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Author
Ang, J. A. | Pagni, P. J.
Title
Forced Flow Boundary Layer Flames With Thermal Cracking.
Coporate
California Univ., Berkeley
Sponsor
National Bureau of Standards, Gaithersburg, MD
Contract
NBS-GRANT-60NANB5D0552
Keywords
diffusion flames | boundary layers | thermal cracking (chemistry) | thermal cracking (chemistry)
Abstract
The classic similarity solutions of boundary layer diffusion flames used the flame sheet approximation to simplify the governing equations by introducing Shvab-Zeldovich variables. In this study, the effect of endothermic cracking of the fuel is introduced to the forced flow boundary layer flame solution by using a simple cracking sheet model and defining new Shvab-Zeldovich variables. A simple model is also presented which replaces the common assumption of constant density-viscosity product with a power law function of temperature. Both effects do not destroy similarity so the advantages of solving Blasius-type equations are preserved. The primary effect of the thermal cracking is to create a second discontinuity which represents the cracking sheet. This sheet pulls the surrounding temperatures down and greatly reduces the temperatures between the wall and the cracking sheet.