2000 年 48 巻 558 号 p. 207-212
The influence of intrinsic instability on the flame velocity is studied by two-and three-dimensional, unsteady calculations of reactive flows, which are based on the compressible Navier-Stokes equation. We consider three basic types of phenomena which are responsible for the intrinsic instability of premixed flames, i. e., the hydrodynamic, diffusive-thermal, and body-force effects. As intrinsic instability becomes stronger, the flame velocity of cellular flames is increased. The increment in flame velocity of three-dimensional flames is about twice that of two-dimensional flames. When the Lewis number is unity, the flame velocity is almost proportional to the flame-surface area. When the Lewis number is lower than unity, on the other hand, the increment in flame velocity is larger than that in flame-surface area. The reason is that the increase in local consumption rate of the unburned gas at a convex flame front with respect to the unburned gas exceeds the decrease at a concave flame front.