|dc.description.abstract||For low-intensity premixed turbulent combustion, we use a pair of specially-designed ion probe sensors, such that turbulent burning velocities of both methane-air and propane-air mixtures are quantitatively measured. Our results show: (1) The results of turbulent burning velocity measurements can be represented as an empirical relation of the form ST/SL=1+1.82(u’’/SL)1.21, where ST is the turbulent burning velocity, SL is the laminar flame speed, and u’’ is turbulent intensity. This result is very close to the previous result obtained by the two-camera method, but higher than that of theories by Clavin & Williams (1979), Kerstein & Ashurst (1994), and Cambray & Joulin (1993). (2) The turbulent burning velocity is proportion to the Reynolds number, but the increasing magnitude varies with the equivalence ratio. (3) At the same turbulent intensity condition, the turbulent burning velocity for Le < 1 is greater than that for Le > 1, where Le = a/D, a is thermal diffusivity and D is mass diffusivity.
To determine the quenching mechanism for high-intensity premixed turbulent combustion, we use the high-speed camera to obtain the instantaneous images from the test section of the burner. The Thermal Conductivity Detector mount is used to measure the methane concentration. We present only some preliminary results about global quenching experiments, which are still conducting in our laboratory.||en_US|