FEM Analysis of Flamelet Wrinkling in a Diffusion Flame

Y. Li[1], T.C. Lieuwen[2], J. Zhou[1], H. Cao[1]
[1]Zhengzhou University, Zhengzhou City, Henan Province, China
[2]Georgia Institute of Technology, Atlanta, GA
Published in 2014

One can hardly get the exact analytic solution of a full time-dependent convection-diffusion equation, for describing the dynamics of a non-premixed flamelet. The analytic solution of the linearized form with such a model was studied by MATLAB®. And also, a numerical computation was made with the linearization model in COMSOL Multiphysics® software, to provide a perfect accordance with the analytical solution. As well as giving a validation to the linearization flamelet model, the results reveal the characteristics of the flamelet positions and wrinkling originated from a harmonic disturbance on the velocity of reactants at the inlet. It is shown that the more closer to the two ends of the flame, the larger are the amplitutes of the wrinkling. The mixture fraction along the axial of the flame damps generally in an exponential law. The paper would provide principal data for deeply understanding with the thermo-acoustic instabilities of non-premixed combustion.