bluuebunny/crossref_metadata_2025 huggingface dataset:
Stochastic Modelling of NOx and Smoke Production in Gas Turbine Combustors
Authors: Aksit I. M. , Moss J. B.
Published: February 2015

The paper describes a hybrid approach to combustor emissions prediction in which a stochastic model of the multi-scalar field necessary for NOx and smoke prediction is combined with that of a flowfield from a coarse CFD calculation in a representative tubular combustor. A transport equation for the joint composition pdf, for example that of mixture fraction, soot mass concentration and number density, is computed using a Monte Carlo simulation in which the mean velocity and turbulence properties are generated by the CFD calculation. By adopting a standard k-ε / presumed scalar pdf approach for the latter, the CFD and Monte Carlo calculations are completely decoupled and the stochastic modelling of the reacting scalars is effected within readily accessible computing resources.
Effects of Geometry on Slot–Jet Film Cooling Performance
Authors: Hyams Daniel G. , McGovern Kevin T. , Leylek James H.
Published: February 2015

The physics of the film cooling process for shaped, inclined slot–jets with realistic slot–length–to–width ratios (L/s) is studied for a range of blowing ratio (M) and density ratio (DR) parameters typical of gas turbine operations. The effect of inlet and exit shaping of the slot–jet on both flow and thermal field characteristics is isolated, and the dominant mechanisms responsible for differences in these characteristics are documented. A previously documented computational methodology was applied for the study of four distinct configurations: (1) slot with straight edges and sharp comers (reference case); (2) slot with shaped inlet region; (3) slot with shaped exit region; and (4) slot with both shaped inlet and exit regions. Detailed field results as well as surface phenomena involving adiabatic film effectiveness (η) and heat transfer coefficient (h) are presented. It is demonstrated that both η and h results are vital in the proper assessment of film cooling performance. The key parameters M and DR were varied from 1.0 to 2.0 and 1.5 to 2.0, respectively, to show their influence. Simulations were repeated for slot length–to–width ratio (L/s) of 3.0 and 4.5 in order to explain the effects of this important parameter. The computational simulations showed exceptionally strong internal consistency. Moreover, the ability of using a state–of–the–art computational methodology to sort the relative performance of different slot–jet film cooling configurations was clearly established.
Internal Passage Heat Transfer Prediction Using Multiblock Grids and a k-ω Turbulence Model
Authors: Rigby David L. , Ameri A. A. , Steinthorsson E.
Published: February 2015

Numerical simulations of the three-dimensional flow and heat transfer in a rectangular duct with a 180° bend were performed. Results are presented for Reynolds numbers of 17,000 and 37,000 and for aspect ratios of 0.5 and 1.0. A k-ω turbulence model with no reference to distance to a wall is used. Direct comparison between single block and multiblock grid calculations are made. Heat transfer and velocity distributions are compared to available literature with good agreement. The multi-block grid system is seen to produce more accurate results compared to a single-block grid with the same number of cells.
Analysis of Gas Turbine Rotor Blade Tip and Shroud Heat Transfer
Authors: Ameri A. A. , Steinthorsson E.
Published: February 2015

Predictions of the rate of heat transfer to the tip and shroud of a gas turbine rotor blade are presented. The simulations are performed with a multiblock computer code which solves the Reynolds Averaged Navier-Stokes equations. The effect of inlet boundary layer thickness as well as rotation rate on the tip and shroud heat transfer is examined. The predictions of the blade tip and shroud heat transfer are in reasonable agreement with the experimental measurements. Areas of large heat transfer rates are identified and physical reasoning for the phenomena presented.
The Turboexpander: A Design, Make and Test Student Project
Authors: Denton J. D.
Published: February 2015

Third year Engineering students at Cambridge University have to undertake a project, occupying about 80 hours of their time, which should involve designing, making and testing some item of Engineering interest. A turbomachinery based project has been developed to fulfil this requirement. The project is based around a “turboexpander” which consists of a centrifugal compressor and a radial inflow turbine on the same shaft. The compressor takes in air from the atmosphere and delivers it directly to the turbine and the assembly is driven by sucking the turbine exhaust with an industrial vacuum cleaner. The flow path is therefore similar to that used in aircraft air conditioning systems or in most gas liquefaction plant, but with the difference that in these cases the objective is to provide cold air and so the air leaving the compressor is cooled before it is expanded in the turbine.
The Path to Predicting Bypass Transition
Authors: Mayle R. E. , Schulz A.
Published: February 2015

A theory is presented for calculating the fluctuations in a laminar boundary layer when the free stream is turbulent. The kinetic energy equation for these fluctuations is derived and a new mechanism is revealed for their production. A methodology is presented for solving the equation using standard boundary layer computer codes. Solutions of the equation show that the fluctuations grow at first almost linearly with distance and then more slowly as viscous dissipation becomes important. Comparisons of calculated growth rates and kinetic energy profiles with data show good agreement.

