A Generalized Presentation of Gas-Turbine Combustor Performance

1957 ◽  
Author(s):  
A. E. Noreen ◽  
W. T. Martin
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Dimensional Analysis ◽  
Combustion Rate ◽  
Laminar Flame ◽  
Empirical Evaluation ◽  
Combustion Efficiency ◽  
Laminar Flame Speed ◽  
Gas Turbine Combustor ◽  
Stability Limits

Experimental data on stability limits and combustion efficiency of a 3-in-diam combustor using gaseous fuel are presented. These data have been correlated by an empirical evaluation of the results of a dimensional analysis. Theories are proposed, based upon the experimental data, regarding combustor-stabilization processes. Laminar flame speed was shown to be a satisfactory index of the influence of base combustion rate on combustor performance.

The Experimental Behavior of Premixed Flames in Tubes: The Effects of Diluent Gases

1980 ◽  
Vol 102 (2) ◽  
pp. 422-426 ◽  
Author(s):  
J. Odgers ◽  
I. White ◽  
D. Kretschmer
Keyword(s):  
Carbon Dioxide ◽  
Transport Properties ◽  
Gas Turbine ◽  
Reaction Rate ◽  
Laminar Flame ◽  
Laminar Flame Speed ◽  
Gaseous Fuels ◽  
Gas Transport Properties ◽  
The Stability ◽  
Stability Limits

One of the problems facing gas turbine users is the proliferation of gaseous fuels which may be available. These are so many that a comprehensive rig/engine study would be far too costly to undertake. The present studies represent an attempt to quantify the behavior of such fuels, in a simple environment. Measurements of the rates of flame travel and the stability limits have been made for propane/oxygen mixtures diluted with nitrogen, carbon dioxide, helium or argon. The results have been used to forecast the laminar flame speed of mixtures, and rates of flame travel for the various mixtures have been correlated with groups representative of reaction rate and gas transport properties.

A Numerical Study on the Reactivity of Biogas/Reformed-Gas/Air and Methane/Reformed-Gas/Air Mixtures at Gas Turbine Relevant Conditions

2016 ◽  
Author(s):  
Pablo Diaz Gomez Maqueo ◽  
Philippe Versailles ◽  
Gilles Bourque ◽  
Jeffrey M. Bergthorson
Keyword(s):  
Gas Turbine ◽  
Laminar Flame ◽  
Numerical Study ◽  
Flame Temperature ◽  
Flame Speed ◽  
Flame Stability ◽  
Laminar Flame Speed ◽  
Fuel Reforming ◽  
Numerical Work ◽  
Chemical Effects

This study investigates the increase in methane and biogas flame reactivity enabled by the addition of syngas produced through fuel reforming. To isolate thermodynamic and chemical effects on the reactivity of the mixture, the burner simulations are performed with a constant adiabatic flame temperature of 1800 K. Compositions and temperatures are calculated with the chemical equilibrium solver of CANTERA® and the reactivity of the mixture is quantified using the adiabatic, freely-propagating premixed flame, and perfectly-stirred reactors of the CHEMKIN-Pro® software package. The results show that the produced syngas has a content of up to 30 % H2 with a temperature up to 950 K. When added to the fuel, it increases the laminar flame speed while maintaining a burning temperature of 1800 K. Even when cooled to 300 K, the laminar flame speed increases up to 30 % from the baseline of pure biogas. Hence, a system can be developed that controls and improves biogas flame stability under low reactivity conditions by varying the fraction of added syngas to the mixture. This motivates future experimental work on reforming technologies coupled with gas turbine exhausts to validate this numerical work.

