A SIMPLE ILLUSTRATION OF TURBULENT FLAME BALL GROWTH

A flame ball growing into a turbulent mixture exhibits a speed which i s proportional to its size-this effect is a consequence of the distort ed flame surface: the inner flame regions ''push'' the outer regions, the magnitude of this velocity depends upon the flame surface density distribution. A simple two-dimensional, zero-thickness flame model int eracting with defined eddies illustrates how rapidly this flame distor tion occurs after a spark ignition. This distributed volume source eff ect is also the functional form of Groffs modified entrainment model o f flame propagation. A result of this size dependent growth is exponen tial growth of flame area which is an essential feature of spark-ignit ion internal combustion engines.