A new Chemical Oxygen-Iodine Laser (COIL) has been developed and demonstrated at chlorine flow rates up to 1 gmol/s. The laser employs a cross flow jet oxygen generator operating with no diluent. The generator product flow enters the laser cavity at Mach 1 and is accelerated by mixing with 5 gmol/s, Mach 5 nitrogen diluent in an ejector nozzle array. The nitrogen also serves as the carrier for iodine. Vortex mixing is achieved through the use of mixing tabs at the nitrogen nozzle exit. Mixing approach design and analysis, including CFD analysis, led to the preferred nozzle configuration. The selected mixing enhancement design was tested in cold flow and the results are in good agreement with the CFD predictions. Good mixing was achieved within the desired cavity flow length of 20 cm and pressure recovery about 90 Torr was measured at the cavity exit. Finally, the design was incorporated into the laser and power extraction as high as 20 kw was measured at the best operating condition of 0.9 gmol/s. Stable resonator mode footprints showed desieable intensity profiles, which none of the sugar scoop profiles characteristic of the conventional COIL designs.
The historical COIL contributions at the McDonnell Douglas Research Laboratory, the Rocketdyne Division of Rockwell International and Boeing's Laser and Electro-Optic Systems organization are briefly described. The latter organization now contains the capabilities of the two heritage organizations. Boeing's new high pressure sealed COIL is also described.