bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressure Effect on NOx and CO Emissions in Industrial Gas Turbines
Authors: Bhargava Anuj , Kendrick Donald W. , Colket Meredith B. , Sowa William A. , Casleton Kent H. , Maloney Daniel J. 
Published: August 2014

In order to determine the effect of pressure on emissions and stability limit, an experimental and modeling study has been performed jointly by UTRC and DOE-FETC. Experiments have been performed at lean conditions in 100–400 psi range with two different nozzles. Measured NOx and CO concentrations have been modeled with a PSR Network using detailed chemistry. Good agreement between the data and model predictions over a wide range of conditions indicate the consistency and reliability of the measured data and validity of the modeling approach.
Experiments were conducted at the DOE-FETC facility in Morgantown. A simple refractory combustor liner with a fuel-air-premixing nozzle was used to map stability margins, emission levels of NOx, CO and combustion efficiency. Each experimental nozzle had a centerbody and wall pilot for flame stabilization. Data was collected at four different pressures of 100, 200, 300 and 400 psi, and at different diffusion pilot and moisture levels. The premixing nozzle hardware could be easily lit and operated over a broad range of flame temperatures with minimal combustion generated noise. Two different nozzles designed at UTRC were used to determine pressure and nozzle effects.
Computations were made for comparison with the experiments. GRI Mech 2.11 kinetics and thermodynamic database was used for modeling the flame chemistry. A Perfectly Stirred Reactor (PSR) network code developed internally at UTRC was used to create a network of PSRs to simulate the flame and combustor. A total of 10 to 15 reactors were used in the network. Residence time varied with the flow rates (air was fixed while fuel flow rate was varied in order to obtain the required equivalence ratio, ϕ).
Good agreement between the measured and modeled NOx (5–10%) was obtained, but the agreement for CO (model predictions are higher by 30–50%) was not as good as for NOx. The experimental data and the modeling predictions indicate that the NOx emission functionality with pressure is dependent on both equivalence ratio and absolute pressure. The CO levels tend to go down with increase in pressure as P−0.5, at different equivalence ratios, consistent with an equilibrium analysis.
Closed-Loop Combustion Control Using OH Radical Emissions
Authors: Meng Zhu (Julie) , Hoffa Robert J. , DeMilo Charles A. , Thamer Todd T. 
Published: August 2014

The combustion process in gas-turbine engines produces emissions, especially nitrogen oxides (NOx) and carbon monoxide (CO), which change dramatically with combustor operating conditions. As part of this study, the application of active feedback control technologies to reduce thermal NOx emissions is modeled numerically and demonstrated experimentally.
A new optical flame sensor, designed by Ametek Power & Industrial Products, has been successfully implemented as the feedback element in a proof-of-concept control system used to minimize NOx emissions. The sensor consists of a robust mechanical package, as well as electronics suitable for severe gas-turbine environments. Results from system rig tests correlate closely to theoretical predictions, as described in literature and produced by a control system simulation model.
The control system simulation model predicts the efficacy of controlling engine operating characteristics based on chemical luminescence of the OH radical. The model consists of a fuel pump and metering device, a fuel-air mixing scheme, a combustion model, the new ultraviolet (UV) feedback flame sensor, and a simple gain block. The input reference to the proportional emissions control is the fuel-to-air equivalence ratio, which is empirically correlated to the desired low level of NOx emissions while satisfying other operating conditions, such as CO emissions and power.
Results from the closed-loop emissions control simulation and rig tests were analyzed to determine the capability of the UV flame sensor to measure and control the combustion process in a gas-turbine engine. The response characteristics, overshoot percentage, rise time, settling time, accuracy, resolution, and repeatability are addressed.
Flow and Spray Characteristics of a Lean Fuel Injection Module With Radial Swirlers
Authors: Seol Woo Seok , Han Yeoung Min , Lee Dae Sung 
Published: August 2014

