Effect of Elliptical Burner Geometry on Stability and Global Emission Characteristics of Pre-Mixed Flames

An important topic in combustion research today is pollutant emission reduction. With the current demand for large amounts of economical, clean power, there is a need for research in both the increase of combustion performance and the reduction of emissions. Two methods of the so-called ‘passive’ flame controls are the use of premixing the air and fuel and the variation of the geometry of the flame. Both mechanisms offer the promise of increasing efficiency as well as reducing harmful emissions. However, the effect of these controls on the stability of the flame has not been fully studied. This paper will attempt to fill in some of this gap and will study the effects of elliptical burner geometry on premixed flames. The study will present stability results for circular and 4:1 aspect ratio elliptical burner geometry for a range of fuel mixtures of propane and hydrogen. The paper will also report the emission indices of CO and NO of the 40% by mass hydrogen in propane mixture. It was found that the 4:1 aspect ratio burner had reduced blow-out stability, produced a much shorter flame, and, in general, produced more carbon monoxide and less nitric oxide than a circular burner.