Improving the Prediction Accuracy of the Extinction of Stretched Methanol/Air Premixed Flames

Experimental measurements of the laminar flame speed and extinction strain rate of premixed methanol/air flames were conducted using the counterflow configuration. The validities of five methanol oxidation chemical kinetic models were verified. The results showed that a notable discrepancy was observed between the experimental and predicted extinction strain rate. Sensitivity analyses showed that the dominating reactions were H-2/O-2 chain branching/propagation reactions, CO/HCO reactions and dehydrogenation reactions of CH3OH and CH2OH. Further kinetic studies revealed that the reaction rate constants of the CH2OH dehydrogenation reactions were important in the prediction of the extinction strain rate. The reaction rate constants of the most sensitive chain branching/propagation reactions in San Diego scheme were updated using the recently published data. This updated San Diego scheme not only remained good performances in predicting laminar flame speed, ignition delay time, and non-premixed extinction limit of methanol/air flames but also significantly improved the prediction of the premixed extinction strain rate.