Burning Velocities of Flamelets in a Turbulent Premixed Flame

Abstract

Burning velocities of flamelets in a vertically oriented, burner-stabilized turbulent premixed propane–air flame in the reaction-sheet regime are investigated by use of a microelectrostatic probe and a laser-doppler velocimeter (LDV) that give components in a vertical plane of the flame-front velocity and the gas velocity, respectively. Under the experimental conditions investigated, the average turbulent fluctuating velocity is of the same order of magnitude as the laminar burning velocity of the planar, unstrained, adiabatic laminar flame. The component of the flamelet motion with respect to the gas in the vertical plane is found from these measurements to be distributed over all directions and to range in magnitude from nearly zero to a few times the planar, unstrained, adiabatic laminar burning velocity. It may be concluded from these observations that the turbulence may exert substantial influences on the flamelets.