Energy transport in two-dimensional laminar premixed methane/air flames

The effect of the burner geometry and confinement on the energy transport in the tip and sides of methane/air flames is investigated. A comparison between the convective and conductive contributions to the energy transport in a one-dimensional flame calcd. with our one-step chem. model and a one-dimensional flame calcd. with skeletal chem. shows that the one-step model is capable of describing the behavior of the energy transport with an acceptable accuracy. Three two-dimensional flames are considered: a flame on a slit burner and one on a cylindrical burner, both confined between similar flames, and an unconfined cylindrical flame burning in an atm. of cold air. The energy transport perpendicular to the local flame contours at the flame sides is large compared to the energy transport along the flame contours, which was largest in the confined flame on the slit burner and smallest in the unconfined cylindrical flame. The investigation shows that the energy transport at the sides of the flame is quasi one-dimensional. The sep. contributions to the energy transport parallel to the flame contours in the flame tip are of the same order of magnitude or larger than the energy transport normal to the flame contours. The net amt. of energy transported along the flame, however, is small. The investigation has resulted in a clear and quant. insight in the effects of burner geometry and confinement on the energy transport in two-dimensional flames.