Effects of Oxygen Contamination on Gas Dynamic Laser Performance.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING
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The effects of oxygen in the fuel of a shock-tube driven gas dynamic laser was observed with a four-inch shock tube. Five test gases comprised of ten percent CO2, three percent H2O, and varying amounts of N2 and O2 were studied. Nominal stagnation conditions were 2000 K and 500 psia. The small-signal gain coefficient was measured on three different rotational transitions for each test gas, permitting a J-line scan to be performed. The gas temperature, vibrational temperature of the upper laser level, and energy available for lasing were calculated using the J-line scan method. It was found that the small-signal gain coefficient, the vibrational temperature of the upper laser level, and the energy available for lasing all decreased linearly as the oxygen concentration in the gas dynamic laser fuel increased. Specifically, an increase in the oxygen content of 1 resulted in a decrease of the gain coefficient by roughly 1.5. Such a decrease is in agreement with previous work.
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