Lean fuel modules are sometimes employed to reduce NOx emissions in aero-engine combustors. With a lean fuel module whose AFR is larger than the stoichiometric AFR, the bulk AFR remains larger than the stoichiometric AFR throughout the combustor, and hence the peak NOx producing regime can be avoided. In addition, by introducing a large amount of air at the fuel injection point and increasing the mixing rate, the existing time of local stoichiometric pockets can be reduced.
In the present study, flow and spray characteristics of a 21AFR lean fuel module, which consists of a pressure jet fuel injector and radial air swirlers, are measured by an adaptive Phase/Doppler technique. Gas phase velocity field, and distributions of droplet size, number density, and liquid phase volume flux are presented for co-swirl and counter-swirl lean modules.
The present study reveals that a strong reverse flow zone is formed by the lean fuel module with radial swirlers. The shape of the reverse flow zone and the reverse flow velocity depend on the swirl direction significantly. The lean fuel module with radial swirlers provides effective atomization, and the SMD distribution near the module exit is quite uniform. The swirl direction has significant effects on the spray characteristics, too.
Integrated Experimental and Numerical Approach for Fuel-Air Mixing Prediction in a Heavy-Duty Gas Turbine LP Burner
Authors: Mori Giulio , Razore Sandro , Ubaldi Marina , Zunino Pietro 
Published: August 2014

An integrated experimental-numerical procedure has been developed for fuel-air mixing prediction in a heavy-duty gas turbine burner. Optical measurements of the degree of mixing have been performed in a full-scale test rig operating with cold flow. Experimental data have been utilized to validate a CFD RANS numerical model. In fact, it is recognized that the turbulence behavior of jets in swirling air-flow stream is not accurately described by standard k-ε turbulence models; therefore advanced turbulence models have been assessed by means of experimental data.
The degree of mixing between simulated fuel and air streams has been evaluated at the burner exit section by means of a planar Mie scattering technique. The experimental apparatus consists of a pulsed Nd:YAG laser and a high resolution CCD video camera connected to a frame grabber. The acquired instantaneous images have been processed through specific procedures that also take into account the laser beam spatial non-uniformity.
A second order discretization scheme with a RSM turbulence model gives the best accordance with the experimental data. Such CFD model will be part of a more general method addressed to numerical prediction of turbulent combustion flames in LP technology.
Alternative Fuels in Gas Turbine Applications: A Simple Method for Assessing the Influence of Fuel on Performances
Authors: Molière Michel , Pommel Frédéric 
Published: August 2014

Gas turbines have by essence access to a broad range of primary energies. This advantage is essentially exploitable by the Heavy Duty branch which, thanks to moderate compression ratios, robust mechanical designs and versatile combustion systems, can utilise a wide series of commercial and process by-products fuels: natural gas, petroleum distillates, gasified coal or biomass, gas condensates, ash-forming fuels, alcohols etc. In this context, a thorough knowledge of the many-facetted fuel/machine interdependency, which seems insufficiently covered by the existing literature on gas turbines, is of prime interest.
This paper is devoted to the thermodynamic aspects of fuel influence. It offers: (i) a review of the main primary energies accessible to stationary gas turbines, (ii) a new, differential method for assessing the impact of fuel on machine thermodynamics, with original equations accounting for the changes in power output, efficiency and exhaust heat.
Assessment of Remote Lift Fan Jet Engines
Authors: Arnulfo Luca , Pilidis Pericles 
Published: August 2014

The design of an Advanced Short Take-Off, Vertical Landing (ASTOVL) poses a major challenge. A successful aircraft of this type with a well integrated airframe and power plant must compete with Conventional Take-Off and Landing (CTOL) aircraft in the combat arena, while keeping the advantage of operations from short fields and small aircraft carriers.
To achieve a performance similar to those of CTOL planes, the recourse to a variable cycle engine appears to be a suitable solution for ASTOVL aircraft. One such design is the remote lift fan engine.
In this paper several alternatives are discussed and four engine designs based on a high performance low bypass core engine, exploiting the opportunity of variable cycle, are studied and compared. Two of these, the shaft driven and the Low Pressure Compressor exit bleed driven remote fans are predicted to be suitable alternatives.
Semi–Closed Hat (SC-HAT) Power Cycle
Authors: Carcasci Carlo , Cosi Lorenzo , Fiaschi Daniele , Manfrida Giampaolo 
Published: August 2014

