Development Of OpenFOAM-based Numerical Simulation Program Of Vibrational Non-equilibrium Nozzle Flow Of Gasdynamic Laser And Its Application

Recently, gasdynamic CO2 laser(GDL) is widely concerned for it has new applications in areas such as beamed energy propulsion, small-scaled high power laser, etc. In this paper, the author developed a simulation program and applied it in research to fulfill the demand for making higher efficient GDL.Transport models and turbulent models which hasn’t been provided by OpenFOAM were applied, and solvers for the premixing and mixing gasdynamic laser were founded as well as the relevant pre-processing and post-processing programs. This work will be described in details in the paper, including the problems which met in the process of developing them.Through analysis of flow parameters, vibrational parameters and some deduced parameters in GDL nozzle flow, the relation between the performance of the nozzle and the flow and vibrational process were obtained: The flow parameters influence the distribution of the vibration time of each vibrational process, and then influence the distribution the changing rate of average vibrational numbers, thus changing the vibrational processes. Also the vibrational processes could influence the flow process by transferring energy to the transition. After doing this work, the mechanism of how working parameters of the nozzle influence its performance through influencing the flow and vibrational processes was investigated. And then, the performance of MLN and ALN in GDL was compared, and the ALN nozzle was optimized. It seemed that ALN can be optimized to improve efficiency by only changing the vibrational processes in the nozzle. By now, the nozzles used in GDL are designed only considering the flow characteristics, and ALN nozzle brings the hope to design nozzles for GDL taking into consideration of vibrational processes.The theoretical analysis of an advanced mixing CO2 GDL nozzle was carried out. The simulation of the vibrational non-equilibrium flow and its analysis were used to investigate the influence of working parameters such as total pressure, total temperature, the content of H2 O of the nozzle on the small signal gain field of it initially.