| Summary: | 碩士 === 逢甲大學 === 機械工程研究所 === 85 === A numerical investigation is conducted to study the performance
of expendable supersonic Nozzles. An implicit numerical solution
is obtained for thecompressible Navier-Stokes equations in
conservative law form and generalizedcurvilinear coordinates.
Different turbulence models are assessed in terms oftheir
ability to predict the shock induced flow separation and the
associatedloss in afterbody/nozzle performance. A axisymmetric
afterbody/nozzle casewith freestream Mach number of 0.0 and 1.25
is calculated at nozzle pressureratio equivalent to 5.0 (over
expanded condition) to validate the effect ofdifferent
turbulence models. The following 3-D flow calculation is based
onthe similar strategy as the above axisymmetric nozzle case to
define the gridand boundary conditions. A long shroud with eight
vented nozzle is applied for3-D afterbody/nozzle flow
investigation. Two flow conditions, freestream Machnumber=0.0
and NPR=19.88, and freestream Mach number=2.5 and NPR=16.89,
areinvestigated for the effect of different turbulence models.
The prediction ofsurface pressure distributions, discharge
coefficient, and thrust minus dragcoefficient are compared to
the experimental data.
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