bluuebunny/crossref_metadata_2025_split huggingface dataset:
Current Status of Industrial and Automotive Ceramic Gas Turbine R&D in Japan
Authors: Nagamatsu Soichi , Mizuhara Kazuyuki , Matsuda Yukio , Iwanaga Akio , Ishiwata Shoji 
Published: March 2015

The current status of Japan’s national Ceramic Gas Turbines (CGTs) projects is overviewed.
The Japanese Ministry of International Trade and Industry (MITI) is conducting two national R&D projects on CGT. These include a project on 300kW industrial CGTs for co-generation and mobile power generation use and a project on 100kW CGT for automotive use.
The 300kW project was started in 1988, and is scheduled to develop three kinds of CGTs over nine years. The New Energy and Industrial Technology Development Organization (NEDO) is the main contractor, and three groups of private industries are sub contractors. Three national research institutes are involved in the project to conduct supportive research of ceramic materials and engine components.
The 100kW project has started in 1990, and is scheduled to develop a single shaft automotive CGT over seven years. Petroleum Energy Center (PEC) and JARI are the main contractors with the cooperation of several petroleum and automotive companies.
The goals for the two projects are 42% and higher for thermal efficiency at a turbine inlet temperature of 1350C. Such targets could not be achieved without applying high temperature ceramics to the engine components. Therefore many R&D objectives are directed towards developing the ceramic components which have a higher flexure strength and fracture toughness.
Currently, 300kW base metal gas turbine engines are being developed to prove the design concepts. Blade shapes suitable to ceramics are being studied by the FEM method. Forming and manufacturing large components are also being studied, and some ceramics components have been successfully made.
Design and Test of a Candidate Topping Combustor for Second Generation PFB Applications
Authors: Garland R. V. , Pillsbury P. W. , Dowdy T. E. 
Published: March 2015

Second Generation Pressurized Fluidized Bed Combustion Combined Cycles utilize topping combustion to raise the combustion turbine inlet temperature to the state of the art. Principally for this reason, cycle efficiency is improved over first generation PFB systems. Topping combustor design requirements differ from conventional gas turbine combustors since hot, vitiated air from the PFB is used for both cooling and combustion. In addition, the topping combustor fuel, a hot, low-heating value gas produced from coal pyrolysis, contains ammonia. This NOx-forming constituent adds to the combustor’s unique design challenges.
The candidate combustor is the multi-annular swirl burner (MASB) based on the design described by J.M. Beér. This concept embodies rich-burn, quick quench, and lean-burn zones formed aerodynamically. The initial test sponsored by the Department of Energy, Morgantown, West Virginia, has been completed and the results of that test are presented.
Marine Gas Turbine Evaluation and Research at the Admiralty Test House, Rae Pyestock
Authors: Bruce C. J. , Cartwright R. A. 
Published: March 2015

The Admiralty Test House (ATH) at the Royal Aerospace Establishment Pyestock has provided test bed facilities for evaluation of marine gas turbines and ancillary equipments for Royal Naval use since 1952.
While the ATH is presently undergoing an extensive refurbishment programme in preparation for trials of the Rolls-Royce 20MW Spey SM1C, research continues on a number of innovative gas turbine condition monitoring techniques.
This paper presents a brief history of the Marine Gas Turbine Section and describes the facilities of the ATH following major refurbishment. The capabilities of the steady state and transient data gathering facilities are outlined, together with the automated engine and test control systems which provide cost effective engine evaluation in both endurance and minor equipment trials.
Statistical and Mathematical Approach for Distribution Function Model for Low Probability of Failures
Authors: Bhonsle S. R. , VanKarsen C. V. , Michler J. R. 
Published: March 2015

