This paper studies the behavior of a counterflow diffusion flame established above a porous cylinder around the stagnation point and its interaction with radiation. A two-flux method is used to formulate the radiation model, in which the medium is approximated as optically-thin and the Planck mean absorption coefficient is variable across the flame. The combustion is described by a one-step overall chemical reaction with finite rate kinetics. The multicomponent diffusion velocity is calculated using Curtiss-Hirschfelder approximation and the thermodynamic properties are expressed as functions of the local temperature and species concentrations. Predictions obtained using the proposed model are compared with experimental data and other theoretical studies. The predicted temperature profile is close to that measured by Tsuji and Yamaoka, whereas those obtained from other models, without considering radiation effects, show a much higher flame temperature peak. The velocity is under predicted on the fuel side because of the lower fuel ejection rate. The concentration profiles match the experimental data. Parametric studies are conducted by varying the velocity gradient and the fuel blowing velocity, respectively. The extinction mechanisms for both effects are identified. A flammability map combining the two effects is given.
|Number of pages||12|
|Journal||Journal of the Chinese Society of Mechanical Engineers, Transactions of the Chinese Institute of Engineers, Series C/Chung-Kuo Chi Hsueh Kung Ch'eng Hsuebo Pao|
|State||Published - 1 Feb 1996|