Extrapolation of laminar flame speeds from stretched flames: Role of finite flame thickness

The finite flame thickness expression of Frankel and Sivashinsky was employed in the extrapolation of laminar flame speeds from experimental data of stretched flame speeds and the essential and independent role of the flame thickness in describing the coupled diffusive and reactive response of the laminar flame structure and propagation. Using numerically generated stretched flame data of the outwardly expanding spherical flame for both lean and rich H₂/air and n-heptane/air mixtures collected resulted demonstrated that the finite thickness expression yields not only improved extraction of the laminar flame speed but also collaterally yields the laminar flame thickness as well as the Markstein length. Also the cause for the inaccuracy of the previous linear and nonlinear extrapolation expressions the effects of pressure on the extrapolation results and the robustness of the various expressions in considering for the experimental errors was addressed.