3-DIMENSIONAL CURVED FLAMES - STATIONARY FLAMES IN CYLINDRICAL-TUBES

Curved axisymmetric stationary flames in cylindrical tubes are investi gated on the basis of a model nonlinear equation for a flame front sub ject to the Landau-Darrieus instability. It is found that the increase of the flame velocity due to a curved shape of the front is much larg er far the case of three-dimensional curved flames compared to the two -dimensional ones. Some of important properties of curved three-dimens ional flames differ qualitatively from the properties of two-dimension al flames, Particularly, a regime of strong initiation of the Landau-D arrieus instability in narrow tubes is obtained, when all perturbation modes of small amplitudes are stable, but a curved stationary flame i s still possible. Another important feature of the three-dimensional f lame propagation is unlimited increase of the flame velocity with the increase of the tube diameter.