bluuebunny/crossref_metadata_2025 huggingface dataset:
European Standardization Activities for Advanced Technical Ceramics
Authors: Kübler Jakob J. , Morrell Roger
Published: February 2015

A summary of the progress being made in Europe towards the provision of standards for advanced technical ceramics is given. Under CEN Technical Committee 184, working groups have been preparing more than 40 standards in the areas of classification, powders, monolithic ceramics, long-fibre composites and ceramic coatings. The target date for this work was the end of 1992. Considerable progress has been made, and by the end of 1993, most of these should have been published. It is hoped that the formation of this standards base will improve the quality of testing and the reliability of property data on this class of materials, and thus improve confidence in their use as engineering materials.
Phased Construction of an IGCC Plant With Pre-Investment in the CC Plant
Authors: Dechamps P. J. , Mathieu Ph.
Published: February 2015

After the Chernobyl accident in April 1986, most western countries have slowed down, suspended or sometimes stopped their nuclear programme. In many cases, natural gas has been regarded as the best alternative to nuclear fuel in the short and mean term and numerous countries have opted for CC plants. However, and it is the case in Belgium, decision-makers and operators want to diversify their fuel sources. Presently, CC plants are not multi-fuel and are the most efficient when fed with natural gas. A good strategy is to avoid a too strong dependence on this fuel, which would lead to a situation with natural gas similar to the one we previously experienced with oil. In that respect, the IGCC technique allows a come back to coal: starting with a CC plant, it is possible to add gasification units several years later and hence to switch from natural gas to coal. However, the price to pay will be capital cost but also a loss of performances of the resulting plant.

A first option which consists in adding a gasification unit to a genuine CC unit several years later has been investigated in a previous paper (4). In this paper, we examine a second option, when a CC plant is built with some of its components oversized in order to allow easy integration of the future connections from and to the gasification unit erected in the second stage of the construction. We calculate the performances of the CC plant for various pre-investment options, inside the heat recovery boiler, in the steam turbine and in the gas turbine. We compare the performances of the resulting IGCC plants when four types of gasifiers are used, i.e. Texaco, Shell, Dow and British-Gas-Lurgi. The performances of the same plants built in stages without pre-investment and built as genuine IGCC plants provide the yardsticks for comparison.
An Inviscid Low-Solidity Cascade Design Routine
Authors: Myers Jerry G. , Wright Terry
Published: February 2015

An investigation was performed to determine a suitable method of designing and analyzing the performance of straight axial fan cascades of solidities below 0.6. The methods investigated included direct interpolation between design values obtained from experimental data at solidities of 0.6 and isolated airfoil theory predictions. A new inviscid design technique developed from a simplified low-solidity analysis procedure by J. Horlock and K. Tanabe was also developed. Testing of these methods was performed using a PC based inviscid “panel” routine developed by McFarland at NASA-Lewis. Results of the investigation yielded a reasonably accurate method for the design of axial fan cascades for solidities ranging from 0.2 to 0.6 which can supplement an existing design system that requires cascade design information lying beyond the range of NACA testing.
Evaluation of Emission Model for Diffusion Flame, Rich/Lean, and Premixed Lean Combustors
Authors: Rizk N. K. , Mongia H. C.
Published: February 2015

A recently developed emission model was used to predict the emission characteristics of a gas turbine combustor. The model involves a multiple-step reaction scheme that addresses the breakup of the fuel into an intermediate hydrocarbon compound of variable structure. The reaction rate expressions developed in the present approach simulated the results obtained using a detailed chemical kinetic mechanism over a wide range of operation that is typically encountered in a conventional diffusion flame combustor, as well as low NOx rich/quench/lean, and premixed/prevaporized lean combustion concepts. The modeling of the combustor involves dividing the combustor into a number of reactors representing various combustion and near wall regions of the combustor. The calculations showed that the fuel reaction could proceed at a completely different rate depending on the conditions prevailing in each region of the combustor. The model results also indicated that at idle power mode the initial rate of NOx formation was high. However, due to the subsequent admission of air, no further addition to the NOx concentration was predicted at downstream locations. At high power levels, the fuel rich region near the combustor dome inhibits the formation of NOx. The admission of air in this case brings the fuel/air mixture close to the stoichiometric value causing a significant amount of NOx to form. The model calculations agreed quite well with the measured data of the combustor.
Numerical Simulation of Fluid Flow and Combustion in Gas Turbine Combustors
Authors: Gran Inge R. , Melaaen M. C. , Magnussen F.
Published: February 2015

