Methods for Examining Anisotropies in Early Combustion Part I: Multi-Scale Experimental Determinations

ABSTRACT

Experimental measures are developed for the description of anisotropic growth in the early stages, of the flame kernel development in an operating spark ignition internal combustion engine. These measures are developments of the support area concept introduced by Bradley and Abdel-Gayed. By applying the technique of multi-scale analysis derived from texture analysis to such anisotropy measures it has shown to be possible to obtain time dependent information about the effect of the various local length scales in the processes that influence early flame growth. The analysis techniques employed are demonstrated to offer very wide scope for characterising anisotropic time varying combustion and the basis is laid for a formal development of this topic as presented in the companion paper. An interesting observation is that for cycles other than partial combustions the largest length scale of process effecting the flame kernel on tends to increase with time during the early flame growth.