Swirling jets have been used as a means of controlling the length, pollutant formation and stability of the flame in combustion chambers.
In this thesis, the behaviors of turbulent diffusion flame with swirling flow are investigated experimentally in a movable-block type swirl burner.
The fundamental experiments have been performed such as measurements of flame lengths by direct photograph, gas time mean temperature and gas concentration in the flames.
Some of the results are described below :
1) Flame length ; a) Flame lengths become short with increasing air-fuel ratio (i.e. decreasing equivalence ratio, Φ) and become constant below Φ=1.0.
With increasing swirl number, flame lengths become shorter at the same equivalence ratio.
For the quarl half angle α, the flame length is shortest at about α=23˚.
b) Parameters influencing flame types is mainly the quarl half angle αand the fuel injection position.
c) In the burner design considering flame stability, it is appropriate that the quarl half angle is near 20˚, and the fuel injection position is at the quarl throat.
2) Gas time mean temperature and gas concentration in the flames ;
a) In stable flames formed in the strong swirl, two distinct type flames (Type 1 flame and Type 2 flame) may be identified, each having different characteristics in regard to the macroscopic flame structure.
b) With increasing the swirl number, stable flames are formed in the wider range of equivalence ratio.
c) For the large swirl number with low equivalence ratio, type 2 flame is always formed and the recirculation zone is formed widely in the central region.
With decreasing the swirl number in the strong swirl, the recirculation zone is formed narrowly and longer in the central region and deflects seriously to one side.