In addition, a hypothesis is advanced for the effective forcing frequency and free-stream turbulence level which produce these fluctuations. Finally, a method to calculate the onset of transition is examined and the results compared to data.
Convective Heat Transfer of Cubic Fin Arrays in a Narrow Channel
Authors: Chyu M. K. , Hsing Y. C. , Natarajan V.
Published: February 2015

The present study explores the heat transfer enhancement induced by arrays of cubic fins. The fin element is either a cube or a diamond in shape. The array configurations studied include both inline and staggered arrays of seven rows and five columns. Both cubic arrays have the same geometric parameters, i.e., H/D=1, S/D=X/D=2.5, which are similar to those of earlier studies on circular pin-fin arrays. The present results indicate that the cube element in either array always yields the highest heat transfer, followed by diamond and circular pin-fin. Arrays with diamond-shaped elements generally cause the greatest pressure loss than those with either cubes or pin fins. For a given element shape, a staggered array generally produces higher heat transfer enhancement and pressure loss than the corresponding inline array. Cubic Arrays can be viable alternatives for pedestal cooling near a blade trailing edge.
Measurements and Prediction of the Effects of Surface Roughness on Profile Losses and Deviation in a Turbine Cascade
Authors: Kind Richard J. , Serjak Peter J. , Abbott Michael W. P.
Published: February 2015

Measurements of pressure distributions, profile losses and flow deviation were carried out on a planar turbine cascade in incompressible flow to assess the effects of partial roughness coverage of the blade surfaces. Spanwise oriented bands of roughness were placed at various locations on the suction and pressure surfaces of the blades. Roughness height, spacing between roughness elements, and band width were varied.

A computational method based on the inviscid/viscous interaction approach was also developed; its predictions were in good agreement with the experimental results. This indicates that good predictions can be expected for a variety of cascade and roughness configurations from any 2-dimensional analysis which couples an inviscid method with a suitable rough surface boundary-layer analysis. The work also suggests that incorporation of the rough wall skin-friction law into a 3-D Navier-Stokes code would enable good predictions of roughness effects in 3-dimensional situations.

Roughness was found to have little effect on static pressure distribution around the blades and on deviation angle, provided that it does not precipitate substantial flow separation. Roughness on the suction surface can cause large increases in profile losses; roughness height and location of the leading edge of the roughness band are particularly important. Loss increments due to pressure-surface roughness are much smaller than those due to similar roughness on the suction surface.
Effect of Periodic Wake Passing on Film Effectiveness of Inclined Discrete Cooling Holes Around the Leading Edge of a Blunt Body
Authors: Funazaki Ken-ichi , Koyabu Eitaro , Yamawaki Shigemichi
Published: February 2015

Detailed studies are conducted on film effectiveness of inclined discrete cooling holes around the leading edge of a blunt body that is subjected to periodically incoming wakes as well as free-stream turbulence with various levels of intensity. The cooling holes have a configuration similar to that of a typical turbine blade and are angled at 30 and 90 degree to the surface in the spanwise and streamwise directions, respectively. A spoked-wheel type wake generator is used in this study to simulate periodically incoming wakes to turbine blades. In addition, two types of turbulence grids are used to elevate a free-stream turbulence intensity. We adopt three blowing ratios of the secondary air to the mainstream. Most of the dominant flow conditions are reproduced in this study except for the air density ratio of the secondary air and the main stream. For each of the blowing ratios, wall temperature around the surface of the test model are measured by thermocouples situated inside the model. The temperature is visualized using liquid crystals to obtain traces of the injected secondary air on the test surface, which consequently helps us interpret the data of the thermocouples.
Aerodynamic Aspects of Endwall Film-Cooling
Authors: Friedrichs S. , Hodson H. P. , Dawes W. N.
Published: February 2015

This paper describes an investigation of the aerodynamic aspects of endwall film-cooling, in which the flow field downstream of a large-scale low-speed linear turbine cascade has been measured. The integrated losses and locations of secondary flow features with and without end wait film-cooling have been determined for variations of both the coolant supply pressure and injection location. Together with previous measurements of adiabatic film-cooling effectiveness and surface-flow visualisation, these results reveal the nature of the interactions between the ejected coolant and the flow in the blade passage. Measured hole massflows and a constant static pressure mixing analysis, together with the measured losses, allow the decomposition of the losses into three distinct entropy generation mechanisms: loss generation within the hole, loss generation due to the mixing of the coolant with the mainstream, and change in secondary loss generation in the blade passage. Results show that the loss generation within the coolant holes is substantial and that ejection into regions of low static pressure increases the loss per unit coolant massflow. Ejection upstream of the three-dimensional separation lines on the endwall changes secondary flow and reduces its associated losses. The results show that it is necessary to take the three-dimensional nature of the endwall flow into account in the design of endwall film-cooling configurations.
Power Turbine Remaining Life Analysis: Experience and Practical Considerations
Authors: Klova Robert J. , Galatis Hermes
Published: February 2015

