Combustion characteristics of impinging premixed jet flame for low calorific gases

For better understanding of low calorific gases, this study experimentally and numerically confirms the combustion characteristics of impinging premixed flames of low calorific gases. In order to select the fuels representing the low calorific gases, the equivalent gas method using the Wobbe index and the specific gravity is used. The Reynolds number and equivalence ratio are varied to evaluate flame stability region. Experimentally, flashback limits of low calorific gases show no significant difference according to calorific value of the fuels. Meanwhile, lifted flame limits and blow out limits are decreased as calorific value of gases decreases. Especially, for gas with calorific value of 6000 kcal/Nm³ (LCG 6000) shows narrower flame stability region than methane flame. Furthermore, numerical analysis is performed using SPIN code to predict the flame structure and temperature distribution of lifted flames. Thus, the results of this study can work as a foundation for designing new type of combustor corresponding to low calorific gases.