Effect of residual CO on combustion-type CO₂-Gas dynamic laser performance

The CO₂-Gas Dynamic Laser (GDL) has been developed as a high-power laser. The combustion-type CO₂-GDL has the particular merit of a readily obtainable high input energy, because it can use chemical reaction energy. In this type of GDL, however, impurities such as CO and O₂which result from imperfect combustion are present in the laser medium. This paper presents experimental studies of the influence of these impurities on CO₂-GDL performance. CO and CH₄fuel is burned with air and N₂is added to form high temperature (1500 K) CO₂–N₂–H₂O gas mixtures. All the observed impurities were CO and O₂. Both gain and power decreased monotonically with the increase of CO mole fraction up to 10%. The mole fraction of O₂was always approximately 0.5%, and higher levels of O₂fraction led to unstable combustion.