The finite-volume approach together with body-fitted curvilinear non-orthogonal coordinates and a non-staggered grid arrangement is used for investigating turbulent reacting flows inside gas turbine combustion chambers. The computational grids are generated by solving elliptic differential equations, permitting an accurate description of the complex geometry of commercial gas turbine combustors. Different combustion models are briefly discussed with a view to their suitability for practical combustor predictions. The k-ε model and the Eddy Dissipation Concept are selected to account for the turbulent combustion in the present study. The governing equations and coordinate transformations needed to derive the discretized equations are reviewed. One isothermal and two combusting flow fields are calculated. The calculations are in reasonable agreement with measurements, but the results should be improved by grid refinement and by using a better turbulence model.
Smoke Number Prediction in Gas Turbine Exhaust
Authors: De Champlain Alain , Tsogo Joseph , Kretschmer Detlef
Published: February 2015

From a large number of experimental data, an equation was developed for prediction of the smoke number as measured in gas turbine exhaust according to the well established SAE standard. Two different scales of combustors were used with inlet temperatures and pressures ranging from 300 to 600 K and from 0,1 to 0,9 MPa respectively. The formulation is based on the residence time which is calculated from the mass flow rate, density and volume of the primary and secondary zones of the combustor. The reaction rate has an Arrhenius form with the global equivalence ratio to account for the air and fuel flow rates. All these parameters can be evaluated from desired operating conditions. Nineteen different types of fuel were used varying from a paraffinic mixture to a pure aromatic compound. The fuel is characterized by its calorific value and hydrogen mass fraction.

With the wide range of fuels burned in the experiment giving a smoke number variation from 0 to 100, the accuracy of the equation (Standard Deviation of 40%) is acceptable for most purposes. The formulation should be particularly useful in assessing the efficiency of new systems for smoke reduction or in calculating the smoke number from older experimental data where it was not measured.
Graphic Data Analysis Identifies Uneven Part Wear
Authors: Jennings Richard M.
Published: February 2015

Uneven user patterns in turbine engine components can be rapidly identified by graphically “mapping” dimensional measurement data onto a solid model of the part and automatically analyzing deviations in surface contours. The same analysis reduces scrap and time to rework parts.
CFD Modeling of Annulus/Port Flows
Authors: McGuirk J. J. , Spencer A.
Published: February 2015

CFD predictions are reported of the flow–field associated with the interaction of an annulus flow with a single row of plain radial holes drilled in the inner annulus surface, creating radially inward jets penetrating an inner core–flow. This situation is typical of annulus air admission port geometries found in all gas turbine combustors. The emphasis of the work is placed on an examination of different levels of geometrical approximation of the hole geometry. Both castellated and hole–fitted methods are studied using a general non–orthogonal body–fitted mesh, and a CFD code based on a pressure–correction methodology combined with a k–ε turbulence model. Noticeable differences are observed between the two approaches in terms of jet entry angle, impingement strength of the resulting radial jets, upstream vortex size, and annulus flow details downstream of the hole. These changes are mainly brought about by variations in the predicted velocity profile over the hole open area, particularly at the edges of the hole. The hole–fitted approach is also used to investigate the predicted differences between a round and a D–shaped hole. Small changes are observed in jet penetration behaviour; also the origin of the vortex in the wake of the jet is predicted to shift due to the addition of a corner in the hole shape.
Design of the EGT Typhoon 2-Shaft Power Turbine Using Concurrent Engineering Techniques
Authors: Carson S. J.
Published: February 2015

The Typhoon is a high thermal efficiency, low component count gas turbine originally launched into service in 1990. The single shaft version, used for power generation (C.H.P.), is rated at 4.1 MW ISO zero loss with a thermal efficiency of 32 per cent. At the date of writing, the Typhoon single shaft machines have accumulated 60,000 hours and 2,500 starts in service with very high levels of reliability.

This paper describes the design of the two shaft version of the Typhoon, intended for operation primarily in the Oil and Gas Industry. The paper will concentrate on the “Concurrent Engineering” techniques used during the design process. The two shaft Typhoon will enter into service in 1994.
Flow Randomness and Tip Losses in Transonic Rotors
Authors: Alday John , Osborne D. J. , Morris Mary Beth , Ng Wing , Gertz Jeff
Published: February 2015

The results of a test program incorporating a dual hot-wire aspirating probe to radially survey the exit flowfields of two axial-flow transonic fans are presented. The probe measures time-resolved total temperature and total pressure, from which the instantaneous isentropic efficiency is calculated. A technique for quantifying the randomness in an unsteady turbomachine flowfield is developed. Randomness is quantified by blade wake aperiodicity (variation of blade passage period) and non-uniformity (variation of blade wake shape). A method of ensemble averaging instantaneous data is presented which produces an identifiable blade passage wake profile even in a random flowfield where traditional techniques often fail. The flowfield randomness for the two fans is shown to correlate well with the respective tip losses. Results also show that the overall efficiency of the best blade on a fan rotor can be 0.5% higher than the performance of the rotor overall average or as much as 0.7% higher than the worst blade on the rotor.
Effects of Damping and Damping Mistuning on the Forced Vibration Response of Bladed Disks
Authors: Lin Chung-Chih , Mignolet Marc P.
Published: February 2015

