Conception Research And Nozzle Design And Simulation Of Air-breathing Gas Dynamic Lazer

Air-breathing gas dynamic laser is developed as a new conception based on ramjet and gas dynamic laser. In this thesis, a series of problems are researched, such as basic concenption of air-breathing gas dynamic laser, nozzle design and simulation, performance analysis, design of experimental facility, and so on.In the design of convergent part of nozzle, method of velocity surface in complex function is used. In the design of divergent part of nozzle, method of characteristic curves and method of minimum length nozzle are used respectively. Merits and faults of the two methods are generalized through analysis and comparison. In the simulation of nonequilibrium flow in nozzle, the relaxation model of two vibration modes and three temperatures and the two steps MacCormack explicit format are used. Through simulation, on one hand, the validity of algorithm is verified; on the other hand, the case of producing laser in air-breathing gas dynamic laser in the condition of low chamber pressure is discussed.Against two parameters of maximum available laser energy and small-signal gain coefficient, performances of air-breathing gas dynamic laser in different work conditions are calculated, analysed and compared carefully. The results indicate that laser can't be produced in some work conditions because there is no population inversion happening. The total pressure in combustion chamber has a small effect on maximum available laser energy but has a big effect on small-signal gain coefficient. With the increasing of total pressure in combustion chamber, the small-signal gain coefficient increases gradually. All of these will provide important reference for the design of air-breathing gas dynamic laser.