Study of Propane-air Flame Propagating in Narrow Channels under Quenching Condition

A new apparatus has been constructed to investigate the quenching of laminar hydrocarbon-air flames, at elevated initial pressures. The pressure-tight quenching channel is of trapezoidal form, with very smooth decrease of the channel width along its one meter length that is almost equivalent to a parallel-plate flame arrester. Propane-air mixture has been tested on the entire flammability domain, for both upward and downward propagation, and for pressure range from 40kPa to 700kPa. Differences between upward and downward propagation have been observed in the lean flammability domain, while for the reach domain, a new flammability limit has been established for the downward propagating flame at elevated initial pressure. A discussion is also made on the differences between experimental quenching distances determined in this study and previously reported literature data.