The effects of blade-to-blade variations in the damping coefficients on the forced response of a bladed disk are investigated. It is found that this nonuniformity of the disk can lead to variations in the blades’ amplitudes of response which are similar, in magnitude, to those obtained with stiffness mistuning but are potentially more dangerous because of the skewness of the distribution toward large amplitudes. The influence of various structural parameters on the scatter of blade amplitudes is also studied. Finally, the adequacy of the combined Closed Form - Perturbation (CFP) method is demonstrated by comparison with simulation results.
The MHTGR Gas Turbine: A Power Plant Ideally Suited to Meeting the Energy Needs of the Newly Industrializing Nations
Authors: McDonald Colin F.
Published: February 2015

It has been estimated, that shortly after the year 2050, the energy use in the developing nations will exceed energy use in the industrialized countries. Utilization of the human resources in the newly industrializing nations will be a key factor to ensure global economic stability, and an important element towards an increase in their standard of living will be assurance of a secure and economic source of power. Lessons learned from the industrialized nations will include avoidance of fragility of their economy based on the dependence of fossil fuels, and the negative environmental consequences; simply stated the economic future of the newly industrializing nations is very dependent on the deployment of nuclear power.

The Modular High-Temperature Gas-Cooled Reactor (MHTGR), with its unquestionable safety, must be viewed as a leading candidate to meet the aforementioned energy needs. Utilizing a helium turbine power conversion system, the basic module rating is around 200 MW(e). The modular approach permits incremental expansion as the electrical grid infrastructure expands. The nuclear gas turbine plant has many attributes, including the following: (1) complete factory fabrication and assembly; (2) minimum site construction work; (3) siting flexibility (cooling water not required since economic dry cooling can be realized with the Brayton cycle); (4) operation in a cogeneration mode without loss of electrical output (i.e., steam production, desalination); and (5) increasing local participation in module fabrication as the system matures.

This paper highlights the advantages of the modular nuclear gas turbine plant, and emphasizes the fact that the major components are based on proven technology. With introduction of this inherently safe, high efficiency, nuclear power plant shortly after the turn of the century, the ever-increasing demand for power throughout the 21st century by the newly industrializing nations will be assured.
Materials Performance in Advanced Combustion Systems
Authors: Natesan K.
Published: February 2015

A number of advanced technologies are being developed to convert coal into clean fuels for use as feedstock in chemical plants and for power generation. From the standpoint of component materials, the environments created by coal conversion and combustion in these technologies and their interactions with materials are of interest. The trend in the new or advanced systems is to improve thermal efficiency and reduce the environmental impact of the process effluents. This paper discusses several systems that are under development and identifies requirements for materials application in those systems. Available data on the performance of materials in several of the environments are used to examine the performance envelopes for materials for several of the systems and to identify needs for additional work in different areas.
Prediction of Turbulent Flow and Heat Transfer in a Ribbed Rectangular Duct With and Without Rotation
Authors: Prakash C. , Zerkle R.
Published: February 2015

The present study deals with the numerical prediction of turbulent flow and heat transfer in a 2:1 aspect ratio rectangular duct with ribs on the two shorter sides. The ribs are of square cross–section, staggered and aligned normal (90–deg) to the main flow direction. The ratio of rib height to duct hydraulic diameter equals 0.063, and the ratio of rib spacing to rib height equals 10. The duct may be stationary or rotating. The axis of rotation is normal to the axis of the duct and parallel to the ribbed walls (i.e., the ribbed walls form the leading and the trailing faces). The problem is three–dimensional and fully elliptic; hence, for computational economy, the present analysis deals only with a periodically–fully–developed situation where the calculation domain is limited to the region between two adjacent ribs. Turbulence is modelled with the k–epsilon model in conjunction with wall–functions. However, since the rib height is small, use of wall–functions necessitates that the Reynolds number be kept high. (Attempts to use a two–layer model that permits integration to the wall did not yield satisfactory results and such modelling issues are discussed at length). Computations are made here for Reynolds number in the range (30,000–100,000) and for Rotation number=0 (stationary), 0.06, and 0.12. For the stationary case, the predicted heat transfer agrees well with the experimental correlations. Due to the Coriolis induced secondary flow, rotation is found to enhance heat transfer from the trailing and the side walls, while decreasing heat transfer from the leading face. Relative to the corresponding stationary case, the effect of rotation is found to be less for a ribbed channel as compared to a smooth channel.
Substitution of Lightweight Ceramics for Alloy and Silicon Carbide in a Hot Gas Filter
Authors: Zievers J. F. , Eggerstedt P. , Aguilar P. , Zievers E. C.
Published: February 2015

Ceramic candle filters have proven to be an effective means of removing particulates to levels exceeding New Source Performance Standards (NSPS) in high temperature applications. The traditional “hard” ceramic filter elements, typically formed from granules of silicon carbide, mullite, etc., however, have shown to be susceptible to failure from physical shock, thermal stress, and chemical attack. Additionally, these hard, dense candles can be costly and present internal filter design problems due to their relatively high weight.