A Power Turbine Remaining Life Analysis, in a fundamental sense, would provide the number of hours and/or starts until critically loaded turbine components require replacement. Often, however, it is more practical to pursue less quantitative results. Remaining Life Analysis is often viewed as a metallographic analysis. However, a variety of damage mechanisms may limit the life of a critical component: creep, corrosion, low cycle fatigue, etc.; not all of which can be evaluated using metallographic techniques alone. In some of the cases, quantitative answers may be obtained only through detailed structural analysis. Both metallographic and structural analysis techniques will yield a wide range of uncertainty. Evaluation of component condition and analytical results must be hacked by years of experience. Fortunately, maintenance decisions often do not require precise quantitative results. This paper discusses the capabilities and limitations of various analytical techniques, and presents them in light of real-world maintenance decisions. Illustrative examples from power turbine evaluations are provided.
Adiabatic Effectiveness and Heat Transfer Coefficient on a Film-Cooled Rotating Blade
Authors: Garg Vijay K.
Published: February 2015

A three-dimensional Navier-Stokes code has been used to compute the adiabatic effectiveness and heat transfer coefficient on a rotating film-cooled turbine blade. The blade chosen is the UTRC rotor with five film-cooling rows containing 83 holes, including three rows on the shower head with 49 holes, covering about 86% of the blade span. The mainstream is akin to that under real engine conditions with stagnation temperature = 1900 K and stagnation pressure = 3 MPa. The blade speed is taken to be 5200 rpm. The adiabatic effectiveness is higher for a rotating blade as compared to that for a stationary blade. Also, the direction of coolant injection from the shower-head holes affects considerably the effectiveness and heat transfer coefficient values on both the pressure and suction surfaces. In all cases, the heat transfer coefficient and adiabatic effectiveness are highly three-dimensional in the vicinity of holes but tend to become two-dimensional far downstream.
Comparison of Predicted and Experimental Nusselt Number for a Film-Cooled Rotating Blade
Authors: Garg Vijay K. , Abhari Reza S.
Published: February 2015

The predictions from a three-dimensional Navier-Stokes code have been compared to the Nusselt number data obtained on a film-cooled, rotating turbine blade. The blade chosen is the ACE rotor with five rows containing 93 film cooling holes covering the entire span. This is the only film-cooled rotating blade over which experimental heat transfer data is available for the present comparison. Over 2.25 million grid points are used to compute the flow over the blade. Usually in a film cooling computation on a stationary blade, the computational domain is just one spanwise pitch of the film-cooling holes, with periodic boundary conditions in the span direction. However, for a rotating blade, the computational domain consists of the entire blade span from hub to tip, as well as the tip clearance region.

As far as the authors are aware of, the present work offers the first comparison of the prediction of surface heat transfer using a three dimensional CFD code with film injection and the measured heat flux on a fully film-cooled rotating transonic turbine blade. In a detailed comparison with the measured data on the suction surface, a reasonably good comparison is obtained, particularly near the hub section. On the pressure surface, however, the comparison between the data and the prediction is poor. A potential reason for the discrepancy on the pressure surface could be the presence of unsteady effects due to stator-rotor interaction in the experiments which are not modeled in the present numerical computations.
Applications of Advanced Liquid Crystal Video Thermography to Turbine Cooling Passage Heat Transfer Measurement
Authors: Campbell Robert P. , Molezzi Michael J.
Published: February 2015

Over the past few years advances in thermochromic liquid crystal (TLC) thermography have improved its usefulness as a quantitative temperature measurement technique. Many of these improvements have been discussed in the literature but few have been directly applied to solving gas turbine heat transfer problems. The purpose of this work is to combine the best of these techniques into an advanced, easy to use, low cost system which can provide accurate, rapid and complete heat transfer data for advanced gas turbine development.

The older, more common technique of using narrow band liquid crystals to map isotherm distributions has been updated to use wide temperature range crystals with full hue-temperature calibrations over their entire response range with accuracy as good or better than thermocouples. The system consists of an RGB video camera, a hue, saturation and intensity (HS1) framegrabber, on-axis lighting and a linear thermal gradient TLC calibrator. Algorithms have been developed for automated data validation, spatial transformations of data taken on non-planar surfaces and superposition of multiple data sets to construct full field data over surfaces with wide ranges of heat transfer coefficients (h). Instead of yielding mean h, h at a few thermocouple locations or h at individual isotherms, this system provides continuous distributions of h.

These techniques have been used to map the heat transfer coefficient distributions in advanced power generation gas turbine internal cooling passages. These include serpentine passages with and without turbulators, leading edge passages and 180° rums. Results are presented in full field plots of heat transfer enhancement, Nu(x,y)/Nudb.
Effects of Steam Injection and Stochiometry on Cyclone Gasification of Wood Powder
Authors: Fredriksson Christian , Degerman Bengt , Kjellström Björn
Published: February 2015

Atmospheric gasification of wood powder in a cyclone has been studied. A cyclone gasifier has been designed where the wood powder is injected into the cyclone with air or air/steam as transport media. The effects of stochiometry and steam injection on the gasification temperature and gas composition are investigated. The experimental results are compared with theoretical equilibrium calculations.

