Fire Plume Along Vertical Surfaces: Effect of Finite-Rate Chemical Reactions

1984 ◽  
Vol 106 (4) ◽  
pp. 713-720 ◽  
Author(s):  
C. H. Chen ◽  
J. S. T’ien
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Chemical Reactions ◽  
Vertical Wall ◽  
Fire Plume ◽  
Gas Phase Reactions ◽  
Finite Rate ◽  
Slowing Down ◽  
Kinetic Rates ◽  
Relative Kinetic

Fire plume along a vertical wall is analyzed using a laminar boundary layer model, including finite-rate, gas-phase chemical kinetics. The chemical reactions include two semiglobal steps: In the first, fuel is oxidized to form carbon monoxide and water vapor, and in the second, carbon monoxide is oxidized to form carbon dioxide. Several important nondimensional kinetic parameters are identified and a parametric study is given. The computed results indicate that by slowing down the relative kinetic rates in the gas-phase reactions, the total surface heat transfer rate and the preheating distance are decreased. Furthermore, slowing down the kinetics also increases the amount of unreacted combustibles that escape from the flame.

The Gas Phase Reactions of Recoil Sulfur Atoms with Carbon Monoxide and Carbon Dioxide1

1964 ◽  
Vol 68 (2) ◽  
pp. 318-322 ◽  
Author(s):  
Edward K. C. Lee ◽  
Y. N. Tang ◽  
F. S. Rowland
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Gas Phase Reactions

Laboratory measurements of gas‐phase reactions of polyatomic carbon ions C+n(n=1–6) and CnH+(n=2–5) with carbon monoxide

1987 ◽  
Vol 87 (12) ◽  
pp. 6934-6938 ◽  
Author(s):  
Diethard K. Bohme ◽  
Stanisl/aw Wl/odek ◽  
Leslie Williams ◽  
Leonard Forte ◽  
Arnold Fox
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Carbon Ions ◽  
Laboratory Measurements ◽  
Gas Phase Reactions

The Role of Starting Potential in the Kinetics of Chemical Reactions under Electrodeless Discharge

1970 ◽  
Vol 25 (11) ◽  
pp. 1772
Author(s):  
T.S.R Ao ◽  
A. Patil
Keyword(s):  
Gas Phase ◽  
Chemical Reactions ◽  
Electric Discharge ◽  
Specific Rate ◽  
Gas Phase Reactions ◽  
Electrodeless Discharge ◽  
First Order ◽  
Kinetics Of

Abstract It has been shown that in kinetically first order gas phase reactions occuring under electric discharge, such as the decomposition of N2O, the application, at various initial pressures, of the same multiple of the respective starting potential ensures that the reaction occurs at the same specific rate.

scholarly journals Astrochemistry of Interstellar Clouds: II. Molecular Formation in a Contracting Cloud

1987 ◽  
Vol 120 ◽  
pp. 273-274
Author(s):  
M.A. El Shalaby ◽  
A. Aiad
Keyword(s):  
Gas Phase ◽  
Optical Depth ◽  
Chemical Reactions ◽  
Particle Density ◽  
Interstellar Cloud ◽  
Gas Phase Reactions ◽  
Interstellar Clouds ◽  
Continous Function ◽  
Molecular Formation ◽  
Self Gravity

The chemistry of an 667 Mo interstellar cloud was studied using 142 reactions for 40 species during the contraction under self gravity in two steps. At first the contraction is allowed without gas phase reactions untill certain optical depth is reached. Secondly, at this optical depth the chemical reactions are started for sufficient cycles in a time dependant scheme till only very small additionally changes in the abundances occur. The so obtained, relative abundances and coulmn densities for different species represent a continous function of the optical depths. The values arround τ=6.3 represent the observations for H2, H2+, H3+, OH, OH+, CH, CH+, CH2, CH2+, CH3+, H2O and H3O+. The region of τ between 1 and 5 i.e. of particle density between 4 102–6 103 is the preferable formation place for the majority of molecules.

Gas-Phase Reactions between Diborane and Carbon Monoxide:  A Theoretical Study

2003 ◽  
Vol 107 (46) ◽  
pp. 9974-9983 ◽  
Author(s):  
Shao-Wen Hu ◽  
Yi Wang ◽  
Xiang-Yun Wang ◽  
Ti-Wei Chu ◽  
Xin-Qi Liu
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Theoretical Study ◽  
Gas Phase Reactions

Global minimum profile error (GMPE) – a least-squares-based approach for extracting macroscopic rate coefficients for complex gas-phase chemical reactions

2018 ◽  
Vol 20 (2) ◽  
pp. 1231-1239 ◽  
Author(s):  
Minh v. Duong ◽  
Hieu T. Nguyen ◽  
Tam V.-T. Mai ◽  
Lam K. Huynh
Keyword(s):  
Master Equation ◽  
Least Squares ◽  
Gas Phase ◽  
Chemical Reactions ◽  
Global Minimum ◽  
Rate Coefficients ◽  
Gas Phase Reactions ◽  
Profile Error ◽  
Time Resolved ◽  
Phase Chemical

The new GMPE method was introduced to derive the macroscopic rate coefficients for complex gas-phase reactions from the time-resolved species profiles obtained from the master equation (ME) solutions.

