Search Results

Multiple ion-probes method provides fine measurement on propagating flame by using multiple ion-probes installed tow-dimensionally on the wall surface of confined chamber. Each ion-probe detects the arrival of propagating flame and the detecting time is recorded. The data set of flame detecting times is able to re-generate the temporary and spatially detailed behavior of flame propagation. Because ion-probe itself generally has physical and thermal strength, multiple ion-probe method is suitable method for detailed measurement of the combustion resulting pulsatile high pressure such as in reciprocating piston engines. In the present study, flame measurement technic by multiple ion-probes has been experimentally introduced for measuring the combustion in 2-stroke gasoline engine. The present paper reports the detailed results of measurement on propagating flame in the engine. In addition, newly clarified technical issues of this technic is also mentioned.

Multiple ion-probes method has an advantage for detailed measurement on high-intensity combustion including engine combustion, oscillation combustion in gas turbine or burner. Multiple ion-probes are installed individually on the surface of the confinement wall in combustion chamber. Detailed behavior of the flame propagation along the chamber wall can be reproduced by the datasets of the flame arrival time detected by individual ion-probes. Main target of this study is to clarify the measurement performance of this multiple ion-probes method for various type of propagating flames generated in confined combustion tube. The characteristics of the flame is largely varied by changing the ratio of dilution with nitrogen on methane-oxygen stoichiometric mixture. No dilution, which means methane-oxygen stoichiometric mixture only, results fastest speed and relatively stable propagation.

A new technic to measure the propagating flame precisely by using densely installed multiple ion-probes has been developed. This system targets the high-intensity and pulsatile combustion, including knocking in gasoline engine, and oscillating combustion in burner or gas turbine combustor. In such environment, observation of details in the combustor by visualization is generally limited because of the strength of observation window. In contrast, ion-probe is physically and thermally strong enough to endure such environment. In the present study, characteristics of the combustion measurement were investigated using the different types of propagating flame with various LPG-oxygen-nitrogen mixtures. The composition of the mixture was stoichiometric LPG-oxygen diluted with nitrogen. Nitrogen dilution ratio was varied to control the flame propagation velocity.