In probabilistic design it is common practice to use statistical models such as normal, lognormal, and Weibull to describe random design factors. However these distribution function models deviate in the lower tail, i.e. percentiles below 1%. The deviation is nonconservative in that since it predicts life longer than observed.
A Statistical Distribution Function called Adaptive Distribution Function Model similar to Abelkis model was developed. It is compatible with the collected data, and it produces conservative designs at low tail ends. It is also relatively easy to use.
Motion and Evaporation of Shear-Driven Liquid Films in Turbulent Gases
Authors: Wittig S. , Himmelsbach J. , Noll B. , Feld H. J. , Samenfink W. 
Published: March 2015

Detailed measurements of wavy liquid films driven by the shear stress of turbulent air flow are obtained for different air temperatures, air velocities and flow rates of the liquid. The experimental conditions are chosen from characteristic data of liquid film flow in prefilming airblast atomizers and film vaporization employing combustors.
For the measurement of the local film thickness and film velocity a new optical instrument — based on the light absorption of the liquid — has been developed, which can be used at high temperatures with evaporation.
The measured data of the gas phase and the liquid film are compared with the results of a numerical code using a laminar as well as a turbulent model for the film flow and a standard numerical finite volume code for the gas phase.
The results utilizing the two models for the liquid film show that the film exhibits laminar rather then turbulent characteristics under a wide range of flow conditions. This is of considerable interest when heat is transferred across the film by heating or cooling of the wall. With this information the optical instrument can also be used to determine the local shear stress of the gas phase at the phase interface.
Using time averaged values for the thickness, the velocity and the roughness of the film the code leads to relatively accurate predictions of the interaction of the liquid film with the gas phase.
The Effects of Friction in Axial Splines on Rotor System Stability
Authors: Artiles Antonio F. 
Published: March 2015

An in depth parametric evaluation of the effects of Coulomb friction in an axial spline joint on the stability of the rotor-bearing system was conducted through time transient integration of the equations of motion. Effects of: spin speed, friction coefficient, spline torque, external damping, imbalance and side load as well as asymmetric bearing stiffnesses were investigated.
A subsynchronous instability is present at the bending critical speed when the spin speed is above this critical. The limit cycle orbit is circular, is proportional to the product of the friction coefficient and spline torque (μT), is inversely proportional to the external damping and is independent of spin speed.
When imbalance is applied to the rotor, beating between the subsynchronous natural frequency and the synchronous (spin speed) frequency occurs. The subsynchronous component of the orbit is proportional to μT, while the synchronous component is proportional to the imbalance.
When a static side load is applied, the unstable node at the center of the orbitally-stable limit cycle grows into an elliptical orbitally-unstable limit cycle, separating stable - from unstable regions of the phase plane. Below a threshold value of side load, the transient motion approaches one of two asymptotic solutions depending on the initial conditions: the larger stable limit cycle or a point at the center of the smaller unstable limit cycle. Beyond the threshold value of side load the rotor-bearing system is stable and all motions decay to a point.
Asymmetry in the bearing stiffnesses reduces the size of the subsynchronous whirl orbit.
Film Cooling Research on the Endwall of a Turbine Nozzle Guide Vane in a Short Duration Annular Cascade: Part 1 — Experimental Technique and Results
Authors: Harasgama S. P. , Burton C. D. 
Published: March 2015

Heat transfer and aerodynamic measurements have been made on the endwalls of an annular cascade of turbine nozzle guide vanes in the presence of film cooling. The results indicate that high levels of cooling effectiveness can be achieved on the endwalls of turbine nozzle guide vanes (NGV). The NGV were operated at the correct engine non-dimensional conditions of Reynolds number, Mach number, gas-to-wall temperature ratio and gas-to-coolant density ratio.
The results show that the secondary flow and horse-shoe vortex act on the coolant which is converted towards the suction side of the NGV endwall passage. Consequently the coolant does not quite reach the pressure side/casing trailing edge, leading to diminished cooling in this region. Increasing the blowing rate from 0.52 to 1.1 results in significant reductions in heat transfer to the endwall. Similar trends are evident when the coolant temperature is reduced. Measured heat transfer rates indicate that over most of the endwall region the film cooling reduces the Nusselt number by 50% to 75%.
Analytical Condition Inspection and Extension of Time Between Overhaul of F3-30 Engine
Authors: Nakao Masato , Ikeyama Masataka , Abe Shinji 
Published: March 2015