Gas Phase Reactions in Horizontal MOCVD Reactors

1987 ◽  
Vol 94 ◽  
Author(s):  
Hitoshi Tanaka ◽  
J. Komeno
Keyword(s):  
Steady State ◽  
Gas Phase ◽  
Chemical Reactions ◽  
Chemical Species ◽  
Kinetic Simulation ◽  
Gas Phase Reactions ◽  
Mocvd Reactor

ABSTRACTWe have applied kinetic simulation to MOCVD chemistry in a horizontal MOCVD reactor. Both chemical reactions and material diffusion are considered. For trimethylgallium decomposition, concentrations of chemical species reach their steady state values which differ largely from the equilibrium values.

Methylene II. Gas phase reactions with ethyl chloride

1968 ◽  
Vol 306 (1485) ◽  
pp. 135-158 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Energy Content ◽  
Incident Light ◽  
Hydrogen Abstraction ◽  
Relative Concentration ◽  
Radical Mechanism ◽  
Gas Phase Reactions ◽  
Free Radical Mechanism ◽  
Singlet Methylene

In this work methylene was prepared by the photolysis of ketene, and the experiments include observations of the effects of changing the wavelength of the photolysing light and of introducing foreign gases. Results are consistent with a free-radical mechanism in which CH 2 abstracts a chlorine or a hydrogen atom from C 2 H 5 Cl: CH 2 +CH 3 CH 2 Cl→ k cl ĊH 2 Cl+CH 3 ĊH 2 , CH 2 +CH 3 CH 2 Cl→ k h1 ĊH 3 +ĊH 3 CH 3 Cl, } CH 2 +CH 3 CH 2 Cl→ k H2 ĊH 3 +CH 3 ċHCl. } ( k H ) All the fourteen products of the radical recombinations have been identified. Disproportionation of radicals and decomposition of excited molecules formed by recombinations yield additional products. Methylene insertion does not appear to play a significant role. When the incident light contains wavelengths in the region 2450 to 4000Å we find that k Cl / k H =1·62, k H1 / k H2 =0·098. If shorter wavelengths are excluded, or if nitrogen is added, lower values of k Cl / k H are obtained. On the other hand, in the presence of carbon monoxide the value of k Cl / k H may be greatly increased. It is suggested that these findings are attributable to differences in reactivity between singlet and triplet methylene. At longer wavelengths, or when nitrogen is present, the relative concentration of the singlet is reduced, but in the presence of carbon monoxide the triplet is removed preferentially (De Graff & Kistiakowsky 1967). Singlet methylene appears to be highly discriminating in its reactions, abstracting chlorine preferentially, while the triplet discriminates in favour of hydrogen abstraction. A kinetic analysis based on these ideas and consistent with the experimental observations shows that k S Cl / k S H >16·3, k T Cl / k T H <0·14. The selectivities shown by the two species of methylene are thought to be a result of differences in electronic structure rather than energy content.

scholarly journals Crossed-beam chemical reaction dynamics probed with universal and state resolved ion imaging

2018 ◽  
Author(s):  
◽  
Alexander Kamasah
Keyword(s):  
Gas Phase ◽  
Chemical Reactions ◽  
Chemical Reaction ◽  
Reaction Dynamics ◽  
Reaction Cross ◽  
Translational Energy ◽  
Gas Phase Reactions ◽  
Chemical Reaction Dynamics ◽  
Products Of Reaction ◽  
State Selection

The main goal of chemical reaction dynamics is to unravel the intimate motions of individual atoms during a chemical transformation. This information must generally be inferred from indirect macroscopic measurement. Very important information such as translational energy dependence of the reaction cross-section, vibrational mode-specific promotion of reactivity, product angular and velocity distributions are normally extracted. Understanding how these chemical reactions occur at the microscopic level gives us a better insight in understanding reactive intermediates and products of reaction. For a better understanding of the elementary chemical reactions, it is imperative that the studies are performed under well-defined laboratory conditions. Over the last few decades, the field has witnessed unprecedented advances in both experiment and theory. Advancements in generating reactants, state selection, improvement of crossed-molecular beam machines and products detection have gone a long way to improve our ability in studying chemical reactions in the gas phase. In 1986, Hershbach,[1] Lee[2] , and Polayni[3] together shared the Nobel Prize in Chemistry for their work on the dynamics of gas phase reactions.

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