JP4081550B2 - Fluidic thrust deflection nozzle with two-stage expansion nozzle - Google Patents

Description

  The present invention relates to a jet engine, a rocket engine, and the like having a convergent and divergent nozzle, and more specifically to a fluid having a two-stage expansion nozzle capable of realizing thrust deflection in a secondary flow with a low flow rate and reduction in thrust loss when no deflection occurs. The present invention relates to a dick thrust deflection nozzle.

  In general, an exhaust nozzle of a jet engine having a convergent / divergent nozzle expands and accelerates the gas passing through the combustion chamber 1 through the convergent part 2 and the divergent part 4 as shown in FIG. It is ejected and thrust is generated by its reaction. Under the condition that the exhaust speed exceeds the sonic speed, the gas speed passing through the throat portion 3 is the sonic speed, and the divergence portion 4 increases the speed to exceed the sonic speed and exhausts.

  The thrust is deflected by changing the ejection angle of the exhaust flow.

  At present, thrust deflection realized in aircraft is achieved by mechanically changing the main flow direction using a movable nozzle, a flap, or the like.

  However, since this method requires the addition of a mechanical movable mechanism, the complexity and weight of the movable part increase the performance of the aircraft.

The fluidic thrust deflection method (see the following non-patent document) can realize thrust deflection with a fixed nozzle, and therefore does not require a complicated mechanical mechanism. Therefore, it is expected to be a next-generation thrust deflection mechanism because it can improve reliability and reduce weight and cost compared to a mechanical thrust deflection mechanism.
Karen A. Deere, "Summary of Fluidic Thrust Vectoring Research Conducted at NASA Langley Research Center", AIAA Paper 2003-3800

Conventionally, the following are mentioned as means of fluidic thrust deflection nozzles.
(1) Method of Flowing Counterflow As shown in FIG. 6, this method provides a secondary flow 5a by providing a wall outside the nozzle and sucking the space between the outer wall 10 and the exhaust flow from the nozzle upstream. However, there is no effective suction method, and there are many disadvantages such as problems with the integration of the external wall and the aircraft, and it has not been put into practical use.

(2) Method of changing the throat position As shown in FIG. 7, this method aerodynamically changes the throat position by ejecting the secondary flow 5a to the throat section 3, and the resulting asymmetry on the nozzle surface However, there is a problem that it is difficult to achieve a large deflection angle.

(3) Method Using Shock Wave This method generates a diagonal shock wave by jetting the secondary flow 5a from the divergent section 4 and deflects the main flow passing through the shock wave 8 as shown in FIG. However, since the divergence angle of the divergent must be increased in order to deflect, there is a problem that an overexpanded flow with a large thrust loss occurs when there is no deflection.

  As described above, all the fluidic thrust deflection systems proposed in the past have problems. The present invention was made to solve the above-mentioned problems of the conventional fluidic thrust deflection system, and can achieve thrust deflection in a secondary flow with a low flow rate and a reduction in thrust loss during no deflection with a simple structure. An object is to provide a jet engine having a fluidic thrust deflecting nozzle.

  In order to solve the above problems, the present invention provides a jet engine and a rocket engine having a convergent and divergent nozzle, wherein a secondary flow injection hole is disposed at the engine nozzle outlet, and further, the same angle as the target deflection angle is provided outside thereof. A two-stage enlarged portion is provided.

As described above, by providing the two-stage enlarged portion at the engine nozzle outlet, the exhaust flow deflected by the secondary flow ejection can be further deflected by the Coanda effect.
Further, when no deflection is applied, the secondary flow ejection holes provided on the entire circumference are opened to the atmosphere, so that the thrust loss of the overexpanded flow can be reduced by the ambient air drawn in by the ejector effect.

