bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationship Between Erosion and Characteristics of Deposits in Gas Turbines Burning Heavy High Sulfur Fuel Oil
Authors: Wong-Moreno Adriana , Sánchez-Villalvazo Alicia 
Published: February 2015

Heavy, brittle and very hard deposits built on the first row vanes have caused severe erosion of all the first stage blades of a gas turbine during operation with washed and treated heavy residual fuel oil. The high sulphur (3.5–4.0 wt.%) fuel oil consumed by the turbine is also high in vanadium (280–290 ppm) and asphaltene content.
In the present work the results of an investigation on the physical and chemical characteristics of erosive ash deposits as a function of operation conditions and fuel oil characteristics are presented. The structure and chemistry of deposits were studied by chemical analysis, x-ray diffraction, microanalysis and scanning electron microscopy. It was confirmed that deposit friability is enhanced by its MgSO4 content and that its hardness depends on the amount of MgO present. It was also found a clear correlation between the gas inlet temperature and the size of the ash particles deposited, and on the degree of compactness and hardness of the deposit. The role of the unburned particles, unavoidable in the combustion of heavy fuel oils, is discussed in relation to their influence on the effectiveness of the magnesium inhibitor.
The Effect of Adding Roughness and Thickness to a Transonic Axial Compressor Rotor
Authors: Suder Kenneth L. , Chima Rodrick V. , Strazisar Anthony J. , Roberts William B. 
Published: February 2015

The performance deterioration of a high speed axial compressor rotor due to surface roughness and airfoil thickness variations is reported. A 0.025 mm (0.001 in.) thick rough coating with a surface finish of 2.54–3.18 RMS μm (100–125 RMS microinches) is applied to the pressure and suction surface of the rotor blades. Coating both surfaces increases the leading edge thickness by 10% at the hub and 20% at the tip. Application of this coating results in a loss in efficiency of 6 points and a 9% reduction in the pressure ratio across the rotor at an operating condition near the design point. To separate the effects of thickness and roughness, a smooth coating of equal thickness is also applied to the blade. The smooth coating surface finish is 0.254–0.508 RMS μm (10–20 RMS microinches), compared to the bare metal blade surface finish of 0.508 RMS μm (20 RMS microinches). The smooth coating results in approximately half of the performance deterioration found from the rough coating. Both coatings are then applied to different portions of the blade surface to determine which portions of the airfoil are most sensitive to thickness/roughness variations.
Aerodynamic performance measurements are presented for a number of coating configurations at 60%, 80%, and 100% of design speed. The results indicate that thickness/roughness over the first 10% of blade chord accounts for virtually all of the observed performance degradation for the smooth coating, compared to about 70% of the observed performance degradation for the rough coating.
The performance deterioration is investigated in more detail at design speed using laser anemometer measurements as well as predictions generated by a quasi-3D Navier-Stokes flow solver which includes a surface roughness model. Measurements and analysis are performed on the baseline blade and the full-coverage smooth and rough coatings. The results indicate that coating the blade causes a thickening of the blade boundary layers. The interaction between the rotor passage shock and the thickened suction surface boundary layer then results in an increase in blockage which reduces the diffusion level in the rear half of the blade passage, thus reducing the aerodynamic performance of the rotor.
Rotor Repairs
Authors: van Gestel Ron , Mattheij Sjef 
Published: February 2015

Often, turbine and generator rotors are produced from a single forging or from two forged bearing ends with a stack of discs in between. As with many other components in rotary equipment these precision machined forgings can be damaged or worm during operation. Due to the sensitivity of the material to any kind of heat treatment, including welding, repair of this damage presents a challenge for repair engineers.
This paper will give a general overview of repair. Repair may include welding, heat treatment, plasma spraying, shaft straightening, stress relieving, etc. Some recent repairs will be discussed.
Design Characteristics and Operating Experience of Nuovo Pignone PGT 16 Gas Turbine
Authors: Sabella D. , Sferruzza S. 
Published: February 2015

