Numerical Investigation of Jet Injection into a Supersonic Cross Flow with Impinging Shocks
The goal of this research is to numerically evaluate
non-reacting fluid flow in the combustion chamber of a scramjet
engine. Numerical analysis will be completed using the steady
state and unsteady Reynolds Averaged Navier Stokes (RANS)
equations. Three cases will be evaluated, a single flush wall
circular injector, a diamond-shaped flush wall injector and an
"aeroramp" injector which consists of four flush wall
injectors arranged in a square pattern. The flow will be
studied both with and without the presence of an upstream shock
that impinges on the injected fuel. Determining and
understanding the effect of shocks when imposed on the fuel
injection system can help improve mixing capabilities which in
turn improve engine performance. In addition, the study of
numerical prediction of three-dimensional, turbulent, unsteady,
supersonic flows is of great interest to the scientific
community for the ongoing advancement in numerical
analysis.
The calculations for this research were performed on Enterprise, a 512 processor SGI Origin 3800
supercomputer which is operated by the Virginia Tech Department
of Aerospace and Ocean Engineering.
Credit to Theresa Campioli for the images and work
represented on this page.
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 | | Picture 2. Description below. |
 | | Picture 3. Description below. |
Pictures 1, 2, and 3: Vorticity contours (red
- highest intensity and blue - lowest intensity) of the
aeroramp injector configuration. Flow is moving left to right.
Picture 1 includes a vertical slice down the centerline of the
flowfield (shown alone in Picture 2) and a horizontal slice
half a diameter from the surface (shown alone in Picture 3).
These picture shows evidence of shocks forming from the front
and rear sets of injectors as well as a horseshoe vortex that
is present near the surface. As the vorticity diffuses with the
flow downstream, the injected mass is mixed with the
freestream. The injection into a supersonic crossflow creates
two counter rotating vortices that rotate up the centerline
from the surface and then away from the centerline. The
behavior of one of the vorticies can be seen in the transverse
slices that progress downstream. (Nov - Dec
2005)
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Pictures 4 and 5: Combination of vorticity
contours and iso-surfaces for the aeroramp injector. Flow is
moving left to right (red - highest intensity and blue -lowest
intensity). Picture 4 includes only a horizontal plane.
Picture 5 includes both horizontal and vertical planes. The
iso-surfaces visualize surfaces of constant vorticity. The rear
injectors lift the plume of the front injectors further away
from the surface allowing less mass to be captured in the near
surface region. (Dec 2005)
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 | | Picture 7. Description below. |
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Pictures 6, 7, and 8: Aeroramp vorticity
iso-surfaces. Each picture represents a different intensity of
vorticity. (Dec 2005)
 | | Picture 9: Single orifice injector iso-surface
of constant voriticity. (Jan 2006) |
 | | Picture 10: Vorticity contours (red - highest
intensity and blue -lowest intensity) of the single
orifice injector configuration. Flow is moving left to
right. The shock caused by the injection can be seen
upstream of the injector as well as a bow shock created
by the expansion of the gas into the freestream. The
intensity of the shock is of concern because of the
large total pressure losses they produce. Total
pressure loss hinders engine performance. (Jan 2006) |
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