Study On Non-Gray Radiation Calculation For Hydrocarbon Combustion Flame

Hydrocarbon combustion flame widely exists in industrial furnaces, boiler furnace and other occasions. The products of combustion involved in radiative heat transfer mainly include gas products(carbon dioxide and water vapor) and soot(particles and aggregates). Radiation properties of the gas present a strong spectral selectivity, and the soot's properties depend on both wavelength and its complex fractal structure. This makes it difficult to solve the radiation problem. Therefore, it is important to understand the radiation properties of hydrocarbon combustion medium in improving the combustion efficiency and analyzing the combustion mechanism.In this paper, the FSK model, the GMM theory, and the DRESOR method were described, respectively. The non-gray radiation properties of gas medium at full spectrum could be attained from the FSK model that based on the k distribution. GMM theory could be used to obtain the spectral radiative properties of particles and aggregates with different fractal structures. DRESOR method together with FSK model and GMM theory will give the spatial distribution of radiation intensity with high-resolution directions.The radiation intensity and flux distribution of different medium in one-dimensional enclosure between two parallel plates was calculated by DRESOR method in combination with FSK model and GMM theory. For gas, the isothermal and temperature stratification as well as the air and oxy-fuel combustion conditions were considered, respectively. The influence of temperature and concentration on the radiation properties was studied. For soot, three models including single particle, double particles and particle clouds are investigated, respectively. The impacts of scale parameter and particle optical constants on its radiation properties are analyzed.The soot aggregate in the axisymmetric C2H4 laminar diffusion flame with different oxidizer of O2/N2 and O2/CO2 was sampled and analyzed by TSPD-TEM method. The fractal parameters of aggregate at various flame height were attained. After that, the fractal structure was simulated, and then be used to calculate the scattering factor and absorption factor distribution via GMM theory. The aggregates formation mechanism and the effects of different oxidizer on the formation of aggregates were analyzed according to the distribution of radiation properties along flame height. The total scattering and absorption properties were analyzed on the basis of spectral radiation properties of aggregates.