The equivalent effect of initial condition coupling on the laminar burning velocity of natural gas diluted by CO₂

Initial temperature has a promoting effect on laminar burning velocity, while initial pressure and dilution rate have an inhibitory effect on laminar burning velocity. Equal laminar burning velocities can be obtained by initial condition coupling with different temperatures, pressures and dilution rates. This paper analysed the equivalent distribution pattern of laminar burning velocity and the variation pattern of an equal weight curve using the coupling effect of the initial pressure (0.1–0.3 MPa), initial temperature (323–423 K) and dilution rate (0–16%). The results show that, as the initial temperature increases, the initial pressure decreases and the dilution rate decreases, the rate of change in laminar burning velocity increases. The equivalent effect of initial condition coupling can obtain equal laminar burning velocity with an dilution rate increase (or decrease) of 2% and an initial temperature increase (or decrease) of 29 K. Moreover, the increase in equivalence ratio leads to the rate of change in laminar burning velocity first increasing and then decreasing, while the increases in dilution rate and initial pressure make the rate of change in laminar burning velocity gradually decrease and the increase in initial temperature makes the rate of change in laminar burning velocity gradually increase. The area of the region, where the initial temperature influence weight is larger, gradually decreases as the dilution rate increases, and the rate of decrease gradually decreases.