The fuel flow has been 26 kg/h corresponding to a thermal input of 140 kW. Equivalence ratio was varied between 0.15 and 0.4. Wood powder has been injected with steam mass flows of 50–80% of the fuel flow. The gas from the cyclone gasifier was analysed regarding CO, H2, CH4 and CO2. The lower heating value of the gas varies between 4 and 6 MJ/Nm3 with lower values for steam injected gasification. Compared to theoretical calculations the air/steam injected measurements showed better agreement with equilibrium predictions than only air injection.
A Unique Approach to HRSG Bypass Dampers
Authors: Ryan David T. , Veatch Judith A. , Pasha Akber
Published: February 2015

‘Soft’ start flow distribution, control capability, sealing performance, and safety, were four reasons Oklahoma Municipal Power Authority (OMPA), in cooperation with Black & Veatch and Vogt, installed Dual BiPlane Heat Recovery Steam Generator (HRSG) Isolation and Bypass Dampers from Damper Design, Inc. on the gas turbine outlet at this facility.

The DDI BiPlane damper is truly a unique damper for this application. This design allowed OMPA to have the safety and isolation of a flap diverter white providing the even gas distribution and accurate flow control to the HRSG under startup conditions available from a louver style damper.

The arrangement consists of two DDI BiPlane dampers, one on the inlet to the HRSG and one isolating the stack. Since safety is highest priority, Damper Design utilized an independent lockout type linkage that allows control of the dampers while positively preventing the closure of both gas paths at the same time.

By installing the DDI BiPlane damper, OMPA has the ability to throttle the gas turbine exhaust flow independently to the HRSG and stack. This allows the gases to enter the HRSG with a much more evenly distributed flow pattern and at lower controlled flow rates than with competing designs.

This paper will address the benefits, design, and operating advantages of the use of the DDI BiPlane Damper specifically in HRSG isolation and bypass installations. It is also applicable to other systems where control and isolation with one damper is desirable.
Prediction of Turbulent Flow and Heat Transfer in Rotating Square and Rectangular Smooth Channels
Authors: Dutta Sandip , Andrews Malcolm J. , Han Je-Chin
Published: February 2015

A two-equation turbulence model with additional terms for Coriolis and rotational buoyancy has been used for prediction of heat transfer from the leading and trailing sides of rotating square and rectangular channels with radially outward flow. Test cases with different Reynolds and rotation numbers are considered. The coolant air used is pressurized and operating conditions are selected to closely match real turbine operating parameters. Results show that previous experimental data can be extrapolated to predict the heat transfer characteristics of coolant passages of actual turbine blades. The internal secondary flow vortex structures for some of the aspect ratio channels are found to be different from the expected vortex structures based on earlier lower rotation speed, lower temperature, and lower pressure operating conditions.
Inlet and Nozzle Technology for 21st Century Fighter Aircraft
Authors: Gridley Marvin C. , Walker Steven H.
Published: February 2015

The focus of propulsion integration technology in the 21st century will be economy. USAF inlet and nozzle technology goals translate into 50% weight reduction and 25% acquisition cost reduction metrics for new aircraft system. Innovative technology to enable these reductions over current state-of-the-art systems in weight and cost is required. For inlet systems, compact diffusers that reduce system volume by 50% will demand fewer parts and improved aerodynamic performance. Exhaust systems will be fixed with fewer parts, requiring a technology like fluidics, for example, to provide area control and thrust vectoring capabilities. Cooperative programs for both inlet and nozzle systems are in place to insure that technologies required to meet weight and cost reduction goals are matured by the year 2000.
Experimental Investigation of Turbulence Structures in the Boundary Layer of a Highly Loaded Turbine Cascade
Authors: Wunderwald Dirk , Fottner Leonhard
Published: February 2015

An experimental study has been performed on a turbine cascade in order to obtain detailed information about the overall performance, the state of the boundary layer, and the topology of turbulent boundary layers. The analysis of profile pressure distributions and wake traverse measurements across the midspan section of the cascade blade provide information on the loss behaviour. Using surface-mounted hol-film gauges on the suction side of the measuring blade, transition modes have been investigated under the influence of various inlet flow conditions representative of engine operation.

Extensive measurements with 3D-hot-sensor anemometry have been evaluated to show essential features of the turbulent suction side boundary layer. The paper describes the dependence of turbulence characteristics, e.g. integral length scales and turbulent kinetic energy distribution, on the inlet flow conditions and the upstream boundary layer development. The influence of free-stream turbulence intensity and streamline curvature is discussed and the non-isotropy of the Reynolds normal stresses is presented. The evaluation of Reynolds stresses as well as triple order correlations should provide a further insight into the structure of turbulence and lead to a more realistic turbulence modelling.
Dutch Experience With Hot Windbox Repowering
Authors: Ploumen P. J. , Veenema J. J.
Published: February 2015

The combination of a topping Brayton (gas turbine) cycle with an existing Rankine (boiler-steam turbine) cycle for improved overall cycle heat rate has been very successful in the Netherlands.

In the years 1985–1989 10 gas-fired power plants with a capacity of nearly 4000 MW were substantially modernized by adding a gas turbine topping cycle.

