稀释率与温度耦合作用对天然气预混燃烧等量影响研究.

The equivalent effects of initial temperature and dilution ratio on premixed combustion of natural gas in the constant volume combustion bomb are studied. The initial pressure pu and equivalence ratio  are set to be 0.3 MPa and 1.0 in experiment, respectively, and the ball type flame extension method by high speed schlieren photography is used in the experiment. Stretched flame propagation velocity Sn, unstretched flame propagation velocity SL, Markstein length Lb, laminar combustion velocity uL and NOx emission are analyzed in detail. The results show that SL, flame development duration and combustion duration are nearly identical, but the laminar burning velocity uL has a big difference at the operating points that have similar Sn value. The influence of dilution ratio on SL and uL is greater than that of initial temperature when the dilution ratio is small. Further research finds that the temperature difference ΔTu= 50 K has equivalent effect on combustion process compared with dilution ratio ΔDR=2%. Under the boundary conditions of the similar Sn, the NOx emission is lower under the conditions of higher initial temperature and dilution ratio compared with the smaller initial temperature and dilution ratio. [ABSTRACT FROM AUTHOR]