Weakly Stretched Methane-Air Laminar Flame Speeds and the Non-Linear Extrapolation to Zero Stretch

摘要

Methane-air Hencken flames at sub-atmospheric pressure were investigated through detailed experiments and simulations to better define the behavior of flames in the weakly stretched regime. The extrapolation to zero-stretch was determined using references of the minimum velocity and 1% temperature rise. The steady, laminar, nearly one-dimensional, minimally curved, and nearly adiabatic premixed flames in the weakly stretched regime allowed for measurements of minimum velocities and the associated axial stretch rates. The results agreed well with two-dimensional simulations regarding the non-linear extrapolation at low stretch rates, as well as providing the validation necessary to use the 1% temperature rise as a reference in the simulations. A non-linear trend using the 1% temperature rise reference was found to be in contrast to the linear trend that was predicted.