A good deal has been written about the use of porous ceramics in the filtration of high temperature gases for removal of particulate matter. Unlike the dense, granular ceramic filter elements, vacuum formed chopped ceramic fiber (VFCF) filters represent an attractive alternative. Composed of commercially available chopped ceramic fibers and utilizing existing vacuum forming technology, low cost filter elements with excellent physical and thermal shock resistance are now available. The ceramic fiber filter “skeleton” can be “post-treated” with refractory materials to enhance strength and chemical resistance, as well as to change permeability to suit a particular application. Also, because the ceramic fiber skeleton has greater porosity and is composed of low density materials, the final product is significantly lighter in weight than the traditional dense ceramic elements, making overall filter design an easier task.

The use of ceramics extends beyond that of filter elements, however. Ceramics in the form of refractory have long been used to protect metal structures from high temperature and abrasion, and an extensive body of literature deals with this subject. Castable refractories, for example, can be utilized to achieve special shapes that exhibit excellent strength at high temperatures. Recently, several other papers have dealt with the use of lightweight ceramics as filter media as well as structural members.
Fibre Optic Interferometric Heat Transfer Sensors for Transient Flow Wind Tunnels
Authors: Kidd S. R. , Barton J. S. , Jones J. D. C. , Chana K. S. , Matthews I. W.
Published: February 2015

A new type of heat transfer sensor has been developed in which the sensing element is a short length (∼3mm) of single mode optical fibre acting as a Fabry-Perot interferometer. The reflected light intensity follows a periodic transfer function, and the phase change is proportional to the sensor’s spatially averaged temperature. We present results from three optical fibre sensors embedded as calorimeter gauges in a ceramic nozzle guide vane end wall model exposed to a transient heat flux of ∼100 kWm−2 in the Isentropic Light Piston Facility at DRA Pyestock Famborough, and validated by comparison with previous data from platinum thin film resistance gauges. The optical sensors exhibit high spatial resolution (∼5μm), high heat transfer resolution (∼1kWm−2), and wide temperature measurement bandwidth (100kHz) with intrinsic calibration. No electrical connections to the measurement volume are required and multiplexing is possible.
Biogas Fired Industrial Gas Turbines: A Technological and Potential Assessment
Authors: Hanagudu Harish
Published: February 2015

This paper reviews the advantages, technical considerations and application of biogas fired Industrial Gas Turbines, and suggests strategies for improving the regeneration of electricity in cane sugar distilleries.

Biogas is produced by the anaerobic treatment of waste by the Indian Distillery and allied alcohol based industries. Treatment of waste has been made mandatory and all distilleries in India are setting up such units. With the generation of biogas, the Indian Distillery has found a novel way of converting waste into energy.

Traditionally, the biogas obtained was fired in boilers to generate steam. Steam could be used for process or to drive a back-pressure steam turbine. A few small units also considered installing dual fuel reciprocating engines.

Recently, a trend setting project of firing biogas directly in a gas turbine to produce electricity and subsequently utilize the hot exhaust gases in a waste heat recovery boiler is being proposed. There are distinct advantages in selecting the gas turbine route over other competing prime movers.
Computer Aided Drafting and Design in Gas Turbine Engineering
Authors: Boswell James S. , Watson William M.
Published: February 2015

The design process involved in Gas Turbine Engineering demands that specific measures be taken to ensure quality product output is achieved. Full utilization of a networked Engineering Database Management System enables designers and engineers to accomplish this. Initially, all Engineering databases must be centrally located. This will ensure complete data integrity over all Engineering projects which have been created by the project related design teams. This will also allow for full design control of multiple design configurations and the creation of material databases within each drawing file database. Maximizing the use of an integrated CADD system will allow for the highest levels of productivity possible as long as individuals recognize this value.
Operability/Maintainability Applications of Design
Authors: Plotkin Paul , Coffman Matt , Engel Robert
Published: February 2015

This paper describes the comprehensive RAM process that is being utilized throughout the Design, Procure, Construct, Operate and Maintain phases of the FPL/Lauderdale Repower Project. A special focus on the transfer of the design analysis to the Operate and Maintain phase is also described herein.
Evolution of Gas Turbines Auxiliary Systems Designed for Reliability
Authors: Misiowiec Jacek , McElwee Tim , DellaVilla Sal
Published: February 2015

Gas turbine design evolution and practice is driven by industry demand for increased output and improved operating efficiencies. New aerothermal design characteristics require a focus on improved materials and coatings, and cooling techniques. As environmental issues continue to confront the industry, Dry Low NOx combustion system designs represent a significant opportunity for meeting new emissions requirements. These issues represent opportunity for significant technology improvements and industry driven advances.

