bluuebunny/crossref_metadata_2025 huggingface dataset:
Subcritical Crack Growth Life Prediction for Ceramic Components of Advanced Heat Engines
Authors: Wu D. C. , Peralta A. D. , Menon M. N. , Cuccio J. C.
Published: February 2015

Advanced, high-strength ceramics are finding increasing application in advanced heat engines. To ensure the long-term reliability of components made from these materials, subcritical crack growth (SCG) from inherent flaws has to be taken into account, as this has been identified as the primary failure mode under sustained loading.

In analyzing fast fracture data, data censoring is necessary to obtain estimates of the inherent strength distributions for competing failure-causing flaw populations. This is particularly important for ceramic designs, where size scaling is a necessary part of the design analysis. While data censoring has become common for fast fracture data, data censoring involving stress rupture data has yet to be widely applied. This paper describes fast fracture and stress rupture tests performed on an advanced silicon nitride ceramic, the test data and fractography results, censored data analysis for both types of data, derivation of the subcritical crack growth parameters, and application of these parameters to verification specimens. Implications of the findings and recommendations for future studies are also presented.
Flow and Heat Transfer in a Pre-Swirl Rotor-Stator System
Authors: Wilson Michael , Pilbrow Robert , Owen J. Michael
Published: February 2015

Conditions in the internal-air system of a high-pressure turbine stage are modelled using a rig comprising an outer pre-swirl chamber separated by a seal from an inner rotor-stator system. Pre-swirl nozzles in the stator supply the “blade-cooling” air, which leaves the system via holes in the rotor, and disc-cooling air enters at the centre of the system and leaves through clearances in the peripheral seals. The experimental rig is instrumented with thermocouples, fluxmeters, pitot tubes and pressure taps enabling temperatures, heat fluxes, velocities and pressures to be measured at a number of radial locations.

For rotational Reynolds numbers of Reϕ ≃ 1.2 × 106, the swirl ratio and the ratios of disc-cooling and blade-cooling flow rates are chosen to be representative of those found inside gas turbines. Measured radial distributions of velocity, temperature and Nusselt number are compared with computations obtained from an axisymmetric elliptic solver, featuring a low-Reynolds-number k-ε turbulence model. For the inner rotor-stator system, the computed core temperatures and velocities are in good agreement with measured values, but the Nusselt numbers are underpredicted. For the outer pre-swirl chamber, it was possible to make comparisons between the measured and computed values for cooling-air temperatures but not for the Nusselt numbers. As expected, the temperature of the blade-cooling air decreases as the swirl ratio increases, but the computed air temperatures are significantly lower than the measured ones. Overall, the results give valuable insight into some of the heat transfer characteristics of this complex system.
Transition Length Prediction for Flows With Rapidly Changing Pressure Gradients
Authors: Solomon W. J. , Walker G. J. , Gostelow J. P.
Published: February 2015

A new method for calculating intermittency in transitional boundary layers with changing pressure gradients is proposed and tested against standard turbomachinery flow cases. It is based on recent experimental studies which show the local pressure gradient parameter to have a significant effect on turbulent spot spreading angles and propagation velocities (and hence transition length). This can be very important for some turbomachinery flows. On a turbine blade suction surface for example, it is possible for transition to start in a region of favorable pressure gradient and finish in a region of adverse pressure gradient. Calculation methods which estimate the transition length from the local pressure gradient parameter at the start of transition will seriously overestimate the transition length under these conditions. Conventional methods based on correlations of zero pressure gradient transition data are similarly inaccurate. The new calculation method continuously adjusts the spot growth parameters in response to changes in the local pressure gradient through transition using correlations based on data given in the companion paper by Gostelow, Melwani and Walker (1995). Recent experimental correlations of Gostelow, Blunden and Walker (1994) are used to estimate the turbulent spot generation rate at the start of transition. The method has been incorporated in a linear combination integral computation and tested with good results on cases which report both the intermittency and surface pressure distribution data. It has resulted in a much reduced sensitivity to errors in predicting the start of the transition zone, and can be recommended for engineering use in calculating boundary layer development on axial turbomachine blades.
Initial Operating Experience and Test Results of ABB’s Gas Turbine GT13E2
Authors: Klohr M. , Schmidtke J. , Tschirren S. , Rihak P.
Published: February 2015

On 20 October 1993, the first ABB GT13E2 gas turbine was put into operation. This 165 MW class gas turbine achieves 35,7% thermal efficiency in single cycle application and up to 54,3% (according ISO standard 3977, Annexe F) in a three pressure system. An optimised turbine and compressor design along with the increased turbine inlet temperature, lead to improved efficiency and electrical output.

A new concept for the combustor aimed at meeting the increasing demands on gas turbine emissions. The GT13E2 is equipped with the new single annular combustor and 72 of the ABB EV double cone burners.

