bluuebunny/crossref_metadata_2025_split huggingface dataset:
Particle Diagnostics and Turbulence Measurements in a Confined Isothermal Liquid Spray
Authors: de la Rosa A. Breña , Sankar S. V. , Wang G. , Bachalo W. D. 
Published: March 2015

This work reports an experimental study of the behaviour and structure of a liquid spray immersed in a strong swirling field. In order to simulate some of the aerodynamic conditions experienced by a spray in a model combustor, an experimental setup using an acrylic chamber, a vane type swirler, and separate air supplies for both the secondary air and the swirl air were integrated to perform the experiments in the wind tunnel. A vane type swirler exhibiting a high swirl number was used to produce a strong recirculation flow field downstream of a pressure swirl atomizer. Properties of the dispersed phase such as velocity, size distributions, and size-velocity correlations were measured at several locations within the swirling flow field. In addition, mean velocity and turbulence properties were obtained for the gas phase. Flow visualization was performed with a laser sheet to gain further understanding of the formation and influence of the recirculation region on the spray. A 2-component PDPA system with a frequency based Doppler Signal Analyzer was used throughout the measurements, and proved most valuable in the toroidal vortex region where low SNR conditions and non-uniform concentration of seed particles prevail. The results show that flow reversal of the drops is present at this swirl intensity within the recirculation region at distances up to X/D = 2.0. Small variations of drop size distribution within the recirculation region are observed, however large variations outside of it are also present.
Plots of the normal Reynolds stresses and Reynolds shear stresses show double-peak radial distributions which indicate regions in the flow where high mean velocity gradients and large shear forces are present. The decay of turbulence velocities in the axial direction was observed to be very fast, an indication of high diffusion and dissipation rates of the kinetic energy of turbulence.
Investigation of Combustion Structure Inside Low NOx Combustors for a 1500°C-Class Gas Turbine
Authors: Matsuzaki H. , Fukue I. , Mandai S. , Tanimura S. , Inada M. 
Published: March 2015

This paper describes the cold flow tests and low pressure combustion tests which were conducted for the development of a 1500°C-class low NOx combustion system. In the cold flow tests, the effect of vane angle and the momentum ratio of fuel to air flow on mixing characteristics inside the premixing nozzles was investigated. The stabilization of the flow field inside the combustor was confirmed by measurement of the axial velocity distribution and observations by using a tuft of soft thread.
Combustion characteristics in terms of emissions and stability were investigated initially by low pressure combustion tests, and the gas temperature distribution inside the combustor was measured. NOx emissions for a 1500°C-class gas turbine as low as 50ppm at 15% oxygen at design pressure were demonstrated.
Modified Combined Cycle With Pressure Fluidized Bed Combustion Boiler
Authors: Dzierzgowski Jacek , Sobkowski Stanislaw 
Published: March 2015

The article describes conversion of conventional steam cycle with 200 MW turbine into combined steam-gas cycle with pressure fluidized bed combustion boiler.
In order to raise cycle thermal efficiency an additional combustion chamber before a gas turbine was introduced. Two modifications of the combined cycle were considered. In one of them natural gas in the additional combustion chamber is burnt with the boiler flue gas only. In the other gas is burnt with additional air stream taken from behind the gas turbine compressor.
Optimizing calculations of the cycle thermal efficiency in function of some cycle’s main parameters were carried out.
An Update on the Development of the T407/GLC38 Modern Technology Gas Turbine Engine
Authors: Zoccoli Michael J. , Rusterholz Kenneth P. 
Published: March 2015

