טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentKheifetz Yuri
SubjectNonlinear Interaction between Stagnation-Point-Flow Flame
and Flame-Grown Solid Film
DepartmentDepartment of Applied Mathematics
Supervisors Professor Emeritus Pismen Leonid
Professor Emeritus Nepomniashchy Alexander


Abstract

A two dimensional model of a laminar flame near a solid surface in an infinite domain is considered. It is supposed that the combustion product condenses on the surface. It is assumed that there is a heat flow between the surface and combustion mixture. High activation energy asymptotic assumptions have been used, film surface geometry has been neglected and constant density of the combustion mixture is supposed. Viscosity of the gaseous combusting mixture has been neglected. High activation energy asymptotic assumption shrinks flame zone to flame surface called flame front. Stationary solutions are found and classified . Substitution of the boundary conditions to stationary solutions of the differential equations gives nonlinear algebraic equation  for possible plane flame front distance from the reacting surface. A Newton method is applied for seeking the roots of this equation . Simple calculus and asymptotic analysis have been used in order to determine the number of solutions of the equation in all possible cases. For different values of the governing parameters there are from 0 to 4 possible solutions. The parameter space has been classified on the basis of the number of stationary solutions . Stability analysis, although incomplete (very fast oscillating perturbations are not considered), has been done for stationary solutions. It has been shown that the method of separation of variables cannot be applied in this model, so only a class of perturbations, which do not depend on the coordinate parallel to the solid surface, is considered. The results have been obtained by a combination of analytical and numerical methods. The program pocket Mathematica has been extensively used.