Calculation of atomic recombination in a decaying high-temperature hydrogen gas column

摘要

The temporal evolution of the concentration ofatomic radicals [H] in a high-temperature hydrogen gas columnhas been evaluated, assuming an exponentially decayingtemperature from 5000 K to 1000 K, and for constant pressuresin the range from 0.125 to 2.0 bar (1 bar = i05 Pa). The initialconcentration [H]t=0, assumed to correspond to thermalequilibrium, would increase with pressure, but the termolecularrecombination processes also become faster with increasingpressure. As a result, high concentration of atomic radicalsrapidly becomes favoured by lower gas pressure after thetemperature has decayed for a certain time. Also, operation atlower pressures would make the decay of [H] radicals lessdependent upon the cooling rate of the gas.