The T407/GLC38 is a modern technology 6000 SHP class turboshaft/turboprop gas turbine engine which is being developed jointly by Textron Lycoming (Stratford, Connecticut), General Electric Aircraft Engines (Lynn, Massachusetts), Bendix Controls (South Bend, Indiana), and Ruston Gas Turbines (Great Britain).
The gas generator core for the T407/GLC38 engine series is also common to the CFE738, a new generation turbofan which is being developed by General Electric and the Garret Engine Division.
The T407 (military)/GLC38 (commercial) is a derivative of the highly successful U.S. Army/GE27 MTDE engine which has been redesigned to meet commercial engine life standards.
The design philosophy for this engine was directed at achieving high output power per unit airflow, reliability from reduced parts count, ease of maintenance via extensive modularity, and state-of-the-art SFC levels that are up to 25% below those of existing 5000–6000 SHP powerplants. The latter characteristic manifests itself in reduced life cycle and direct operating costs and (where applicable) tradeoff versatility amongst range, time on station, and payload increase.
This paper is a continuation in a documentary series on the T407/GLC38 design and development. It traces the evolution of the T407/GLC38 program from First Engine to Test, wherein all thermodynamic and mechanical objectives were essentially achieved or exceeded, through full system turboprop evaluation, turbofan development testing, and qualification/certification testing completed to date.
A comprehensive review of the test objectives, testing requirements, setup, and basic results are provided; in addition, the relevancy and impact of each phase of engine testing towards the goal of qualification/certification and ultimately production is provided.
Comparison Between Experiment and Prediction for a Subsonic Turbulent Separated Boundary Layer
Authors: Bohn D. , Dibelius G. H. , Sucharski Z. 
Published: March 2015

Experimental and theoretical investigations were conducted for examining the effects of high free-stream turbulence at a high adverse pressure gradient and of periodically unsteady perturbations on the turbulent boundary layer development along the suction side of a turbine blade.
As part of the experimental test rig the blade suction side is represented by a flat plate of 550 mm length. A pressure distribution typical for a turbine blade channel is generated by a curved wall opposite to this plate. The separated region towards the trailing end of the plate is 25 % of its total length. For simulating the unsteady effect of wakes being shed from the previous blade row, a wake generator is installed in the inlet cross section of the test rig. The turbulence level is raised by a turbulence grid just ahead of the wake generator. An LDV with high spatial resolution is used for measuring averaged and fluctuating components of the velocity and turbulence related quantities in the boundary layer. New correlations for the measured velocity profiles and other flow quantities especially for the separated near wall region are presented.
Two separated turbulent boundary layers in a steady stream i.e. the forementioned and that measured by Simpson as well as an unseparated unsteady turbulent boundary layer have been theoretically examined. The solutions were obtained with a finite-difference boundary layer computer code and as well as with a fully elliptic finite-volume calculation procedure. The Cebeci-Smith algebraic, the Johnson-King nonequilibrium algebraic and two variants of the k-ε turbulence models were used in these calculations. The results of the various turbulence models for these flows are compared with the experimental data.
An Analysis System for Blade Forced Response
Authors: Chiang Hsiao-Wei D. , Kielb Robert E. 
Published: March 2015

A frequent cause of turbomachinery blade failure is excessive resonant response. The most common excitation source is the nonuniform flow field generated by inlet distortion, wakes, and/or pressure disturbances from adjacent blade rows. The standard method for dealing with this problem is to avoid resonant conditions using a Campbell diagram. Unfortunately, it is impossible to avoid all resonant conditions. Therefore, judgements based on past experience are used to determine the acceptability of a blade design.
A new analysis system has been developed to predict blade forced response. The system provides a design tool, over and above the standard Campbell diagram approach, for predicting potential forced response problems. The incoming excitation sources are modeled using a semi-empirical rotor wake/vortex model for wake excitation, measured data for inlet distortion, and a quasi-3D Euler code for pressure disturbances. Using these aerodynamic stimuli, and the blade’s natural frequencies and mode shapes from a finite element model, the unsteady aerodynamic modal forces and the aerodynamic damping are calculated. A modal response solution is then performed.
This system has been applied to current engine designs. A recent investigation involved fan blade response due to inlet distortion. An aeromechanical test had been run with two different distortion screens. The resulting distortion entering the fan was measured. With this as input data, the predicted response agreed almost exactly with the measured response. In another application, the response of the LPT blades of a counter-rotating supersonic turbine was determined. In this case the blades were excited by both a wake and a shock wave. The shock response was predicted to be three times larger than that of the wake. Thus, the system identified a new forcing function mechanism for supersonic turbines.
This paper provides a basic description of the system, which includes: 1) models for the wake excitation, inlet distortion, and pressure disturbance; 2) a kernel function solution technique for unsteady aerodynamics; and 3) a modal aeroelastic solution using strip theory. Also, results of the two applications are presented.
Discharge Coefficients of Holes Angled to the Flow Direction
Authors: Hay N. , Henshall S. E. , Manning A. 
Published: March 2015