Combustion Characteristics of Small Size Gas Turbine Combustor Fueled by Biomass Gas Employing Flameless Combustion

2007 ◽  
Author(s):  
Masato Hiramatsu ◽  
Yoshifumi Nakashima ◽  
Sadamasa Adachi ◽  
Yudai Yamasaki ◽  
Shigehiko Kaneko
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Flameless Combustion ◽  
Engine Exhaust ◽  
Micro Gas Turbine

One approach to achieving 99% combustion efficiency (C.E.) and 10 ppmV or lower NOx (at 15%O2) in a micro gas turbine (MGT) combustor fueled by biomass gas at a variety of operating conditions is with the use of flameless combustion (FLC). This paper compares experimentally obtained results and CHEMKIN analysis conducted for the developed combustor. As a result, increase the number of stage of FLC combustion enlarges the MGT operation range with low-NOx emissions and high-C.E. The composition of fuel has a small effect on the characteristics of ignition in FLC. In addition, NOx in the engine exhaust is reduced by higher levels of CO2 in the fuel.

Combustion of Coal/Water Mixtures With Thermal Preconditioning

1987 ◽  
Vol 109 (3) ◽  
pp. 313-318 ◽  
Author(s):  
M. Novack ◽  
G. Roffe ◽  
G. Miller
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
Experimental Program ◽  
Water Mixture ◽  
Gas Turbine Combustor ◽  
Hydrocarbon Gases ◽  
Sampling Probe ◽  
Stable Flame ◽  
Thermal Preconditioning ◽  
Gaseous Form

Thermal preconditioning is a process in which coal/water mixtures are vaporized to produce coal/steam suspensions, and then superheated to allow the coal to devolatilize producing suspensions of char particles in hydrocarbon gases and steam. This final product of the process can be injected without atomization, and burned directly in a gas turbine combustor. This paper reports on the results of an experimental program in which thermally preconditioned coal/water mixture was successfully burned with a stable flame in a gas turbine combustor test rig. Tests were performed at a mixture flowrate of 300 lb/hr and combustor pressure of 8 atm. The coal/water mixture was thermally preconditioned and injected into the combustor over a temperature range from 350°F to 600°F, and combustion air was supplied at between 600°F to 725°F. Test durations varied between 10 and 20 min. Major results of the combustion testing were that: A stable flame was maintained over a wide equivalence ratio range, between φ = 2.2 (rich) and 0.2 (lean); and combustion efficiency of over 99 percent was achieved when the mixture was preconditioned to 600°F and the combustion air preheated to 725°F. Measurements of ash particulates, captured in the exhaust sampling probe located 20 in. from the injector face, show typical sizes collected to be about 1 μm, with agglomerates of these particulates to be not more than 8 μm. The original mean coal particle size for these tests, prior to preconditioning, was 25 μm. Results of additional tests showed that one third of the sulfur contained in the solids of a coal/water mixture with 3 percent sulfur was evolved in gaseous form (under mild thermolized conditions) mainly as H2S with the remainder as light mercaptans.

Optical and Numerical Investigations of Flame Propagation in a Heavy Duty Spark Ignited Natural Gas Engine

2021 ◽  
Author(s):  
Jinlong Liu ◽  
Christopher Ulishney ◽  
Cosmin E. Dumitrescu
Keyword(s):  
Natural Gas ◽  
Flame Propagation ◽  
Turbulence Intensity ◽  
Laminar Flame ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Heavy Duty ◽  
Piston Chamber

Abstract Increasing the natural gas (NG) use in heavy-duty engines is beneficial for reducing greenhouse-gas emissions from power generation and transportation. However, converting compression ignition (CI) engines to NG spark ignition operation can increase methane emissions without expensive aftertreatment, thereby defeating the purpose of utilizing a low carbon fuel. The widely accepted explanation for the low combustion efficiency in such retrofitted engines is the lower laminar flame speed of natural gas. In addition, diesel engine’s larger bowl size compared to the traditional gasoline engines increases the flame travel length inside the chamber and extends the combustion duration. However, optical measurements performed in this study suggested that a fast-propagating flame was developed inside the cylinder even at extremely lean operation. This was supported by a three-dimensional numerical simulation, which indicated that the squish region of the bowl-in-piston chamber generated a high turbulence intensity inside the bowl. However, the flame propagation experienced a sudden 2.25x reduction in speed when transiting from the bowl to the squish region. Such a phenomenon was caused by the large decrease in the turbulence intensity inside the squish region during the combustion process. Moreover, the squish volume trapped an important fuel fraction, and it is this fraction that experienced a slow and inefficient burning process during the expansion stroke. This resulted in increased methane emissions and reduced combustion efficiency. Overall, it was the specifics of the combustion process inside a bowl-in-piston chamber not the methane’s slow laminar flame speed that contributed to the low methane combustion efficiency for the retrofitted engine. The results suggest that optimizing the chamber shape is paramount to boost engine efficiency and decrease its emissions.

