Fyzikální ústav Akademie věd ČR

Investigated with a financial support of the US Air Force Research Laboratory, Kirtland AF Base, NM, USA, via the Grant of the USAF EOARD (European Office for Aerospace Research and Development) (see Projects)

Experimental and theoretical research on a centrifugal spray generator of singlet oxygen (Centrifugal Spray Singlet Oxygen Generator) for a COIL (Chemical Oxygen-Iodine Laser)

A centrifugal spray generator of singlet oxygen (CentSpraySOG), originally designed and constructed for pumping a chemical oxygen-iodine laser (COIL), has two main advantages against other generators employed so far in the COIL technology: (i) gaseous singlet oxygen O₂(¹Δ), formed by a chemical surface gas-liquid reaction, is generated in a spray reaction system with large specific surface area, which results in increased reaction efficiency, (ii) the centrifugal force of rotating separator is used for efficient separation of liquid spray from generated O₂(¹Δ). A design of experimental device of CentSpraySOG was based on a detailed theoretical modelling of kinetics of O₂(¹Δ) production in the spray system and hydrodynamic modelling of the separation process, taking into account also O₂(¹Δ) losses in the whole device by homogeneous and heterogeneous quenching. By extensive experimental study, optimal conditions for the generator operation were found (e.g., gas and liquid input flow rates, pressure in the generator, a rotation speed of the separator, etc.) with respect to output generator parameters important for the COIL operation. Quantitative measurements showed that O₂(¹Δ) could be generated in the spray system with a high yield (~70%) at even very high pressure in the generator (up to 90 kPa), and the centrifugal separator could separate aerosol droplets of the diameter 0.5-2 µm from generated O₂(¹Δ) at 7000-9000 r.p.m. Possibility of O₂(¹Δ) generation at high pressures in the generator has advantageous consequences for a fluid dynamics of continuous COIL. Exceptional feature of CentSpraySOG is also a very high liquid utilization in the spray reaction system, which has a practical consequence. Currently, CentSpraySOG is prepared for testing on the COIL available in our laboratory.