A SPECTROSCOPIC TEMPERATURE-MEASUREMENT OF CONVERGING DETONATIONS BY THE EMISSION SPECTRAL MATCHING METHOD

Experimental studies on converging detonations were performed aiming at applications to high-power pulse lasers and production of high-temperature plasmas. Viewing that the duration time of the detonation is relatively short ( less than 10 mu s) at the converging point, spectroscopic measurements are often used as diagnostic techniques. In the present study, the emission of CN violet bands from a converging point was analyzed using a microdensitometer. In order to determine the temperature at the converging point of a detonation, a method of matching the entire emission spectra was utilized. The anticipated emission spectra of the observed band can be theoretically calculated with a combination of the gasdynamic quantities, assuming Boltzmann distributions for rotational, vibrational and electronic energy levels. After several trial-and-error processes, the best fit was obtained for T equals 11,000 K, N equals 7. 5 multiplied by 10**1**6/cc and the Lorentian broadening half-width W//l equals 0. 003 nm: The detonation was produced using equi-molar oxyacetylene mixtures at P//1 equals 60 Torr (8. 0 multiplied by 10**3 Pa) and T//1 equals room temperature in an 80-cm-dia. double-disc-type detonation chamber. It was found, as a result, that unavoidable doppler broadening inherent to high temperature experiments and a wide slit function could be handled with no essential difficulty and a correct rotational/vibrational temperature could be obtained.