JP4164742B2 - Microwave reflection control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to suppression of reflection of microwaves by an inlet fan rotor blade of a turbo engine.
[0002]
[Prior art]
Some aircraft, such as fighter aircraft, do not like the image of the aircraft in the radar due to their strategy, and some aircraft require stealth. For this reason, stealth has been improved by devising the shape of the airframe surface and adding a radio wave absorber.
While devices for the airframe are being advanced, various devices have been made for the reflection of microwaves from the engine body. Since the engine side surface is usually covered with the shape of the airframe surface to improve stealth, the problem is microwaves that enter the engine through the duct and are reflected.
That is, as shown in FIG. 6, the duct 1 of the turbine engine is connected to the fan rotor blade 3 through the struts 4, the vanes 6, and the like. When the engine is stopped, the microwave incident from the duct by the curved surface portion of the fan rotor blade 3 is often diffusely reflected and attenuated. However, after the engine is started, the rotating fan rotor blade 3 becomes a reflection plane and directly reflects the microwave that has entered the duct 1.
Therefore, in the prior art, as shown in Patent Document 1, the shape of the air intake duct (intake) is bent, and the fan rotor blade is visually shielded, so that the microwave is reflected obliquely by the curved surface in the duct. In other words, the microwave incident on the fan rotor blade 3 is shielded and diffused by the curved surface, thereby suppressing the reflection of the microwave.
However, due to this duct shape, during the supersonic flight, separation of the intake air occurs and the pressure distribution in the duct becomes uneven, which causes a reduction in the operating range of the engine and greatly limits the operation of the aircraft. Therefore, in this prior art, as shown in FIG. 5, in order to suppress air separation, air is sucked in the duct by a compressor.
Moreover, in patent document 2, the peeling of the air at the time of supersonic flight was suppressed by providing the long duct which changes gradually, and suppression of a microwave reflection and the restriction | limiting of an aircraft operation were made compatible.
Further, in Patent Document 3 and the like, a similar effect was intended by providing a cavity having a radio wave absorber on the inner side in front of the duct.
[0003]
[Patent Document 1]
US Pat. No. 4,989,807 [Patent Document 2]
US Pat. No. 5,683,061 [Patent Document 3]
US Pat. No. 4,148,032 specification
[Problems to be solved by the invention]
However, each of these prior arts requires a special means for sucking the air in the duct, requires a very long duct, and the installation of the radio wave absorber increases the weight and limits the function of the aircraft. Therefore, there is a problem that the design of the shape of the entire aircraft is restricted.
The present invention has been developed to solve the above-described problems. In other words, unlike the prior art, the purpose is to reduce the influence of the engine's operating range and expand the range of aircraft operation by suppressing the reflection of microwaves without significantly changing the outer shape of the air intake duct. And
[0005]
[Means for Solving the Problems]
To achieve the above object the present invention includes a plurality of reflecting curved surfaces dividing the inlet duct (1) in the against the duct central axis release morphism shaped gas turbine engine (10), the reflection curved surface, the inlet Shielding and diffusing the microwave that enters the fan blade (3) from the duct (1), and suppressing the reflection of the microwave by the fan blade ,
A plurality of struts (4) mounted radially in the inlet duct have the reflective curved surface,
Each of the struts has one side surface and the other side surface in the circumferential direction around the duct central axis,
Both the one side surface and the other side surface extend from the upstream side of the air flow in the inlet duct to the downstream side of the air flow inclining from the direction of the duct central axis to the same one side in the circumferential direction. It is characterized in that the reflection curved surface .
[0006]
According to the configuration of the present invention, the reflection curved surface (2) composed of a plurality of curved surfaces in which the shape of the structure at the front end of the fan rotor blade (3) is devised without changing the outer peripheral shape of the inlet duct (1). By blocking the incidence of microwaves on the fan rotor blade (3), the reflection of the microwaves can be prevented. Furthermore, after the microwave is reflected obliquely with respect to the traveling direction, it is attenuated by being scattered a plurality of times inside the duct.
Unlike the case where the same effect is obtained by bending a conventional duct, the influence on the air flow in the duct can be kept low. Therefore, the pressure distribution of the inflowing air can be kept uniform, and the influence on the engine performance can be kept low.
