Alexander Burcat | Technion Israel Institute of Technology (original) (raw)

Papers by Alexander Burcat

Research paper thumbnail of Kerosene Ignition and Combustion: An experimental and modelling study

The ignition delay time of two JET-A samples obtained at random at two locations (Haifa and Stutt... more The ignition delay time of two JET-A samples obtained at random at two locations (Haifa and Stuttgart) have been investigated in parallel, by two groups of researchers. The experiments carried out in two different shock tube devices covered a temperature range of 1100 to 1900 K at pressures between 2.4 and 6 bar. The four sets of experiments consisting of almost 400 shocks are analyzed, statistically evaluated, and compared with ignition delay experiments for decane. Computer simulation of two surrogate fuel models (i) pure n-decane, (ii) a mixture of 70% n-decane, 30% propylbenzene, are compared to the experimental data. It was found that all measured ignition delay time data can be represented by a single statistical fit. Furthermore, predictions by using pure n-decane as the surrogate fuel match the statistical fit obtained for all the experiments, and explicitly the Stuttgart experiments. A. Introduction Kerosene is the main fuel for all aircrafts, civil and military. Kerosene is a complex fuel containing about 180 individual chemicals. Furthermore, their concentrations and identity change not only according to the source of the fuel, but also according to the refinery where the fuel was distilled. However, in order to cope with the demands of international civil and military aviation, kerosene is the only fuel produced under very strict physical standards defined as Jet-A, Jet A1 and for American Military as JP-4, JP5 etc. (Ranges of boiling point, freezing point, viscosity, polarity, minimum ignition temperature etc. are defined). The chemical composition is not a part of these standards. The physical standards take care of the transport and flow of the jet fuel in the jet aircraft, but the combustion is a function of the chemical components of the fuel. In Fig 1 we present schematically a jet engine combustor. The compressed air at 600 K is flown together with a spray of fuel. The spray vaporizes at very high velocity, within a short time to the gas phase where it is combusted. This information is trivial for aeronautical engineers, but chemists and mechanical engineers have only recently addressed to it [34]. The understanding of how fuels burn and having a computer simulator for the way they release energy is a very important tool in the hands of designers of car and jet engines, rocket engines etc. Without these tools, pollution reduction and increase of efficiencies is problematic. The facts of the real combustion devices are usually not taken into account. Fig 1. Schematic diagram of a jet engine combustion chamber. 400% air flows into the engine at high altitude. The air is compressed aerodynamically by the compressor and its temperature reaches 600 K. 300% of the air flows around the combustion chamber for cooling purposes. Only 100% of the needed air for full combustion of the kerosene enters the combustion chamber at different stages. 12% enter primarily with the fuel spray and causes it to heat and start to evaporate. The droplets travel at high speed and have to fully evaporate before the end of the combustion zone. Droplets that manage to go out of the combustion chamber will hit the turbine and damage it.

Research paper thumbnail of Thermochemical Data for Combustion Calculations

Combustion Chemistry, 1984

Research paper thumbnail of Ideal Gas Thermodynamic Properties of Propellants and Explosive Compounds

Journal of Propulsion and Power, 2000

Research paper thumbnail of The Ideal Gas Thermochemistry of Oxonium Cations

Journal of Chemical & Engineering Data, 2016

Research paper thumbnail of Ideal gas thermodynamic functions of hydrides and deuterides, part 1

Unknown, Jun 1, 1980

Thermochemical tables of some deuterides and their respective hydrides are presented in the JANAF... more Thermochemical tables of some deuterides and their respective hydrides are presented in the JANAF type format for the temperature range 0 to 6000 K. The tables include the following species: D, H, D2, H2, HD, CD, CH, CD2, CH2, CD3, CH3, CD4, CD3H, CD2H2, CDH3, CH4, C2D4, C2H4, C2H6, OD, OH, H20, D20, HDO, CDO and CHO. All the tables are in SI units. NASA type polynomials of the thermodynamic properties are also presented.