In the cooling passages of gas turbine blades, branches are often angled to the direction of the internal flow. This is particularly the case with film cooling holes. Accurate knowledge of the discharge coefficient of such holes at the design stage is vital so that the holes are correctly sized thus avoiding wastage of coolant and the formation of hot spots on the blade.
This paper describes an experimental investigation to determine the discharge coefficient of 30° inclined holes with various degrees of inlet radiusing and with the axis of the hole at various orientation angles to the direction of the flow. Results are given for nominal main flow Mach numbers of 0, 0.15 and 0.3.
The effects of radiusing, orientation and cross flow Mach number are quantified in the paper, the general trends are described, and the criteria for optimum performance are identified.
Interactions Between Embedded Vortices and Injectant From Film Cooling Holes With Compound Angle Orientations in a Turbulent Boundary Layer
Authors: Ligrani P. M. , Mitchell S. W. 
Published: March 2015

Experimental results are presented which describe the effects of embedded, longitudinal vortices on heat transfer and film injectant downstream of two staggered rows of film cooling holes with compound angle orientations. Holes are oriented so that their angles with respect to the test surface are 30 degrees in a spanwise/normal plane projection, and 35 degrees in a streamwise/normal plane projection. A blowing ratio of 0.5, non-dimensional injection temperature parameter θ of about 1.5, and freestream velocity of 10 m/s are employed. Injection hole diameter is 0.945 cm to give a ratio of vortex core diameter to hole diameter of 1.6–1.67 just downstream of the injection holes (x/d=10.2). At the same location, vortex circulation magnitudes range from 0.15 m2/s to 0.18 m2/s. By changing the sign of the angle of attack of the half-delta wings used to generate the vortices, vortices are produced which rotate either clockwise or counter-clockwise when viewed looking downstream in spanwise/normal planes.
The most important conclusion is that local heat transfer and injectant distributions are strongly affected by the longitudinal embedded vortices, including their directions of rotation and their spanwise positions with respect to film injection holes. Differences resulting from vortex rotation are due to secondary flow vectors, especially beneath vortex cores, which are in different directions with respect to the spanwise velocity components of injectant after it exits the holes. When secondary flow vectors near the wall are in the same direction as the spanwise components of the injectant velocity (clockwise rotating vortices R0-R4), the film injectant is more readily swept beneath vortex cores and into vortex upwash regions than for the opposite situation in which near-wall secondary flow vectors are opposite to the spanwise components of the injectant velocity (counter-clockwise rotating vortices L0-L4). Consequently, higher St/Sto are present over larger portions of the test surface with vortices R0-R4 than with vortices L0-L4. These disruptions to the injectant and heat transfer from the vortices are different from the disruptions which result when similar vortices interact with injectant from holes with simple angle orientations. Surveys of streamwise mean velocity, secondary flow vectors, total pressure, and streamwise mean vorticity are also presented which further substantiate these findings.
Application of Digital Video Interactive Technology for Operation and Maintenance of Industrial Gas Turbines
Authors: Golas K. , Mutter S. , Smalley A. J. , Quentin G. 
Published: March 2015

The operation and maintenance of large combustion turbines for electric power generation can be enhanced by training plant operators and maintenance technicians using Digital Video Interactive (DVI®) technology.
DVI® is an all digital format for generating motion video, audio, animation, and graphics and still images. Using DVI® for visual information display provides effective training that encompasses both functional and diagnostic training, and can be augmented by on-line access to gas turbine documentation. The success of DVI® as a training vehicle is expected to be patterned after the success of interactive videodisc with the added advantage of an all digital format. DVI® is being integrated with other advanced technologies including expert systems and intelligent tutoring to form a complete informational resource for diagnostic training, visual data bases, and post disturbance analysis and blade inspection.
These informational resources can be applied to on-site training using a new low-cost portable delivery system combining powerful microcomputers, dual visual displays, and large disk storage media. This portable information system is an outgrowth of the EPRI research into field troubleshooting based upon the SA*VANT® system. SA*VANT® is a portable computer-based expert system advisor to aid technicians in troubleshooting the Westinghouse 501 during fail-to-start situations.
Conceptual Design of Turbo-Accelerator for HST Combined Cycle Engine
Authors: Yanagi R. , Morita M. , Watanabe Y. , Itahara H. , Sasaki Y. , Aoki T. 
Published: March 2015

Hypersonic Transport Propulsion System Research (HYPR) Project was started in 1900 to develop technologies for the propulsion system of a Mach 5 Hypersonic Civil Transport, which could be environmentally acceptable and economically viable. The engine being studied is the methane fueled combined cycle engine composed of a turbo-accelerator for low speed range and a ramjet engine for high speed range. what is called a turbo/ramjet engine. The turbo-accelerator is required to meet the low noise regulations at take-off and achieve high specific thrust at high speed flight like the second generation SST (Supersonic Transport) engine. The single bypass turbofan engine (SBE) with variable cycle concept was selected as the turbo-accelerator engine to meet the above requirements in one engine. The engine was conceived to have variable geometry in compressor stator, low pressure turbine stator, fan bypass flow nozzle aren and exhaust nozzle area for low jet velocity at take-off and high jet velocity at altitude high speed and be equipped with a mixer ejector in the exhaust nozzle for further noise reduction.
This paper describes the cycle study and conceptual design of the demonstrator of a turbo-accelerator engine being planned to be tested in 1903.
Progress on the Advanced Turbine Technology Applications Project (ATTAP), and Automotive Gas Turbine Outlook
Authors: Haley Philip J. 
Published: March 2015

Of the four key technology areas attendant to the automotive gas turbine (ACT), structural ceramic components are the prime focus of the Department of Energy (DOE)-sponsored, NASA-managed ATTAP. The General Motors (GM) ATTAP team first focused on the ceramic gasifier turbine rotor, and in 1990 achieved full design temperature (2500°F TIT) at 100%N1 (gasifier speed). Four generations of axial-rotor design have led to such success, which also includes demonstrated resistance to foreign object impact; functionality after impact and minor damage; survivability in high-speed tip rub; and a 1000-hour durability demonstration. The ceramic gasifier turbine static structure, comprising scroll and vaneset (plus other support components), has also been successfully demonstrated at full (2500°F) design conditions, including successful completion of a 100-hour durability test of an all-ceramic gasifier stage. This major contractual milestone was completed during 1991. These successes represent fundamental technology progress, not only in the GM designs, but in the materials and processes implemented by the Kyocera Corporation, Norton/TRW Ceramics, and GTE Labs.
Heat management (regenerator system and thermal insulation) and combustion are other key AGT technologies. Ceramic regenerator disk efforts with Corning focus on developing extrusion technology in concert with evaluation of four ceramic material systems, to provide a disk with the requisite geometry, strength, survivability, and cost characteristics. Insulation activities with Manville target developing a ceramic refractory fiber-based system, which is wet injection molded directly in-place, and has the required thermal, adhesion, durability, and erosion properties. During 1991 a turbine engine component was successfully injection molded with this system. Some ATTAP effort has been directed toward design of a prevaporizing/premixing combustor to meet the California 0.2 gm/mile NOx standard.
The Role of Laminar-Turbulent Transition in Gas Turbine Engines: A Discussion
Authors: Walker G. J. 
Published: March 2015