The commissioning and testing of the first GT13E2 was carried out at the Kawasaki Gas Turbine Research Center (KGRC) in Sodegaura City near Tokyo, Japan. The gas turbine was assembled with various measurement systems to monitor static and dynamic pressure, gas and metal temperature, expansion, vibration, velocity and emissions. The facility will be used during a 15 year joint test program by ABB and Kawasaki Heavy Industries (KHI) to obtain a sound database of operating experience for further improvements of the GT13E2 gas turbine. Therefore, mid 1994 a second test phase was conducted and early 1995 a third test period is scheduled.

In parallel, the 2nd and 3rd GT13E2’s were commissioned and tested at the Deeside Combined Cycle Power Plant near Chester, Great Britain.

In November 1994, the 4th GT13E2 at Lage Weide was successfully commissioned.

This paper describes the operating experience with the GT13E2 during the first commissioning and test phases at KGRC and Deeside. The design features, the test facility, the instrumentation, the commissioning and test results are presented and discussed.
Material Characterization of Candidate Silicon Based Ceramics for Stationary Gas Turbine Applications
Authors: Parthasarathy Vijay M. , Price Jeffrey R. , Brentnall William D. , Graves George , Goodrich Steven
Published: February 2015

The Ceramic Stationary Gas Turbine (CSGT) Program is evaluating the potential of using monolithic and composite ceramics in the hot section of industrial gas turbines. Solar Turbine’s Centaur 50 engine is being used as the test bed for ceramic components. The first stage blade, first stage nozzle and the combustor have been selected to develop designs with retrofit potential, which will result in improved performance and lowered emissions. As part of this DOE sponsored initiative a design and life prediction database under relevant conditions is being generated. This paper covers experiments conducted to date on the evaluation of monolithic silicon based ceramics. Mechanical property characterizations have included dynamic fatigue testing of tensile as well as flexural specimens at the temperatures representative of the blade root, the blade airfoil and the nozzle airfoil. Data from subcomponent testing of blade attachment concepts are also included.
Estimation of the Fracture Origin of Ceramic Gas Turbine Rotors
Authors: Yoshikawa Takaya , Hotta Nobuyuki , Ito Masaya
Published: February 2015

The fracture origin of ceramic gas turbine rotors has been estimated by photographing the moment of burst during high speed spinning. Three types of ceramic rotors were designed to induce a fracture at the surface, the inside, and a pre-defect area. From photographic analysis of typical fracture behavior of these rotors, the fracture origins of ceramic rotors were estimated. The estimated fracture origins did not correspond to the calculated maximum stress areas in the rotors.
Dynamic Characteristics Analysis of Complex Rotor–Support–Case System
Authors: Hua Mingda , Li Qihan , Mao Jinxin
Published: February 2015

The paper presents an analysis of the steady–state and transient dynamic characteristics of complex rotor system based on Transfer Matrix–Modal Synthetic Method. Critical speeds and modes are calculated using substructure transfer matrix method. The transient response is calculated using modal synthetic method respectively. The effects on the transient response of rotor system under the cases of various sudden unbalance levels, radial oil film clearances of damper and different rotor speeds are also investigated. The effectiveness and the capability of squeeze film damper (SFD) for suppressing instability are analyzed and it is found that in order to reduce the vibration of rotor system effectively, the damper parameters must be designed properly.

The Transfer Matrix–Modal Synthetic Method discussed in the paper is valuable in theory and practice. The method and results are very useful both in the design and development of complex rotor system.
An Advanced Control and Monitoring System for Turbomachinery
Authors: Blotenberg Wilfried
Published: February 2015

An advanced digital control and monitoring system for turbomachinery is introduced. Important aspects for the design of anti-surge control systems, such as the influence of the controller program execution time on the performance, are investigated. The influence of the gas composition (molecular weight) on the compressor surge line is demonstrated. Control laws are discussed. The design basis of an ultra-high speed anti-surge and speed control system is shown and the data-logging features are demonstrated on the log of a compressor surge. The paper closes describing some dynamic process simulation being performed using the controller hardware and software for process simulations.
Advanced Power Generation: The Potential of Indirectly-Fired Combined Cycles
Authors: Klara Julianne M. , Izsak Michael S. , Wherley Michael R.
Published: February 2015

The next generation of coal-fueled power plants must be efficient, clean, and cost-effective. The U.S. Department of Energy (DOE) sponsors a program to develop an advanced, coal-based power system called HIPPS, or High Performance Power System, to meet these requirements. In the HIPPS cycle, air from a gas turbine compressor is indirectly heated in a coal-fueled furnace and then further heated directly with natural gas to power a gas turbine. Indirect heating of the gas turbine working fluid avoids the problems associated with expansion of a corrosive, coal-derived gas through a turbine. Steam is also generated to power a bottoming Rankine cycle.

