This report describes the experimental and theoretical analysis of a cross-flow jet-type singlet oxygen generator (cross-flow J-SOG) in order to identify the optimal conditions needed to satisfy the ejector-COIL requirement. The optimal conditions had been analyzed under various generator geometries (reaction region length, jet diameter, and chlorine inlet height), gas/BHP flow rates, and gas pressures. The performance was achieved Cl2 utilization of 90% and O2(1Δ) yield of 70% at the plenum pressure of 20 Torr.
Chemical oxygen-iodine laser (COIL) has a great potential for applications such as decommissioning and dismantlement (D&D) of nuclear reactor, rock destruction and removal and extraction of a natural resource (Methane hydrate) because of the unique characteristics such as power scalability, high optical beam quality and optical fiber beam. Five-kilowatt Chemical oxygen-iodine laser (COIL) test facility has been developed. The chemical efficiency of 27% has been demonstrated with a moderate beam quality for optical fiber coupling. Our research program contains conventional/ejector-COIL scheme, Jet-SOG/Mist-SOG optimization, fiber delivery and long-term operation.
Chemical oxygen-iodine laser (COIL) has a great potential for applications such as decommissioning and dismantlement (D&D) of nuclear reactor, rock destruction and removal and extraction of a natural resource (Methane hydrate) because of the unique characteristics such as power scalability, high optical beam quality and optical fiber beam. Five-kilowatt Chemical oxygen-iodine laser (COIL) test facility has been developed. The chemical efficiency of 27% has been demonstrated with a moderate beam quality for optical fiber coupling. Our research program contains conventional/ejector-COIL scheme, Jet-SOG/Mist-SOG optimization, fiber delivery and long-term operation.
A cross flow jet SOG has been developed in Miki Pulley Co. Ltd. to supply O2(1D) for different types of COILs. Performance testing of the SOG has been conducted through a wide range of gas pressures (5~40 Torr), specific surface areas (4~7 cm-1), gas velocities (5~30 m/s), and gas temperatures to characterize and optimize the device. The inflow and out flow of the reactants and products, including O2(1D), Cl2, H2O were measured using optical and conventional techniques. The gas temperatures in the measurement duct were estimated from stagnation pressures, mass flow rates, and critical cross section at the gas chocking point in order to determine the partial pressures of the gas products at the measurement point. Calibration method of the O2(1D) measurement suggested by Zagidullin is basically employed with a slight correction of upper limit definition of O2(1D) yield associated with the pooling loss, which remains even at the minimum P t condition of our device. Assuming that the gas temperature after passing through the jets is equilibrium with that of the BHP jets (-18 degree Celsius) in our calibration condition, the upper limit yield can be derived from the increase in the gas temperature. The estimated value of the yield limit was 94 %. A wide range of output values (40-95 % of Cl2 utilization, 50-90 % of O2(1D) yield) was obtained and analyzed to characterize the device. As a result of optimization, a 27 % of chemical efficiency was obtained when Cl2 utilization was 95 %, O2(1D) was 90 %, O2 partial pressure was 6.7 Torr, and N2 dilution ratio was 2. Discussion on the validity of the gas temperature estimation method is provided by comparing the results to the heat release based on the pooling model.
KEYWORDS: Diffusers, Throat, Iodine, Chemical oxygen iodine lasers, Laser resonators, Chemical analysis, Chemical reactions, Molecules, Laser development, Chemical lasers
Optimization of iodine injection scheme was conducted in Miki Pulley Co., Ltd. using CFD approach. Variation of the mixing speed as a function of an I2 jet penetration depth, nozzle expansion ratio, and I2 injection point are analyzed. It was found that the inherent geometry of our nozzle and I2 injector affects the I2 mixing process. Influence of a backpressure to the cavity flow condition was also investigated in order to estimate the pressure recovery capability of our diffuser. The normal shock based diffuser efficiency for Mach=2.7 flow was 54.5%.
Miki Pulley has pursued the development of a prototype COIL module for field and industrial applications since its transfer from Tokai University in 2000. The test module has already been constructed in our laboratory. The current status of the development is presented. The achieved chemical efficiency was 17.5% at the chlorine flow rate of 13.2mol/min. The corresponding laser power was 3.5kW.
Laser medium parameters of multi-kW grid nozzle supersonic Chemical Oxygen Iodine Laser (COIL) were experimentally studied. Small-signal gain (SSG) diagnostics was done by a narrow line width tunable laser by scanning 1 GHz range around (2P1/2 ) - (2P3/2) spin-orbit transition line of atomic iodine. SSG was investigated as a function of Mach number and gas flow rates. Modeling of gain for different flow conditions was done as well. Multi-kW COIL device was recently developed in Miki Pulley Co., Ltd. (Japan) and has 37.5 cm length of active medium.
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