Flight vehicle with air inlet isolator having wedge on inner mold line
A flight vehicle engine includes an isolator with a swept-back wedge to improve flow mixing. The wedge includes forward shock-anchoring locations, such as edges or rapidly-curved portions, that anchor oblique shocks in situations where the isolator has sufficient back pressure. The swept-back wedge may also create swept oblique shocks along its length. Boundary layer flow streamlines are diverted running parallel to or parallel but moving outward conically to the swept-wedge leading edge moving outboard and upward. The non-viscous flow outside the boundary layer is processed through the swept-back ramp shock and diverted outboard and upward as well. The outboard aft portion of the wedge at the sidewall intersection may also induce shocks and divert flow near the walls closer toward the walls and upward, and/or improve flow mixing.
1. A flight vehicle comprising:
a fuselage; and
a propulsion system mechanically coupled to the fuselage;
wherein the propulsion system includes:
an air inlet;
an isolator downstream of the air inlet; and
a combustor downstream of the isolator where fuel is added; and
wherein the isolator includes a swept-back wedge on an inner surface of the isolator, with the isolator having a rounded perimeter at an axial location of the swept-back wedge;
wherein in operation a forward part of the wedge produces an oblique shock, and features of the wedge divert boundary-layer and core flow that is close to a surface of the wedge, radially outboard and circumferentially along the walls of the isolator as the flow proceeds axially downstream through the isolator, to improve flow mixing;
wherein the swept-back wedge is a band around the rounded perimeter of the isolator, with the band angled relative to an axial direction along the isolator; and
wherein the band is tapered, with a compression angle decreasing from a maximum value to a minimum value that is less than the maximum value.
2. The flight vehicle of claim 1 , wherein the features of the wedge are an aft part of the wedge.
3. The flight vehicle of claim 2 ,
wherein the forward part of the wedge is at a bottom-centerline of the isolator; and
wherein the aft part of the wedge is along outboard sides of the isolator.
4. The flight vehicle of claim 1 , wherein the oblique shock produced at the forward part of the wedge due to back pressure impositions is part of a shock train that also includes an additional oblique shock produced at a location on the isolator that is on an opposite side of the isolator, opposed from the forward part of the wedge.
5. The flight vehicle of claim 1 , wherein the forward part of the wedge is at a bottom of the isolator, wherein the bottom of the isolator is farthest from the fuselage.
6. The flight vehicle of claim 5 , wherein the wedge has a maximum compression angle at the forward part, wherein the maximum compression angle is the maximum angle in a direction away from the inner surface, where the wedge is joined to the inner surface.
7. The flight vehicle of claim 6 , wherein the compression angle tapers from the maximum at the bottom to a minimum at the aft part of the wedge, along sides of the isolator.
8. The flight vehicle of claim 6 , wherein the maximum compression angle of the wedge is 5°-50°.
9. The flight vehicle of claim 6 , wherein the maximum compression angle of the wedge is 10°-30°.
10. The flight vehicle of claim 1 , wherein the wedge has a sweep back angle, swept back in an axial flow direction, of 20°-75°.
11. The flight vehicle of claim 1 , wherein the swept-back wedge transitions to be flush with walls of the isolator downstream of the wedge.
12. The flight vehicle of claim 1 , wherein the wedge has a sweep back angle, swept back in an axial flow direction, of 45°-65°.
13. The flight vehicle of claim 1 , wherein the band has varying wedge angle along the rounded perimeter, with a steepest wedge angle at a bottom of the isolator, furthest from the fuselage, and a reduced wedge angle at sides of the isolator.