This paper presents an analysis of the performance of HIPPS that is achievable using current technology and projects the level of performance as technology advances. The HIPPS cycle using current technology produces electricity from coal at a thermal efficiency that is more than 40 percent higher than that of today’s average coal-based power plants. The effect of advanced gas turbines, a novel gas turbine cycle, high performance steam cycles, and advanced coal-fueled furnace materials/designs is estimated with the use of computer-based engineering tools. Promising system configurations for future generations of HIPPS are identified with cycle efficiencies as high as 49.3 percent on a higher heating value basis.
Helium and Combustion Gas Turbine Power Conversion Systems Comparison
Authors: McDonald Colin F.
Published: February 2015

For closed-cycle gas turbines, in a size to meet utility power generation needs, the selection of helium as the working fluid represents the best solution in terms of the overall power conversion system considering the differing requirements of the turbomachinery and heat exchangers. Helium is well suited for the nuclear Brayton cycle because it is neutronically inert.

The impact of helium’s unique properties on the performance and size of the power conversion system components is discussed in this paper. The helium gas turbine plants, that have operated were based on 1950s and 1960s technology, represent a valuable technology base in terms of practical experience gained. However, the design of the Gas Turbine Modular Helium Reactor (GT-MHR), which could see utility service in the first decade of the 21st century will utilize turbomachinery and heat exchanger technologies from the combustion gas turbine and aerospace industries. An understanding of how the design of power conversion systems for closed-cycle plants and combustion gas turbines are affected by the working fluids (i.e., helium and air, respectively) is the major theme of this paper.
Development of 300 kW Class Ceramic Gas Turbine (CGT302)
Authors: Nishio Kozi , Fujioka Junzo , Tatsumi Tetsuo , Takehara Isashi
Published: February 2015

With the aim of achieving higher efficiency, lower pollutant emissions, and multi-fuel capability for small to medium-sized gas turbine engines for use in co-generation systems, a ceramic gas turbine (CGT) research and development program is being promoted by the Japanese Ministry of International Trade and Industry (MITI) as a part of its “New Sunshine Project”. Kawasaki Heavy Industries (KHI) is participating in this program and developing a regenerative two-shaft CGT (CGT302).

In 1993, KHI conducted the first test run of an engine with full ceramic components. At present, the CGT302 achieves 28.8% thermal efficiency at a turbine inlet temperature (TIT) of 1117°C under ISO standard conditions and an actual TIT of 1250°C has been confirmed at the rated speed of the basic CGT.

This paper consists of the current state of development of the CGT302 and how ceramic components are applied.
Qualifying Combustion Turbines for Inlet Air Cooling Capacity Enhancement
Authors: Kitchen Brian J. , Ebeling Jerry A.
Published: February 2015

The relative potential of combustion turbines for capacity enhancement by inlet air cooling was examined. A new inlet air cooling effectiveness factor was developed for this purpose. It was found that combustion turbines vary significantly in terms of inlet air cooling effectiveness. Of the combustion turbines presented in this paper, the best-ranked combustion turbine had an effectiveness factor of 0.48 while the lowest-ranked turbine had a factor of 1.35. No strong correlation was found between the inlet air cooling effectiveness factor and the ISO turbine performance parameters of heat rate, pressure ratio, exhaust temperature, and the ratio of inlet air mass flow rate to power output.
A Numerical Method for Power Plant Simulations
Authors: Carcasci Carlo , Facchini Bruno
Published: February 2015

The continual increase in both efficiency and specific power of power plants determines the complexity of power generation units. Therefore, thermodynamic calculations with a high degree of accuracy and flexibility are required.

This paper describes a highly flexible computerized method of calculating thermodynamics in a power cycle. The computerized method analyzed here permits the study of steam, gas and combined plants. Its flexibility is not restricted by any defined cycle scheme.

A power plant consists of simple elements (turbine, compressor, combustor chamber, pump, etc.). Each power plant component is represented by its typical equations relating to fundamental mechanical and thermodynamic laws, so a power plant system is represented by algebraic equations, which are the typical equations of components, continuity equations, and data concerning plant conditions. This equation system is not linear, but can be reduced to a linear equation system with variable coefficients. The solution is determined by an iterative process.

An example of a simple gas turbine cycle demonstrates the applied technique. This paper also presents the user interface based on MS-Windows.

The input data, the results, and any characteristic parameters of a complex cycle scheme are also shown.
Gas Turbine Power Generation Evolutionary Advances for the Future
Authors: Corman James C.
Published: February 2015

Gas turbines have reached a point in their development where they are becoming the preferred choice for utility and industrial power generation applications. In the last decade, this power generation technology has evolved rapidly both in terms of unit rating and in performance. The successful commercialization of the “F” (2350F [1288C] class) machine is the most recent step in this evolution. Although more “F” technology has been a significant accomplishment, it must be viewed as just one step in the evolution of gas turbine power generation systems to advanced conditions. As this development trend continues, these power generation systems will be under increasing pressure to meet tighter emission standards and to accommodate lower-grade fuels. Active development programs are now in place to meet both of these challenges. Dry Low NOx (DLN) combustion systems on advanced gas turbines will permit operation at even higher temperatures while controlling emissions. An integrated gasification gas turbine combined cycle (IGCC) using low-grade fuels — coal, residual oil, and biomass — is now approaching commercial status. The technology base for continuing the development of these gas turbine power generation systems far into the future exists and/or is under development. The DOE sponsored Advanced Turbine System Program is a key element in the development and ultimate commercial demonstration of this Next Generation System.
Synchronous Condensing Using the Generator of Peak Load Plant
Authors: Hendry Morgan L. , McGough John C.
Published: February 2015

