Influence of the condensation of water vapor on the operation of a carbon dioxide gas-dynamic laser

An investigation was made of the influence of the condensation of water vapor, which could occur in a CO₂–H₂O–N₂ gas-dynamic laser, on the gain of the active medium. It was found that when the composition of the working mixture was CO₂:N₂ = 1:10 and it contained ~7.5% water vapor heated to a temperature of 1200–1500°K, the condensation did not affect (within the limits of the experimental error) the value of the gain at a pressure of ~20 atm. However, in the case of a CO₂–N₂–He mixture the addition of water vapor resulted in a considerable reduction in the gain in some part of the stream and this could be explained by the condensation of water vapor in the supersonic stream.