bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Momentum Integral Method to Predict the Frictional Torque of a Rotating Disk With Protruding Bolts
Authors: Gärtner W. 
Published: December 2014

A momentum integral method was developed to predict the frictional torque of a disk rotating in quiescent air with cylindrical protrusions mounted on its surface.
The predicted torque is compared to experimental data taken for the protrusions placed on two different radii on the disk with two different numbers of protrusions on each radius.
A critical review of the calculated results reveals that caused by the protrusions the predicted thickness of the boundary layer on the disk is of the same magnitude as the radius of the disk. Since in this case Prandtl’s simplifications for the boundary layer on which the momentum integral equations are based upon are not valid their use appears to be doubtful.
However, the predicted frictional torque is in good agreement with the measurements for all configurations tested except for that with the smallest circumferential distance between the protrusions where the torque is overpredicted by the method.
The application of the method for a disk rotating in a stationary housing is briefly discussed.
VECTOR Program Background and Plan
Authors: Schondel J. Patrick , Robinson Michael R. 
Published: December 2014

The U.S. Navy in cooperation with the Ministries of Defense of Germany and Sweden are initiating a 3-year demonstration program in 1998 to evaluate and define the benefits of thrust vectoring beyond those already understood for Close-in-Combat (CiC). The VECTOR (Vectoring ESTOL Control and Tailless Operational Research) program will capitalize on the X-31 airframe and a contractor team that includes Boeing, G.E., DASA, Volvo, and SAAB to demonstrate the following technologies:
• AVEN® Nozzle - a G.E. designed vectoring nozzle applicable to the F404 family of engines
• Extremely Short Takeoff and Landing (ESTOL) - employ thrust vectoring and precision control for poststall flight in approach to landing and during take off
• Reduced Tail/Tailless - rely on thrust vectoring for primary aircraft stability and control
• Advanced Air Data System (AADS) - flush air data ports or optical air data system integrated with the control system to handle the extensive angle-of-attack and sideslip envelope.
The flight test activity will be conducted in the United States. However, technical development activities will be conducted in all three countries. Germany and Sweden will contribute technical expertise primarily related to flight control and propulsion system integration, respectively.
A Frequency Domain Analysis: Turbine Pressure Side Heat Transfer
Authors: Holmberg D. G. , Diller T. E. , Ng W. F. 
Published: December 2014

Simultaneous time-resolved surface heat flux and velocity measurements have been made along the pressure side of an engine-similar turbine blade in a linear cascade. Direct heat flux was measured using inserted Heat Flux Microsensors at three axial locations along the high turning transonic blade. Miniature hot-wires measured velocity above these locations. Grids produced two turbulence fields with different inlet length scales at constant turbulence intensity.
This work allows a unique look at fluctuating heat transfer on the blade and its relationship to the fluctuating velocity field above. While fluctuating free-stream flow energy and length scale decays continuously in the passage, surface heat flux energy increases continuously. Low frequency flow energy is attenuated in the constricted passage, while growth of low frequency energy in the heat flux is attributed to boundary layer transition activity. Coherence between heat flux and velocity is seen at all frequencies near the leading edge of the blade but only at higher frequencies farther downstream on the pressure side. Existing mean heat transfer correlations do not perform well in this complicated flow.
Fault Detection and Isolation Based on Dynamic Observers Applied to Gas Turbine Control Sensors
Authors: Simani S. , Spina P. R. , Beghelli S. , Bettocchi R. , Fantuzzi C. 
Published: December 2014

In order to prevent machine malfunctions and to determine the machine operating state, it is necessary to use correct measurements from actual system inputs and outputs. This requires the use of techniques for the detection and isolation of sensor faults.
In this paper an approach based on analytical redundancy which uses dynamic observers is suggested to solve the sensor fault detection and isolation problem for a single-shaft industrial gas turbine. The proposed technique requires the generation of classical residual functions obtained with different observer configurations. The diagnosis is performed by checking fluctuations of these residuals caused by faults.
Performance Benefit Assessment of Ceramic Components in an MS9001FA Gas Turbine
Authors: Grondahl Clayton M. , Tsuchiya Toshiaki 
Published: December 2014