This paper will describe how a generator of a peak load turbine, when operated as a synchronous condenser, can help improve electrical system power factor and therefore help maintain reactive power balances between sources of generation and demand points. It is particularly appropriate to use peak load plant with either industrial or aero-derivative gas turbines for synchronous condensing. By using a clutch to disconnect the turbine from the generator, losses from the turbine are avoided enabling more efficient synchronous condensing operation. Details of specific clutch designs for turbine generator synchronous condenser applications and experience at various B.C. Hydro installations are provided.
Full Coverage Effusion Film Cooling With Inclined Holes
Authors: Andrews G. E. , Khalifa I. M. , Asere A. A. , Bazdidi-Tehrani F.
Published: February 2015

Effusion cooling with 15 film cooling rows of holes was investigated and a comparison of normal and inclined holes was undertaken for laser drilled holes. Overall and adiabatic cooling effectiveness data are presented for a density ratio of 2.5 for N=9688 holes per square metre and an X/D of 11. The main variable studied was the angle of inclination of the 30° film holes to the crossflow, 30°, 90° and 150°.

Comparison was made with 90° holes of similar X/D and a smaller X/D of 4.5, which was shown to be as effective as inclining the holes for improving the cooling effectiveness.

The opposed film cooling flow of the 150° inclined hole was very effective in providing a good film protection at the leading rows of holes. A cooling effectiveness of 0.7 was demonstrated at a mass flow per unit surface area G of 0.35–0.4 kg/sm2 bar with both 30° and 150° holes. This was equivalent to 15–20% of the combustor air flow for a typical gas turbine combustor. Comparison with previous work on effusion cooling showed reasonable agreement for similar geometries, although very few previous workers have reported overall cooling effectiveness results. Also the present work covered a much wider range of film cooling mass flow, a larger number of rows of holes and a more practical density ratio than in previous work.
Compatibility Between Low-NOx Emissions and High–Combustion Efficiency by Lean Direct Injection Combustion
Authors: Hayashi Shigeru
Published: February 2015

This paper describes the low–emissions capability of lean direct injection, liquid–fueled burners for gas turbine combustors. The emissions characteristics of direct injection and premixed–prevaporized combustion systems were evaluated at inlet air temperatures of 450, 550 and 650 K and at atmospheric pressure. The equivalence ratio was varied in a range from about 1.2 to values close to flammability limits. The effects of fuel nozzle capacity and mixing tube length were also investigated. In the direct injection system, a double swirler/fuel nozzle module was used to inject fuel spray and air into combustion chamber. Fuel was atomized into the circular swirling jet using a pressure fuel nozzle placed 15 mm upstream of the inner swirler channel exit. In the lean premixed–prevaporized combustion system, the same double swirler/fuel nozzle module was used also for fuel–air mixing and a tube was inserted between the double swirler/fuel nozzle module and the end wall of the combustor chamber for fuel prevaporization. At lean conditions, combustion was more complete for the direct injection combustion system than premixed–prevaporized combustion system, though both were capable of very low NOx emissions.
The NPARC Alliance
Authors: Cossentine Jay A. , Matty Jere J. , Shaw Robert J.
Published: February 2015

The Arnold Engineering Development Center (AEDC) and the NASA Lewis Research Center (LeRC) have formed a government alliance aimed at establishing and supporting a national, application-oriented computational fluid dynamics (CFD) capability, centered around the NPARC flow simulation software. The Alliance is supported by and responsive to an association made up of more that 100 active users at over 60 government, industry, and academic institutions. This paper discusses the history, structure, and philosophy of the NPARC Alliance.
Energy Industry Changes: The Role of Advanced Combustion Turbine Technology
Authors: Touchton George , Cohn Arthur
Published: February 2015

The Electric Power industry is in transition — where meeting the customer’s individual variable power needs will count more than just providing gross kilowatt hours production or some thoretical “generation mix” criteria. A number of advanced combustion turbine power plants are being developed for this market: the Intercooled Aeroderivative, the Humid Air Turbine/Cascaded Humidified Advanced Turbine, and the Compressed Air Storage with Humidification plants. Combustion turbines for the distributed generation application are also being emphasized. This success of all combustion turbine plants depend on meeting and maintaining the goals of high levels of durability, reliability, and availability. A number of technologies which EPRI has successfully applied that have materially assisted in meeting these goals are outlined.
Ensuring Adequate Coolant Purity for Advanced Gas Turbines
Authors: Woodmansee D. E. , Tolpadi A. K. , Hwang T. H. , Maddaus A. D.
Published: February 2015

