Mixing Nozzle Research Articles

CO chemical laser utilizing combustor-generated reactants

A CO chemical laser utilizing combustor-generated CS and S is described. The combustor is fueled with NF3-CH4-H2-CS2 and produces CS and S and the side products HF and N2. A common supersonic expansion mixing nozzle is used to extract the CS and S from the combustor and mix O2 and diluent (N2 or He) into the flow stream. A chain reaction between CS and O2 in the mixed flow stream, initiated by S atoms, produces vibrationally excited CO. The maximum power obtained from the laser was 700 W operating with He in a free expansion. Pressure and temperature measurements of the supersonic flow stream are compared with the results of a one-dimensional fluid-dynamics model, and the results of mass-spectrometric sampling are presented. It is concluded that the power extraction efficiency could be greatly improved by operation of the laser with either a combustor fuel–oxidizer combination that does not produce HF or an improved supersonic mixing nozzle. Nevertheless, it has been demonstrated that the output power of this device scales with mass flowrate.

Thermochemical generation of CS and S for CO chemical lasers

A thermochemical equilibrium calculation is compared with the experimental results of active mass spectrometric sampling of a high-temperature NF3-CH4-H2-CS2 flame. The predicted flow rate of the products HF, CS, N2, and CS2 is found to agree with the experimental data. The presence of S among the product species is inferred from a second experiment, in which the flux from the high-temperature combustor was extracted through a supersonic nozzle and mixed with a second supersonic stream containing He and O2. The flow rate of the reaction product CO determined during the latter experiment is compared with the flow rate predicted by a kinetics model of the chain reaction between CS and O2 initiated by small amounts of S. It is suggested that such a CS and S generator coupled with a supersonic mixing nozzle could be utilized to construct a completely chemical CO laser of any desired output power.

Supersonic mixing nozzle for gas-dynamic lasers

A supersonic mixing nozzle for CO2 gas-dynamic lasers is presented. It is shown that satisfactory mixing can be obtained with an increase of the freeze efficiency over simple expansion nozzles for premixed flows. Gain constants in the vicinity of 3% cm−1 are found, and a twofold improvement of the thermal-to-optical conversion efficiency over conventional GDL is predicted.

Topic of the Month—Corrosion Experience With a Mixing Nozzle For Dilute Sulfuric Acid

Topic of the Month—Corrosion Experience With a Mixing Nozzle For Dilute Sulfuric Acid