Shock Tube Studies on the Ignition Delay of Methane at Elevated Temperatures

Shock Tube Studies on the Ignition Delay of Methane at Elevated Temperatures PDF Author: R. Ravi Kumar
Publisher:
ISBN:
Category :
Languages : en
Pages : 476

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Shock Tube Studies on the Ignition Delay of Methane at Elevated Temperatures

Shock Tube Studies on the Ignition Delay of Methane at Elevated Temperatures PDF Author: R. Ravi Kumar
Publisher:
ISBN:
Category :
Languages : en
Pages : 476

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Shock Tube and Mid-infrared Laser Absorption Measurements of Ignition Delay Times and Species Time-histories

Shock Tube and Mid-infrared Laser Absorption Measurements of Ignition Delay Times and Species Time-histories PDF Author: Batikan Koroglu
Publisher:
ISBN:
Category :
Languages : en
Pages : 120

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The dissertation discusses the details of the four following items: 1) design, assembly, and testing of a shock tube setup as well as a laser diagnostics apparatus for studying ignition characteristics of fuels and associated reaction rates, 2) measurements of methane and propanal infrared spectra at room and high temperatures using a Fourier Transformed Infrared Spectrometer (FTIR) and a shock tube , 3) measurements of ignition delay times and reaction rates during propanal thermal decomposition and ignition, and 4) investigation of ignition characteristics of methane during its combustion in carbon-dioxide diluted bath gas. The main benefit and application of this work is the experimental data which can be used in future studies to constrain reaction mechanism development.

An Experimental Study Into the Ignition of Methane and Ethane Blends in a New Shock-tube Facility

An Experimental Study Into the Ignition of Methane and Ethane Blends in a New Shock-tube Facility PDF Author: Christopher Joseph Erik Aul
Publisher:
ISBN:
Category :
Languages : en
Pages :

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A new shock tube targeting low temperature, high pressure, and long test times was designed and installed at the Turbomachinery Laboratory in December of 2008. The single-pulse shock tube uses either lexan diaphragms or die-scored aluminum disks of up to 4 mm in thickness. The modular design of the tube allows for optimum operation over a large range of thermodynamic conditions from 1 to 100 atm and between 600-4000 K behind the reflected shock wave. The new facility allows for ignition delay time, chemical kinetics, high-temperature spectroscopy, vaporization, atomization, and solid particulate experiments. An example series of ignition delay time experiments was made on mixtures of CH4/C2H6/O2/Ar at pressures from 1 to 30.7 atm, intermediate temperatures from 1082 to 2248 K, varying dilutions (between 75 and 98% diluent), and equivalence ratios ranging from fuel lean (0.5) to fuel rich (2.0) in this new facility. The percentage by volume variation and equivalence ratios for the mixtures studied were chosen to cover a wide parameter space not previously well studied. Results are then used to validate and improve a detailed kinetics mechanism which models the oxidation and ignition of methane and other higher order hydrocarbons, through C4, with interest in further developing reactions important to methane- and ethane-related chemistry.

Methane and Dimethyl Ether Oxidation at Elevated Temperatures and Pressure

Methane and Dimethyl Ether Oxidation at Elevated Temperatures and Pressure PDF Author: Christopher Michael Zinner
Publisher:
ISBN:
Category : Gas-turbines
Languages : en
Pages : 65

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Book Description
Autoignition and oxidation of two Methane (CH4) and Dimethyl Ether (CH3OCH3 or DME) mixtures in air were studied in shock tubes over a wide range of equivalence ratios at elevated temperatures and pressures. These experiments were conducted in the reflected shock region with pressures ranging from 0.8 to 35.7 atmospheres, temperatures ranging from 913 to 1650 K, and equivalence ratios of 2.0, 1.0, 0.5, and 0.3. Ignition delay times were obtained from shock-tube endwall pressure traces for fuel mixtures of CH4/CH3OCH3 in ratios of 80/20 percent volume and 60/40 percent volume, respectively. Close examination of the data revealed that energy release from the mixture is occurring in the time between the arrival of the incident shock wave and the ignition event. An adjustment scheme for temperature and pressure was devised to account for this energy release and its effect on the ignition of the mixture. Two separate ignition delay correlations were developed for these pressure- and temperature-adjusted data. These correlations estimate ignition delay from known temperature, pressure, and species mole fractions of methane, dimethyl ether, and air (0.21 O2 + 0.79 N2). The first correlation was developed for ignition delay occurring at temperatures greater than or equal to 1175 K and pressures ranging from 0.8 to 35.3 atm. The second correlation was developed for ignition delay occurring at temperatures less than or equal to 1175 K and pressures ranging from 18.5 to 40.0 atm. Overall good agreement was found to exist between the two correlations and the data of these experiments. Findings of these experiments also include that with pressures at or below ten atm, increased concentrations of dimethyl ether will consistently produce faster ignition times. At pressures greater than ten atmospheres it is possible for fuel rich mixtures with lower concentrations of dimethyl ether to give the fastest ignition times. This work represents the most thorough shock tube investigation for oxidation of methane with high concentration levels of dimethyl ether at gas turbine engine relevant temperatures and pressures. The findings of this study should serve as a validation for detailed chemical kinetics mechanisms.