In all these cases the Hot Wind box repowering or Windbox repowering with a supplementary boiler option was chosen.

Besides the improvement of the heat rate it was remarkable that a NOx-emission reduction was achieved between 50 and 85%.

So far more than 500,000 hours experience with hot windbox is available.

If NOx-reduction becomes very important windbox repowering is the best option to modernize power plants.
A Study of the Flow Characteristics in the Inducer Bleed Slot of a Centrifugal Compressor
Authors: Eynon P. A. , Whitfield A. , Firth M. R. , Parkes A. J. , Saxton R.
Published: February 2015

A broad operating range between surge and choke is so important for turbocharger compressors and many other applications that a vaneless diffuser, with its reduced efficiency, is usually adopted. With the demand for increased pressure ratio the operating range naturally reduces and techniques to extend the range are necessary. The inducer bleed slot is a technique which has been adopted in turbocharger compressors. This approach was first reported by Fisher (1988) and was described as a Map Width Enhancement slot (MWE). The flow conditions in the MWE slot and impeller inlet duct were investigated with a view to developing an improved understanding of the flow mechanisms involved as the flow rate was reduced from choice to surge. Mean temperature and pressure measurements were recorded in the MWE passage, the main inducer duct to the impeller and the inlet duct upstream of the compressor. In addition the development of flow pulsations were monitored with pressure transducers in the MWE passage, the main inducer duct and the inlet duct, together with the application of flow visualisation techniques. The transient pressure measurements showed that low frequency flow pulsations developed in the MWE passage at high flow rates. As the flow rate was reduced the low frequency pulsations disappeared and flow reversal through the MWE passage developed. It was shown that flow reversal through the MWE passage commenced at flow rates close to the peak efficiency point for the compressor.
Effect of Circumferential Inlet Flow Distortion and Swirl on the Flow Field of an Axial Flow Fan Stage
Authors: Viswanath K. , Govardhan M.
Published: February 2015

This paper reports a study of the combined effects of swirl and circumferential inlet flow distortion on the flow field of an axial flow fan stage. The study involves steady state measurements of the flow field at the rotor inlet, exit and the stator exit of the single stage axial flow fan subjected to circumferential inlet flow distortion and swirl. Flow field survey was done at two flow coefficients, namely, ϕ = 0.45 and ϕ = 0.285. The flow at the inlet to the rotor was measured using a three hole pressure probe and five hole pressure probes were used at the rotor and stator exits. The study indicated that at the design flow coefficient swirl had caused deterioration of the performance in addition to that caused by distortion. In addition, the attenuation of distortion was high in the presence of swirl.
A Probabilistic Creep Fatigue Computer Program for Structural Integrity Analysis
Authors: Millwater Harry R. , Chell Graham G. , Riha David S.
Published: February 2015

This paper describes a computer program which can determine the probability of failure of gas turbine structures as a function of time due to creep fatigue crack growth. The probability of failure is computed by combining stress analysis and creep fatigue analysis with probabilistic analysis methods. The creep fatigue analysis is based on a reference stress approach which provides a simple, accurate, and efficient method for determining the steady state component, C*, of the time dependent fracture mechanics parameter C(t). Stress intensity factors are computed from stress distributions derived from a linear elastic finite element analysis of the uncracked structure and weight functions. Several probabilistic methods are available such as efficient approximate methods, importance sampling and Monte Carlo sampling. Efficient approximate methods and importance sampling methods are typically one to two orders of magnitude more efficient than Monte Carlo sampling. Probabilistic sensitivity measures are generated as a byproduct of the probabilistic analysis and indicate the importance of the random variables to the reliability of the structure. The theoretical background, computer code and an example problem are presented.
Predicting Gas Turbine Reliability to Assess Risks for Purchased Power Agreements
Authors: Krockow Wolfram
Published: February 2015

Availability and Reliability have become a major concern for operating companies; especially for those where unscheduled outages due to purchased power agreements may be highly penalized. On the other hand, high revenues by the sale of electricity can be achieved if the power generating set performs according to its demand.

Economic calculations demonstrate that the bottom line between profit and loss lies within the high 90th% of availability. This paper summarizes the results of an analysis based on the regulations in France with its so-called EJP days (Effacement Jour Pointe). Any loss of highly penalized EJP days is quantified based on known RAM (Reliability, Availability, Maintainability) values of the equipment, as these are the Mean Time Between Failures MTBF’s and the Mean Times To Repair MTTR’s of the overall equipment as well as its subassemblies. In formulating the demand, the past 12 years of assigned EJP days by the Electricité de France, EdF, was analyzed to derive probability ratings of seasonal distributions, weekly distributions and day block distributions.

