A series of microgravity experiments were performed at MGLAB drop-shaft facility in Japan, in order to investigate the flame propagation process of an n-Decane linear droplet array in stagnant atmospheric air. In the experiments, all droplets in an array were simultaneously generated on the cross-point of X-shaped two SiC fibers. One end droplet of the array was ignited by a hot wire to initiate the flame spreading along the array. Direct images of the propagating flame were recorded by normal speed (30fps) digital video camcorder and hydroxyl [OH*] radical self-emission intensity distributions on the projection plane were observed and recorded with high speed (500fps) video camera. In this paper, time-resolved flame propagating mechanisms between the neighboring droplets were discussed. The observed [OH*] radical images precisely describe the flame propagating mechanisms and the switching process from premixed combustion of evaporated fuel to diffusive combustion around the droplet.
A model predicting the ignition probability of the lean-burn SI engine in the vicinity of the lean-burn limit was constructed using the percolation model in continuous space. Calculated percolation probabilities reproduced the experimental results when the following conditions were applied, considering the actual ignition on SI engine. First, the heat generation of the spark plug should be larger (15 to 20 times) than that of the exothermic reaction of the fuel particle. Second, the scale of the percolation should be more than the twice of the range of the heat generation of the spark plug. This result suggested that the size of the flame core would have about the twice size as the effective range of heating by the spark plug.
In a catalytic combustion deodorizer, it is advantageous for the running cost to use the premixed fuel combustion technique which requires that the premixed gas be burned completely in the catalysts. This paper describes the catalytic combustion characteristics of the premixed gas and the stable combustion region for kerosene in platinum catalysts, which were examined using a fundamental experimental setup. The stable combustion conditions were obtained under the inlet temperature Tin of the premixed fuel gas, where Tin≧465 K, the space velocity SV≦24000 hr-1, and the equivalence ratio is the optimum value, depending on the Tin. Applying these results to the catalytic deodorizer with a heat exchanger, we found that in order to broaden the stable combustion region, it was effective to increase the space velocity, the heat exchange ratio, and the inlet temperature of a foul-smelling gas.