Influence of fuel volatility on combustion and emission characteristics in a gas turbine combustor at different inlet pressures and swirl conditions

2002 ◽  
Vol 216 (3) ◽  
pp. 257-268 ◽  
Author(s):  
N. Y. Sharma ◽  
S. K. Som
Keyword(s):  
Gas Turbine ◽  
Gas Phase ◽  
Combustion Efficiency ◽  
Inlet Pressure ◽  
Emission Characteristics ◽  
Spray Parameters ◽  
Gas Turbine Combustor ◽  
Spray Cone ◽  
Emission Level ◽  
Inlet Swirl

The practical challenges in research in the field of gas turbine combustion mainly centre around a clean emission, a low liner wall temperature and a desirable exit temperature distribution for turboma-chinery applications, along with fuel economy of the combustion process. An attempt has been made in the present paper to develop a computational model based on stochastic separated flow analysis of typical diffusion-controlled spray combustion of liquid fuel in a gas turbine combustor to study the influence of fuel volatility at different combustor pressures and inlet swirls on combustion and emission characteristics. A κ-ɛ model with wall function treatment for the near-wall region has been adopted for the solution of conservation equations in gas phase. The initial spray parameters are specified by a suitable probability distribution function (PDF) size distribution and a given spray cone angle. A radiation model for the gas phase, based on the first-order moment method, has been adopted in consideration of the gas phase as a grey absorbing-emitting medium. The formation of thermal NO x as a post-combustion reaction process is determined from the Zeldovich mechanism. It has been recognized from the present work that an increase in fuel volatility increases combustion efficiency only at higher pressures. For a given fuel, an increase in combustor pressure, at a constant inlet temperature, always reduces the combustion efficiency, while the influence of inlet swirl is found to decrease the combustion efficiency only at higher pressure. The influence of inlet pressure on pattern factor is contrasting in nature for fuels with lower and higher volatilities. For a higher-volatility fuel, a reduction in inlet pressure decreases the value of the pattern factor, while the trend is exactly the opposite in the case of fuels with lower volatilities. The NOx emission level increases with decrease in fuel volatility at all combustor pressures and inlet swirls. For a given fuel, the NOx emission level decreases with a reduction in combustor pressure and an increase in inlet swirl number.

The Vorbix Burner: A New Approach to Gas Turbine Combustors

1975 ◽  
Author(s):  
S. J. Markowski ◽  
R. P. Lohmann ◽  
R. S. Reilly
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
High Rate ◽  
Rayleigh Instability ◽  
Gas Turbine Combustor ◽  
New Approach ◽  
High Power Operation ◽  
Power Operation ◽  
Definition Of ◽  
Excellent Stability

The vorbix burner (acronym for Vortex Burning and Mixing) represents a new approach to a practical gas turbine combustor design. The concept exploits the Rayleigh instability of swirling flows to enhance the mixing and combustion rates. The combination of a two-stage fuel system with a piloted combustor leads to a unique high rate technique for fuel prevaporization within the combustor proper. This paper presents the fundamental concepts in the definition of the vorbix combustor and the results of exploratory tests conducted on can (tubular) and annular vorbix combustors. The results indicate that this type of combustor has unique performance characteristics that include excellent stability and high combustion efficiency over wide excursions in operating fuel air ratios in addition to substantially reduced emission levels during high power operation.

