Date of Publication :22nd March 2018

Abstract: Flaming combustion is sub-classified into premixed and diffusion flames, the type of flames that are ubiquitous. From jet engines to rocket engines these types of flames are utilized to generate thrust for our vehicles. With careful observation and inference, it can be clearly stated that in real time applications it’s a combination of these two flames in unison that is in work, rather than either one alone. Although innumerable work has been done in the past that concern the two types of flames individually very few research works exists that concerns the transition between these two regimes nor their combined effect on the efficiency of combustion. Current work is aimed at gaining fundamental knowledge of transition, by studying a few of the many factors that influence transition and their corresponding effects on the physical parameters. A butane cylinder fitted with nozzle containing 3 equidistant sets of 4 holes each that have an equal diameter for air entrainment is used for carrying out the study. Parameters like entrainment area, the orientation of nozzle, the mass flow rate of fuel and various positions and combinations of air entrainment holes are manually varied to observe the physical changes in the flame like flame height and intensity. Image processing is used as a potential resource along with regular CCD camera. The phenomenon is systematically video-graphed and image segmentation is carried out to obtain desired characteristics. These methods are jointly used utilized to establish a non-dimensional parameter that theoretically characterizes transition phenomena. The results obtained from this experiment could be easily applied to combustion chambers present in jet engines as the experiment is aimed to mimic jet engine combustion chamber to a certain extent. Further, the results can provide a prospective understanding of the physics behind transition phenomena and a concept of premixed strength that can in the near future pave way for greener and efficient propulsion systems.

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