Effects of thermal expansion, strain rate, and gravity force on the steady propagation of a premixed flame in semi-closed channels

The flame dynamics of steady propagation of a premixed flame in semi-closed channels is investigated. The hydrodynamic model takes into account impacts of channel width, thermal expansion, straining effect, and downward gravity force on the flame front. The steady flame shape and its velocity field could be determined by numerical iteration of a weakly nonlinear front equation and linearized governing equations with Fourier transform, respectively. Results reveal that the introduction of thermal expansion and gravity force enhance the flame curvature and increase the burning velocity, while the straining effect suppresses the flame bending processes. In addition, a non-monotonic dependence of the burning velocity on the Peclet number is further demonstrated. It reveals that the thermal expansion and strain effect would have impacts on the burning velocity as well.