Improved six-temperature model and simulation for dynamics of high-power TEA CO2 lasers considering effect of hydrogen

Abstract

Six-temperature model is a main model to simulate dynamics of molecular gas lasers including transversely excited atmospheric-pressure (TEA) CO₂ lasers. We propose a method to predict the effect of hydrogen on the dynamics of TEA CO₂ laser by the six-temperature model. A new term was added to the six-temperature model to allow for the interaction of hydrogen with the gas mixture. We also determined some relaxation times of the molecular energy levels from the vibrational energy exchange rates between hydrogen and the gas mixture. The system of ordinary differential equations including five energy densities, ambient temperature and light intensity was simulated using the standard Runge-Kutta method. The simulation results were also compared with the experimental results in the literature to verify the accuracy of an improved six-temperature model and simulation method. Using the proposed method, the optimum gas mixture ratio, total pressure, laser cavity and discharge gap geometry can be theoretically determined and these values will be very useful for high-power TEA CO₂ laser design.