The paper outlines the main features of the PGT 16 gas turbine with its auxiliaries and summarizes the experiences made in the field with the first seven units put in service starting in the first quarter of 1992.
The PGT 16 gas turbine utilizes an aero-derivative gas generator, the LM 1600 manufactured by General Electric, coupled with a heavy-duty power turbine designed and manufactured by Nuovo Pignone. This power turbine is the same utilized for the 14000 HP heavy-duty gas turbine Nuovo Pignone PGT 10. The nominal shaft power is 18600 HP, with 36.4% efficiency.
The design shaft speed of 7900 rpm makes this unit particularly suitable for mechanical drive applications, matching the typical speed range of centrifugal compressors in its power range. At the same time the high efficiency makes this unit attractive for both simple cycle and combined cycle power generation plants.
The package design privileges maintenance requirements to minimize the downtime and to provide the highest possible degree of availability.
The first 5 units in service have been installed along the Transcanada Pipeline and drive pipeline booster ‘compressors, PCL and BCL type: the other two units are in operation in a cogeneration facility in a paper-mill. At October ’93 the seven units have totalled 60,000 fired hours and the fleet leader 13,000 fired hours approximately.
Modeling of Boundary Layer Transition in Turbulent Flows by Linear Combination Integral Method
Authors: Gostelow J. P. , Hong G. , Walker G. J. , Dey J. 
Published: February 2015

Transitional boundary layer parameters in zero and variable pressure gradient flows, typical of turbomachinery applications, are predicted using an integral method of the linear combination type. The code used is that of Dey and Narasimha and the turbulent layer is calculated by a lag-entrainment method. The predictions of test data represent an improvement upon earlier methods; although reasonable agreement is obtained for these low Reynolds number test cases further refinement of predictive correlations to account for free-stream turbulence effects on laminar boundary layers and transition inception is indicated.
The transitional parameters are found to be particularly sensitive to the initial conditions selected for the turbulent layer. Techniques are identified for overcoming this sensitivity and for adequately representing the transition region. Free-stream turbulence effects are quite strong, particularly on the velocity profile of the laminar layer. Modifications to laminar methods are advocated to account for the strong effects on the velocity profile and the early formation of turbulent spots.
A 26 MW Gas Turbine Applied to a Three Casing Storage/Pipeline Compressor String
Authors: Colwell Paul J. 
Published: February 2015

Union Gas, like many of the natural gas companies across Canada, has seen significant expansion of it’s compression and pipeline facilities in the past few years. Much of this expansion has been dedicated to the gas storage and transmission needs of the Eastern Canadian and American markets. With the capital costs of these facilities continually on the rise it is critical to ensure that each facility will yield maximum utility to the system for the proposed investment.
Union Gas has a unique position within the Canadian gas industry as not only a major distribution company but also an operator of over 120 BCF of underground gas storage and a transmission pipeline system which is an integral part of the transCanadian gas supply infrastructure. Union’s transmission and storage system provides a vital link between the TransCanada PipeLines transmission system running through Northern Ontario and Central Michigan and several delivery points into the Northeastern United States and Eastern Canada. The diverse nature of Union’s operating facilities dictate a system with two distinctively different modes of compression during the winter operating season. These modes being storage withdrawal, which is typically a high head low flow operation and pipeline transmission which is a low head high flow operation. Each of these modes require specific compressor performance designs which do not typically display the flexibility to be utilized in either mode.
With system demands consistently on the increase it can be very difficult to maintain adequate backup in the event of a compressor plant outage; this is particularly evident’ when considering the different operating requirements at various locations in the system. In an effort to maximize the operational flexibility of a new facility, Union Gas has implemented a new design consisting of a triple case compressor train driven off a single engine gas turbine package. With the external unit piping configured for both series and parallel operation this new design can effectively duplicate all possible modes of operation in Union’s present operating system, for both storage withdrawal and pipeline transmission.
This paper will discuss the extent of operational flexibility this system can offer and the various design concerns associated with this type of compression plant facility.
Experimental Validation of Turbine Blade Dynamics Design Methodology
Authors: Salvano S. , Schips C. 
Published: February 2015

