Mixing/reacting zone structure and small signal gain coefficient of a supersonic flow chemical oxygen-iodine laser

Abstract

The flow field of a supersonic flow chemical oxygen-iodine laser is simulated solving three-dimensional Navier-Stokes equations, and the dependence of the mixing/reacting zone structure and the resulting gain region on the effective velocity ratio of I<SUB>2</SUB> jet to the primary flow is studied. It is assumed that the flow is laminar and the water vapor condensation due to the supersonic cooling is ignored. A chemical kinetic model encompassing 21 chemical reactions and 10 chemical species is used to determine the chemical composition of gas mixture. The I<SUB>2</SUB>He ratio and plenum pressure of the secondary flow are varied in order that the amount of iodine injected into the primary flow is kept constant in each effective velocity ratio. The present results demonstrate that a pair of contrarotating vortices generated behind the I<SUB>2</SUB> jet greatly enhances the mixing and the simultaneous chemical reaction of I<SUB>2</SUB> and O<SUB>2</SUB>(<SUP>1</SUP>$DELTA). It is shown that the optimum condition for the secondary I<SUB>2</SUB> jet momentum exists. The I<SUB>2</SUB> jet which causes the high gain penetrates into the primary flow moderately deeply and does not collide with the counter one.