Binomial mixing model for premixed reacting turbulent flows applied to autoignition

A turbulent mixing model based on a stochastic process using a binomially distributed random variable is presented and tested in a premixed decaying turbulent flow. Attention is focused on the joint probability density function (PDF) of reactive and inert scalar that are calculated by the PDF transport equation. The numerical work under study is applied to a field similar to autoignition in which the initial medium is composed of partially burnt gas distributed within the fresh mixture. Three dimensional direct numerical simulation has been performed in order to check the prediction capability of the model whose results showed an excellent agreement with the data from numerical experiments. The joint PDF distribution calculated by the binomial model demonstrates that binomial sampling process successfully describes the realistic features of the PDF evolution.