The Study Of Supsunic Free-Vortex Aerodynamic Window And Its Optical Quality

In fields of high power laser apparatus, the high power aerodynamics laser and the high power chemical laser are the most progressing light source at present. Because the working media of laser is gas, and the pressure difference between the inner apparatus and environment of laser is large, so the window of output laser beam must be sealed. Due to the inevitable absorption of crystal window, the crystal window will be distorted even burst while the power of high energy laser apparatus is several hundred thousand watt even mega-watt, so the quality of laser beam will be influenced and the laser apparatus will not work properly. The free vortex aerodynamics window is used to be the window of high power laser beam, which takes advantage of the centripetal force of the free vortex motion of fluid.The fundamental thought of this paper is to research the principle the design method of free vortex aerodynamics window, then the free vortex field jet is designed with equal-entropy relation, and the asymmetry free vortex nozzle is designed with character line method. In order to validate the effectiveness of design, we applied numerical methods to research the field of asymmetry nozzle and that of free vortex aerodynamics window. Some problems will come up because of the influence of viscous and the real conditions, so the experiment method is adopted solve these problems.This paper contains two parts, one is the principle, design method, experiment research and test of supersonic free vortex aerodynamics window, the other is the research of optics performance in relation to jet shear layer of supersonic free vortex aerodynamics window..First, the importance of high power laser in military and industry and critical effect of aerodynamics window in high power laser system is introduced in this paper, also the survey of foreign research about aerodynamics window and the special advantages of supersonic free vortex window is introduced. The problem of aerodynamics and optics in researching aerodynamics window is analyzed, the importance of developing supersonic shear layer optics technique and its applications in aerodynamics window are put forward. The possible difficult problems which might be met in numerical and experimental research about supersonic shear layer optics technique are also analyzed in this paper.Two aerodynamics layouts of free vortex aerodynamics window geometry is put forward, then the parameter distribution of the field about free vortex aerodynamics window is deduced in detail, then we get the distribution about pressure, density, temperature and Mach number in field of aerodynamics window, the mass flow rate of the working gas in supersonic free vortexThe design method of free vortex nozzle, in which the parameter of outlet is free vortex distribution, is put out and researched. The design process of free vortex nozzle is inferred with character line method. The SSL-MLN design method of nozzle symmetry part is improved and optimized. In the improved method, arc transition is adopted in the throat, as a result, the quality of flow field is improved and the length of nozzle is minimized. The integrative software of free vortex nozzle design and shape line of nozzle wall is edited, then the numerical simulation of the flow field of free vortex nozzle is proceed, and the result shows that the structure of flow field designed in this paper satisfied designed demand, and the flow parameter distribution of free vortex jet is achieved in the outlet of nozzle.The performance of aero-optic performance of free vortex flow field is researched, and the transmit trail of beam in free vortex field is simulated by numerical method, the distribution of light length difference along the trail is worked out, then the aerodynamics lens effect of beam, which is generate by the free vortex aerodynamics window, is analyzed. In order to optimized optic performance of supersonic shear layer, the pressure matched and refractive index matched design method is put out in designing supersonic free vortex aerody...