The introduction of a ceramic gas turbine component in commercial power generation service will require significant effort. A careful assessment of the power plant performance benefit achievable from the use of ceramic components is necessary to rationalize the priority of this development compared to other alternatives. This paper overviews a study in which the performance benefit from ceramic components was evaluated for an MS9001FA gas turbine in a combined cycle power plant configuration. The study was performed with guidelines of maintaining constant compressor inlet airflow and turbine exit NOx emissions, effectively setting the combustion reaction zone temperature. Cooling flow estimates were calculated to maintain standard design life expectancy of all components.
Monolithic silicon nitride ceramic was considered for application to the transition piece, stage one and two buckets, nozzles and shrouds. Performance benefit was calculated both for ceramic properties at 1093C (2200F) and for the more optimistic 1315C (2400F) oxidatian limit of the ceramic. Hybrid ceramic-metal components were evaluated in the less optimistic case.
Volatile, Low Lubricity Fuels in Gas Turbine Plants: A Review of Main Fuel Options and Their Respective Merits
Authors: Molière M. , Geiger F. , Deramond E. , Becker T. 
Published: December 2014

While natural gas is achieving unrivalled penetration in the power generation sector, especially in gas-turbine combined cycles (CCGT), an increasing number of alternative fuels are in a position to take up the ground left vacant by this major primary energy. In particular, within the thriving family of liquid fuels, the class of volatile products opens interesting prospects for clean and efficient power generation in CCGT plants. Therefore, it has become a necessity for the gas turbine industry to extensively evaluate such new fuel candidates, among which: naphtha’s; kerosines; gas condensates; Natural Gas Liquids (NGL) and alcohols are the most prominent representatives. From a technical standpoint, the success of such projects requires both a careful approach to several specific issues (eg: fuel handling & storage, operation safety) and a clear identification of technological limits. For instance, while the purity of gas condensates meets the requirements of heavy-duty technologies, it generally appears unsuitable for aeroderivative machines.
This paper offers a succinct but comprehensive technical approach and overviews some experience acquired in this area with heavy duty gas turbines. Its aim is to inform gas turbine users/engineers and project developers who envisage volatile fuels as alternative primary energies in gas turbine plants.
A Numerical Study of the Influence of Grid Refinement and Turbulence Modelling on the Flow Field Inside a Highly Loaded Turbine Cascade
Authors: Hildebrandt Thomas , Fottner Leonhard 
Published: December 2014

A thorough numerical study was conducted to simulate the flow field inside a highly loaded linear turbine cascade. The numerical investigation was focused on the secondary flow field as well as on the prediction of the overall design goals within reasonable accuracy limits. The influence of grid resolution was investigated in order to obtain detailed information about the requirements of a grid independent solution. Three different two-equation turbulence models were applied to two numerical grids of different resolution. Emphasis was laid on separating the influences of grid resolution and turbulence models. The Mach- and Reynolds numbers as well as the level of freestream turbulence were set to values typical of turbomachinery conditions.
The computational study was carried out using a 3D state-of-the-art blockstructured Navier-Stokes solver. The comparison of the numerical results with experiments clearly revealed the different degree of agreement between simulation and measurement.
This paper describes the application of a modern flow solver to a testcase which is relevant for practical turbomachinery design purposes. The agreement between the experiments and the results of the numerical study is good and in most cases well within the accuracy limits proposed by Strazisar and Denton (1995).
It was found out that the main effect on the quality of the computations is the resolution of the numerical grid. The finest grid used reached over one million points halfspan, showing clearly superior results compared with a coarser, though still fine grid. The influence of different turbulence models on the numerically obtained flow field was relatively small in comparison with the the grid influence.
Numerical Simulation of Impeller–Volute Interaction in Centrifugal Compressors
Authors: Hillewaert Koen , Van den Braembussche René A. 
Published: December 2014