Research paper thumbnail of 1994 Ideal Gas Thermodynamic Data for Combustion and Air-Pollutant Use

Research paper thumbnail of Isotope Exchange Rates. V. The Homogeneous Reaction between H2S and D2

The Journal of Chemical Physics

ABSTRACT

Research paper thumbnail of The evolution of a shock wave generated by a point explosion in a combustible medium

Research paper thumbnail of Ideal gas thermodynamic properties for the phenyl, phenoxy, and o-biphenyl radicals

Ideal gas thermodynamicpropertiesof the phenyl and o-blphenylradicals, their deuteratedanalogs an... more Ideal gas thermodynamicpropertiesof the phenyl and o-blphenylradicals, their deuteratedanalogs and the phenoxy radicalwere calculatedto 5000 K o using estimatedvibrationalfrequenciesand structures. The ideal gas thermodynamic propertiesof benzene,blphenyl their deuteratedanalogs and phenol ! were also calculated.

Research paper thumbnail of The Propagation of Blasts from Solid Explosives to two-phase media

Propellants, Explosives, Pyrotechnics, 1978

... The system consisted of a ball explosive charge that was fit into a cubic box of approx. (40)... more ... The system consisted of a ball explosive charge that was fit into a cubic box of approx. (40)3 cm3. ... The explosive-ball was fit into one of the faces of the box, where half a ball is inside the box while the other half is outside it, in the open. ...

Research paper thumbnail of Thermodynamic Properties of Ideal Gas Nitro and Nitrate Compounds

Journal of Physical and Chemical Reference Data, 1999

Research paper thumbnail of Ab initio calculations of carbon-containing species and comparison with group additivity results: Part I. C 5 species

International Journal of Chemical Kinetics, 2007

ABSTRACT

Research paper thumbnail of Cracking of propylene in a shock tube

Fuel, 1975

The high-temperature decomposition of propylene has been investigated in a single-pulse shock tub... more The high-temperature decomposition of propylene has been investigated in a single-pulse shock tube in the temperature range 1160-1700 K. The stable products observed were hydrogen, methane, ethylene, acetylene, ethane, allene and propyne. The rate of evolution of the different products was found to have a similar concentration-dependence except for ethane, which was found to be dependent only on the third-body concentration. A computer model of the kinetics is presented, according to which the first step of the propylene decomposition has a rate constant calorie units) of: k,[Ar] (mol/cm3s) = (10t3+u.5) exp [(-74 f 1) X 103/RT]

Research paper thumbnail of Kinetics of the Ignition of Fuels in Artificial Air Mixtures. II: Oxidation of Propyne

Combustion Science and Technology, 1987

Shock tube measurements of the ignition delay times of propyne-oxygen-nitrogen and propyne-oxygen... more Shock tube measurements of the ignition delay times of propyne-oxygen-nitrogen and propyne-oxygen-argon mixtures are presented. Temperatures in the range of 1125-2000 K are achieved and the reflected pressure varies from 4 to 13 atmospheres.The measured delay times are well correlated by the following overall kinetic equationThe reaction mechanism for propyne-oxygen-nitrogen and propyne-oxygen-argon mixtures is investigated numerically using the routines LSODE and CHEMEQ. This investigation resulted in a kinetic scheme of 68 reactions among 26 species. The agreement between the measured ignition delay times and the numerical calculations is mixed. An overall ignition delay time correlation deduced from the numerical predictions is more similar to experimentally obtained correlations for propane and propene than for propyne.For some of the experimental conditions, a detonation-like pattern is observed after ignition. This phenomenon is investigated by comparing the measurements with calculated Chapman-Jouguet detonation parameters.

Research paper thumbnail of Calculation of the ignition delay times for methaneoxygennitrogen dioxideargon mixtures

Combustion and Flame, 1977

The experimental ignition delay values of methane-oxygen-argon-nitrogen dioxide mixtures publishe... more The experimental ignition delay values of methane-oxygen-argon-nitrogen dioxide mixtures published recently are confirmed and explained in this paper with the help of calculated ignition delay data. Calculation was done using a computer program with 38 reactions whose values were taken from the literature. Only two of these reactions were iteratively fitted and their rates were found to be 2.4 × 1011 cc/mole sec for CH 3 + NO 2 -, NO + CHsO and 1.0 × 1011 cc/mole sec for the CH30 + 02 -~ CH20 + HO 2 reaction.