However, just as important is the design evolution of the Control and Auxiliary systems which support the gas turbine. Historically, these support systems, as demonstrated by the Operational Reliability Analysis Program (ORAP), are typically the primary drivers of plant Availability and Reliability. Following a rigorous “Design for Reliability” approach provides opportunities for ensuring that the design meets three critical requirements: starting reliability, a minimum of unit shutdowns during operating demand periods and ease of maintenance. The design approach for the Control and Auxiliary systems for new turbine design (product improvement) therefore provides an opportunity for developing a uniform and standardized approach which continues to focus on Reliability, Availability, and Maintainability. This design approach also provides opportunities for improved field installation and reduced cycle time, a major benefit for the end user.

This paper will describe the “Design for Reliability” approach followed by ABB Power Generation, Inc., and supported by Strategic Power Systems, Inc.® (SPS) for the GT11N2 auxiliary systems. The extension of the ORAP system for auxiliary systems will be discussed as the approach for monitoring unit Availability and Reliability, maintaining configuration control, and for promoting continuous improvement.
A Cold Heat Transfer Tunnel for Gas Turbine Research on an Annular Cascade
Authors: Martinez-Botas R. F. , Main A. J. , Lock G. D. , Jones T. V.
Published: February 2015

The Oxford University Blowdown Tunnel has been substantially modified to test a large annular cascade of high pressure nozzle guide vanes (mean blade diameter of 1.11 m and axial chord of 0.0673 m). The new transonic facility has been constructed to obtain complete contours of heat transfer coefficient for both the end walls and blade surfaces using the transient liquid crystal technique, to measure pressure distributions and losses, and to study fundamental aspects of boundary layers and secondary flows. The facility allows an independent variation of Reynolds and Mach numbers, providing aerodynamic and heat transfer measurements in the region of interest for gas turbine design. The mass flow rate through the cascade at NGV design conditions (exit Mach number 0.96 and Reynolds number 2.0 × 106) is 38 kg/s and the pressure-regulated test duration exceeds 7 seconds.
Fluid Flow and Heat Transfer Prediction in a Non-Rotating Axial Turbine Internal Coolant Passage and Comparison With Experiment
Authors: Dawes W. N. , White A. J.
Published: February 2015

This paper describes the application of an unstructured mesh, solution-adaptive, 3D Navier-Stokes solver to the numerical simulation of the flow in a complex, three pass, turbulated, serpentine coolant passage, typical of modern axial gas turbine practice. The predicted variation of heat transfer coefficient on the convex, pressure side of the passage is in encouraging agreement with measurements from a very similar geometry, particularly as regards spatial distribution. The absolute level of the predicted heat transfer coefficients is somewhat lower than in the measurements but this is consistent with the post-processing difficulty of defining the temperature difference used to form the coefficient. A strong inter-relationship was observed between the secondary flows in the coolant passage and the heat transfer distribution. The paper attempts to show that the benefits of unstructured meshing, solution-adaption and a general purpose flow solver combine to produce a very powerful analytical ability which now permits routine solution of complex geometries such as that described here.
A Study of the Feasibility of Steam-Augmented Gas Turbines for Surface Ships
Authors: Urbach Herman B. , Knauss Donald T. , Patchett David B. , Purnell John G. , Muench Rolf K. , Garman Richard W. , Bielitz Charles L. , Stoffel William H. , Doyle Timothy J.
Published: February 2015

The steam-augmented gas turbine (SAGT) has attracted attention because of its increased fuel efficiency. It yields significant, cost-effective increments of output power, particularly when steam/water injection is increased to levels approaching 50% of air flow. Such high levels of steam/water consumption permit burner operation near stoichiometric combustion ratios with specific powers exceeding 580 hp-sec/lb anticipated.

This paper examines steam-augmented gas turbines for their applicability in Navy DDG-class ship environments. SAGT engine concepts exhibit efficiencies approaching the Navy’s intercooled regenerative (ICR) engine, and an impressive compactness that arises from the high specific power of steam.