A numerical procedure to predict the impeller/volute interaction in a single-stage centrifugal compressor is presented. The method couples a three-dimensional unsteady flow calculation in the impeller with a three-dimensional time-averaged flow calculation in the volute through an iterative updating of the boundary conditions on the interface of both calculation domains.
The method has been used to calculate the flow in a compressor with an external volute at off-design operation. Computed circumferential variations of flow angles, total temperature and pressure are shown and compared with measurements. The good agreement between the predictions and measurements confirms the validity of the approach.
Three-Dimensional Analysis of a Multistage Compressor Flow Field
Authors: Elmendorf Wolfgang , Mildner Frank , Röper Ralf , Krüger Uwe , Kluck Michael 
Published: December 2014

A 3D-Navier-Stokes solver was used to analyse the complete flow field of the 15-stage axial compressor of Siemens model V84.3A advanced gas turbine.
The paper presents the flow simulation including modelling of rotor tip clearances and bleeds for turbine cooling air supply. All computations were performed for coupled blade rows to account for the time averaged impact of interaction effects arising from adjacent airfoil rows. The evaluation of such two-blade-row calculations allows the update of the inlet boundary conditions for the following downstream two-blade-row combination. Successive computations from inlet guide vanes to exit stator thus yield the flow field of the whole compressor.
The main objective is the analysis of the numerical results. Special attention is given to the front stage, stage matching, endwall flow effects, tip leakage and the cooling air extractions. The comparison to experimental data of the full load gas turbine test facility generally shows a good agreement. The results demonstrate the reliability and power of a modern CFD tool to perform advanced design studies, geometry modifications and calibration of fast 2D-Codes more efficiently and less expensively than performing any physical experiments.
Rotating Stall Control in a High-Speed Stage With Inlet Distortion: Part II — Circumferential Distortion
Authors: Spakovszky Z. S. , van Schalkwyk C. M. , Weigl H. J. , Paduano J. D. , Suder K. L. , Bright M. M. 
Published: December 2014

This paper presents the first attempt to stabilize rotating stall in a single-stage transonic axial flow compressor with inlet distortion using active feedback control. The experiments were conducted at the NASA Lewis Research Center on a single-stage transonic core compressor inlet stage. An array of 12 jet injectors located upstream of the compressor was used for forced response testing and feedback stabilization. Results for a circumferential total pressure distortion of about one dynamic head and a 120° extent (DC(60) = 0.61) are reported in this paper. Part I (Spakovszky et al. (1998)) reports results for radial distortion.
Control laws were designed using empirical transfer function estimates determined from forced response results. Distortion introduces coupling between the harmonics of circumferential pressure perturbations, requiring multi-variable identification and control design techniques. The compressor response displayed a strong first spatial harmonic, dominated by the well known incompressible Moore-Greitzer mode.
Steady axisymmetric injection of 4% of the compressor mass flow resulted in a 6.2% reduction of stalling mass flow. Constant gain feedback, using unsteady asymmetric injection, yielded a further range extension of 9%. A more sophisticated robust controller allowed a reduction in stalling mass flow of 10.2% relative to steady injection, yielding a total reduction in stalling mass flow of 16.4%.
Integrated Testing of the Full Authority Digital Control and Redundant Independent Mechanical Start System for the U.S. Navy’s DDG-51 Ship Service Gas Turbine Generator Sets
Authors: Kozuhowski Helen J. , Hoffman Matthew G. , Mako C. David , Overton Leonard L. , Masincup William E. 
Published: December 2014

