Kinetics and structure of the CS2/O2 flame laser

Abstract

This thesis is a study of the interactions of chemical kinetics, relaxation processes, and low-speed fluid mechanics for the deflagration of gaseous carbon disulfide and oxygen under conditions for which laser action has been demonstrated. A four-reaction branching chain reaction mechanism is deduced from experimental evidence and reaction rates to represent the chemical kinetics of CS2/O2 combustion. This chain mechanism is used to explain some explosion phenomena and to obtain the initial conditions and initial chemical kinetics expected for the different types of CS2/O2 chemical lasers. The dynamics of chemical population and relaxation, including selective depopulation, of the vibrational levels of CO are discussed. Three analytical methods are employed to solve the premixed laminar flame problem for the CS2/O2 flame. The von Karman approximations and the thermal theory approximation are two of these methods; the third, which considers diffusion of only the chain carrier, is termed the single-species diffusion approximation. The flame speed, which is the eigenvalue of laminar flame propagation theories, was experimentally determined for the low-pressure CS2/O2 flame and compared to the magnitude and dependencies calculated by the analytic methods. Some qualitative measures of flame structure are compared to the calculated structure. Details are given for a multi-slit injector whose design allows complete control over mixing. Results for this burner and premixed configuration burners are discussed. CO emission spectra were taken from CS2/O2 flames and the relative vibrational populations determined. The rates of population of the upper vibrational levels are calculated from these experimental spectra.