The reduction in laminar burning velocity and Markstein length extrapolation uncertainty for TRF-air mixtures

The laminar burning velocity and Markstein length of TRF (n-heptane, isooctane, and toluene)-air mixtures were investigated at the initial temperature of 400 K and 453 K, initial pressure of 1 bar, and an equivalence ratio range of 0.8–1.5. The effects of extrapolation radius (R_f) and Markstein length (L_b) were discussed on the linear and nonlinear extrapolation models. The results showed that the linear model leads to higher extrapolation result for all equivalence ratios compared with the nonlinear model due to the differences in the third term of Taylor expansion. Finally, the laminar burning velocity and Markstein length uncertainty caused by the extrapolation model can be minimized by adjusting [Formula presented] (R_f1 refers to the flame initial extrapolated radius). When the value of [Formula presented] was below 0.012, the laminar burning velocity and Markstein length uncertainty can be controlled at < 0.05 and < 0.5, respectively.