The U.S. Navy and Allison Engine Company successfully completed a second round of testing which integrated a new Woodward Governor Full Authority Digital Control (FADC) system for gas turbine control and a Redundant Independent Mechanical Start System (RIMSS). This integrated system will be installed on Allison Model AG9140 Ship Service Gas Turbine Generators (SSGTGs) on hull numbers DDG-86 and follow of the U.S. Navy’s Arleigh Burke (DDG-51) class destroyers.
The Full Authority Digital Control (FADC) Local Operating Panel (LOCOP) will be a direct replacement of the original AG9140 LOCOP and will control both the Allison 501-K34 gas turbine and the RIMSS unit. RIMSS is a gas turbine powered, mechanically coupled start system for the SSGTGs and is designed to replace the high pressure start air system on DDG-51 class ships.
This paper describes the FADC and RIMSS systems and details Phase II testing that was conducted on the AG9140 SSGTG located at the Naval Surface Warfare Center, Carderock Division - Ship Systems Engineering Station (NSWCCD-SSES) DDG-51 Land Based Engineering Site (LBES), Figure 1. The test program embodied the second portion of RIMSS testing which included the addition of the final prototype FADC control system. The test agenda included electric plant operations with the FADC and a second 500 start endurance test of RIMSS. The primary objective of Phase II testing was to evaluate the FADC control system and to further validate engine life predictions for the RIMSS engine.
The Ultimate NOx Solution for Gas Turbines
Authors: Solt J. Charles 
Published: December 2014

Since the introduction of emission standards for gas turbines in the late ‘70s and early ‘80s, the gas turbine industry has responded with a variety of combustion and cleanup alternatives that have improved emissions. While the emissions were being reduced, the cost of control, and the negative environmental impacts were often significant.
Thanks to a technological breakthrough, catalytic combustion has now been achieved, and can fulfill the promise of low cost NOx elimination without the high cost of SCR or the operational problems associated with Lean Pre-Mix.
Measurement of Air-Fuel Ratio Fluctuations Caused by Combustor Driven Oscillations
Authors: Mongia Rajiv , Dibble Robert , Lovett Jeff 
Published: December 2014

Lean premixed combustion has emerged as a method of achieving low pollutant emissions from gas turbines. A common problem of lean premixed combustion is combustion instability. As conditions inside lean premixed combustors approach the lean flammability limit, large pressure variations are encountered. As a consequence, certain desirable gas turbine operating regimes are not approachable. In minimizing these regimes, combustor designers must rely upon trial and error because combustion instabilities are not well understood (and thus difficult to model). When they occur, pressure oscillations in the combustor can induce fluctuations in fuel mole fraction that can augment the pressure oscillations (undesirable) or dampen the pressure oscillations (desirable). In this paper, we demonstrate a method for measuring the fuel mole fraction oscillations which occur in the premixing section during combustion instabilities produced in the combustor that is downstream of the premixer.
The fuel mole fraction in the premixer is measured with kHz resolution by the absorption of light from a 3.39 μm He-Ne laser. A sudden expansion combustor is constructed to demonstrate this fuel mole fraction measurement technique. Under several operating conditions, we measure significant fuel mole fraction fluctuations that are caused by pressure oscillations in the combustion chamber. Since the fuel mole fraction is sampled continuously, a power spectrum is easily generated. The fuel mole fraction power spectrum clearly indicates fuel mole fraction fluctuation frequencies are the same as the pressure fluctuation frequencies under some operating conditions.
Construction, Startup, Commissioning and Testing of a 240 MW Gas Turbine Spinning Reserve Power Plant, Cambalache, Puerto Rico
Authors: Parece Neil M. , van der Linden Septimus , Diaz Ismael Brito 
Published: December 2014

The Cambalache Power Station, engineered from 1993 to 1995, and constructed from 1996 to 1997, provides the island grid of Puerto Rico with 240 MW of flexible gas turbine power. The plant, now in commercial operation, has demonstrated the capability of a steam enhanced gas turbine to provide highly efficient simple cycle base load power and spinning reserve power to an island network which cannot rely on outside power generators to supplement demand in the event of forced outages and emergencies in other power stations. The plant also demonstrates the first application of a high temperature selective catalytic reactor for NOx reduction to less than 10 ppm (No. 2 fuel oil) on a volume basis corrected to 15% O2.
Finally, the installation demonstrated the benefits to the owner, the Puerto Rico Electric Power Authority (PREPA), of a turnkey contract with the entire plant, including offsite oil barge delivery facilities, water wells, and 230 kV substation, designed, supplied and installed by one contractor. The power station was engineered, constructed and started by a limited partnership led by ABB Power Generation Inc. with Metric Constructors. Civil, structural and balance of plant engineering was performed by Lockwood Greene Scott and Associates., Cambalache Limited Partnership (CLP).
Rotor Power Losses in Planar Radial Magnetic Bearings — Effects of Number of Stator Poles, Air Gap Thickness, and Magnetic Flux Density
Authors: Allaire P. E. , Kasarda M. E. F. , Fujita L. K. 
Published: December 2014

