Velocity of turbulent flamelets with realistic fuel expansion.

Nonlinear model equation for weakly turbulent premixed flames with realistic fuel expansion is proposed. The equation describes both the hydrodynamic flame instability and flame response to external turbulence in the regime of flamelets. On the basis of the proposed equation the velocity of turbulent flames is investigated for the cases of both weak and relatively strong turbulence. Comparison of the obtained turbulent velocity to experimental results shows that the model equation contains the essence of a more complete theory of turbulent flame speed.