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Clean Air: International Journal on Energy for a Clean Environment

ISSN for PRINT: 1561-4417

Institutional price:	$451.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2005, Volume6

166 pages

DOI: 10.1615/InterJEnerCleanEnv.v6.i3

Issue price - $108.00

TURBULENCE-CHEMISTRY INTERACTION CALCULATIONS FOR IMPROVED NO_x PREDICTIONS

Y. Levy
Faculty of Aerospace Engineering, Technion— Israel Institute of Technology, Haifa, Israel

P. Arfi
Faculty of Aerospace Engineering, Technion— Israel Institute of Technology, Haifa, Israel

ABSTRACT

NO_x predictions in combustion systems are highly dependent on the accuracy of the temperature field inside the combustor and on the accuracy of its chemistry modeling. Turbulence-chemistry interaction affects local temperature, local extinction, and hence flame stability. In the present study, local extinction phenomena as well as the NO_x formation processes were studied based on a perfectly stirred reactor model, modeled by the eddy dissipation concept. The chemical quenching time is calculated using a detailed mechanism for different inlet conditions (temperature, equivalence ratio, and dilution with combustion products). Results of this parametric study show close agreement with the literature. It was observed that at high inlet temperatures, the effect of the fuel air ratio on chemical quenching time is reduced with temperature and becomes nearly insignificant for temperatures higher than about 1200 K. In addition, it appears that the deterioration of flame stability due to air vitiation by combustion products can be counterbalanced by an increase in the air inlet temperature. This is of special interest since the combined effect of an ultralean mixture at increased inlet air temperature together with air vitiation allows stabilizing the combustion process at lower temperatures, and thereby allows for a safe and significant dry NO_x reduction method.