Research paper thumbnail of Reply to Michael W. Slack's comment

Combustion and Flame, 1977

Research paper thumbnail of High temperature oxidation of propene

Combustion and Flame, 1985

The reaction mechanism for propene---oxygen---argon mixtures is investigated numerically and the ... more The reaction mechanism for propene---oxygen---argon mixtures is investigated numerically and the results compared to the experimental data. ... The numerical calculations are performed with two integration techniques, LSODE and CHEMEQ, converging on a kinetic scheme ...

Research paper thumbnail of Energy Barrier of the cis-trans Isomerization of Difluorodiazine

Journal of the American Chemical Society, 1966

Research paper thumbnail of Kinetics of the reaction NO2 + CO.far.NO + CO2. Single-pulse shock tube studies

The Journal of Physical Chemistry, 1970

... of Composition % - Series shocks NOa GO Ar "6, OK 1095-1300 1137-1304 1080-1262 11 15-13... more ... of Composition % - Series shocks NOa GO Ar "6, OK 1095-1300 1137-1304 1080-1262 11 15-1342 1075-1585 1008-1 2 15 1103-1287 1070-1255 1095-1262 PI, mm 66 270 39 158 38 227 265 120 120 11 11 10 17 16 10 8 17 13 ... (12) B. 3. McBride, S. Heimel, JG Ehlers, and S ...

Research paper thumbnail of Pyrolysis of allene and propyne behind reflected shocks

The Journal of Physical Chemistry, 1976

... Pyrolysis of Allene and Propyne behind Reflected Shocks Assa Lifshitr,* Michael Frenklach,la ... more ... Pyrolysis of Allene and Propyne behind Reflected Shocks Assa Lifshitr,* Michael Frenklach,la Department of Physical Chemistry, The Hebrew University, Jerusalem, lsrael and Alexander Burcat ... 2437 Page 2. 2438 A. Lifshitz, M. Frenklach, and A. Burcat 11. ...

Research paper thumbnail of Kerosene Ignition and Combustion: An experimental and modelling study

The ignition delay time of two JET-A samples obtained at random at two locations (Haifa and Stutt... more The ignition delay time of two JET-A samples obtained at random at two locations (Haifa and Stuttgart) have been investigated in parallel, by two groups of researchers. The experiments carried out in two different shock tube devices covered a temperature range of 1100 to 1900 K at pressures between 2.4 and 6 bar. The four sets of experiments consisting of almost 400 shocks are analyzed, statistically evaluated, and compared with ignition delay experiments for decane. Computer simulation of two surrogate fuel models (i) pure n-decane, (ii) a mixture of 70% n-decane, 30% propylbenzene, are compared to the experimental data. It was found that all measured ignition delay time data can be represented by a single statistical fit. Furthermore, predictions by using pure n-decane as the surrogate fuel match the statistical fit obtained for all the experiments, and explicitly the Stuttgart experiments. A. Introduction Kerosene is the main fuel for all aircrafts, civil and military. Kerosene is a complex fuel containing about 180 individual chemicals. Furthermore, their concentrations and identity change not only according to the source of the fuel, but also according to the refinery where the fuel was distilled. However, in order to cope with the demands of international civil and military aviation, kerosene is the only fuel produced under very strict physical standards defined as Jet-A, Jet A1 and for American Military as JP-4, JP5 etc. (Ranges of boiling point, freezing point, viscosity, polarity, minimum ignition temperature etc. are defined). The chemical composition is not a part of these standards. The physical standards take care of the transport and flow of the jet fuel in the jet aircraft, but the combustion is a function of the chemical components of the fuel. In Fig 1 we present schematically a jet engine combustor. The compressed air at 600 K is flown together with a spray of fuel. The spray vaporizes at very high velocity, within a short time to the gas phase where it is combusted. This information is trivial for aeronautical engineers, but chemists and mechanical engineers have only recently addressed to it [34]. The understanding of how fuels burn and having a computer simulator for the way they release energy is a very important tool in the hands of designers of car and jet engines, rocket engines etc. Without these tools, pollution reduction and increase of efficiencies is problematic. The facts of the real combustion devices are usually not taken into account. Fig 1. Schematic diagram of a jet engine combustion chamber. 400% air flows into the engine at high altitude. The air is compressed aerodynamically by the compressor and its temperature reaches 600 K. 300% of the air flows around the combustion chamber for cooling purposes. Only 100% of the needed air for full combustion of the kerosene enters the combustion chamber at different stages. 12% enter primarily with the fuel spray and causes it to heat and start to evaporate. The droplets travel at high speed and have to fully evaporate before the end of the combustion zone. Droplets that manage to go out of the combustion chamber will hit the turbine and damage it.

