Turbulent combustion of preheated natural gas-air mixture

摘要

The flame structure at small Damkoehler number and large Karlovitz number is still unknown. In the present study, the reaction zone structure in a distributed reaction zone regime was investigated extensively. The OH-PLIF images suggested that there are no thin laminar flamelets and that the reacting eddies were distributed throughout the reactor. With the cross-correlation of ion signals, the scale of the reacting eddies was determined to be of the order of 4 mm, and the convection velocity of these eddies or zones was found to coincide with the mean flow velocity of the order of 100 m/s. In this combustion regime, high intensity combustion can be realized with extremely low NO_x emission. These features are very attractive for the practical use (for example, vehicles and aircrafts) to meet the environmental requirements.