Investigation of the flame of natural gas in the combustion chamber of a tractor diesel engine

Heat exchange by radiation in the working space of high-temperature combustion chambers is the predominant type of heat exchange, depending both on the temperature of the flame and on its emissivity. As is known, a luminous flame differs from a non-luminous one in that it emits thermal energy not selectively within the CO₂ and H₂O bands, but over the entire spectrum, including the visible region. Moreover, it is in the visible region of the glowing flame of natural gas that a significant amount of thermal energy is emitted. This is explained by the fact that the dispersed phase (soot), which arose during the decomposition of methane, contains particles of such sizes (0.05-0.2 microns), which are characterized by maximum radiation in the visible and near-infrared regions of the spectrum. Thus, the emissivity of a luminous flame is significantly higher than the emissivity of a non-luminous flame. This ability of the luminous flame is the reason for its use in diesel internal combustion engines (DICE).