Polished water consumption may be 425,000 gal/day for a 100,000-hp SAGT-engine ship plant. Nevertheless, SAGT engine systems impose little if any negative ship impact even after accounting for water purification systems. Moreover, because of their high specific power, SAGT systems are as affordable, on a first-acquisition-cost basis, as the current gas turbine systems in the fleet, and in the present supply pipeline.
Robust Controller Design for Active Vibration Control
Authors: Jagannathan S. , Palazzolo A. B. , Kascak A. F. , Montague G. T.
Published: February 2015

A novel frequency-domain technique, having its roots in Quantitative Feedback Theory (QFT), has been developed to design controllers for active vibration control (AVC). The advantages are a plant-based design according to performance specifications, and the ability to include structured uncertainties in the critical plant parameters like passive bearing stiffness or damping. In this paper, we describe the background theory of single-input, single-output (SISO) and multi-input, multi-output (MIMO) QFT design, followed by development of the theory adapted for AVC. Application examples are considered next, outlining the design method for both cases. Simulation results for the systems studied are presented showing the effectiveness of the technique in attenuating vibration.
Upgrading a Power Turbine Stator for Greater Creep Life, Incorporating a Material Change to Haynes 230
Authors: Klova Robert J. , Sobaru Constantin S.
Published: February 2015

This paper reviews the process of redesigning and manufacturing a power turbine first stage stator, upgraded to eliminate a chronic creep problem. Field experience with the redesigned stator is also presented. Geometry changes to reduce predicted stress levels are discussed. Material selection and manufacturing considerations using Haynes Alloy 230 are reviewed. Included in this discussion are the aspects of engineering and manufacturing a component for very low production volume.
Turning Gear Operation: Its Influence on Combustion Turbine Rotor Eccentricity and Starting Dynamics
Authors: Simmons Harold R. , Troxler Paul J. , Smalley Anthony J. , Robinson George J. , Frischmuth Robert W.
Published: February 2015

This paper presents an experimental program which investigates how turning gear operation influences thermal distortion and start quality of a power generation combustion turbine. It presents results which quantify how taking a turbine off turning gear under hot or cold conditions influences rotor distortion. It further shows how time on turning gear reduces rotor eccentricity. This paper uses available unbalanced sensitivity data and rotor eccentricity measured on turning gear to estimate the margin for vibration trip on start-up. The paper discusses how rotor eccentricity data can be independently obtained with limited additional non-intrusive instrumentation, and how the data can help guide turning gear operational strategies for different utility load profiles.
Compressor Blade Forced Response due to Downstream Vane-Strut Potential Interaction
Authors: Chiang Hsiao-Wei D. , Turner Mark G.
Published: February 2015

A blade forced response prediction system has been developed using an implicit 2D CFD solver to model the rotor blade forced response due to the static pressure distortion (potential disturbance) from the downstream stator vanes and struts. The CFD solver predicts the static pressure distortion upstream of the stator vanes and struts, which is used to calculate the induced velocity perturbation at the rotor inlet. Using the velocity perturbation 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. The results show that the stator vanes cause a significant amplification of the potential disturbances due to the struts. Effects of strut and vane modifications are examined using the analysis. A vane modification with an “optimized” flow angle distribution shows that the disturbance can be greatly reduced. Recent testing of the strut modification shows exceptional correlation with the prediction.
Suppression of Mixed-Flow Pump Instability and Surge by the Active Alteration of Impeller Secondary Flows
Authors: Goto Akira
Published: February 2015

An active method for enhancing pump stability, featuring water jet injection at impeller inlet, was applied to a mixed-flow pump. The stall margin, between the design point and the positive slope region of the head-flow characteristic, was most effectively enlarged by injecting the jet in the counter-rotating direction of the impeller. The counter-rotating streamwise vorticity along the casing, generated by the velocity discontinuity due to the jet injection, altered the secondary flow pattern in the impeller by opposing the passage vortex and assisting the tip leakage vortex motion. The location of the wake flow was displaced away from the casing-suction surface corner of the impeller, thus avoiding the onset of the extensive corner separation, the cause of positive slope region of the head-flow characteristic. This method was also confirmed to be effective for stabilizing a pump system already in a state of surge.
Dynamic Forces From Single Gland Labyrinth Seals: Part I — Ideal and Viscous Decomposition
Authors: Millsaps Knox T. , Martinez-Sanchez Manuel
Published: February 2015

A theoretical and experimental investigation on the aerodynamic forces generated by a single gland labyrinth seal executing a spinning/whirling motion has been conducted. A lumped parameter model which includes the kinetic energy carry-over effect is presented along with a linear perturbation solution technique. The resulting system is nondimensionalized and the physical significance of the reduced parameters is discussed. Closed form algebraic formulas are given for some simple limiting cases. It is shown that the total cross-force predicted by this model can be represented as the sum of an ideal component due to an inviscid flow with entry swirl and a viscous part due to the change in swirl created by friction inside the gland. The frequency dependent ideal part is solely responsible for the rotordynamic direct damping. The facility designed and built to measure these frequency dependent forces is described. Experimental data confirm the validity and usefulness of this ideal/viscous decomposition. A method for calculating the damping coefficients based on the force decomposition using the static measurements only is presented.
Development of a New Front Stage for an Industrial Axial Flow Compressor
Authors: Eisenberg B.
Published: February 2015

Industrial axial flow compressors are specially designed to achieve a wide operating range. The analysis of an existing 6 stage axial flow research compressor indicated that the front stage could be improved significantly using modern design technique. To demonstrate the advantages of such a technique a redesign of the current front stage was conducted.

