Dynamic effects of autoignition centers for hydrogen and C1,2-hydrocarbon fuels

Department

Mechanical Engineering

Document Type

Article

Publication Title

Symposium (International) on Combustion

ISSN

0082-0784

Volume

22

Issue

1

DOI

10.1016/S0082-0784(89)80181-X

First Page

1683

Last Page

1693

Publication Date

1-1-1989

Abstract

A chemical kinetics model is used to compute the dynamics of a local autoignition center in a combustible mixture. Such centers arise from inhomogeneities in the bulk mixture and ignite earlier than the surrounding mixture. The model of an exothermic center considers a small, homogeneous mass of reacting mixture that is surrounded by an inert mixture. The model combines energy and species equations for the reacting mixture with a gas dynamic constraint for the expansion of the exploding center. The induction time, the time of chemical energy release, and the exothermic energy and power of the centers are evaluated for a variety of stoichiometric fuel-air mixtures. Fuels include hydrogen, methane, acetylene, ethylene, and ethane. An important dynamic effect of the center is the compression wave it produces in the surrounding mixture. The computations show that compression ratios of 1.2 to 1.8 are produced by a center in these fuels at high pressure. © 1997 Combustion Institute.

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