Study On Some Problem About Pressure Recovery Of The Combustion Driven DF/HF Chemical Laser

The continuous wave DF/HF chemical laser is widely used in the field of industry and military affairs. In order to be convenient for use ,reducing the volume of the whole laser system has become the important goal for the designer .The pressure recovery system (PRS) takes up the most of the volume of the laser system .So, to study on how to improve the recovered pressure of the laser can reduce the burden of the PRS at the end of the laser system ,then the volume of the whole laser system can be reduced . It is that the paper's significance is .Firstly ,the structure of the continuous wave DF/HF chemical laser is illuminated here and the principle of the PRS is the emphases . Then ,the one dimensional model is used to study on some factors (viscosity ,the heat given out by the chemical reaction in the chemical laser) which bring the loss of the total pressure .The answer shows that increasing the mach number at out of the nozzles in the laser can reduce the loss of the total pressure . And the whole laser system including PRS is modeled with one dimensional gas dynamics .The answer shows that the pressure at the out of the nozzles in the laser is the most important factor that affects the PRS .Secondly ,the CFD method is used to study the flowfields in the laser chamber and the loss of the total pressure in several types of nozzles .The answer shows that reducing the length of the nozzles and the high of the throats in the nozzles can reducing the loss of the total pressure .And the answer also shows that the small nozzles with helium injected in the base region are good for laser chamber pressure recovery .Thirdly ,the structure of ejecting in the base region with unmatched pressure (SEBUP) is introduced .The SEBUP can produce a high average pressure in the laser chamber ,while the low pressure which is needed by the active medium is set up locally too .The steady flowfields and the unsteady flowfields in start-up course of SEBUP are also simulated with CFD method ,and the experiment of SEBUP is made .The...