An aerothermochemical analysis of solid carbon combustion in the stagnation flow accompanied by homogeneous CO oxidation

Journal Article · Thu Oct 01 00:00:00 EDT 1987 · Combust. Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(87)90161-1· OSTI ID:7255778

Matsui, K; Tsuji, H

An analysis is made of a model in which the heterogeneous reaction is 2C/sub (s)/ + O/sub 2/ ..-->.. 2CO and the CO produced thereby undergoes the homogeneous reaction 2CO + O/sub 2/ ..-->.. 2CO/sub 2/; the homogeneous reaction interferes with the heterogeneous reaction through the consumption of O/sub 2/. Constant density and unity Lewis number of the gas mixture are assumed. Self-similarity of the flow is also assumed, and the analysis is reduced to a problem of solving an ordinary differential equation for energy conservation. The effects of the surface Damkohler number D/sub s/, the gas-phase Damkohler number D/sub g/, and the dimensionless surface temperature T/sub w//sup --/ on the dimensionless combustion rate -f/sub w/ are investigated. When D/sub g/ = O or D/sub g/ ..-->.. infinity, the solution can be obtained from degenerate governing equations; -f/sub w/ is independent of T/sub w/, and simple relations hold between D/sub s/ and -f/sub w/. The solution for D/sub g/ ..-->.. infinity exhibits singularity at the carbon surface. When neither D/sub g/ = O nor D/sub g/ ..-->.., infinity the variations of -f/sub w/(D/sub s/), -f/sub w/(D/sub g/), and -f/sub w/(T/sub w//sup --/) are determined numerically for the ranges of D/sub s/ (0.001-100), D/sub g/(10/sup 2/-10/sup 14/), and T/sub w//sup --/ (0.15-0.40). It is found that (1) a sharp gas-phase reaction zone located away from the surface does not form, (2) -f/sub w/ increases with increasing D/sub s/ for any value of D/sub g/ and T/sub w//sup --/, (3) at a given D/sub s/, -f/sub w/ decreases with increasing D/sub g/ for any value of T/sub w//sup ..-->../-how -f/sub w/ decreases with increasing log D/sub g/ is roughly the same for all the values of T/sub w//sup --/, (4) at a given D/sub s/, -f/sub w/ decreases with increasing T/sub w//sup --/ for any value of D/sub g/-how -f/sub w/ decreases with increasing T/sub w//sup --/ differs greatly with the value of D/sub g/.

• Research Organization: Institute of Interdisciplinary Research, Faculty of Engineering, The Univ. of Tokyo, Tokyo 153 (JP)
• OSTI ID: 7255778
• Journal Information: Combust. Flame; (United States), Vol. 70:1
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON
COMBUSTION KINETICS
CALCULATION METHODS
CARBON MONOXIDE
MATHEMATICAL MODELS
OXIDATION
STAGNATION POINT
THERMOCHEMICAL PROCESSES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
ELEMENTS
KINETICS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry