Effects of Premixed Gas Components on NOx Pathways Based on Chemical Reactor Network Model

To investigate the effects of premix gas components on NOx generation under different pathways, four chemical reactor network models, namely single PSR(Perfectly-stirred reactor), 2PSR, 3PSR and PSR+PFR, were constructed and optimized based on the characteristics of CFD flow field in high-pressure jet stirred reactor. Under the condition of lean premix combustion, the NOx generation of pure CH4 and its mixture in different pathways were studied, and the NOx generation of each pathway in different reaction areas in the combustion chamber was obtained. The results show that NOx produced by pure CH4 combustion mainly comes from three pathways: thermal NOx, prompt NOx and N2O-intermediate NOx. It is found that thermal and N2O-intermediate NOx emission increase with the increase of adiabatic flame temperature. With the addition of H2 in CH4 or CO, the total NOx emission decreases and the rate of prompt NOx decreases, especially in the flame brush area. In addition, NOx emission increases with the CO mole fraction increasing in the CH4/CO mixture. © 2022, Editorial Department of Journal of Propulsion Technology. All right reserved.