This paper deals with the most relevant experimental results regarding turbine blade dynamics acquired from several designs: from both military and commercial aeroengines to industrial gas turbines. On this basis, a common design methodology has been validated for the different applications.
Campbell and Goodman diagrams are the basic tools used to verify resonances and vibratory stress margins. In addition to that, a frequency response type of calculation was developed, nevertheless facing the problem of exciting force and damping assumption. High emphasis is given to evaluating the damping characteristics of the blade: in-house programs have been validated through dedicated tests of shroud optimization and platform damper design.
Experimental tests are in any case necessary when a new blade is designed; however the confidence in the design tools gained by their experimental validation is likely to give better chances to have a good new design, shortening the relative development phase.
Numerical Analysis of Nozzle and Afterbody Flow of Hypersonic Transport Systems
Authors: Esch Thomas , Glehrl Marcus 
Published: February 2015

Using an implicit Finite-Volume Navier-Stokes code the flow field in a Single Expansion Ramp Nozzle (SERN) for a hypersonic aircraft is studied. Comparisons between experimental data and CFD calculations for certain components of the integrated exhaust system (cold 2D nozzle flow, high temperature reacting 3D combustion chamber flow and 2D nozzle flow with external flow) are presented.
To show the sensitivity of the considered components to off-design operating conditions, comprehensive numerical studies have been carried out.
For the determination of nozzle performance a detailed 20 analysis from transonic to hypersonic flight Mach numbers has been performed. A direct optimization method has been used to investigate the influence of the lower nozzle flap shape on the thrust vector.
Technology Demonstration Nozzle for Mach 7 Turboramjets
Authors: Pirker K. , Knott U. 
Published: February 2015

Under the German Hypersonic Technology Program, future-oriented designs and technologies for reusable space vehicles, such as SÄNGER, are being developed. Pioneering the way in a new field of technology, MTU constructed and tested, with success from the very beginning, an actively cooled, asymmetric rectangular nozzle (SERN - single expansion ramp nozzle) of advanced design, characterized by the following innovative features:
- rectangular, flap-controlled variable flow cross section;
- liquid-hydrogen-cooled structures;
- high-temperature-resistant sealing system for variable nozzle flaps; and
- uncooled expansion ramp in carbon/carbon composite with anti-oxidation coating.
Development of the nozzle called for the mastery of new manufacturing techniques; proof of concept was provided in the successful performance of initial tests of 300 seconds duration.
Processing of Continuous Fiber Reinforced SI3N4 Matrix Composites for Gas Turbine Engine Components
Authors: Iwata Misao , Isoda Takeshi , Itoh Takuji 
Published: February 2015

The purpose of this study is to significantly improve the fracture toughness of ceramic materials by incorporating continuous fiber reinforcement, and demonstrate the ability to fabricate gas turbine engine components, such as shrouds and liners.
SI3N4, matrix composites were prepared by stacking precursor tapes consisting of carbon fibers coated with a slurry of SI3N4, Al2O3, Y2O3, perhydropolysilazane and xylene.
After sintering the continuous fiber reinforced SI3N4-matrix composites had a 4 to 5 times higher fracture toughness of 28.1 MPam1 /2 and a 250 to 300 times higher work-of-fracture of 2.5 × 104 j/m2, than typical monolithic SI3N4 ceramics.
In the meantime, the preform tape wound at a helical-angle of 45° was used for forming green bodies of the gas turbine engine components by means of the deep drawing method. In order to sinter these preforms, the preceramic polymer infiltration method (P.C.P.I. method) and pseudo hot isostatic press method were applied for fabricating the shroud and liners, respectively.
Pattern Factor Reduction in a Reverse Flow Gas Turbine Combustor Using Angled Dilution Jets
Authors: Crocker D. Scott , Smith Clifford E. , Myers Geoff D. 
Published: February 2015

