New approach for simple temperature measurements of metal combustion
In combustion processes of metal or metal containing energetic materials the combustion temperature is one of the most critical physical parameters for thermodynamic calculations and necessary for a better understanding of the involved phenomena. Thereby the temperature of the vapor phase is a special challenge. A fit of the continuum radiation with a grey body function provides the temperature of the burning bulk material. One of the methods to determine the temperature of the vapor phase is to observe the emission of the atom lines or diatomic molecules, calculate their spectra and fit them to the experimental spectra. In most cases this process requires a high resolution spectrometer, high computing efforts and a lot of knowledge about the properties of the spectra. To avoid these requirements a parameterized function modeling only the vibrational bands was developed from calculated high resolution spectra. Therein, the temperature is a free fit parameter. The full width at half maximum of the lines was adapted to the resolution of an overview spectrometer (delta lambda about 3nm). In a first step the model function was parameterized for the aluminum monoxide B(exp 2)sigma-X(exp 2)sigma transition. The model was tested with low- and high-resolution spectra of burning aluminum particles in oxygen. A good agreement between them was achieved. The determined vapor phase temperature was validated in comparison to the continuum temperature and calculated adiabatic temperature.