Spectral Radiative Model Of High Temperature Gas For Specified Band

The cognizance of radiative properties of high temperature gas originated from researching about the gases that participate in radiative heat transfer in the furnace chamber. In the high temperature project which contains gas, the radiation from high temperature gas has become a very important heat transfer form. In recent years, new technology applications which make use of gas spectral radiative properties have been developed one by one in many fields such as energy, metallurgy, space flight and meteorology. For example, the new technologies are applied to multi-spectra radiation thermometry, infrared remote sensing, target detection and tracing, infrared guidance and so on.Most spectral models take solving gas radiative heat transfer in certain region as a goal. They have described essentially approximate gas properties in different levels of spectral gap. The main difference between them lies in spectral gap width, namely from line by line to the entire spectrum. Unfortunately, it remains a difficult task this day due to inadequate knowledge of radiative properties of important participating gases in setting model for spectrum, and the lack of efficient and accurate radiative models.In this dissertation, a particular analysis of former spectral radiative model is given first. Then based on the molecular spectroscopy theory, the influence imposed on gas radiative absorption coefficients from temperature is researched. And on the grounds of the massive experiments, the approximate calculation formula for the absorption coefficients of the different specified bands is calculated. Take the new HITEMP database as the foundation, and the specified band transmissivity is calculated by using the USF HITRAN-PC software, then the band absorption coefficients are obtained. The model parameters are calculated making use of the fitting formula. At the end of the thesis, the absorption coefficients of CO2, H2O and the mixture of them in the bands for different purpose are studied, and the corresponding fitting parameter are calculated using the non-linear least square approximation. The specified band transmissivities have been calculated in the different optical thickness with the fitting model; the results indicate that fitting model is close to the line by line calculation in most bands if optical thickness less than 1.0, and the biggest errors are not greater than 20%. Otherwise, fitting model will get the results far apart from LBL. Finally, with this fitting model, the problem of rocket tail flame is treated, and reasonable results have been achieved.