This new power cycle is derived from a simplified HAT cycle, with a partial recirculation of the exhaust gases added with respect to the traditional HAT configuration. The basic idea of applying recirculation to the HAT cycle stems from the interesting performance levels and general environmental advantages obtainable applying this technique to combined-cycle (SCGT/CC) and regenerative GT solutions (SCGT/RE); these power plants all share the integration with CO2 chemical scrubbing of the exhaust stack in order to reduce greenhouse effects.
A relevant advantage of the proposed configuration over the original HAT solution is the possibility of complete water recovery from the separator before the recirculation node; here the temperature level is necessarily very low, allowing thus condensation of water produced by the natural-gas combustion process. This allows the self–sustainement of the HAT cycle, from the water consumption point of view, without any external supply. For the water separator, two thermodynamic models were developed (respectively simulating a single- and a multiple temperature condensation process), which have provided similar results.
The whole cycle is modeled using a modular code, thoroughly tested against the performance of a large set of existing GTs. The layout is derived from an existing HAT configuration, with suppression of the economizer section in the regenerator and the possible practice of external (non-recuperative) intercooling between the two compressors. The first choice is imposed by the presence of an additional low-temperature heat load for the CO2 removal plant, while the second is sometimes necessary depending on the compressor pressure ratios and the possibility of including inside the cycle low-temperature internal cycle regeneration.
The expected performance of the plant is relatively high and close to those typical of HAT, SCGT/RE and SCGT/CC cycles: a LHV-based efficiency level exceeding 50% inclusive of CO2 separation and delivery at ambient pressure and temperature; the specific work levels — in the range of 680 kJ/kg for the basic configuration — are lower than those of the HAT cycle but larger than for SCGT/CC and SCGT/RE solutions; the cycle requires relatively high overall pressure ratios (35–40). A notable improvement in specific work can be obtained with reheat.
On-Design and Off-Design Performance Analysis of a Gas Turbine Combined Cycle Using the Exergy Method
Authors: Codeceira Neto Alcides , Pilidis Pericles 
Published: August 2014

The present paper describes an on-design and an off-design performance study of gas turbine combined cycle based power plants. The exergy analysis has been carried out along with the performance assessment, considering the overall plant exergetic efficiency and the exergy destruction in the various components of the plant. The exergy method highlights irreversibility within the plant components, and it is of particular interest in this investigation.
A computational analysis has been carried out to investigate the effects of compressor pressure ratio and gas turbine entry temperature on the thermodynamic performance of combined gas / steam power cycles. The exergy analysis has been performed for on-design point calculations, considering single shaft gas turbines with different compressor pressure ratios and turbine entry temperatures. Nearly 100 MW shaft power gas turbine engines burning natural gas fuel have been selected in this study. The off-design calculations have been performed for one of the gas turbines selected from the on-design point studies. For this particular gas turbine engine, fuel has been changed from natural gas to a low calorific value fuel gas originated from the gasification of wood.
The exergy analysis indicates that maximum exergy is destroyed in the combustor, in the case of combined gas / steam cycles burning natural gas. For these studies on-design point, the exergy destruction in the combustor is found to decrease with increasing compressor pressure ratio to an optimum value and with increasing turbine entry temperature.
In the off-design case the gas turbine engine is burning low calorific value fuel originated from the gasification of wood. The maximum exergy destruction occurs in the gasification process, followed by the combustion process in the gas turbine.
New Concept of CO2 Removal Technologies in Power Generation, Combined With Fossil Fuel Recovery and Long Term CO2 Sequestration
Authors: Mathieu Ph. , Dubuisson R. , Houyou S. , Nihart R. 
Published: August 2014