Comparison of Numerical and Experimental Results of a Premixed DLE Gas Turbine Combustor

2001 ◽  
Author(s):  
Ruud L. G. M. Eggels ◽  
Christopher T. Brown
Keyword(s):  
Reaction Mechanism ◽  
Gas Turbine ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Gas Turbine Combustor ◽  
Cfd Modelling ◽  
Recirculation Length ◽  
Global Reaction ◽  
Presumed Pdf ◽  
Pdf Model

A numerical and experimental study on a premixed DLE gas turbine combustor has been performed. Experiments and CFD modelling have been carried out at isothermal and combusting conditions. The measurements were obtained at ERC using two component Laser Doppler Velocimetry. To be able to access the inner part of the combustor, the liners of the combustion chamber were outfitted with quartz windows. Temperature measurements were obtained at a few planes using a thermocouple. Modelling of the combustor has been performed using an in-house CFD code. The combustion process has been modelled using a global reaction mechanism and a Flame Generated Manifold reaction mechanism in combination with a presumed PDF model to incorporate the effect of turbulent fluctuations. The Flame Generated Manifold method uses a flame library, which has been generated by performing a number of laminar one-dimensional flame calculations at representative conditions. Comparing the numerical and experimental quite some differences are observed. The CFD model is able to predict the main features of the flow and combustion process, but does not predict the recirculation length accurately. Both combustion models, however, are able to predict the low combustion efficiency measured at the 1atm test condition.

Preliminary design and performance analysis of a low emission aero-derived gas turbine combustor

2013 ◽  
Vol 117 (1198) ◽  
pp. 1249-1271 ◽  
Author(s):  
B. Khandelwal ◽  
A. Karakurt ◽  
V. Sethi ◽  
R. Singh ◽  
Z. Quan
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Gas Turbine Combustor ◽  
Detailed Method ◽  
Low Emission ◽  
Heat Shields ◽  
Lean Fuel ◽  
Reduce Emissions ◽  
And Performance

Abstract Modern gas turbine combustor design is a complex task which includes both experimental and empirical knowledge. Numerous parameters have to be considered for combustor designs which include combustor size, combustion efficiency, emissions and so on. Several empirical correlations and experienced approaches have been developed and summarised in literature for designing conventional combustors. A large number of advanced technologies have been successfully employed to reduce emissions significantly in the last few decades. There is no literature in the public domain for providing detailed design methodologies of triple annular combustors. The objective of this study is to provide a detailed method designing a triple annular dry low emission industrial combustor and evaluate its performance, based on the operating conditions of an industrial engine. The design methodology employs semi-empirical and empirical models for designing different components of gas turbine combustors. Meanwhile, advanced DLE methods such as lean fuel combustion, premixed methods, staged combustion, triple annular, multi-passage diffusers, machined cooling rings, DACRS and heat shields are employed to cut down emissions. The design process is shown step by step for design and performance evaluation of the combustor. The performance of this combustor is predicted, it shows that NO x emissions could be reduced by 60%-90% as compared with conventional single annular combustors.

scholarly journals A Model for Bluff Body Flame Stabilization

1986 ◽  
Author(s):  
J. A. De Champlain ◽  
M. F. Bardon
Keyword(s):  
Experimental Data ◽  
Equivalence Ratio ◽  
Bluff Body ◽  
Laminar Flame ◽  
Flame Stabilization ◽  
Effect Of Temperature ◽  
Laminar Flame Speed ◽  
Tabular Form ◽  
Chemical Effects ◽  
Stirred Reactor

Previous work on bluff body stabilization mechanisms is reviewed, and existing models are categorized in tabular form, showing the underlying assumptions and resulting equations. Lacunae in existing models are discussed, particularly their reliance on characteristics such as laminar flame speed which is difficult to predict for the conditions encountered in turbojet afterburners. A model for bluff body flame stabilization is proposed based on the stirred reactor approach. In addition to the effect of temperature, pressure and geometry, it includes chemical effects such as vitiation and fuel-air equivalence ratio. Blow off velocities predicted by the model are compared to experimental data for various conditions.

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