Characteristics of Propane Combustion in a Tubular Flame Burner Under High Oxygen Mole Fraction

Rapidly mixed tubular flame burners of different inlet sizes were adopted to investigate the oxy-fuel combustion of propane. The variations of flame structure, flammable range, sound pressure and combustion mode were carried out on two burners with disparate inlet size 0.5/0.5(A) and 0.25/0.5(B). And the mechanisms were analyzed based on Chemkin. The results illustrated that when β≤0.5, a uniform and stable tubular flame could be established within a similar range; In burner A, when increasingβto 0.7, the flame became unstable in structure due to shorter reaction time; Burner B, with smaller inlet size, consequently larger inlet velocity and better mixing condition, sustained a stable tubular flame up toβ=0.7. By further increasing β to 0.8, the flame became non-uniform but still stable. Besides, whenβ≥0.7, the sound pressure fluctuation in both burners arose at low equivalence ratio and stoichiometric equivalence ratio. Furthermore, tubular flame range shrunk with β increasing.