Two main processes are playing the key role during formation of the COIL active medium: mixing and chemical reactions. The mixing control is extremely important for the optimal operation of the laser. Experimental optimization of mixing is not enough effective, because the outcome of laser experiments depends of all subsystems. Numerous attempts to find "optimal" nozzle design confirm this. By the other hand, the full-scale 3D numerical simulation is hard enough and deep parametric study is impossible by this way. Only final numerical test of the system as a whole can be fulfilled. Taking this into account, the simplified models are very important. New two-layer simplified model developed and tested in the paper based on 1D gas-dynamic approach. The simplest model of mixing include two separate flows. Each flow is described by separate set of 1D differential equations. Mixing is modeled by source terms in convection equations. Mixing rate is considered as external parameter. The main idea is to close uncertain mixing phenomena by phenomenological model. After this wide parametric study should give us the ranges and possibilities of mixing control. This approach help us to clarify the mixing rate which is optimal from point of view of laser operation.
Andrew V. Savin, Andrew V. Savin,
"Two-layer gas dynamic model of COIL active medium", Proc. SPIE 5447, Lasers for Measurements and Information Transfer 2004, 544705 (16 February 2005); doi: 10.1117/12.610607; https://doi.org/10.1117/12.610607