Probabilistic Approach to Predict Abnormal Combustion in Spark Ignition Engines
This study is performed to predict the outcome of combustion process based on a given RANS solution by performing statistical analysis of Sa number and refined ignition theory proposed by Im et.al . A criterion to predict strong auto-ignition/detonation a priori is used in this study, which is based on Sankaran-Zeldovich criterion. The Sankaran number, Sa, is normalized by sound speed and is calculated for the bulk mixture with temperature and equivalence ratio stratifications. The initial conditions from previous pre-ignition simulations were used to calculate the Sankaran number, probability density function of Sa, and the detonation probability, PD. Sankaran number decreased and detonation probability increased significantly with increase of temperature. The mean Sankaran number calculated for the entire computational domain and the predicted Sankaran number were found to be nearly identical.