In this paper, the mentioned cycle has been transformed in a CO2 regenerative Ericsson-like cycle and therefore is named E-MATIANT. The removed CO2 can still be available at a pressure higher than the critical one (73 bar). When optimising the cycle, the calculated optimum pressure will be around 60 bar; this makes the technical issues easier to deal with than when using a supercritical fluid, namely the material strains and corrosion behavior. A sensitivity analysis is performed with respect to the CO2 delivery pressure in order to evaluate the performance changes. The fuel flexibility is an important asset of the newly designed cycle: mixtures of CO and H2 produced either in gasification or steam reforming processes can indeed be burnt in the combustion chamber. In a future work, the combination of a solid oxide fuel cell (SOFC) and this cycle both fed by a CO and H2 mixture will be considered as an option for the improvement of the global efficiency.
If not fixed in a chemical or biological system, the delivered CO2 can be used in industry or in the enhancement of fossil fuels recovery from their deposits, with a marginal compression consumption work. In this paper, CO2 injection is used to enhance methane recovery from coal seams by some 20 to 30%, in comparison with water pumping. The depleted seam can afterwards be used as the host site for long run CO2 sequestration.
As a conclusion, the combination of quasi-zero emission power plants with CO2 geological storage and enhanced fuel recovery provides a CO2 flow, otherwise considered as a waste or a byproduct, with an exergetic and a commercial added value. This makes this option a serious alternative to other CO2 control technologies.
Assessment of Molten Carbonate Fuel Cell Models and Integration With Gas and Steam Cycles
Authors: Massardo A. F. , Bosio B. 
Published: August 2014

The aim of this work is to investigate the performance of Molten Carbonate Fuel Cells (MCFCs), with external reforming and Gas Turbine/Steam Turbine (GT/ST) combined cycles.
The analysis of these MCFC-GT/ST combined cycles has been carried out using the Thermo Economic Modular Program TEMP (Agazzani and Massardo, 1997) modified to allow MCFC, external sensible heat reformer, and catalytic burner performance to be carefully taken into account. The code has been verified through the use of a detailed MCFC model (Bosio et al., 1999) and of the data available for an existing MCFC unit.
The thermodynamic and exergy analysis of a number of MCFC combined cycles is presented and discussed, taking into account the influence of technological constraints, also evaluated with the sophisticated model, and the influence of the post-combustion of the fuel directly in the external catalytic burner. The results are presented and discussed in depth.
Developing the Next Generation Gas Turbine Systems — A National Partnership
Authors: Layne A. W. 
Published: August 2014

The U.S. Department of Energy is in its 7th year of a 9-year program to develop the next generation of advanced turbine systems (ATS). Under this program, partnerships between industry, universities, national laboratories, government agencies and institutions, and the U.S. Department of Energy (DOE) are performing research and development required to commercialize the ATS. The ATS Program is jointly sponsored by the U.S. DOE Offices of Fossil Energy and Energy Efficiency and Renewable Energy. Supporting R&D, recent ATS accomplishments and future advanced concepts for next generation gas turbine systems are described and discussed in this paper.
As the ATS program winds down, DOE’s National Energy Technology Center (NETL) is evaluating the technology and market needs for continuing DOE support to develop advanced turbine systems. As part of this effort, NETL is sponsoring market and technology assessments, regional focus group discussions, and public workshops. The purpose of this paper is to provide the status of the ATS Program and the NETL perspective on potential options for future research and development needs, and public-private development programs addressing turbine based power generation for systems 30MW or greater in output.
Early Detection of Combustor Pulsations and Optimized Operation Through On-Line Monitoring Systems
Authors: Andersen Helmer 
Published: August 2014