F3-30 is the low-bypass-ratio turbofan engine developed to power the T-4 intermediate trainer for the Japan Air Self Defense Force (JASDF). The actual field service was started in September, 1988.
The program to extend time between overhaul (TBO) of the F3-30 has been running. Analytical condition inspection (ACI) and accelerated mission testing (AMT) were conducted to confirm the sufficient durability to extend TBO.
Most deteriorations of parts and performance due to AMT were also found by ACI after field operation with approximately same deterioration rate. On the other hand, some deteriorations were found by ACI only. These results show that ACI after field operation is also necessary to confirm the TBO extension, though AMT simulates the deterioration in the field operation very well. The deteriorations which would be caused by the field operation during one extended-TBO were estimated with the results of ACI and AMT, and it was concluded that the F3-30 has the sufficient durability for TBO extension to the next step.
Modelling of Unsteady Transitional Boundary Layers
Authors: Addison J. S. , Hodson H. P. 
Published: March 2015

In turbomachinery, a considerable proportion of the blade surface area can be covered by transitional boundary layers. This means that accurate prediction of the profile loss and boundary layer behaviour in general depends on the accurate modelling of the transitional boundary layers, especially at low Reynolds numbers. This paper presents a model for determining the intermittency resulting from the unsteady transition caused by the passage of wakes over a blade surface. The model is founded on work by Emmons (1951) who showed that the intermittency could be calculated from a knowledge of the behaviour of randomly formed turbulent spots.
The model is used to calculate the development of the boundary layer on the rotor of a low Reynolds number single-stage turbine. The predictions are compared with experimental results obtained using surface-mounted hot-film anemometers and hot-wire traverses of the rotor mid-span boundary layer at two different rotor-stator gaps. The validity and limitations of the model are discussed.
Non-Intrusive Measurement of Blade Tip Vibration in Turbomachines
Authors: Andrenelli L. , Paone N. , Rossi G. , Tomasini E. P. 
Published: March 2015

It is discussed the need for non-intrusive monitoring of rotating blade vibration. The advantages over conventional techniques are outlined.
The vibration of a compressor blade has been investigated by strain gages, with particular attention to time evolution of the frequency spectra, at different operating speeds of the machine. These information are fundamental to the correct design of the non-intrusive measurement system.
The non-intrusive measurement technique has been presented, with special attention on uncertainty and resolution. The necessary hardware is discussed and the design of an optical sensor is presented.
Scalar Measurements in Bluff Body Stabilized Flames Using Cars Diagnostics
Authors: Pan J. C. , Vangsness M. D. , Heneghan S. P. , Ballal D. R. 
Published: March 2015

Measurements of mean and rms temperature fluctuations were performed in confined turbulent premixed methane-air flames, stabilized on a conical flameholder. A CARS system was used for these measurements. These tests employed flameholders of different blockage ratios (13% and 25%), and mixtures with different equivalence ratios (0.56, 0.65, 0.8, and 0.9) and approach turbulence intensity (2%, 17%, and 22%).
It was found that the recirculation zone closely resembles a perfectly well-stirred reactor. Blockage ratio, equivalence ratio, or approach turbulence intensity did not alter the scalar field. The turbulent flame structure enveloping the recirculation zone comprises: (i) an ignition/thin flame region in the vicinity of the flameholder base, (ii) a reacting shear layer region of large-scale coherent structures, and (iii) a thick flame region where entrainment is the dominant mechanism. Finally, analysis suggests that the scalar gradient-diffusion relationship is valid and areas of non-gradient diffusion, if any, are probably small.
Development of Improved Processing and Evaluation of Silicon Nitride
Authors: Pujari V. K. , Amin K. E. , Tewari P. H. 
Published: March 2015

