The effect of ozonolysis activated autoignition on jet flame dynamics is investigated with two non-premixed configurations, counter-flow and co-flow, respectively. For the counter-flow configuration, the fuel and oxidizer are supplied from two opposite inlets of a tee connector and the partially premixed reactant jet is autoignited when ozone (O_3) is added. Different flame stabilization mechanisms are observed during this transient process. These include the conventional flame propagation, autoignition-assisted flame propagation and coexistence of multiple autoignition kernels. The autoignition-assisted propagation features a high propagation speed (approximately 30 times of laminar flame speed at corresponding condition). The coexistence of multiple autoignition kernels significantly accelerates the "propagation" of flames to a speed of approximately 100 times of S_L. For the co-flow configuration, the fuel jet is the center and oxidizer is the co-flow. The flashback propagation speed in the mixing layer after ignition is investigated. It is found that for unsaturated hydrocarbon fuels (C_2H_4 and C_3H_6), O_3 addition can enhance the propagation speed by 70%-220% at low dilution level. However, a very minor effect (5% enhancement) was observed with O_3 addition if the fuel was switched to CH_4. The significant enhancement of "propagation" speed observed with ozonolysis activated autoignition is promising to stabilize the flame at extremely high flow velocity.
展开▼