Research paper thumbnail of Thermochemical Data for Combustion Calculations

Combustion Chemistry, 1984

Research paper thumbnail of Ideal Gas Thermodynamic Properties of Propellants and Explosive Compounds

Journal of Propulsion and Power, 2000

Research paper thumbnail of The Ideal Gas Thermochemistry of Oxonium Cations

Journal of Chemical & Engineering Data, 2016

Research paper thumbnail of Ideal gas thermodynamic functions of hydrides and deuterides, part 1

Unknown, Jun 1, 1980

Thermochemical tables of some deuterides and their respective hydrides are presented in the JANAF... more Thermochemical tables of some deuterides and their respective hydrides are presented in the JANAF type format for the temperature range 0 to 6000 K. The tables include the following species: D, H, D2, H2, HD, CD, CH, CD2, CH2, CD3, CH3, CD4, CD3H, CD2H2, CDH3, CH4, C2D4, C2H4, C2H6, OD, OH, H20, D20, HDO, CDO and CHO. All the tables are in SI units. NASA type polynomials of the thermodynamic properties are also presented.

Research paper thumbnail of 1994 Ideal Gas Thermodynamic Data for Combustion and Air-Pollutant Use

Research paper thumbnail of Isotope Exchange Rates. V. The Homogeneous Reaction between H2S and D2

The Journal of Chemical Physics

ABSTRACT

Research paper thumbnail of The evolution of a shock wave generated by a point explosion in a combustible medium

Research paper thumbnail of Ideal gas thermodynamic properties for the phenyl, phenoxy, and o-biphenyl radicals

Ideal gas thermodynamicpropertiesof the phenyl and o-blphenylradicals, their deuteratedanalogs an... more Ideal gas thermodynamicpropertiesof the phenyl and o-blphenylradicals, their deuteratedanalogs and the phenoxy radicalwere calculatedto 5000 K o using estimatedvibrationalfrequenciesand structures. The ideal gas thermodynamic propertiesof benzene,blphenyl their deuteratedanalogs and phenol ! were also calculated.

Research paper thumbnail of The Propagation of Blasts from Solid Explosives to two-phase media

Propellants, Explosives, Pyrotechnics, 1978

... The system consisted of a ball explosive charge that was fit into a cubic box of approx. (40)... more ... The system consisted of a ball explosive charge that was fit into a cubic box of approx. (40)3 cm3. ... The explosive-ball was fit into one of the faces of the box, where half a ball is inside the box while the other half is outside it, in the open. ...

Research paper thumbnail of Thermodynamic Properties of Ideal Gas Nitro and Nitrate Compounds

Journal of Physical and Chemical Reference Data, 1999

Research paper thumbnail of Ab initio calculations of carbon-containing species and comparison with group additivity results: Part I. C 5 species

International Journal of Chemical Kinetics, 2007

ABSTRACT

Research paper thumbnail of Cracking of propylene in a shock tube

Fuel, 1975

The high-temperature decomposition of propylene has been investigated in a single-pulse shock tub... more The high-temperature decomposition of propylene has been investigated in a single-pulse shock tube in the temperature range 1160-1700 K. The stable products observed were hydrogen, methane, ethylene, acetylene, ethane, allene and propyne. The rate of evolution of the different products was found to have a similar concentration-dependence except for ethane, which was found to be dependent only on the third-body concentration. A computer model of the kinetics is presented, according to which the first step of the propylene decomposition has a rate constant calorie units) of: k,[Ar] (mol/cm3s) = (10t3+u.5) exp [(-74 f 1) X 103/RT]

Research paper thumbnail of Kinetics of the Ignition of Fuels in Artificial Air Mixtures. II: Oxidation of Propyne

Combustion Science and Technology, 1987

Shock tube measurements of the ignition delay times of propyne-oxygen-nitrogen and propyne-oxygen... more Shock tube measurements of the ignition delay times of propyne-oxygen-nitrogen and propyne-oxygen-argon mixtures are presented. Temperatures in the range of 1125-2000 K are achieved and the reflected pressure varies from 4 to 13 atmospheres.The measured delay times are well correlated by the following overall kinetic equationThe reaction mechanism for propyne-oxygen-nitrogen and propyne-oxygen-argon mixtures is investigated numerically using the routines LSODE and CHEMEQ. This investigation resulted in a kinetic scheme of 68 reactions among 26 species. The agreement between the measured ignition delay times and the numerical calculations is mixed. An overall ignition delay time correlation deduced from the numerical predictions is more similar to experimentally obtained correlations for propane and propene than for propyne.For some of the experimental conditions, a detonation-like pattern is observed after ignition. This phenomenon is investigated by comparing the measurements with calculated Chapman-Jouguet detonation parameters.

Research paper thumbnail of Calculation of the ignition delay times for methaneoxygennitrogen dioxideargon mixtures

Combustion and Flame, 1977

The experimental ignition delay values of methane-oxygen-argon-nitrogen dioxide mixtures publishe... more The experimental ignition delay values of methane-oxygen-argon-nitrogen dioxide mixtures published recently are confirmed and explained in this paper with the help of calculated ignition delay data. Calculation was done using a computer program with 38 reactions whose values were taken from the literature. Only two of these reactions were iteratively fitted and their rates were found to be 2.4 × 1011 cc/mole sec for CH 3 + NO 2 -, NO + CHsO and 1.0 × 1011 cc/mole sec for the CH30 + 02 -~ CH20 + HO 2 reaction.

Research paper thumbnail of Reply to Michael W. Slack's comment

Combustion and Flame, 1977

Research paper thumbnail of High temperature oxidation of propene

Combustion and Flame, 1985

The reaction mechanism for propene---oxygen---argon mixtures is investigated numerically and the ... more The reaction mechanism for propene---oxygen---argon mixtures is investigated numerically and the results compared to the experimental data. ... The numerical calculations are performed with two integration techniques, LSODE and CHEMEQ, converging on a kinetic scheme ...

Research paper thumbnail of Energy Barrier of the cis-trans Isomerization of Difluorodiazine

Journal of the American Chemical Society, 1966

Research paper thumbnail of Kinetics of the reaction NO2 + CO.far.NO + CO2. Single-pulse shock tube studies

The Journal of Physical Chemistry, 1970

... of Composition % - Series shocks NOa GO Ar "6, OK 1095-1300 1137-1304 1080-1262 11 15-13... more ... of Composition % - Series shocks NOa GO Ar "6, OK 1095-1300 1137-1304 1080-1262 11 15-1342 1075-1585 1008-1 2 15 1103-1287 1070-1255 1095-1262 PI, mm 66 270 39 158 38 227 265 120 120 11 11 10 17 16 10 8 17 13 ... (12) B. 3. McBride, S. Heimel, JG Ehlers, and S ...

Research paper thumbnail of Pyrolysis of allene and propyne behind reflected shocks

The Journal of Physical Chemistry, 1976

... Pyrolysis of Allene and Propyne behind Reflected Shocks Assa Lifshitr,* Michael Frenklach,la ... more ... Pyrolysis of Allene and Propyne behind Reflected Shocks Assa Lifshitr,* Michael Frenklach,la Department of Physical Chemistry, The Hebrew University, Jerusalem, lsrael and Alexander Burcat ... 2437 Page 2. 2438 A. Lifshitz, M. Frenklach, and A. Burcat 11. ...