Experimental study of momentum transfer in a cellular flame of rich and lean propane-butane/air mixture

To simulate a cellular flame, rich (equivalent ratio phi = 1.4) and lean (phi = 0.9) propane-butane/air mixtures were used in a burner, which forms a stationary flame with a single cell. Experimental data on the temperature fields were obtained using the coherent anti-Stokes Raman scattering (CARS) method; the velocity components were measured using PIV (Particle Image Velocimetry) equipment. The terms of friction stress and static pressure in the momentum transfer equations were calculated using the balance method. It is shown that the equality of dynamic and static pressures associated with the thermal expansion of the combustion products is satisfied on the cellular flame surface. Flameout occurs when the magnitude of the pressure head becomes greater than the magnitude of a static pressure change. The shear stress profiles contain extrema, whose coordinates are associated with streamline curvatures and are close to the position of the heat release region at combustion of lean and rich mixtures.