The goals of this program are to develop and demonstrate significant improvements in processing methods, process controls, and nondestructive evaluation (NDE) which can be commercially implemented to produce high-reliability silicon nitride components for advanced heat engine applications at temperatures to 1370°C. Achievement of this goal is being sought by
• The use of silicon nitride - 4% yttria composition which is consolidated by glass encapsulated HIP’ping.
• The generation of baseline tensile strength data from an initial process route involving injection molding.
• Fabrication of tensile test bars by colloidal techniques, e.g. injection molding and colloidal consolidation.
• Identification of (critical) flaw populations through NDE and fractographic analysis of tensile bars.
• Correlation of measured tensile strength with flaw populations and process parameters.
• Minimization of these flaws through innovative improvements in process methods and controls.
The program goals are:
• mean room temperature tensile strength of 900 MPa and Weibull modulus of 20;
• mean 1370°C fast fracture tensile strength of 500 MPa;
• mean 1230°C tensile stress rupture life of 100 hours at 350 MPa.
This report describes the progress made to date in developing injection molding and colloidal consolidation processes for the net shape forming (NSF) of tensile bars, nondestructive evaluation of processed material, and tensile testing of net shape bars in green and densified states.
Rotordynamic Coefficients for Partially Roughened Annular Gas Seals
Authors: Scharrer Joseph K. , Nelson Clay C. 
Published: March 2015

The basic equations are derived for compressible flow in an annular seal with partially roughened surfaces. The flow is assumed to be completely turbulent in the axial and circumferential directions with no separation, and is modeled by Moody’s equation for roughness. Linearized zeroth and first-order perturbation equations are developed for small motion about a centered position by an expansion in the eccentricity ratio. The zeroth-order continuity and momentum equations are solved exactly, yielding the axial and circumferential velocity components and the pressure distribution. The first-order equations are reduced to three ordinary, complex, differential equations in the axial coordinate Z. The equations are integrated to satisfy the boundary conditions and yield the perturbation pressure distribution. This resultant pressure distribution is integrated along and around the seal to yield the force developed by the seal and the corresponding dynamic coefficients.
Since no test data exist for this type of seal, the results of a parametric study on the effect of the rough length/smooth length ratio on the seal leakage and rotordynamic coefficients is presented.
Testing at the U.S. Navy’s Gas Turbine Systems Engineering Complex: Part II
Authors: Preisel John H. 
Published: March 2015

Full-scale testing has continued at the US Navy’s Gas Turbine Systems Engineering Complex. The test complex, which is based on the US Navy’s DDG-51 class propulsion plant, has fully transitioned from the construction phase to the testing phase. A complete LM 2500-based propulsion train exists, as well as an electrical generation, distribution and control system. The purpose of this paper is to provide an update to last year’s test report, and to document the new tests and systems integration tasks that have taken place.
Particular areas to be discussed include:
- electrical system design, installation and testing
- crew training and integrated plant operations
- full-scale casualty control exercises
- integration and testing of an Auxiliary Power Unit
- control system upgrades and communication testing
At the time that this paper is being written, final design approval has been given to move a second 2500 kW gas turbine generator to the test site. This will be a cogeneration system, since it has a waste heat recovery system installed in the exhaust system. The paper describes the plans for integrating this system into the gas turbine complex. The proposed electrical system test plan is also discussed.
The paper concludes by outlining the component and system testing programs that are planned for the future. The future tests represent a continuing commitment to land based test sites and full scale integration testing.
Garrett GTP50-1 Multipurpose Small Power Unit Technology Demonstrator Program
Authors: Annati R. E. , Smyth J. R. 
Published: March 2015