The mathematics of this simulation model are based on well proven statistical procedures (i.e. the Monte Carlo Method). By performing parameter variations, the model can also quantitatively predict how much the Mean Time Between Failures of a heavy duty gas turbine must usually be better for this application when compared to an aeroderivative gas turbine. This is because it normally takes longer to repair or replace a heavy duty gas turbine versus an aeroderivative unit in case of a major unscheduled or forced outage.
Sensitivity Controlled Response Surface Approach for Reliability Based Design
Authors: Reh Stefan , Scheu Martin
Published: February 2015

The stochastic Finite-Element-Method (FEM) is a suitable tool to assess the reliability of lifetime prediction models for complex components. Due to its demands on the number of FE analysis it has been rarely used on FE models of real components under realistic operational conditions. In the following a response surface approach is suggested that minimizes the number of FE calculations. Based on a first order method the sensitivity of the failure probability with respect to the random input quantities is evaluated. Subsequently a response surface of higher order, weighting the important and unimportant input uncertainties appropriately, is used to assess the reliability of the lifetime prediction. The method is used to analyze the reliability of typical rotor disks concerning failure due to creep rupture and low cycle fatigue (LCF) during static and transient operation.
ASTM Standards for Monolithic and Composite Advanced Ceramics: Industrial, Governmental and Academic Cooperation
Authors: Jenkins Michael G. , Quinn George D.
Published: February 2015

Monolithic and composite advanced ceramics have reached sufficient levels of material development to warrant serious consideration for applications in advanced heat engines. These applications require optimum material behavior with physical and mechanical property reproducibility, component reliability, and well-defined methods of data treatment and materials analysis. As new materials are introduced into the market place, these issues are best dealt with via standard methods. The primary standards writing organization in the U.S. is the American Society for Testing and Materials (ASTM), a private, nonprofit corporation which relies upon the voluntary cooperation of industry, government, and academe to develop standards by consensus. ASTM Committee C28 “Advanced Ceramics” has been active since 1986 and currently has 16 standards “on the books” with 17 standards in the balloting process. Overviews of the five subcommittees of C28 are presented. Accomplishments to date are discussed, as well as future activities, including a brief summary of joint cooperative efforts with international standards formulating organizations.
SPE “Mashproekt” Gas Turbine Engines for Gas Pumping Sets
Authors: Romanov Victor I. , Lupandin Vladimir V. , Kovalenko Anatoliy V. , Shelestyuk Anatoliy I.
Published: February 2015

The paper describes the experience gained in designing, developing and operation of gas turbine engines for gas pumping units on the marine gas turbine engine’s base.

More than 800 Mashproekt gas turbines of various power output have been in service in gas pumping application since 1980.

This paper shows the SPE Mashproekt designing and developing approach for gas turbines to be installed in gas pumping units along with their full-scale testing in the test bed of close gas loop type equipped with gas compressor and gas coolers to simulate operation of the gas pumping unit in the real gas pipeline conditions.

The gas turbines for gas pumping application on the 2.5 MW, 6 MW, 10 MW, 16 MW and 25 MW engines base were developed in the period of 1990–1995 for replacement of the existing old gas turbine line-up and installation in the new gas pumping units at the compressor stations in Russia and Ukraine. We are replacing engines with Mashproekt gas turbines at the following gas pumping units: Russian GTN-25, Ukrainian GPA-6.3, GPA-16 and “Coberra-182” (Great Britain) gas pumping units. The comparison of the technical characteristics of these replacements is given in the paper.

Technical data on 2.5–25 MW Mashproekt gas turbines for gas pumping units is also presented in this paper.
Refurbishment of a Solar Centaur Compressor Set to Meet European Environmental Regulations
Authors: Rohrbacher Herbert , Barron John
Published: February 2015

This paper will review the conversion of a Solar T3002R recuperated Centaur tandem compressor set, with over 100.000 fired operating hours, into a T4502S simple cycle Centaur SoLoNOx™ unit. The object was to carry out a planned overhaul on the existing engine in order to improve reliability and availability of gas compression at the Auersthal station and at the same time, to incorporate the latest Solar low Nox technology, with a view to meeting or exceeding any future environmental emissions requirements.
Power Plant Simulation Software for Optimizing Thermodynamic and Financial Plant Operation
Authors: Griffin Patrick R. , Elmasri Maher , Chen Gwo-Tung , Kamppila Stephen , Basile Frank
Published: February 2015

A modular software system was developed to optimize thermodynamic and financial operation of the 350 MW Selkirk Cogen combined cycle power plant. The package is derived from commercially available modeling software, customized for this site. The system satisfies the information needs of both technical and business oriented personnel by: (1) direct simulation utilizing the simulator’s detailed, accurate, component-wise models and (2) lookup into a large database of pre-simulated plant scenarios which obey an established operating methodology. An unattended on-line module, with access to the distributed control system, continually compares simulator output with plant measurements. This provides measures of instrumentation health and current equipment performance indicators which are fed back to update the pre-simulated database. A series of example uses of the software is provided.
Application of Aeroengine Aerodynamic Design Codes to Industrial Gas Turbine Design
Authors: Little David A. , Cobley Keith
Published: February 2015

In 1992, Westinghouse Electric Corporation and Rolls-Royce signed a technology transfer agreement. The initial application for this aeroengine technology was the design by Westinghouse of the turbine for the 1500°C turbine inlet temperature, 58% (net) combined cycle efficiency, 501G engine. A key ingredient of the large jump in combined cycle efficiency over that of its predecessor, the 501F, was the reduction in the surface area of the first 3 cooled turbine stages. This reduction was made possible by the application of aerodynamic design and analysis which allowed accurate prediction of suction surface boundary layer growth in a 3D viscous environment. Thus, the number of aerofoils or the aerofoil chords were reduced in each cooled row, until the suction surface boundary layers were predicted to be a specified margin from separation at the trailing edge.

