temperature (TIT): 1350°C]
- Emission Characteristics: Conformity to regulations for gasoline-fueled passenger cars.
Loss Prediction for Rotating Passages in Secondary Air Systems
Authors: Reichert A. W. , Brillert D. , Simon H. 
Published: December 2014

Modern heavy duty gas turbines operate with high turbine inlet temperatures, and thus require a complex secondary air system to ensure that the blades and vanes are supplied with the required amount of cooling air. Gas turbines with high thermal efficiency and with low emissions require minimum amounts of cooling and sealing air which means that the design of the secondary air system must be extremely accurate.
A previous paper introduced the secondary air system for the new Siemens Vx4.3A gas turbines and the calculation method used for its design. This paper deals with the detailed calculation of flow field losses in cooling air passages in rotating disks (rotating passages). The paper starts with a brief review of the work on this topic described in the literature and then presents a consistent model for the prediction of the flow field losses in rotating passages of different lengths and with varying upstream swirl. Particularly short passages with developing flow at the passage exit can he calculated using this model. The calculation system is completed by matching the correlations to experimental data.