The role of particulate contaminants in advanced gas turbine coolants is discussed, especially in light of the extremely high G-field regions they will experience in service. Predictions of sedimentation in both laminar and highly turbulent accelerating flows using a computational fluid dynamics code are made for a range of particulate sizes to show that particles over 0.5 µm are of concern. Possible techniques for limiting access of these particulates to the gas turbines themselves are presented. Overall, contaminant deposition appears controllable, limiting required cleaning of coolant channels to regularly scheduled inspections.
The KEMA Gas Turbines Target Project: Overview and Status
Authors: Rooth R. A.
Published: February 2015

Recently, in the Netherlands a number of 11 combi blocks with prefitted gas turbines have been built. Additionally, there are preparations for five 335 MWe units at the Eems power station and plans for a further seven 250 MW heat and power stations. This means that by 2002 the generating industry will be operating seventy-five gas turbines with a total gas turbine power of 5700 MWe. These data serve to illustrate that gas turbines will be the workhorse of the Dutch generating industry in the coming decades, and that security of supply, efficiency, emissions and generating cost will to a large extent be determined by the gas turbine. However, the introduction of the gas turbine, the increase in scale of the machines and the fact that they are increasingly being used in base load units have also led to problems and forced unavailability. The problems are related to creep, thermal stresses and fatigue of combustion chambers, turbine rotor blades, rotors etc. Apart from these problem areas, other subjects of interest are optimization of inlet air filtering and compressor cleaning. It is the Dutch Electricity Production industry who realized that a substantial R&D effort is necessary to solve those user related problems and who formulated and ordered the execution of the target project Gas turbines
Research and Development Status of Advanced Material Gas-Generator (AMG) Project
Authors: Hiromatsu M. , Yamamura T. , Chikata T. , Sekido T. , Ohama S. , Miyagawa H. , Murakami I. , Seki S.
Published: February 2015

Advanced Material Gas-Generator (AMG) R&D Project was initiated in 1993 as a ten year’s program with a joint investment from Japan Key Technology Center and fourteen participating domestic companies.

The program objective is to establish basic key technologies for next generation gas-generator using advanced materials, which should have the features of significantly low fuel consumption with reduced weight and size, and should be environmentally acceptable, toward the realization of future industrial, marine and aerospace gas-turbine.

The R&D themes in this project cover advanced gas-generator conceptual study, advanced material and structures, innovative system and control, and advanced components technologies such as low NOx combustor.

Each R&D theme is underway toward achieving the program goal.

The 1st conceptual drawing of the advanced material gas-generator is completed as the result of the conceptual study.

PMC (Polymer Matrix Composites), MMC (Metal Matrix Composites), CMC (Ceramic Matrix Composites) and TiAl (Titanium-Aluminide) are considered as the candidate material for the advanced material gas-generator.

This paper introduces the outline of this project, and describes the status of conceptual study and each R&D themes.
Influence of Leading-Edge Geometry on Profile Losses in Turbines at Off-Design Incidence: Experimental Results and an Improved Correlation
Authors: Benner M. W. , Sjolander S. A. , Moustapha S. H.
Published: February 2015

The most recent correlations for turbine profile losses at off-design incidence include the leading-edge diameter as the only aspect of the leading-edge geometry which influences the losses. Cascade measurements are presented for two turbine blades which differ primarily in their leading-edge geometries. The incidence was varied over a range of ±20 degrees and the results show significant discrepancies between the observed profile losses and those predicted by the available correlations. Using data from the present experiments, as well as cases from the literature for which sufficient geometric data are given, a revised correlation has been developed. The new correlation is a function of both the leading-edge diameter and the wedge angle, and it is significantly more successful than the existing correlations. It is argued that the off-design loss behaviour of the blade is influenced by the magnitude of the discontinuity in curvature at the points where the leading-edge circle meets the rest of the blade profile. The wedge angle appears to be an approximate and convenient measure of the discontinuity in curvature at these blend points.
Combined Helium and Combustion Gas Turbine Plant Exploiting Liquid Hydrogen (LH2) Physical Exergy
Authors: Bisio Giacomo , Massardo Aristide , Agazzani Alessio
Published: February 2015

The aim of this work is the energy and exergy analysis of a combined plant made up of a conventional gas turbine (heavy-duty or aeroderivative) and a closed helium turbine cycle which exploits liquid hydrogen (LH2) as a lower exergy source.

A helium turbine with the characteristics of the fluid allows us to operate between the usual temperatures of the top turbine waste gas and those of the liquid hydrogen available. In this way the combined system reaches efficiency values greater than every combined system proposed to date.