Since the resulting aerofoil loading (back surface diffusion) was higher than previous Westinghouse experience, a 0.32 scale model of a first stage turbine was built and tested in a cold rig at the National Research Council of Canada (NRCC), to substantiate the design codes when applied to industrial turbines. The purpose of the test was threefold: (1) to verify that higher levels of back surface diffusion were possible without boundary layer separation, (2) to verify that aeroengine turbine empirical loss/efficiency prediction correlations were applicable to industrial turbines, and (3) to see how well the single row, 3D, steady, Navier Stokes analysis code used during design predicted actual swallowing capacity, and radial variations in turning and loss.

The paper will describe the aerodynamic design tools and their validation, the test facility, hardware, measurement techniques, test results, and comparisons of prediction vs measurement, thus confirming the applicability of aeroengine aerodynamic technology to the design of large industrial gas turbines.
Applications of Continuous Fiber Reinforced Ceramic Composites in Military Turbojet Engines
Authors: Spriet Patrick , Habarou Georges
Published: February 2015

Over the last twenty years, significant performance improvements of turbojet engines have been achieved by optimizing engine thermodynamic cycle along with the introduction of new materials providing higher temperature capability and weight reduction.

Metal Matrix Composites (MMC) and Ceramic Matrix Composites (CMC) are candidate material systems to meet the required thrust-to-weight ratio of 15 or higher.

Continuous fiber reinforced ceramic composites, which have been developed by SEP for more than 15 years for thermostructural applications in oxidative environment, aim at increased operating temperature over superalloys and intermetallic alloys.

This paper is a review of the main CMC component demonstrations performed by SEP over the last 10 years for turbojet engines along with an analysis of consequences on materials development and design methodology.

The development status of a new thermostructural material specifically developed for turbojet environment with the prospect of higher design stress allowables and longer operating life at high temperature is presented.
Collaborative Advanced Gas Turbine (CAGT) Program Status: An International Initiative to Catalyze an Intercooled Aeroderivative (ICAD) Gas Turbine Launch Order
Authors: Davidson Barry , Whitney Dan , Laursen Niels , Cohn Art , Hay George A.
Published: February 2015

This paper describes the status of the Collaborative Advanced Gas Turbine (CAGT) Program’s initiative to commercialize interCooled AeroDerivative gas turbine (ICAD) technology. CAGT is a consortium of domestic and international electric companies, gas companies and research organizations. ICAD gas turbine technology was selected by CAGT member companies and potential suppliers in a competitive $5 million screening study of various advanced gas turbine options in the 1992–94 time frame. Efforts to commercialize ICAD began in 1994–95. The most attractive ICAD gas turbine options were based on high thrust engines produced by General Electric. Pratt & Whitney and Rolls Royce aircraft divisions. Simple cycle ICAD represents a new intermediate load gas turbine product class with costs and performance unlike any other product available today. Simple cycle efficiencies will approach Chose of many operating combined cycles, but with the low capital costs and rapid start times of a peaking gas turbine. ICAD simple cycle units would be in the 100–130 MW size range with efficiencies in the range of 45–48% + LHV and combined cycle efficiencies potentially as high as 60% + LHV. All efficiencies are presented in the paper in lower heating value (LHV). ICAD gas turbines will eddress a wide range of simple cycle, cogeneration. innovative repowering, combined cycle, distributed generation and renewable energy applications. CAGT members have several projects underway with the goal of the first ICAD unit to begin operation before the year 2000. Industry restructuring has reduced near-term demand for new generation in the United States with a corresponding drop in gas turbine prices. Given the large development cost for any new gas turbine product, potential ICAD suppliers have indicated the need for a launch order to proceed with development. CAGT is pursuing a number of project development and strategic alliance strategies globally to organize a launch order in the range of 10–15 projects. Efforts are also underway to examine options for demonstrating ICAD on a smaller scale (Small ICAD or SICAD) which would address the emerging market for distributed generation. CAGT members feel the low costs and flexibility offered by ICAD could be a significant source of competitive advantage in restructuring electric markets. CAGT members invite others to join the program.
Effects of Surface Roughness on Film Cooling
Authors: Schmidt Donald L. , Sen Basav , Bogard David G.
Published: February 2015

A flat plate test section was used to study how surface roughness representative of an in-service turbine affects the film cooling adiabatic effectiveness and heat transfer coefficient for a round hole geometry. The injection was from a single row of round film cooling holes with injection angle of 30°. The density ratio of the injectant to the mainstream was 2.0 for the adiabatic effectiveness tests, and 1.0 for the heat transfer coefficient tests. A range of momentum flux ratios was examined to characterize the adiabatic effectiveness and heat transfer performance. Streamwise distributions of adiabatic effectiveness and heat transfer coefficients were obtained along the hole center line, and lateral distributions extending to halfway between hole centerlines were obtained at selected streamwise locations to 90 hole diameters downstream. Two rough surfaces with a factor of two difference in roughness levels were compared to an aerodynamically smooth surface.