High Temperature Shock Tube Ignition Studies of CO2́2 Diluted Mixtures

High Temperature Shock Tube Ignition Studies of CO2́2 Diluted Mixtures PDF Author: Owen Marcus Pryor
Publisher:
ISBN:
Category :
Languages : en
Pages : 66

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Book Description
Experimental data for ignition delay times and species time-histories (CH4) were obtained in mixtures diluted with CO2. Experiments were performed behind reflected shockwaves from temperatures of 1200 to 2000 K for pressures ranging from 1 to 11 atm. Ignition times were obtained from emission and laser absorption measurements. Current experimental data were compared with the predictions of detailed chemical kinetic models (available from literature) that will allow for accurate design and modeling of combustion systems.

Shock-tube Investigation of Ignition Delay Times of Blends of Methane and Ethane with Oxygen

Shock-tube Investigation of Ignition Delay Times of Blends of Methane and Ethane with Oxygen PDF Author: Brian Christopher Walker
Publisher:
ISBN:
Category :
Languages : en
Pages : 98

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Book Description
The combustion behavior of methane and ethane is important to the study of natural gas and other alternative fuels that are comprised primarily of these two basic hydrocarbons. Understanding the transition from methane-dominated ignition kinetics to ethane-dominated kinetics for increasing levels of ethane is also of fundamental interest toward the understanding of hydrocarbon chemical kinetics. Much research has been conducted on the two fuels individually, but experimental data of the combustion of blends of methane and ethane is limited to ratios that recreate typical natural gas compositions (up to ~20% ethane molar concentration). The goal of this study was to provide a comprehensive data set of ignition delay times of the combustion of blends of methane and ethane at near atmospheric pressure.

Combustion Chemistry

Combustion Chemistry PDF Author: W. C. Jr. Gardiner
Publisher: Springer Science & Business Media
ISBN: 1468401866
Category : Science
Languages : en
Pages : 515

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Book Description
Detailed study of the rates and mechanisms of combustion reactions has not been in the mainstream of combustion research until the recent recognition that further progress in optimizing burner performance and reducing pollutant emission can only be done with fundamental understanding of combustion chemistry. This has become apparent at a time when our understanding of the chemistry, at least of small-molecule combustion, and our ability to model combustion processes on large computers have developed to the point that real confidence can be placed in the results. This book is an introduction for outsiders or beginners as well as a reference work for people already active in the field. Because the spectrum of combustion scientists ranges from chemists with little computing experience to engineers who have had only one college chemistry course, everything needed to bring all kinds of beginners up to the level of current practice in detailed combustion modeling is included. It was a temptation to include critical discussions of modeling results and computer programs that would enable outsiders to start quickly into problem solving. We elected not to do either, because we feel that the former are better put into the primary research literature and that people who are going to do combustion modeling should either write their own programs or collaborate with experts. The only exception to this is in the thermochemical area, where programs have been included to do routine fitting operations. For reference purposes there are tables of thermochemical, transport-property, and rate coefficient data.

Combustion Measurements

Combustion Measurements PDF Author: Norman Chigier
Publisher: CRC Press
ISBN: 9781560320289
Category : Technology & Engineering
Languages : en
Pages : 556

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Book Description
The book begins with an introduction to the general problems of making measurements in high temperature and a presentation of chemically reacting flow systems. It describes each instrument with the various diagnostic techniques and discusses measurements that have been made in furnaces, flames, and rocket engines. The detailed measurement techniques described in this book cover a wide spectrum of applications in combustion systems, including gas turbine, rocket measurement techniques that were developed in laboratories. Information obtained on detailed temperature, velocity, particle size, and gas concentration distribution is leading to improve understanding of the chemical combustion process and to design imporvements in combustors.

A Shock Tube Study of the Ignition Delay of Hydrogen-air Mixtures Mear the Second Explosion Limit

A Shock Tube Study of the Ignition Delay of Hydrogen-air Mixtures Mear the Second Explosion Limit PDF Author: Roger Ronald Craig
Publisher:
ISBN:
Category : Shock tubes
Languages : en
Pages : 62

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Numerical Study of Shock-induced Combustion in Methane-air Mixtures

Numerical Study of Shock-induced Combustion in Methane-air Mixtures PDF Author: Shaye Yungster
Publisher:
ISBN:
Category : Detonation waves
Languages : en
Pages : 18

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