摘要:

An examination has been conducted of the oxidation of iso-butylene and an iso-butylene/n-octane mixture at 1080 K and one atmosphere. It was found that the addition of iso-butylene to n-octane results in a delay in the formation of CO and CO2even ifenough additional O2is added to maintain a n overall equivalence ratio of one. Analysis of the oxidation of iso-butylene alone suggests that the inhibiting effect of iso-butylene addition results from a reduction in radical concentrations due to the abstraction reactions of the radicals with the iso-butylene to yield unreactive methyl radicaland allene.

ISSN:0010-2202    

DOI:10.1080/00102208608923853

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Ion/molecule reaction pathways and reaction rate coefficients for both cyclic (cyclo-propenylium) and linear (propargylium) C3H3isomers reacting with aromatic hydrocarbons (benzene, toluene, indene, naphthalene, 1 - and 2-methyl naphthalenes) and alcohols (methanol, ethanol, n-butanol) at low pressures and near room temperature have been determined using ion cyclotron resonance (icr) mass spectrometric techniques. Rate coefficients near the Langevin limit were found for reactions of the propargylium isomer with most of the aromatic hydrocarbons, with charge and hydride transfer reactions predominating. Somewhat lou,er rate coefficients were determined for reactions of the propargylium isomer with the three alcohols, with proton, hydride, and OH-transfer representing the major reaction channels. Implications of these results for an ionic soot formation mechanism are discussed.

ISSN:0010-2202    

DOI:10.1080/00102208608923854

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The combustion of an idealized "pancake-shaped" natural gas and air fuel cloud mixture (height=30 m, diameter ∼800 m) with central ignition on the ground is described for a high burning velocity flame. The induced overpressures, velocities, and temperatures are predicted in a two-dimensional axisymmetric geometry using a n Eulerian code which solves the dynamic multiphase equations of motion with a n implicit finite difference technique. The maximum predicted name speed (85 m /s) and overpressure (100 mbar) occur at ∼I s after ignition which corresponds to the initiation of upper fuel boundary burnout when the ∼3 m thick flame has reached a height and radius of ∼60 m. Buoyancy forces and inward acceleration of combustion products cause the formation of a strong vortex flow field. Peak upward velocities of ∼185 m/s are predicted at ∼=9.5 s.

ISSN:0010-2202    

DOI:10.1080/00102208608923855

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Wehave performed coherent anti-Stokes Raman scattering (CARS)measurements of acetylene in a laminarCH4/C2H2/air flame. The acetyleneconcentration was determined from the ratio of the resonant acetyleneCARS signal to the nonresonant background CARS signal. The resonantand nonresonant signals were detected separately on each laser shotusing polarization analysis and a two-channel detection system. Theflame temperature profile was determined from fits of nitrogen CARSspectra. Experimental acetylene CARS spectra are compared with theoretical spectra.

ISSN:0010-2202    

DOI:10.1080/00102208608923856

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The work sets out to determine a suitable analytical model to represent the decay of axial velocity from underexpanded sonic jets. Experiments are carried out using shadowgraphy and laser Doppler anemometry to determine the near field jet structure and the axial velocity distribution for the complete field down to 30 mls over a range of exit nozzle diameters, exit pressure ratios and jet gases. Comparisons are made with existing data and the best models available for fully expanded jets. It is shown that the decay law proposed by Kleinstein, with suitable choice of parameters, gives a good representation when the exit diameter is modified by the exit pressure ratio.

ISSN:0010-2202    

DOI:10.1080/00102208608923857

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A computer model has been developed to describe heat and mass transfer in the vicinity of a single reacting coal particle entrained in a laminar gas stream. The model describes the various processes that occur during devolatilization and combustion in the boundary layer between the particle surface and the bulk gas stream. Global reaction rates are used in the gas phase, with light and heavy volatiles represented by methane and benzene. Although the model was developed for a two-dimensional treatment. one-dimensional simulations are shown to yield meaningful results at low particle Reynolds numbers. Simulations indicate that the region of homogeneous volatiles combustion may extend for several particle diameters, implying that flame sheet approximations are not applicable during devolatilization. Parametric studies indicate that particle heating is dominated by homogeneous volatiles combustion for large particles and by heterogeneous reaction for small particles.

ISSN:0010-2202    

DOI:10.1080/00102208608923858

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0010-2202    

DOI:10.1080/00102208608923859

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Long continuous strips of unburned crowns sometimes remain in the aftermath of a high-intensity fire in forest stands that otherwise are completely burned out (understory and overstory) with respect to their thin-fuel loading. A physical mechanism is proposed to explain this observation: occasional lulls in the strong winds that virtually invariably occur in connection with active crown fires. An observational effort that could yield evidence to support the proposal is discussed.

ISSN:0010-2202    

DOI:10.1080/00102208608923860

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Numerical results reported in the literature for burning velocities of steady one-dimensional, planar,adiabatic flames with two reactants and irreversible one-step reaction are systematically compared to results obtained by activation-energy asymptotics. In particular. hydrogen/air and methane/air flames are considered over a wide range of stoichiometries. For these flames the accuracy of the asymptotic solution in the first and second approximation is determined explicitly as a function of the Zel'dovich number and of the equivalence ratio.

ISSN:0010-2202    

DOI:10.1080/00102208608923861

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor