Research on COIL employing no-flake-nozzle and CO2 as buffer gas

The supersonic nozzles lower temperature to 170-180 K better for the small signal gain coefficient. But at this temperature, the CO2 buffer gas may become liquid state. A chemical oxygen-iodine laser (COIL) employing CO2 as buffer gas and no-flake-nozzle was studied. Some mathematical simulation in three-dimensional computation fluid dynamics was adopted first to validate its usability. New nozzles gave the temperature higher than 400 K and considerable small signal gain coefficient. In the same conditions as simulation, experiments gave a 23% of chemical efficiency and 2.5 kW of output power. And it have got rid of “black area”, which was familiar in the supersonic COIL both in simulation and experimental results.