RESEARCH ON EXTREMELY NONEQUILIBRIUM REACTIVE FLOWS

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In flow fields around a vehicleat hypervelocity at a high altitude, thermochemical nonequilibrium regions will inevitably occured owing to its high velocity and low density. Focusing on an interaction between such nonequilibrium states and high velocity flows, numerical and experimental researches were performed co-operatively on nonequilibrium plasma flows, strong shock waves, supersonic combustion flows, gasdynamic lasers, and low density flows.1. The variations of molecular vibrational and rotational, and free electron energies bimolecular dissociation and recombination reactions were eatimated quantitatively. The effects of the energy variations and wall catalysis upon shock layrs of a reenty body was investigated numerically. Expansion flows of arc heated air and argon plasmas were investigated numerically, and remarkably different distributions of vibrational temperature for air molecules were found.2. The method of spectroscopic measurements with a high time-wavelength resolutio … More n was established for strong shock waves. From detailed measurements of air shock waves, abnormal vibratory variations of molecular emission with time were detected for the first time. It was found that in strong shock wave reflection phenomena, chemical nonequilibrium effects must be included. Technique of simulutaneous many point measurements was completed for shock tube experiments.3. An efficient numerical method for supersonic and hypersonic flows was proposed, whick could be applied to supersonic combustion flows with fast chain reactions and complex boundaries. The characteristics of an ignition and reaction mechanisms of hydrogen/oxygen/methane in supersonic shear flows, and the factors affecting the stability of detonation initiated by a shock wave were clarified.4. The continuous and highly repetition operation characteristics of wind tunnel-type laser was found experimentally. The characteristics and performance were investigated for supersonic iodine laser, gasdynamic laser with heat exchangers, and benzene combustion CO_2 laser, experimentally. The effect of vapor condensation by gas expansion on the iodine laser was cleared up numerically.5. Knudsen layr developed along catalytic and reactive walls was analyzed and the validity of diffusion reflection wall boundry conditions was discussed. The DSMC numerical method was applied to rarefied supersonic jets, and its capability was confirmed. Structure of low density supersonic jets, its stability and the effect of rarefaction on it were solved numerically and experimentally. Less