Comparison of subsonic and supersonic mixing mechanisms for the chemical oxygen-iodine laser (COIL) using computational fluid dynamic (CFD) simulations

Abstract

Simulation of chemical lasers such as the chemical oxygen-iodine laser (COIL) laser is of timely interest due to ongoing commercial and military development programs. Accurate models of the gas dynamics and chemistry within a COIL have been developed using Computational Fluid Dynamics (CFD) codes, matching data from experiments designed to probe these physics. This work details the use of these codes to investigate the supersonic injection of molecular I2 and atomic I into the supersonic region of the O2(1?) flow in the COIL, and compare these results with a simulation of sonic injection of I2 into the subsonic region of the O2(1?) flow. The performance of each of these injection mechanisms is characterized by the theoretical power extracted from a Fabry-Perot resonator model, which then serves as the primary basis for comparison. Additional quantities such as power available and chemical efficiency are used to compare and contrast the performance of each concept. Based on these comparisons, the supersonic-supersonic injection methods demonstrate a performance increase over the traditional subsonic methods, with supersonic injection of I atoms providing the greatest performance increase.