Numerical simulation of throat-mixing system for supersonic flow chemical oxygen-iodine laser

Abstract

Throat-mixing systems for the supersonic flow chemical oxygen-iodine laser (SCOIL) are proposed and assessed in the present study. Three-dimensional, numerical simulation solving compressible gas dynamics together with chemical kinetics has been made for investigating the characteristics of the mixing condition and chemical reactions. The compressible Navier-Stokes equations and a chemical kinetic model encompassing 21 chemical reactions and 10 chemical species are solved by means of full-implicit finite difference method. Two types of nozzles, a Laval nozzle and cylinder nozzle are adopted. The results show satisfactorily high values of the small signal gain coefficient (SSG). The SSG value increases along the flow in the nozzle in relatively short distance of x, reaches to the maximum at the position of 25 ~ 47 mm distant from the throat, and decreases slightly downstream the flow. The proposed throat-mixing system shows higher efficiency than the supersonic parallel-mixing system. The Laval nozzle is found to give the peak SSG value of 40 % higher than that of the parallel-mixing system. It is also noted that the cylinder nozzle has superior ability than the parallel-mixing system, in spite of its exceedingly simple structure.