The work contains a detailed analysis of the relative entropy productions of the helium cycle and considerations about the realization and technological aspects of helium turbines.
Evaluation of the Interaction Losses in a Transonic Turbine HP Rotor / LP Vane Configuration
Authors: Jennions I. K. , Adamczyk J. J.
Published: February 2015

Transonic turbine rotors produce shock waves, wakes, tip leakage flows and other secondary flows that the downstream stators have to ingest. While the physics of wake ingestion and shock interaction have been studied quite extensively, few ideas for reducing the aerodynamic interaction losses have been forthcoming. This paper aims to extend previously reported work performed by GE Aircraft Engines in this area. It reports on both average-passage (steady) and unsteady 3D numerical simulations of a candidate design to shed light on the interaction loss mechanisms and evaluate the design. The results from these simulations are first shown against test data for a Baseline configuration to engender confidence in the numerical approach. Simulations with the proposed newly designed rotor are then performed to show the trade-offs that are being made in such designs. The new rotor does improve the overall efficiency of the group and physical explanations are presented based on examining entropy production.
Three-Dimensional Navier-Stokes Computation of Turbine Nozzle Flow With Advanced Turbulence Models
Authors: Luo J. , Lakshminarayana B.
Published: February 2015

A three-dimensional Navier-Stokes procedure has been used to compute the three-dimensional viscous flow through the turbine nozzle passage of a single stage turbine. A low Reynolds number k-ε model and a zonal k-ε/ARSM (algebraic Reynolds stress model) are utilized for turbulence closure. The algebraic Reynolds stress model is used only in the endwall region to represent the anisotropy of turbulence. A four-stage Runge-Kutta scheme is used for time-integration of both the mean-flow and the turbulence transport equations. For the turbine nozzle flow, comprehensive comparisons between the predictions and the experimental data obtained at Penn State show that most features of the vortex-dominated endwall flow, as well as nozzle wake structure, have been captured well by the numerical procedure. An assessment of the performance of the turbulence models has been carried out The two models are found to provide similar predictions for the mean flow parameters, although slight improvement in the prediction of some secondary flow quantities has been obtained by the ARSM model.
An Experimental Investigation of the Conversion of NO to NO2 at High Pressure
Authors: Hunderup James W. , Roby Richard J.
Published: February 2015

Unexpectedly high concentrations of NO2 have been noted in stack emissions from industrial combustors. NO2 formation has been reported to occur through the so called “HO2 mechanism” in which NO combines with HO2 to produce NO2 and OH. In this study, the formation of NO2 was investigated at super-atmospheric pressures through experiments and computer modeling. Computer modeling utilized the CHEMKIN chemical kinetics program and a subset of a previously published C-H-O-N system mechanism. Experimental work was conducted using a high pressure flow reactor designed and built in the course of the study. The effects of pressure, temperature, and the presence of a NO2 promoting hydrocarbon, methane, were investigated. It was discovered that as pressure increased from 1 atm. to 8.5 atm., the rate and amount of NO converted to NO2 also increased. The results also show a temperature “window” between approximately 800 K and 1000 K in which NO to NO2 conversion readily occurred. The presence of methane was seen to enhance NO conversion to NO2, and a ratio of [CH4]/[NO] was found to be a useful parameter in predicting NO2 formation. Significant NO conversion to NO2 was noted for [CH4]/[NO]>1 at the hydrocarbon injection point. Experimental results validated those trends obtained from modeling with a modified C-H-O-N mechanism.
An Experimental and Computational Study of Swirling Hydrogen Jet Diffusion Flames
Authors: Anand M. S. , Takahashi F. , Vangsness M. D. , Durbin M. D. , Schmoll W. J.
Published: February 2015

Computations using the joint velocity-scalar probability density function (pdf) method as well as benchmark quality experimental data for swirling and nonswirling hydrogen jet diffusion flames are reported. Previous studies of diffusion flames reported in literature have been limited to nonswirling flames and have had no detailed velocity data reported in the developing (near-nozzle) region of the flames. The measurements and computations reported herein include velocities (mean and higher moments up to fourth order) and temperature (mean and variance) near the burner exit and downstream locations up to 26.5 jet diameters. The velocities were measured with a three-component laser Doppler velocimeter (LDV) and the temperature was measured using coherent anti-Stokes Raman spectroscopy (CARS). The joint pdf method offers significant advantages over conventional methods for computing turbulent reacting flow, and the computed results are in good agreement with data. This study serves to present data that can be used for model validation as well as to further validate the joint pdf method.
Energy Analysis to the Design of Rotor-Bearing Systems
Authors: Chen W. J.
Published: February 2015

In the design of rotating machinery, it is often desirable and necessary to change a subset of system parameters to meet the design requirements. The success in designing rotor bearing systems and/or in solving the vibration problems depends heavily upon the understanding of fundamental physical properties and insights of the systems. The modeling improvements and computational techniques have been extensively presented over the years. The design methodologies and fundamental properties have not been widely addressed to assist design engineers in solving their practical problems. The objective of this paper is to relate the various forms of energy and work and their contributions to the system dynamic characteristics. The design strategies and methodologies using the energy approach are also presented and illustrated in a turbine driven machine.
The Effect of a Constant Volume Recuperator on Brayton Cycle Efficiency and Equipment Cost
Authors: Fineblum Solomon S.
Published: February 2015