An advanced method for dilution zone mixing in reverse flow gas turbine combustors was experimentally investigated. To enhance circumferential mixing, dilution jets were injected with a high circumferential (swirl) velocity component. The jets on the outer liner were angled in one direction while the jets on the inner liner were angled in the opposite direction.
To demonstrate reduced pattern factor, AlliedSignal Engines’ F109 combustor was tested at sea level takeoff conditions. For the baseline (conventional) configuration, the experimental results showed that large scale circumferential temperature non-uniformities at the turbine inlet were caused primarily by fuel flow variations from nozzle to nozzle. These temperature variations were significantly reduced by angled dilution jets. A pattern factor of 0.102 was achieved compared to the best case pattern factor of 0.163 for the baseline configuration. The only combustor modification was the dilution hole configuration. The radial average temperature profile produced by angled dilution jets was very similar to the profile produced by the baseline configuration.
An Assessment of the Thermodynamic Performance of Mixed Gas-Steam Cycles: Part B — Water-Injected and Hat Cycles
Authors: Chiesa Paolo , Lozza Giovanni , Macchi Ennio , Consonni Stefano 
Published: February 2015

Part B of this paper focuses on intercooled recuperated cycles where water is injected to improve both efficiency and power output. This concept is investigated for two basic cycle configurations: a Recuperated Water Injected (RWI) cycle, where water is simply injected downstream the HP compressor, and a Humid Air Turbine (HAT) cycle, where air/water mixing is accomplished in a counter-current heat/mass transfer column called “saturator”.
For both configurations we discuss the selection and the optimization of the main cycle parameters, and track the variations of efficiency and specific work with overall gas turbine pressure ratio and turbine inlet temperature (TIT). TIT can vary to take advantage of lower gas turbine coolant temperatures, but only within the capabilities of current technology. For HAT cycles we also address the modelization of the saturator and the sensitivity to the most crucial characteristics of novel components (temperature differences and pressure drops in heat/mass transfer equipment). The efficiency penalties associated to each process are evaluated by a second-law analysis which also includes the cycles considered in Part A.
For any given TIT in the range considered (1250 to 1500°C), the more reversible air/water mixing mechanism realized in the saturator allows HAT cycles to achieve efficiencies about 2 percentage points higher than those of RWI cycles: at the TIT of 1500°C made possible by intercooling, state-of-the-art aero-engines embodying the above cycle modifications can reach net electrical efficiencies of about 57% and 55%, respectively. This compares to efficiencies slightly below 56% achievable by combined cycles based upon large-scale heavy duty machines with TIT = 1280°C.
Retrofittable Dry Low Emissions Combustor for 501-K Industrial Gas Turbine Engines
Authors: Razdan Mohan K. , McLeroy Jacob T. , Weaver William E. 
Published: February 2015

This paper describes progress in the development of a 25 ppm NOx combustor that requires no diluent injection or post-combustion treatment The combustor will be retrofittable in all existing Allison Model 501-K series industrial engines. The approach undertaken is based on lean-premix combustion design incorporating an efficient fuel and air pre-mixing, fuel staging, and advanced wall cooling.
Extensive use has been made of Computational Combustor Dynamics (CCD) codes in the design of the low NOx combustor. Experimental work in support of the present effort includes atmospheric bench scale testing and high pressure rig testing. The bench tests have been performed to evaluate several candidate designs, to gain better understanding of general lean pre-mixed combustor behavior, and to verify model predictions. The bench test results have indicated good fuel/air mixing performance of the lean premixing domes. The high pressure simulated engine rig tests of the dry lean pre-mixed low emissions combustors using natural gas have demonstrated NOx levels less than 15 ppm vd (15% O2 corrected), well below the program goals.
Applications of Laser Systems to Cutting, Drilling and Welding Turbine Engine Parts
Authors: VanderWert Terry L. 
Published: February 2015

