A set of combustion relcvant rate coefficients recommended by a group of European kincticists has been tested by calculating laminar burning velocities. Virtually without any adjustments, a good match with cxperirnental data has been achieved for H2/air flames, H2/CO/air flames, and CHJair flamcs. In ordcr to extend this set by inclusion of the reactions forming the CH,OH oxidation subsystem, the current knowledge of these reactions if first reviewed. The extended set yields calculated burning velocities for CH?OH/air flames in good agreement with measurements recently obtained under stretch free conditions. By using a sensitivity analysis, the remaining deficiencies of the model are highlighted and it is made clear where further experimental work is particularly needed.
The temperature inside the cylinder of a methanol‐fuelled single‐cylinder research engine running under knocking conditions is measured by means of Coherent Anti‐Stokes Raman Scattering (CARS) spectroscopy, and the pressure is measured with a piezoelectric transducer. In order to obviate any errors arising from possible deficiencies in the spectral scaling laws which are commonly used to represent nitrogen Q‐branch CARS spectra at high pressure, a purely experimental technique is employed to derive temperatures from CARS spectra by cross‐correlation with a reference library of spectra recorded in an accurately calibrated high‐pressure high‐temperature optical cell. — The temperature and pressure profiles measured in the running engine are then used as input data for chemical kinetic modeling of the endgas autoignition. Exactly the same exhaustive chemical mechanism and exactly the same rate coefficient expressions are used for the autoignition modeling as are employed in Part I [1] for the modeling of methanol flame velocities. A good qualitative understanding of the mechanism underlying endgas autoignition in the engine can be obtained, although the calculated autoignition point occurs slightly earlier than the observed point. — The importance in the autoignition mechanism of hydroperoxyl radical reactions and of the thermal decomposition of hydrogen peroxide is demonstrated by means of a sensitivity analysis. – For purposes of comparison, the autoignition modeling is also undertaken using earlier reaction schemes and rate coefficient data, notably those of Grotheer and Kelm (1989), Norton and Dryer (1989), Esser and Warnatz (1987), and Dove and Warnatz (1983). The discrepancies between results of the various models can be understood in terms of a very small number of sensitive reactions for which there are conflicting kinetic data.
The normal temperatures are calculated for an optical thin plasma which is not in local thermodynamic equilibrium. The following cases are investigated: 1. The normal temperatures for spectral lines of neutral atoms, 2. The normal temperatures for ion-lines. Further there was distinguished between lines of which the upper energy levels were higher or lower than the "thermal limit". Formulae for the normal temperatures could be derived for all important cases. The method determining electron-temperatures by finding the normal-temperatures can now be used also for plasmas which are not in LTE.
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