An extended discussion of Mayle’s (1991) critical study of transition phenomena in gas turbine engines is presented. Attention is focussed on transition in decelerating flow regions which are the major sources of loss production for axial turbomachine blades.
The following points are examined in detail:
(a) the physics of transition and its implications for the correlation of various transition phenomena;
(b) the relative importance of pressure gradient and free-stream turbulence in controlling transition;
(c) the influence of pressure gradient on periodic-unsteady transition;
(d) the correlation of transition length under conditions of arbitrary pressure gradient and free-stream turbulence level; and
(e) transition behavior in laminar separation bubbles.
The discussion examines various differences in philosophy concerning the above phenomena and corrects some areas of misinterpretation in the subject review paper. It concludes with further suggestions for transition research which may assist in resolving the issues raised.
Ceramic Matrix Composite Applications in Advanced Liquid Fuel Rocket Engine Turbomachinery
Authors: Brockmeyer Jerry W. 
Published: March 2015

Hot gas path components of current generation, liquid fuel rocket engine turbopumps (T/P) are exposed to severe thermal shock, extremely high heat fluxes, corrosive atmospheres and erosive flows. These conditions, combined with high operating stresses, are severely degradative to conventional materials. Advanced turbomachinery (T/M) applications will impose harsher demands on the turbine materials. These demands include higher turbine inlet temperature for improved performance and efficiency, lighter weight for improved thrust-to-weight ratio, and longer life for reduced maintenance of re-usable engines.
Conventional materials are not expected to meet these demands, and fiber-reinforced ceramic matrix composites (FRCMC) have been identified as candidate materials for these applications. This paper summarizes rocket engine T/M needs, reviews the properties and capabilities of FRCMC, identifies candidate FRCMC materials and assesses their potential benefits, and summarizes the status of FRCMC component development with respect to advanced liquid fuel rocket engine T/M applications.
Second-Generation Low-Emission Combustors for ABB Gas Turbines: Field Measurements With GT11N-EV
Authors: Aigner M. , Müller G. 
Published: March 2015

In February 1991 a type GT11N gas turbine (Midland U.S.A.) was retrofitted with ABB’s new EV-Silo-Combustor. Tests were then carried out to examine the operation concept, to demonstrate the technical reliability and to confirm the low emission performance of this new technology. This paper will describe:
1.) The combustor design:
- one single silo combustor mounted on the turbine and equipped with 37 EV-burners.
2.) The results of the extensive field measurements:
The operation concept (lean premix combustion without any pilot diffusion flames, 7 burner groups) is simple and reliable:
- The emission targets
NOx < 25 ppmv (15% O2, natural gas)
CO < 8 ppmv
UHC < 5 ppmv
were reached. NOx-values are even lower than 15 ppmv at base load.
- The NOx-predictions for the GT11N-EV, based on the results of high pressure tests in Cologne (ASME PAPER 90-GT-308), compare very well with the results of field measurements.
The Comparison of Different Simplified Mathematical Models of the Gas Turbine Combustion Chamber as an Object of Temperature and Pressure Control
Authors: Dzida Marek 
Published: March 2015

The paper presents the mathematical model of the combustion chamber as an object of temperature and pressure control. Using the step function characteristics and the frequency method (in the range of low frequency f<20Hz), the theoretical models with different degrees of simplifications were compared with the results of the experimental investigations.
The proposed theoretical model may turn out very useful in the research of the gas turbine dynamics.
Magnetic Particle Inspection of Turbine Blades in Power Generating Plants
Authors: Imbert Clement , Rampersad Krishna 
Published: March 2015

Modern societies expect and depend on regular, relatively uninterrupted, supply of electric power. Preventive maintenance is therefore vital for power generating plants. Non-Destructive Evaluation (NDE) is a significant element of the maintenance programme of power plants. Power plants use a wide variety of steam and gas turbines. Turbine failure can occur without warning and with disastrous results. Such failures are invariably caused by cracks. Such defects are readily detected by NDE techniques such as Magnetic Particle Inspection (MPI) if they are on or near the surface and accessible.
This paper reports on the use of MPI in the examination of martensitic stainless steel turbine blades in power plants in Trinidad and Tobago so as to quantify the testing parameters and determine field strength in relation to defect detectability. Specific recommendations are made regarding the configuration and optimum placement of magnetizing coils for turbine blade inspection insitu and detached.