| Summary: | 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.
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