This article describes the objectives of an on-line monitoring system, the development and capabilities of the system and the experiences gained with it.
The objectives of the monitoring system were formulated after several transition pieces between the combustor and the turbine inlet had failed. The failures occurred within less than two months in a plant that had operated for more than 7 years without unusual problems. The system development was based on this experience and the goal to prevent future catastrophic failures. It provides:
• Data logs of selectable operational parameters
• Combustor pressure pulsations including a frequency spectrum
• True firing temperature based on a heat balance calculation
It thus provides the basis for predictive maintenance and optimum equipment performance. Several gas turbines with low NOx combustion system were equipped with the monitoring system in the summer of 1997. Data provided by the system over a period of almost 3 years identifies several parameters that are very indicative of the condition of the equipment.
These parameters are discussed as well as the consequences for the operation, maintenance and reliability of the units.
Risk-Based Inspection of Combustion Turbines
Authors: Schmidt Michael E. G. , Mauney David A. 
Published: August 2014

Combustion turbine users, particularly in an unregulated environment, are faced with a multivariate optimizing problem. They need to run their machines in a way that ensures that the bondholders will be paid or maximizes shareholder value — or both, depending upon the owner’s finances. Meeting the financial challenge might require maximum reliability and availability at all times but it is more likely to require maximum reliability and availability at specific times, such as peak demand times of day or seasons. Maintenance is the biggest factor in reliability and availability control, and risk-based methods can focus maintenance for the best financial performance. One model can mathematically solve inspection program timing and component replacement decisions. Safety, environmental, financial and other constraints can bound the optimizing algorithm.
This paper outlines risk-based inspection program development. It focuses on the logical basis for a risk-based decision model, and briefly presents three simple examples. It references American Society of Mechanical Engineers (ASME) International documents that provide more information about risk-based inspection programs.
Cooling Effectiveness Measurements With Thermal Radiometry in a Turbine Cascade
Authors: Moon H. K. , Jaiswal R. 
Published: August 2014

Airfoil temperature measurements in a hot cascade were traditionally conducted with thermocouples in spite of their limitations. In the present work, a real-time full imaging of the airfoil temperature distribution is demonstrated in a turbine cascade using a thermal radiometry system. Two synthetic sapphire windows provided infrared (IR)-viewing access from the outside. The apparent emissivity of the test airfoil was calibrated with thermocouples buried flush into the wall. The turbine cascade, fabricated with actual engine hardware, provided heat transfer similarity by matching Re, Ma, and Tu. The effect of gas to coolant temperature ratio (Tg/Tc) on the cooling effectiveness was investigated.
Heating (“reverse” cooling) of the test airfoil in a relatively cold mainstream air resulted in a much more detailed temperature image than the normal (forward) cooling case, as it significantly reduced the background radiation. A methodology to correct the cooling effectiveness obtained at different gas to coolant temperature ratios than the engine condition was developed and has been experimentally validated.
Innovative Cyclone Cooling Scheme for Gas Turbine Blade: Thermal-Hydraulic Performance Evaluation
Authors: Khalatov Artem , Syred Nick , Bowen Philip , Al-Ajmi Rashed , Kozlov Alexander , Schukin Andrey 
Published: August 2014

The potential of currently used internal blade cooling technologies is nearly exhausted and the further improvements in the cooling efficiency can only be achieved through increases either in the air flow rate bled from the compressor or through reductions in the cooling passage size. This however results in the decrease of the gas turbine efficiency, and can cause dirt blockage problems. Several research programs were recently launched in the USA, UK and Germany to explore some novel concepts and to study innovative cooling techniques with improved parameters. One of them is an internal cyclone cooling technique, based on generation of swirl flow in blade cooling passages. Several designs of cyclone cooling, based on a two cooling passage configuration have been proposed and investigated in the USA and the former USSR over the last ten years, and these investigations have already demonstrated the superior heat transfer rate compared with conventional cooling techniques.
The novel three passage serpentine cyclone cooling scheme was proposed by the authors recently in which coolant moves successively through three cooling passages in two of those swirling flow is generated. New experimental data and the experimental correlations regarding heat transfer and fluid flow parameters in passages of an innovative cyclone cooling scheme have been obtained. The diagram of thermal-hydraulic performance is presented and comparison with conventional cooling techniques is given. The three passage cyclone cooling scheme has demonstrated the high rate of heat transfer and thermal-hydraulic performance at acceptable energy losses.