Flame wall interaction:: effect of stretch

An experimental study of flame-wall interaction is presented. The flame is a laminar, flat methane-air one at three different equivalent ratio: 1, 0.8, 0.6. Temporal PIV system was used to acquire images sequences of the interaction. Evolution of velocity field and flame contour shows that stagnation points appear between the reactive zone and the wall. Even if the maximum velocity value is relatively low, fresh gases motion amplifies wrinkle perturbation of the flame front. To explore more precisely the curvature evolution and its repercussion on the stretch rate, the stretch rate was calculated by determining local strain rate and curvature stretch term. Evolution of the stretch rate versus the time shows that the quenching stretch rate can be reached and locally, the extinction of the flame can appear for the equivalent ratio near the stoichiometry. We show that the interaction between a flame and a wall is controlled and disturbed by the modification of the velocity field of the fresh gases trapped between the reactive zone and the wall. (C) 2003 Elsevier Science Inc. All rights reserved.