Assessment of the Role of Fuel Autoignition Delay at the Limits of Gas Turbine Combustion and Ignition

2009 ◽  
Author(s):  
Victor Burger ◽  
Andy Yates ◽  
Nicholas Savage ◽  
Owen Metcalf
Keyword(s):  
Gas Turbine ◽  
Laminar Flame ◽  
Chemical Kinetic ◽  
Jet Fuel ◽  
Laminar Flame Speed ◽  
Lean Blowout ◽  
Boiling Points ◽  
Fuel Evaporation ◽  
Autoignition Delay

The influence of fuel autoignition chemistry is known to be relevant when approaching the limits of lean blowout and lean ignition in a continuous combustion environment. This was investigated by employing four reference fuels having very different autoignition delay profiles but similar boiling points to interrogate various test environments and thereby to assess the relevance of the differences in autoignition chemistry. A combustion bomb apparatus was used to characterize the reference fuels together with a sample of commercial Jet A-1 for comparison. The measurements were cross-checked using a chemical kinetic simulation model. A continuous combustion rig was used to study the threshold ignition and blowout performance of the pre-vaporized reference fuels and a laminar flame speed bomb was used to study the influence of autoignition chemistry on normal, stoichiometric combustion and normal ignition conditions. In all the experiments, the results reflected the distinctive differences of the test fuels in terms of their autoignition delay timescales. The findings were interpreted against the background of the commercial jet fuel autoignition chemistry and the relevance of traditional autoignition delay metrics such as Octane or Cetane rating. Notwithstanding the influence of fuel evaporation and mixing timescales which can exert an overriding influence in a practical, gas turbine application, it was concluded that the fuel’s autoignition delay timescale also plays a very significant role in threshold operational situations.

Experimental Investigation of Laminar Flame Speeds for Medium Calorific Gas With Various Amounts of Hydrogen and Carbon Monoxide Content at Gas Turbine Temperatures

2010 ◽  
Author(s):  
Ivan R. Sigfrid ◽  
Ronald Whiddon ◽  
Robert Collin ◽  
Jens Klingmann
Keyword(s):  
Gas Turbine ◽  
Equivalence Ratio ◽  
Room Temperature ◽  
Laminar Flame ◽  
Chemical Kinetic ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Kinetic Mechanisms ◽  
Group A ◽  
Group B

It is expected that, in the future, gas turbines will be operated on gaseous fuels currently unutilized. The ability to predict the range of feasible fuels, and the extent to which existing turbines must be modified to accommodate these fuels, rests on the nature of these fuels in the combustion environment. Understanding the combustion behavior is aided by investigation of syngases of similar composition. As part of an ongoing project at the Lund University Departments of Thermal Power Engineering and Combustion Physics, to investigate syngases in gas turbine combustion, the laminar flame speed of five syngases (see table) have been measured. The syngases examined are of two groups. The first gas group (A), contains blends of H2, CO and CH4, with high hydrogen content. The group A gases exhibit a maximum flame speed at an equivalence ratio of approximately 1.4, and a flame speed roughly four times that of methane. The second gas group (B) contains mixtures of CH4 and H2 diluted with CO2. Group B gases exhibit maximum flame speed at an equivalence ratio of 1, and flame speeds about 3/4 that of methane. A long tube Bunsen-type burner was used and the conical flame was visualized by Schlieren imaging. The flame speeds were measured for a range of equivalence ratios using a constrained cone half-angle method. The equivalence ratio for measurements ranged from stable lean combustion to rich combustion for room temperature (25°C) and an elevated temperature representative of a gas turbine at full load (270°C). The experimental procedure was verified by methane laminar flame speed measurement; and, experimental results were compared against numerical simulations based on GRI 3.0, Hoyerman and San Diego chemical kinetic mechanisms using the DARS v2.02 combustion modeler. On examination, all measured laminar flame speeds at room temperature were higher than values predicted by the aforementioned chemical kinetic mechanisms, with the exception of group A gases, which were lower than predicted.

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.

An experimental and reduced modeling study of the laminar flame speed of jet fuel surrogate components

Fuel ◽  
2013 ◽  
Vol 113 ◽  
pp. 586-597 ◽  
Author(s):  
J.D. Munzar ◽  
B. Akih-Kumgeh ◽  
B.M. Denman ◽  
A. Zia ◽  
J.M. Bergthorson
Keyword(s):  
Laminar Flame ◽  
Jet Fuel ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Reduced Modeling ◽  
Fuel Surrogate ◽  
Modeling Study

scholarly journals Development of a chemical-kinetic database for the laminar flame speed under GDI and water injection engine conditions

2018 ◽  
Vol 148 ◽  
pp. 154-161 ◽  
Author(s):  
Giulio Cazzoli ◽  
Stefania Falfari ◽  
Gian Marco Bianchi ◽  
Claudio Forte
Keyword(s):  
Laminar Flame ◽  
Water Injection ◽  
Chemical Kinetic ◽  
Flame Speed ◽  
Laminar Flame Speed

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.