The Multipurpose Small Power Unit (MPSPU) Advanced Development Program is providing the United States Army and other Department of Defense branches with advanced technology for current and future auxiliary power units (APUs)/secondary power systems (SPSs) in aircraft, combat vehicles, and mobile shelters. The design includes low specific fuel consumption (SFC), weight and volume, acquisition and life cycle costs (LCC), and high reliability and durability.
The Garrett Auxiliary Power Division (GAPD) Model GTP50-1 MPSPU has demonstrated major advances in small gas turbine power unit design and manufacturing technologies. Component test rigs have completed extensive development testing. Power unit operation of 214 hours, with 557 starts, has been accumulated. Power unit and rig testing has demonstrated program goals and identified areas for continued technical development. The program has demonstrated 77.6 kW (104 shp), corrected to sea level standard day, at an SFC of 0.5 kg/kW-hr (0.8 lb/hp-hr).
Off-Design Evaluation of a Multiple Expansion Reheating Gas Turbine in Cogeneration Applications
Authors: Benvenuti Erio , Bettocchi Roberto , Cantore Giuseppe , Di Montenegro Giorgio Negri 
Published: March 2015

The multiple expansion reheating gas turbine proves to have a potential of good operational flexibility for the intrinsic capability of responding to variations in electric and thermal power demands without appreciable impact on efficiency.
The present study deals with evaluation of the performance attainable in off-design operation, with power control obtained through changes in the first and second combustor firing temperatures and in the compressor intake air flow achieved by means of variable inlet guide vanes.
Because of the important impact of the hot part cooling air flows on performance, the study includes also a hypothesis of controlling such flows in off-design operation through external means.
The predicted off-design performance results superior in the hypothesis of external cooling air flow control, thus making such a system worthy of consideration for possible future developments of machines in this category.
To evaluate the suitability of the multiple expansion reheating gas turbine in cogeneration applications, the electric efficiency and the electrical index have been taken into consideration.
The capability of varying the reheating temperature represents an effective way of controlling the electrical index with good efficiencies in industrial cogeneration with strongly varying electric power and process heat requirements.
With regard to the cooling air control through external means, implementation of such a more complex system seems to be avoidable at least when the gas turbine is intended specifically for application in cogeneration, because of its smaller impact on the overall efficiency of the system.
Ceramic Matrix Composites and its Application in Gas Turbine Engines
Authors: Naik Subhash K. , Massar Andrew , Lecostaouec Jean F. , Thomson Bruce 
Published: March 2015

The key technology requirement for advanced gas turbine engines is the availability of lightweight, higher temperature materials which will allow the components to operate with little or no cooling air. Ceramic Matrix Composites represent one such category. An interturbine duct has been selected as the first component for introducing silicon carbide fiber reinforced silicon nitride composites in advanced engines.
An ongoing program is focused on process development, fabrication of components and measurement of mechanical properties. A significant property base continues to be developed for both uni-directional and multi-directional reinforced ceramic composites. The results of the program are presented.
Low NOx Combustor for Automotive Ceramic Gas Turbine: Conceptual Design
Authors: Sasaki Masafumi , Kumakura Hirotaka , Suzuki Daishi 
Published: March 2015

Three low NOx combustors, i.e. a lean premixing combustor, a rich-lean two stage combustor and a lean diffusion flame combustor, were tested in order to find out a suitable combustion concept for an automotive ceramic gas turbine combustor. The prevaporization-premixing lean combustion was proposed as the most promising candidate to meet Japanese 10 mode regulation for gasoline passenger car.
The required conditions for the uniform premixture formation in the prevaporization-premixing tube were achieved by a fine droplet size atomizer and by means of swirl and turbulent generator. Air ratio range, air loading and other dimension criteria in the lean primary combustion zone were also proposed in the present paper.
Development and Early Field Experience of the Typhoon Gas Turbine
Authors: Carchedi F. , Gallimore S. , Siemiernik A. F. , Goodman D. A. 
Published: March 2015

The Typhoon gas turbine is a third generation industrial gas turbine of high thermal efficiency and significantly reduced component count. It is designed for all power generation duties within the 4 MW power bracket and is available in both 50 Hz and 60 Hz output.
The paper describes, and presents results, from the Development programme undertaken, including performance, emissions, package tests and cyclic endurance programme. Early field experience is also reviewed.