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Ignition Delay Associated with a Strained StripIgnition processes associated with two adjacent fuel-oxidizer interferences bounding a strained fuel strip are explored here using single-step activation energy asymptotics. Calculations are made for constant as well as temporally decaying strain fields. There possible models of ignition are determined: one in which the two interfaces ignite independently as diffusion flames; one in which the two interfaces ignite dependently and in which ignition occurs to form a single , premixed flame at very high strain rates before ignition is completely prevented. In contrast to a single, isolated interface in which ignition can be prevented by overmatching heat production with heat convection due to strain, ignition of a strained fuel strip can also be prevented if the finite extend of fuel is diluted by oxidizer more quickly than heat production can cause a positive feedback thermal runaway. These behaviors are dependent on the relative sizes of timescales associated with species and heat diffusion, with convection due to strain, and with the chemical reaction. The result here indicate that adjacent, strained species interfaces may ignite quite differently in nature from ignition of a single, strained intrface and that their interdependence should be considered as the interfaces are brought closer together in complex strain fields. Critical strain rates leading to complete ignition delay are found to be considerably smaller for the fuel strip than those for single interfaces as the fuel strip is made thin in comparison to diffusion and chemical length scales.
Document ID
19990109047
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Gerk, T. J.
(California Univ. Los Angeles, CA United States)
Karagozian, A. R.
(California Univ. Los Angeles, CA United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1996
Subject Category
Inorganic And Physical Chemistry
Meeting Information
Meeting: Combustion
Location: Pittsburgh, PA
Country: United States
Start Date: January 1, 1996
Funding Number(s)
CONTRACT_GRANT: NCC2-374
CONTRACT_GRANT: N00014-93-I-1383
Distribution Limits
Public
Copyright
Other

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