Both rough surfaces degraded the film cooling effectiveness with increasing degradation farther downstream. Degradation of film cooling effectiveness was greater at low momentum flux ratios. At momentum flux ratios high enough so that the cooling jets completely detached from the surface, the rough surfaces slightly increased adiabatic effectiveness in some cases. There was little difference in the effectiveness results between the two rough surfaces. Film cooling injection had little effect on heat transfer rates for any of the surfaces.
Predicted Turbine Heat Transfer for a Range of Test Conditions
Authors: Boyle R. J. , Lucci B. L.
Published: February 2015

Comparisons are shown between predictions and experimental data for blade and end wall heat transfer. The comparisons are given for both vane and rotor geometries over an extensive range of Reynolds and Mach numbers. Comparisons are made with experimental data from a variety of sources. A number of turbulence models are available for predicting blade surface heat transfer, as well as aerodynamic performance. The results of an investigation to determine the turbulence model which gives the best agreement with experimental data over a wide range of test conditions are presented.
A Novel Fluids Research Technique: Three-State Anemometry
Authors: Funes-Gallanzi M.
Published: February 2015

A new flow measurement technique is described which allows for the non-intrusive simultaneous measurement of flow velocity, density, and viscosity. The viscosity information can be used to derive the flow field temperature. The combination of the three measured variables and the perfect-gas law then leads to an estimate of the flow field pressure. Thus, the instantaneous state of a flow field can be completely described.

Three-State anemometry (3SA), a derivative of PIV, which uses a combination of three monodisperse sizes of styrene seeding particles is proposed. A marker seeding is chosen to follow the flow as closely as possible, while intermediate and large seeding populations provide two supplementary velocity fields, which are also dependent on fluid density and viscosity. A simplified particle motion equation, for turbomachinery applications, is then solved over the whole field to provide both density and viscosity data. The three velocity fields can be separated in a number of ways. The simplest and that proposed in this paper is to dye the different populations and look through interferometric filters at the region of interest.

The two critical aspects needed to enable the implementation of such a technique are a suitable selection of the diameters of the particle populations, and the separation of the velocity fields. There has been extensive work on the seeding particle behaviour which allows an estimate of the suitable particle diameters to be made. A technique is described in this paper to allow the separation of μm range particle velocity fields through fluorescence (separation through intensity also being possible). Some preliminary results by computer simulations of a 3SA image are also presented. The particle sizes chosen were 1 μm and 5 μm tested on the near-wake flow past a cylinder to investigate viscosity only, assuming uniform flow density. The accuracy of the technique, derived from simulations of swirling flows, is estimated as 0.5% RMS for velocity, 2% RMS for the density and viscosity, and 4% RMS for the temperature estimate.
Secondary Flow and its Contribution to Heat Transfer Enhancement in a Blade Cooling Passage With Discrete Ribs
Authors: Hu Zhengjun , Shen Jiarui
Published: February 2015

A detailed map of heat transfer coefficients has been measured in a converging blade cooling passage with 45 deg. discrete ribs on two opposite walls for a range of engine representative Re of 10,000 ∼ 50,000. Flow visualization showed that there were four different types of secondary flow created by the discrete ribs: skewed boundary layer, secondary flow in front of the rib, secondary flow behind the rib, swirling longitudinal vortex flow and for large rib heights there were vortex streets. The origin of these secondary flows and their structure are discussed together with their contribution to the local enhancement of heat transfer. The results were used to understand the mechanism of heat transfer enhancement using secondary flow created by rib turbulators and from this to develop new design methods for improved enhanced heat transfer.
Development of the Next Generation 1500°C Class Advanced Gas Turbine for 50Hz Utilities
Authors: Aoki S. , Tsukuda Y. , Akita E. , Iwasaki Y. , Tomat R. , Rosso M. , Schips C.
Published: February 2015

The 701G1 50Hz Combustion Turbine continues a long line of large heavy-duty single-shaft combustion turbines by combining the proven efficient and reliable concepts of the 501F and 701F. The output of the 701G1 is 255MW with combined cycle net efficiency of over 57%. A pan of component development was conducted under the joint development program with Tohoku Electric Power Co., Inc. and a part of the design work was carried out under the cooperation with Westinghouse Electric Corporation in the U.S.A. and Fiat Avio in Italy.

This gas turbine is going to be installed to “Higashi Niigata Power Plants NO.4” of Tohoku Electric Power Co., Inc. in Japan. This plant will begin commercial operation in 1999.

This paper describes some design results and new technologies in designing and developing this next generation 1500°C class advanced gas turbine.