Flame-Jet Ignition of Fuel-Air Mixtures. Experimental Findings and Modeling

The aim of the study is to provide experimental and theoretical grounds for better understanding flame-jet ignition of fuel-air mixtures, studied elsewhere [1-8]. Several experimental facilities are employed (small-, middle- and large scale) to reveal the effect of scale on the phenomenon. Various measuring techniques are used (high-speed Schlieren cinematography and self-emission detection, pressure histories, LDV, ionization probes, LIF of OH radicals) for obtaining a scope of data on physical and chemical variables involved. A hierarchy of theoretical models is developed (from simple zero-dimensional to multi-dimensional) and applied for getting better insight into the processes. Experimental All experimental facilities consist of two chambers separated by a partition with a single circular orifice of diameter d. Total volumes of the facilities are 1.6 10-4, 3.75 10-4, and 1.53 m3. Hydrogen-, methane-, and propane-air mixtures are investigated. Fuel-air mixture in the first chamber is ignited by a spark plug. Ignition-induced flame propagates in the first chamber and, due to pressure raise, a jet of fresh mixture followed by combustion products emerges through the orifice into the second chamber. Depending on the experimental conditions and the orifice diameter, the mixture in the second chamber is either ignited or not. Ignition can occu