By controlling the diffusion inside the blade sections with an inverse design method, loading was enlarged. Higher loading normally results in a reduction of profile incidence range. For compensation a wide chord application was chosen. Compared to the original compressor version, experiments resulted in steeper characteristic curves together with larger usable operating range. Keeping the same outer and inner diameter, mass flow was increased by 6%. Measurements of performance curves with variable speed and for guide vane control are presented. Theoretical calculations achieve a high degree of agreement with measured performance.
A Review of Research on Turbomachinery at MIT Traceable to Support From Mel Hartmann
Authors: Kerrebrock Jack L.
Published: February 2015

Research conducted at MIT since 1968 stemming from early initiatives on the Blowdown Compressor Experiment and on transonic three dimensional CFD, is reviewed from the viewpoint of the consequences of enlightened support of research by exceptionally capable leaders of government research. Among the consequences in this case are development of detailed understanding of the unsteady flows in transonic compressors and their contribution to losses, and the ability to compute the three-dimensional transonic flow in such machines. Analogous results for turbines include the ability to measure and compute the unsteady heat flux distribution on turbine blades and vanes as well as the flow field. In addition to these research results, the programs which are traceable to Mel Hartmann’s early support have produced more than seven faculty members who continue to teach and conduct research in aircraft propulsion and closely related fields, and a corresponding number of students.
Some Results of NASA-Iowa State University Research on Axial-Flow Pumps
Authors: Serovy George K. , Okiishi Theodore H.
Published: February 2015

This paper is a commentary on a small chapter in the recent history of turbomachinery research. It was written to describe the positive influence of an individual, Melvin J. Hartmann, working in a federal research center, on a particular university research program. However, in its final form, it cannot help but shed some light on the long-term effects of small-scale mission-oriented, federal agency funding of engineering research in universities. Secondarily, it will recall a series of experimental investigations of axial-flow pump configurations which produced data of possible relevance to current compressor and pump problems.
Lean Blowout Research in a Generic Gas Turbine Combustor With High Optical Access
Authors: Sturgess G. J. , Shouse D.
Published: February 2015

The U.S. Air Force is conducting a comprehensive research program aimed at improving the design and analysis capabilities for flame stability and lean blowout in the combustors of aircraft gas turbine engines. As part of this program, a simplified version of a generic gas turbine combustor is used. The intent is to provide an experimental data base against which lean blowout modeling might be evaluated and calibrated. The design features of the combustor and its instrumentation are highlighted, and the test facility is described. Lean blowout results for gaseous propane fuel are presented over a range of operating conditions at three different dome flow splits. Comparison of results with those of a simplified research combustor is also made. Lean blowout behavior is complex, so that simple phenomenological correlations of experimental data will not be general enough for use as design tools.
Test Result of Low NOx Catalytic Combustor for Gas Turbine
Authors: Ozawa Y. , Hirano J. , Sato M. , Saiga M. , Watanabe S.
Published: February 2015

Catalytic combustion is an ultra low NOx combustion method, so it is expected that this method will be applied to gas turbine combustor. However, it is difficult to develop catalytic combustor because catalytic reliability at high temperature is still insufficient.

To overcome this difficulty, we designed a catalytic combustor in which premixed combustion was combined. By this device, it is possible to obtain combustion gas at a combustion temperature of 1300°C while keeping the catalytic temperature below 1000°C.

After performing preliminary tests using LPG, we designed two types of combustors for natural gas with a capacity equivalent to 1 combustor used in a 20MW–class multi–can type gas turbine. Combustion tests were conducted at atmospheric pressure using natural gas.

As a result, it was confirmed that a combustor in which catalytic combustor segments were arranged alternately with premixing nozzles could achieve low NOx and high combustion efficiency in the range from 1000°C to 1300°C of the combustor exit gas temperature.
A Diagnostic Expert System for Oil Systems of Aeroengines
Authors: Cao Hong , Ma Mei
Published: February 2015

DIAG, a diagnostic expert system for oil systems of aeroengines, is presented in this paper. Using artificial intelligence, DIAG, which simulates the role of human experts in solving problems, can solve the complicated problems in diagnosing the faults and failures of oil systems of gas turbine engines. The paper concentrates on the design of DIAG as well as the process of handling the complex relation and uncertainty of problems. It also includes graphic subsystem and data subsystem. It is affirmed by the expected goal of diagnosing the faults and failures of oil system and engine of CFM56 engine on Boeing 737–300 airplane.
Technology Considerations for Optimizing IGCC Plant Performance
Authors: Corman James C. , Todd Douglas M.
Published: February 2015

