Experimental Studies on the Turbulent Burning Velocities of Premixed Mixtures in a Closed Bomb (Influences of Oxygen Concentration and Ignition Energy)

In order to clarify the influences of oxygen concentration and ignition energy on turbulent burning velocity, experiments on turbulent burning velocity have been carried out in a closed bomb using premixed mixtures. In the first series of experiments, only the oxygen concentration has been varied, keeping the other parameters, such as laminar burning velocity, laminar flame thickness, turbulence intensity, and mean spatial scale, constant. As to the hydrogen and methane mixtures, larger turbulent burning velocities were obtained for mixtures with higher oxygen concentration. But for propane mixtures, the above tendency was inversed. In the next series of experiments, turbulent burning velocities have been measured for comparatively large and small ignition energies, keeping the other parameters, including the oxygen concentration, constant. As a result, the upper limit of turbulence intensity at which flames can propagate without extinction has apparently increased with a rise in ignition energy.