Multi-axis laser materials processing systems are having a significant impact on the way turbine engine parts are being cut, drilled, and welded. The success of laser cutting, drilling and welding is based in the ability to concentrate laser energy into a small area and to produce features having narrow heat affected zones.
Reduced tooling expense, fast turnaround, and flexibility for handling design changes and for economical small lot manufacturing are some of the benefits associated with laser processing of turbine engine parts. For example, in replacing hand trimming, laser cutting has increased throughput for trimming a deep drawn gas turbine engine part from 18 pieces per day to 18 pieces in 30 minutes. For another company, laser cutting saved $75,000 in tooling expense for an application involving drilling of 3500, 0.33 mm diameter holes in a 0.36 mm thick turbine engine blade insert. Laser cutting and welding have been key to a major aircraft manufacturer’s implementation of Just-In-Time manufacturing practices.
Recent advances in design and control of laser processing systems have increased the number of applications for laser processing turbine engine parts. New processes have increased the range of applications for which laser processing is qualified. In-process gaging has been used to automate processes that were previously manual and, in doing so, increase the quality of the finished part and productivity of the manufacturing operation.
This paper reviews the laser processes used to cut, drill, and weld turbine engine parts. Some typical applications are presented to illustrate the benefits of laser systems for processing turbine engine parts.
Evaluation of Ceramic Rotor Strength by Cold and Hot Spin Tests
Authors: Watanabe Makoto , Ogita Hiroshi 
Published: February 2015

Presently in Japan 100 kW ceramic gas turbines (CGT) for automobiles are under development, parts of which include a turbine rotor, scrolls, a combustor, and other parts made of ceramics and ceramic matrix composites. The rotor is designed to rotate at 110,000 rpm, equal to the maximum stress of 300 MPa and to be exposed to temperatures up to 1350°C. Initially, the strength of ceramic rotors was evaluated by a burst test using a cold spin tester. The burst picture was observed and compared with the 4pt bending strength of the ceramic test specimens. Next, the strength of the rotors was tested by a hot spin test and the burst result of the rotor was evaluated.
A high speed camera was used to observe the rotor at the instant of burst under a high temperature condition.
Applying the result of the cold and hot spin tests, ceramics for turbine rotor were selected and the shape of the rotor was designed as a practical automotive engine began in 1990 as a project of the Petroleum Energy Center with financial support from the Agency of Natural Resources and Energy, the Ministry of International Trade and Industry. In order to obtain a 40% or higher thermal efficiency, the automotive gas turbine requires the use of a turbine rotor, combustor, shroud and other engine parts that can withstand high temperatures of 1200°C to 1500°C. In addition, since their resistance to thermal stress and impact are primary considerations, it is necessary to develop high heat-resistant materials (ceramic type materials). Fig. 1 shows a sectional model of the automotive ceramic gas turbine now under development. Under this project, a monolithic ceramic rotor was first evaluated as a turbine rotor. Ceramic matrix composites were then studied.
The Model V84.3 Shot Tests: Compressor Flow Field Measurements and Evaluation
Authors: Janssen M. , Mönig R. , Seume J. , Hönen H. , Lösch-Schloms R. , Gallus H. E. 
Published: February 2015

Detailed experimental investigations were carried out at the Siemens test-facility in Berlin to validate and develop further the compressor design of the Model V84.3 gas turbine and to generate a comprehensive data base for the verification of the flow calculation programs. The test facility enables Siemens to confirm the design with regard to performance and reliability in the full scale machine under full load and off-design condition.
Various measuring techniques well established in the laboratory were applied to the full scale compressor to examine the flow field. Along with rather conventional 5-hole probes for measuring the flow field in the core region, miniaturized 3-hole probes were developed at the Turbomachinery Laboratory of the Technical University of Aachen, tested and finally used for the measurements of endwall boundary layer profiles and their development throughout the compressor. In addition to the probe measurements, wall static-pressure measurements, as well as probed vane measurements, were carried out.
The paper briefly describes the test facility, the compressor under investigation, and the instrumentation for the flow measurements. A comparison of the 3-hole and 5-hole probe measurements is presented. The experimental results are compared with calculated results taken from a two-dimensional off-design calculation program with standard loss models. By means of the measured static-pressure rise at the casing wall and the total pressure distributions downstream of the rotor rows, a modification of the loss modeling was performed. The calculated flow field is compared to the results of the 3-hole and 5-hole probe measurements in terms of radial distributions for flow angle. Mach number and total pressure.