The purpose of this analysis is to predict the thermodynamic and design effects of a constant volume recuperator in a Brayton cycle. First Law and Second Law energy efficiencies were computed. Constant volume recuperators produce higher pressure, denser air for admission into the combustion chamber and turbine. Greater pressure and density in the combustion chamber results in higher fuel evaporation and combustion rates. The higher system pressure across the turbine also generates a slightly higher turbine efficiency. Furthermore, the increased density permits a smaller turbine in the first, hottest and most expensive stages. A novel constant volume, constant flow recuperator is described.
Feasibility of Utilizing a Bio-Mass Derived Fuel for Industrial Gas Turbine Applications
Authors: Andrews R. G. , Patnaik P. C. , Michniewicz J. W. , Jankowski L. J. , Romanov V. I. , Lupandin V. V. , Ravich A. V.
Published: February 2015

This paper describes a development program aimed at determining the technical feasibility of utilizing a bio-mass derived fuel in an industrial gas turbine engine. The fuel addressed is a flammable bio-fuel oil derived from wood waste through flash pyrolysis. The fuel has a heating value of approximately 18 MJ/kg, a density of 1.2 kg/l and specialized wet filtration techniques are used to minimize the particulate matter in the fuel.

The turbine engine selected, as the test vehicle, is a 2.5 MW class-GT2500 engine designed and built by Mashproekt in the Ukraine. The standard operating conditions and layout of this engine provide flexibility in optimization of the combustion system to accept lower than conventional grade fuels.

The characteristics of the fuel, the fuel handling system, and the considerations with respect to igniting and maintaining combustion with a fuel of this nature are discussed.
A High Efficiency Recuperated Cycle, Optimized for Reliable, Low Cost, Industrial Gas Turbine Engines
Authors: Ragland Thomas L.
Published: February 2015

With the increasing need for more efficient industrial gas turbine engines, the recuperated engine cycle is being considered as a means of meeting these needs.

This paper discusses a recuperated cycle design that is optimized to take full advantage of the recuperator but at the same time accommodate the real world market constraints of reliability, durability and cost.

Current simple cycle industrial engines are evolving to very high pressure ratios and high firing temperatures in order to reach cycle efficiencies in the 37% to 39% range. Some simple cycle industrial gas turbines with lower cycle pressure ratios and firing temperatures have been modified so a recuperated option can be added. Although the addition of a recuperator to these engines does improve cycle efficiency, levels of only the 33% to 35% range are reached. This is mainly due to the fact that the resulting cycles are not optimized for a recuperator.

An engine cycle that is optimized around a recuperator could obtain cycle efficiencies in the 43% to 45% range. Fortunately, this cycle optimizes at low pressure ratios and modest firing temperatures which results in lower cost components which tend to offset the additional cost of the recuperator.
Minimum Coolant and Resulting Cavity Temperatures for Eccentric Rim Seals With a Mainstream
Authors: Guo Zhou , Rhode David L.
Published: February 2015

A 3-D Navier-Stokes computer model, which was previously experimentally verified, was used to explore eccentricity effects on the minimum required coolant flow to prevent ingress (Cw,min) and blade root/retainer temperature. A recently developed three-scale k-ϵ turbulence model was experimentally verified and utilized in the computations. The temperature, pressure, Mach number and Reynolds number of a typical commercial gas turbine engine were specified for the mainstream, coolant stream and turbine wheel. It was found that Cw,min increases markedly with rotor eccentricity, even for small eccentricity values, in an almost linear fashion. The computations were used to establish a correlation for the dependence of Cw,min on eccentricity. It was found, for example, that an eccentricity increase from 5% to only 12.5% of the rim seal clearance increases Cw,min from approximately 8000 to 11000. In addition, for 25% eccentricity, the highest blade root/retainer temperature for Cw = 3600 is 49% higher than that for Cw = 7200, whereas for 12.5% eccentricity, it is only 20% higher.
An Experimental Study of NOx Reduction in Laminar Diffusion Flames by Addition of High Levels of Steam
Authors: Blevins Linda G. , Roby Richard J.
Published: February 2015

An experimental study of the effects of steam injection on NOx formation in laminar, opposed flow diffusion flames was performed. This study was done to determine if the failure of high amounts of steam injection to totally suppress NOx in industrial gas turbine combustors is caused by the formation of Fenimore’s “prompt NO” mechanism. Nitric oxide concentrations and temperatures were measured at various locations along the stagnation plane of the flame for varying amounts of steam injection. These tests were performed with either CH4, C2H4, CO, CO/H2 (1:1), or CO/H2 (1:2) as the diffusion flame fuel. Results in the laboratory burner reproduced the observation from industrial combustors that at low levels of steam addition NO is suppressed, but that high levels of steam addition are unable to drive no concentrations to zero. However, the results also showed that high levels of steam injection were not effective at suppressing flame temperatures in the burner. In all cases, at least a sixty percent reduction in NO was observed as a result of the steam addition. Similar trends were observed for both the hydrocarbon and non-hydrocarbon fuels. Based on these results, it was concluded that the limit in NO reduction observed for these flames could be explained in terms of the limit in temperature reduction effected by the steam addition without the need to invoke Fenimore’s “prompt NO” mechanism. Thus, the limit on NOx suppression at high levels of steam addition may be due to a limit on how much steam can diffuse into the flame front of diffusion flames, rather than on significant contributions from Fenimore’s “prompt NO” mechanism.
Development and Commercialization of Hot Gas Filters for Power Generation Applications
Authors: Lippert Thomas E. , Newby Richard A.
Published: February 2015

