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At our laboratory, radiation characteristics of air micro-plasmajets have been studied systematically. Up to the present, we measured radiation of the plasmajets mainly on a flow axis at atmospheric and low pressures. Temperatures were estimated with the aid of spectral matching method and Boltzmann-plot method. Rotational temperatures were estimated 5,000 to 8,000 K, and vibrational temperatures 34,000 to 70,000 K, both with some axial variations. Electronic excitation temperatures of oxygen atomic lines were estimated 5,000 to 9,300 K. It was found that the rotational temperatures had large difference from the gas temperature based on an empirical formula for a supersonic free-jet, but decreased downstream in the expansion flow region, and also the vibrational temperatures were much higher than those expected. The present paper showed the preliminary results of radiation characteristics at an off-axis position in the expansion flow region, too., 資料番号: AA0063742023, レポート番号: JAXA-SP-07-016

When a space vehicle reenters onto the atmosphere with high velocity, radiative heating from the shocked air ahead of the vehicle plays an important role on the heat flux to the wall surface as well as convective heating. In the laboratory, the spectroscopic system has been developed for temperature measurement of radiation behind strong shock waves. In this paper, CARS method (Coherent Anti-Stokes Raman Spectroscopy) for radiative flow behind strong shock waves of high Mach number has been developed. The CARS measurement system consists of a YAG laser, a dye laser, optical system, and high-sensitivity I.I.-CCD camera systems with spectroscopy. The preliminary tests have been performed for the purpose of detecting CARS signal from strong shock waves with velocity range over 5 km/s. Finally, both vibrational and rotational temperatures could be estimated by fitting of the CARS spectra obtained from experiment and analytical calculation over Mach 15., 資料番号: AA0048089018

Radiation from a shock layer around a water-cooled flat head model was measured spectroscopically in the ISTA/JAXA 750 kW arc-heated wind tunnel. Experimental spectra were obtained at 12 radial points for 5 axial flow positions to investigate the spatial characteristics of radiation in the shock layer. Electron temperature was estimated by comparing the intensities of two atomic nitrogen lines. Rotational temperature was determined by applying a spectral matching method to NO bands. It was found that the rotational temperature was uniform at about 3,000 K in front of the model., 資料番号: AA0047120026

資料番号: AA0045913007