The integrated gasification combined cycle (IGCC) concept is gaining acceptance as the Clean Coal technology with the best potential for continued improvement in performance and continued reduction in capital cost. In large part this potential will be realized by optimizing the integration of power generation and fuel conversion subsystems and by exploiting advances in gas turbine technology. This paper discusses the impact that technology advances in the gas turbine combined cycle are having on the commercial viability of the IGCC concept. Technical innovations in such areas as coal gas combustion, plant control, and system integration will ensure that IGCC technology will continue to advance well into the future.
Turbulent Spot Development Under a Moderate Adverse Pressure Gradient
Authors: Gostelow J. P. , Hong G. , Melwani N. , Walker G. J.
Published: February 2015

Triggered turbulent spots are under investigation in a wind tunnel. A turbulent spot was initiated in a flat plate boundary layer under a moderate adverse pressure gradient. The spot was traversed at four streamwise locations using conventional hot-wire anemometry techniques. A triggering jet provided a phase reference for data sampling. Phase-averaged velocity traces, boundary layer integral properties and contours of velocity perturbation and disturbance level are presented. The central region resembles a zero pressure gradient spot but much of the span is dominated by the different behavioral stages of a stongly-amplified wave packet. The celerities of the spot leading and trailing edges under an adverse pressure gradient are significantly lower than those associated with zero pressure gradient spots but the lateral spreading rate is much higher. This combination of turbulent spot and wave packet, which spreads at an included angle as high as 60° is quite different from the well-documented zero pressure gradient spot spreading at an included angle of about 20°. Improvements in transition region predictions are therefore dependent on further detailed measurements of spots and wave packets under adverse pressure gradients.
Control-Oriented High-Frequency Turbomachinery Modeling: General 1D Model Development
Authors: Badmus O. O. , Eveker K. M. , Nett C. N.
Published: February 2015

In this paper, an approach for control-oriented high–frequency turbomachinery modeling previously developed by the authors is applied to develop 1D unsteady compressible viscous flow models for a generic turbojet engine and a generic compression system. We begin by developing models for various components which are commonly found in turbomachinery systems. These components include: ducting without combustion, blading, ducting with combustion, heat soak, blading with heat soak, inlet, nozzle, abrupt area change with incurred total pressure losses, flow splitting, bleed, mixing, and the spool. Once the component models have been developed, they are combined to form system models for a generic turbojet engine and a generic compression system. These models are developed so that they can be easily modified and used with appropriate maps to form a model for a specific rig. It is shown that these system models are explicit (i.e. can be solved with any standard ODE solver without iteration) due to the approach used in their development. Furthermore, since the nonlinear models are explicit, explicit analytical linear models can be derived from the nonlinear models. The procedure for developing these analytical linear models is discussed. An interesting feature of the models developed here is the use of effective lengths within the models, as functions of axial Mach number and nondimensional rotational speed, for rotating components. These effective lengths account for the helical path of the flow as it moves through a rotating component. Use of these effective lengths in the unsteady conservation equations introduces a nonlinear dynamic lag consistent with experimentally observed compressor lag and replaces less accurate linear first order empirical lags proposed to account for this phenomenon. Models of the type developed here are expected to prove useful in the design and simulation of (integrated) surge control and rotating stall avoidance schemes.
Chaotic Behavior of Rotor/Stator Systems With Rubs
Authors: Goldman Paul , Muszynska Agnes
Published: February 2015

This paper outlines the dynamic behavior of externally excited rotor/stator systems with occasional, partial rubbing conditions. The observed phenomenon have one major source of a strong nonlinearity: transition from no contact to contact state between mechanical elements, one of which is rotating. This results in variable stiffness and damping, impacting, and intermittent involvement of friction. A new model for such a transition (impact) is developed. In case of the contact between rotating and stationary elements, it correlates the local radial and tangential (“super ball”) effects with global behavior of the system. The results of numerical simulations of a simple rotor/stator system based on that model are presented in the form of bifurcation diagrams, rotor lateral vibration time–base waves, and orbits. The vibrational behavior of the considered system is characterized by orderly harmonic and subharmonic responses, as well as by chaotic vibrations. A new result (additional subharmonic regime of vibration) is obtained for the case of heavy rub of an anisotropically supported rotor. The correspondence between numerical simulation and previously obtained experimental data supports the adequacy of the new model of impact.
Industrial RB211 Dry Low Emission Combustion
Authors: Willis Jeff D. , Toon Ian J. , Schweiger Tom , Owen David A.
Published: February 2015

The inital combustor development of a pre-mix lean burn arrangement for an aero-derivative gas generator is described. The emission targets of the practical system were for the NOx and CO to be less than 25 vppm (15% O2) over a wide range of powers and ambient temperatures. From combustion rig testing of a two stage (in series) system at 1,5 and 20 atmospheres the baseload engine emissions are predicted to be NOx = 17 vppm (15% O2) and CO = 5 vppm with a turn down of 30% power. To achieve a wider power turn down a three stage (in series) system is required.