Study on combustion characteristics of premixed methane/oxygen in meso-combustors with different cross-sections

Abstract

The combustion characteristics of premixed methane/oxygen in three kinds of meso-combustors with the same hydraulic diameter were compared. The upper flammability limits of the premixed gas in the combustors with different cross-sections were measured experimentally. And the temperature field, flow field and OH concentration distribution in the meso-combustors were analyzed by numerical simulation. In addition, the effects of equivalence ratio and inlet velocity on OH mass fraction and wall temperature of combustors were also investigated. The results showed that the upper flammability limits of premixed gases decreased in turn when the methane flow rate was same for the combustion process of circular, square and rectangular cross-sections combustors. Under the same inlet parameters, the intensity of gas-phase reaction in the circular cross-section combustor was greater than that in the combustor with square cross-section, and that in the combustor with rectangular cross-section was the least. When the equivalence ratio or inlet velocity was constant, the mean temperature of the “square” cross-section combustor was higher, but the temperature difference in the combustor with circular cross-section was smaller and the temperature was more uniform.