Numerical Investigation of the Flow Characteristics in an Aerodynamic Window

• Main Authors: Te-Biung Shih, 史德彬
• Other Authors: Shen-Min Liang
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/48431937581283666416

碩士 === 國立成功大學 === 航空太空工程學系 === 82 === The function of any aerodynamic window is to provide a means of isolating a low-pressure laser cavity from the atmosphere while enabling a laser beam to pass through the gas flow. In order to produce the flow of the aerodynamic window, we must have a non- symmetric nozzle, which can produce shear flow. The flow structure of such a non-symmetric nozzle is complicated. To see the complicated flow field of the non-symmetric nozzle, the purpose of the present study is to simulate and analyze it's flow field. We assume steady, two-dimensional, homentropic, and isoenergetic flow of a perfect gas. To solve the Euler's equation numerically, the upwind TVD method proposed by Yee and Harten[15]is used, in conjuction with the control volume and characteristic methods. On comparing the flow field results of two aerodynamic window with designed Mach number ratio of 1.6/3.0, and 1.2/3.2, it was observed the all of them can produce a very uniform supersonic shear flow in the free vortex type shear flow generation section. To prove that the present numerical method can properly simulate this physical problem, we compare the pressure, Mach number, and the pressure difference of the exit plane with the theorem values. We find that our results is accurate. In this study, we replace the sharp corner throat of minimum-length nozzle(MLN) by a circular- arc. We find that the pressure difference of the exit plane is not changing. This prove that the replacement of sharp corner throat by a circular-arc is suitable.