Rotor power losses in magnetic bearings cannot be accurately calculated at this time because of the complexity of the magnetic field distribution and several other effects. The losses are due to eddy currents, hysteresis, and windage. This paper presents measured results in radial magnetic bearing configurations with 8 pole and 16 pole stators and two laminated rotors. Two different air gaps were tested. The rotor power losses were determined by measuring the rundown speed of the rotor after the rotor was spun up to speeds of approximately 30,000 rpm, DN = 2,670,000 mm-rpm, in atmospheric air. The kinetic energy of the rotor is converted to heat by magnetic and air drag power loss mechanisms during the run down. Given past publications and the opinions of researchers in the field, the results were quite unexpected. The measured power losses were found to be nearly independent of the number of poles in the bearing. Also, the overall measured rotor power loss increased significantly as the magnetic flux density increased and also increased significantly as the air gap thickness decreased.
A method of separating the hysteresis, eddy current and windage losses is presented. Eddy current effects were found to be the most important loss mechanism in the data analysis, for large clearance bearings. Hysteresis and windage effects did not change much from one configuration to the other.
A Study of Low NOx Combustion in Medium-Btu Fueled 1300 °C-Class Gas Turbine Combustor in IGCC
Authors: Hasegawa Takeharu , Hisamatsu Tohru , Katsuki Yasunari , Sato Mikio , Yamada Masahiko , Onoda Akihiro , Utsunomiya Masaharu 
Published: December 2014

The development of integrated coal gasification combined cycle (IGCC) systems ensures cost-effective and environmentally sound options for supplying future coal utilizing power generation needs. The Japanese government and the electric power industries in Japan promoted research and development of an IGCC system using an air-blown entrained-flow coal gasifier. We worked on developing a low-Btu fueled gas turbine combustor to improve the thermal efficiency of the IGCC by raising the inlet-gas temperature of gas turbine.
On the other hand, Europe and the United States are now developing the oxygen-blown IGCC demonstration plants. Coal gasified fuel produced in an oxygen-blown entrained-flow coal gasifier, has a calorific value of 8.6MJ/m 3 which is one fifth that of natural gas. However, the adiabatic flame temperature of oxygen-blown medium-Btu coal gaseous fuel is higher than that of natural gas and so NOx production from nitrogen fixation is expected to increase significantly. In the oxygen-blown IGCC system, a surplus nitrogen in quantity is produced in the oxygen-production unit. When nitrogen premixed with coal gasified fuel is injected into the combustor, the power to compress nitrogen increases. A low NOx combustion technology which is capable of decreasing the power to compress nitrogen is a significant advance in gas turbine development with an oxygen-blown IGCC system. We have started to develop a low NOx combustion technology using medium-Btu coal gasified fuel produced in the oxygen-blown IGCC process.
In this paper, the effect of nitrogen injected directly into the combustor on the thermal efficiency of the plant is discussed. A 1300 °C-class gas turbine combustor with a swirling nitrogen injection function designed with a stable and low NOx combustion technology was constructed and the performance of this combustor was evaluated under atmospheric pressure conditions. Analyses confirmed that the thermal efficiency of the plant improved by 0.2 percent (absolute), compared with a case where nitrogen is premixed with coal gasified fuel before injection into the combustor. Moreover, this new technique which injects nitrogen directly into the high temperature region in the combustor results in a significant reduction in NOx production from nitrogen fixation. We estimate that CO emission concentration decreases to a significant level under high pressure conditions, while CO emission concentration in contrast to NOx emission rises sharply with increases in quantity of nitrogen injected into the combustor.