Westinghouse, with the Department of Energy (Morgantown Energy Technology Center), is developing hot gas particulate filters for application in advanced fossil energy power generation, i.e., pressurized fluidized bed combustion (PFBC) and coal gasification combined cycle (GCC). Westinghouse candle filter units are currently being operated in various coal based pilot plant and demonstration facilities (PFBC and GCC) to demonstrate their operating characteristics and performance and to identify potential commercial viability. Oxide and nonoxide filter materials, representing both first and second generation designs, are being tested and evaluated. In-house testing to characterize ash caking behavior is also being conducted in support of the field test programs. This paper summarizes this activity and presents current results of the field test programs.
Vane Swirler Performance
Authors: Lilley David G.
Published: February 2015

Swirler performance characteristics are investigated under low speed, low turbulence intensity conditions so as to aid in computer modeling of flowfields, and in the development and evaluation of turbulence models for swirling confined flow. The swirler studied is annular with a hub-to-swirler diameter ratio of 0.25 and ten adjustable vanes of pitch-to-chord ratio 0.68. Measurements of time-mean axial, radial, and swirl velocities are made at the swirler exit plane using a five-hole pitot probe technique with computer data reduction. A theoretical study is included of idealized exit-plane velocity profiles relating the swirl numbers S and S′ to the ratio of maximum swirl and axial velocities for each idealized case. The time-mean velocity components measured at the swirler exit plane show clearly the effects of centrifugal forces, recirculation zones, and blade wakes on the exit-plane velocity profiles. Assumptions of flat axial and swirl profiles are found to be progressively less realistic as the swirl vane angle increases, with axial and swirl velocities peaking strongly at the outer edges of the swirler exit and significant non-zero radial velocities present. Nonaxisymmetry is present in all swirl cases investigated.
Trial Operation Results of the Fully-Fired Combined Cycle Generating Plants in Chita
Authors: Mita T. , Ando N. , Kawauchi A. , Morikawa K.
Published: February 2015

A fully-fired combined cycle power plant (FFCCPP) combines a steam thermal power plant with a gas turbine. Hot exhaust gases fed from the gas turbine are used as combustion air for the boiler, thus increasing total plant output and efficiency.

An unusually hot spell in Japan in the summer of 1990 brought about such a rapid surge in power demand for air conditioning so that all electric power companies registered record highs in consumption.

This promoted Chubu Electric Power Co. to decide to add a 154-MW gas turbine to each of its six existing steam thermal power plants (four 700-MW and two 375-MW units), thus repowering their system into an FFCCPP.

Construction work began in 1992. In September, 1994, two 700-MW steam thermal power plants (Chita Thermal Power Plant’s No. 6 unit and Chita Second Thermal Power Plant’s No. 1 unit) were modified into FFCCPPs, which then began operating in a trouble-free manner.

This paper reports the characteristics and test-run results of the above two plants, which have been operating in good condition as the largest-capacity FFCCPPs in the world.
Development and Engine Testing of a Dry Low Emissions Combustor for Allison 501-K Industrial Gas Turbine Engines
Authors: McLeroy Jacob T. , Smith Duane A. , Razdan Mohan K.
Published: February 2015

The Allison Engine Company has been developing a low emission, can-annular combustion system for the 501K industrial gas turbine engine to satisfy increasingly stringent environmental requirements. This paper describes the progress achieved, over that previously reported by Razdan et al. (1994), through subsequent design evolution, bench testing, and engine evaluation. Allison’s goal is to develop a retrofittable, can-annular combustion system that limits emission levels to less than 25 ppm nitrogen oxide (NOx), 50 ppm carbon monoxide (CO), and 20 ppm unburned hydrocarbon (UHC), while operating at full load conditions. The interim emissions goals for the combustion system are 37 ppm NOx, 80 ppm CO, and 20 ppm UHC (all dry 15% O2 corrected).

The combustion system under development employs a dual mode combustion approach to meet engine operability requirements and high power emission targets without the use of combustor diluent injection or postcombustor exhaust treatment. A lean premixed combustion mode is used to minimize combustion zone temperature and limit NOx production during high power engine operation. The lean premix mode is augmented with a diffusion flame pilot mode for engine starting and low power operation.

Initial engine testing showed a dry low NOx combustion system, designed to meet a 37 ppm NOx limit, produced less than 34 ppm NOx and less than 10 ppm CO and UHC in test stand verification test. Continued burner rig testing with modified primary combustion zone stoichiometry has demonstrated NOx less than 25 ppm, CO less than 50 ppm, and UHC less than 20 ppm with simulated engine conditions representing 20 to 100% power. Development activity continues on the combustion system as engine field evaluation trials proceed.