Modeling of flame radiation at burning of methane-air mixtures at initial stage of development

Modeling of flame radiation at burning of methane-air mixtures at an initial stage of development is executed. The basic analytical dependences for modeling are defined at an assumption, that burning is isothermal on volume and has the sphere form. Calculation of spectral radiant exitance from a surface of fireball is executed. Irradiance on an elementary platform depending on distance to fireball without absorption of the intermediate environment is determined. Adequacy of model has been checked up on the basis of calculated and experimental data of other authors. Maximums of spectral radiant exitance from fireball surface correspond to wavelengths for carbonic gas - 1.34, 4.26, 7.45 microns, for water steams - 1.29, 1.87, 2.66, 2.74 and 6.27 microns. Values of radiant exitance are in a range from 20 to 210 kW/m² for fireballs with diameters from 0.1 to 5 m. Emissivity of fireball changes in range of values from 0.015 to 0.21 for values of diameters from 0.1 to 10 m.