Ignition Delay Time and Laminar Flame Speed Calculations for Natural Gas/Hydrogen Blends at Elevated Pressures

2012 ◽  
Author(s):  
Marissa Brower ◽  
Eric Petersen ◽  
Wayne Metcalfe ◽  
Henry J. Curran ◽  
Marc Füri ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Chemical Kinetics ◽  
Ignition Delay ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Turbulent Flame ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Hydrogen Addition

Applications of natural gas and hydrogen co-firing have received increased attention in the gas turbine market, which aims at higher flexibility due to concerns over the availability of fuels. While much work has been done in the development of a fuels database and corresponding chemical kinetics mechanism for natural gas mixtures, there are nonetheless few if any data for mixtures with high levels of hydrogen at conditions of interest to gas turbines. The focus of the present paper is on gas turbine engines with primary and secondary reaction zones as represented in the Alstom and Rolls Royce product portfolio. The present effort includes a parametric study, a gas turbine model study, and turbulent flame speed predictions. Using a highly optimized chemical kinetics mechanism, ignition delay times and laminar burning velocities were calculated for fuels from pure methane to pure hydrogen and with natural gas/hydrogen mixtures. A wide range of engine-relevant conditions were studied: pressures from 1 to 30 atm, flame temperatures from 1600 to 2200 K, primary combustor inlet temperature from 300 to 900 K, and secondary combustor inlet temperatures from 900 to 1400 K. Hydrogen addition was found to increase the reactivity of hydrocarbon fuels at all conditions by increasing the laminar flame speed and decreasing the ignition delay time. Predictions of turbulent flame speeds from the laminar flame speeds show that hydrogen addition affects the reactivity more when turbulence is considered. This combined effort of industrial and university partners brings together the know-how of applied, as well as experimental and theoretical disciplines.

Influence of Radiation Reabsorption on Laminar Burning Velocity of Methane Premixed Flame Composed With Steam and Carbon Dioxide

2005 ◽  
Author(s):  
Takumi Ebara ◽  
Norihiko Iki ◽  
Sanyo Takahashi ◽  
Won-Hee Park
Keyword(s):  
Carbon Dioxide ◽  
Gas Turbine ◽  
Laminar Flame ◽  
Burning Velocity ◽  
Chemical Kinetic ◽  
Laminar Burning Velocity ◽  
Premixed Laminar ◽  
Kinetic Calculations ◽  
Reforming Gas ◽  
Radiation Reabsorption

Replacing the Nitrogen with another kind of inert gas such as steam and Carbon dioxide is effective for both reducing NOx and enhancing system efficiency in gas turbine combustor. But the flame properties of such radiative mixture are complicated because of the third body effect and radiation reabsorption. So, we made detailed chemical kinetic calculations including the effect of radiation reabsorption to clarify the premixed laminar flame speed of such mixture as one of the most important properties for controlling the combustion. The concentrations of mixture are varied, and addition of other species such as Carbon monoxide and Hydrogen are also calculated to simulate the utilization of reforming gas and partially oxidized gas. And the pressure was varied up to 5.0 MPa to simulate the 1700 °C class combined gas turbine system. The results show remarkable incensement of laminar burning velocity by considering the radiation reabsorption. Laminar burning velocities were accelerated up to 150% in cases of Methane–Oxygen and steam or Carbon dioxide mixture. It was found that preheating of upstream-unburned mixture caused this acceleration. And the influence of radiation reabsorption was much larger in case of lower pressure.

scholarly journals Chemical kinetic model uncertainty minimization through laminar flame speed measurements

2016 ◽  
Vol 172 ◽  
pp. 136-152 ◽  
Author(s):  
Okjoo Park ◽  
Peter S. Veloo ◽  
David A. Sheen ◽  
Yujie Tao ◽  
Fokion N. Egolfopoulos ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Model Uncertainty ◽  
Laminar Flame ◽  
Chemical Kinetic ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Chemical Kinetic Model ◽  
Uncertainty Minimization
Sign in / Sign up

Export Citation Format

Share Document