  Next, examples will be described. FIG. 1 is a schematic configuration diagram showing an embodiment of a fluidic thrust deflection nozzle having a two-stage enlarged nozzle according to the present invention. In FIG. 1, 1 is a combustion chamber, 2 is a convergent part, 3 is a throat part, 4 is a divergent part, and these structures are the same as those of the prior art. 6 is a two-stage enlarged portion according to the invention for further deflecting the exhaust flow deflected by the secondary flow 5a of FIG. 2 supplied into the nozzle from the secondary flow ejection hole 5, and is the same as the target deflection angle. It has a spread angle. An exhaust secondary flow is supplied to the secondary flow ejection holes 5 via secondary flow supply holes 11 formed in a branched shape in the nozzle body. A large number of secondary flow ejection holes 5 are densely provided at substantially equal intervals so as to open to substantially the entire circumference of the inner and outer walls of the nozzle. As shown in FIG. 2, for thrust deflection, the secondary flow 5 a is ejected from the ejection hole 5 opposite to the direction in which the deflection is performed, and supply is not performed from the other ejection holes 5.

  In the system of the present invention, the divergent section 4 having a divergence angle in consideration of the normal nozzle efficiency is expanded up to the deflection start point, and then the overexpanded flow (FIG. 3) in the two-stage expansion section 6 is caused by the three-way valve 7. Thrust loss can be reduced by the ambient air 9 drawn by closing the secondary flow supply side and opening the secondary flow ejection holes 5 provided on the entire circumference to the atmosphere (FIG. 4). Therefore, even if the divergence angle of the two-stage enlarged portion is designed to be larger for the purpose of further increasing the target deflection angle, it is possible to prevent an increase in thrust loss during no deflection.

  As described above based on the embodiments, according to the present invention, since the divergent portion designed in consideration of the normal nozzle efficiency is provided with the two-stage expansion portion for thrust deflection, all of the non-deflection times are provided. Thrust loss can be reduced by opening the secondary flow ejection holes provided in the periphery to the atmosphere, and thrust can be further deflected by the Coanda effect at the time of thrust deflection. Therefore, thrust can be deflected by a secondary flow with a low flow rate. In the above description, the secondary flow supply side and the atmosphere release side are opened and closed by the three-way valve, but a method of providing valves on both the secondary flow supply side and the atmosphere release side may be used.

It is sectional drawing which shows the structural example of the fluidic thrust deflection | deviation nozzle which has a 2 step | paragraph expansion nozzle which concerns on this invention. It is a figure which shows the aspect at the time of the same thrust deflection | deviation. It is a figure which shows the aspect at the time of the same non-deflection. It is a figure which shows the aspect at the time of the non-deflection by the secondary flow ejection hole air | atmosphere release system. It is sectional drawing which shows the structural example of the conventional jet engine. It is sectional drawing which shows the structural example of the conventional fluidic thrust deflection nozzle. It is sectional drawing which shows the structural example of the other conventional fluidic thrust deflection | deviation nozzle. It is sectional drawing which shows the structural example of the other conventional fluidic thrust deflection | deviation nozzle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Combustion chamber 2 Convergent part 3 Throat part 4 Divergent part 5 Secondary flow ejection hole 5a Secondary flow 6 Two step expansion part 7 Three-way valve 8 Shock wave 9 Ambient air 10 External wall 11 Secondary flow supply hole

Claims (3)

In jet engines and rocket engines with convergent and divergent nozzles, a secondary flow injection hole is provided on the entire circumference of the divergent outlet, and the secondary flow is discharged from the secondary flow injection hole on the opposite side to the direction of deflection. A two-stage expansion nozzle that deflects thrust in a secondary flow with a low flow rate by the Coanda effect by deflecting thrust and providing a two-stage expansion section at the same angle as the target deflection angle in the exhaust section Having fluidic thrust deflection nozzle. The secondary flow ejection hole opens on the inner wall and the outer wall of the divergent outlet, and shuts off the secondary flow supplied to the secondary flow ejection hole by operating an on-off valve or an arbitrary opening on the inner wall side. A fluidic thrust deflection nozzle having a two-stage enlarged nozzle according to claim 1, wherein the nozzle is freely ejected from the nozzle. The two-stage enlarged portion shuts off the supply of the secondary flow to the secondary flow ejection holes when there is no deflection, and opens the secondary flow ejection holes provided on the entire circumference to the atmosphere. 3. A fluidic thrust deflection nozzle having a two-stage expansion nozzle according to claim 1, wherein thrust loss due to the expansion flow can be reduced.

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