Energy characteristics of a supersonic continuous-wave chemical HF laser using hydrazine decomposition products

We report the results of calculations and experimental studies of specific energy characteristics of a supersonic cw chemical HF laser with a flat nozzle block corresponding to the nozzle – nozzle reagent mixing scheme, in which catalytic decomposition products of hydrazine N₂H₄ (H₂ + N₂ + NH₃) are used as a secondary fuel. As a result of experiments with cold (300 K) model mixtures, the specific energy extraction of the laser is found to decrease in this case by 43% compared with the laser utilising pure hydrogen. The calculations show that the main reason for a decrease in the specific energy of the laser is an increase in the temperature in the mixing zone of the oxidising gas and secondary fuel jets. A strong effect of ammonia is revealed. Taking into account the actual heating of the products (up to 1000 K) during the catalytic decomposition of N₂H₄ allows the level of specific energy extraction from the laser to approach that of energy extraction from the laser operated on pure hydrogen by 13%, which will lead to a decrease in the specific energy extraction by only 30% in the absence of NH₃ decomposition products.