A Semi-Analytical Model for Prediction of Wall Quenching Distances of Premixed Flames

In order to predict the variation of the wall quenching distance of a premixed flame under different equivalence ratios and incoming flow velocities, a semi-analytical model applied to both lean single-layer flame and rich double-layer flame has been derived based on the conservation of energy in the quenching zone. In this model the flame surface radiation plays an important role. Factors influencing the radiation have been analyzed, respectively. The model indicates that the factors affecting the quenching distance in premixed flame are more complicated than that in single-wall flames or flames in tube. To fit the empirical coefficient in this model, a methane-air premixed flame quenching distance experiment under both lean and rich conditions has been performed. The comparison between the theoretical prediction and the experiment result shows that this semi-analytical model gives a suitable description of the quenching distance. The relative error of the quenching distance under different equivalence ratios and incoming flow velocities is less than ±15%.