[0008]
According to the above configuration of the present invention, the shape of the plurality of struts (2) is devised to be a reflection curved surface without changing the outer peripheral shape of the inlet duct (1), so that the micro blades to the fan rotor blade (3) can be obtained. By blocking the incidence of waves, the reflection of microwaves can be prevented. Furthermore, after the microwave is reflected obliquely with respect to the traveling direction, it is attenuated by being scattered a plurality of times inside the duct. The strut is essentially a structural member for supporting the nose cone (7) and the like.
Unlike the case where the same effect is obtained by using the conventional duct shape, the influence on the air flow in the duct can be kept low, and the pressure distribution of the inflowing air can be kept more uniform, thereby improving the engine performance. It becomes possible to suppress the influence of.
[0009]
In order to achieve the object of the present invention, the gas turbine engine (10) has a plurality of reflection curved surfaces that concentrically divide the inside of the inlet duct (1) with respect to the central axis of the duct. 1) shielding and diffusing the microwave that enters the fan rotor blade (3) from above, and suppressing the reflection of the microwave by the fan rotor blade;
A strut (4) is mounted in the inlet duct, and a circumferential guide vane extending in the circumferential direction around the duct central axis is spaced apart from the strut in a direction perpendicular to the duct central axis. There are several installed,
Each circumferential guide vane has one side surface facing the duct central axis side, and the other side surface facing the one side surface,
Both the one side surface and the other side surface are inclined in a direction perpendicular to the duct central axis and away from the duct central axis from the air flow upstream side to the air flow downstream side in the inlet duct. The reflection curved surface is formed by extending .
[0010]
According to the above configuration of the present invention, the microwave to the fan rotor blade can be obtained by devising the shape of the plurality of circumferential guide vanes (5) provided without bending the inlet duct (1) and forming a reflection curved surface. Can prevent the reflection of microwaves. Furthermore, after the microwave is reflected obliquely with respect to the traveling direction, it is attenuated by being scattered a plurality of times inside the duct.
The circumferential guide vane (5) is a mechanism for keeping the inflow direction, flow velocity and pressure of the air originally flowing into the fan rotor blade (3) optimal.
Unlike the case where the same effect is obtained by bending a conventional duct, the effect on the air flow in the duct can be kept low, and the pressure distribution of the incoming air can be kept more uniform, thereby affecting the engine performance. Can be kept low.
[0011]
In order to achieve the object of the present invention, the reflection curved surface suppresses reflection by a circumferential guide vane (5) and a duct having a similar shape with an interval from the outermost circumferential shape of the circumferential guide vane. It was characterized.
[0012]
According to the configuration of the present invention, the shape of the inlet duct (1) follows the shape of the circumferential guide vane (5), the cross-sectional area of the microwave incident on the fan rotor blade is reduced, and the reflection of the microwave is prevented. be able to.
That is, by simultaneously using the duct having the outer peripheral shape followed, it is possible to suppress the microwave from entering the duct, and to suppress the reflection of the penetrated microwave by shielding and diffusing with the circumferential guide vane.
[0013]
In order to achieve the object of the present invention, the reflection curved surface includes a movable guide vane (6) concentrically or radially mounted in a duct.
[0014]
According to the above configuration of the present invention, it is possible to further suppress the incidence of microwaves on the fan rotor blade, particularly when the movable guide vane is closed when the engine has low thrust. That is, the microwave reflection of the movable guide vane itself makes it possible to obtain a further microwave reflection suppression effect in combination with other configurations.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG. 1 and FIG.
In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 shows an embodiment provided with a structure having a reflection curved surface 2 obtained by extending a conventional strut 4 and a variable guide vane 6. Further, FIG. 2 is a local cross-sectional view of the strut. In this practical example, a plurality of struts 4 and variable guide vanes 6 are provided between the duct inlet 1 and the fan rotor blade 3. As shown in FIG. 2, the strut 4 is curved toward the rear end of the engine, and has a structure in which the microwave incident from the duct inlet 1 is diffusely reflected and diffused before entering the fan rotor blade 3. Further, at the time of low thrust, the movable guide vane 6 swings and closes around its front end shaft as shown by the broken line in FIG. 2, and this effect is further enhanced.
[0016]
According to the present embodiment, the effect of suppressing the reflection of microwaves from the fan rotor blade 3 can be obtained without bending the duct as in the conventional example shown in FIG. Since the duct is not bent, separation of air in the duct during supersonic flight can be suppressed, and air can be sent to the fan rotor blade 3 with more uniform pressure.
Therefore, it has the outstanding characteristic that a stealth property and flight performance can be improved with a compact and minimum component structure.
[0017]
Another embodiment of the present invention will be described with reference to FIG.
In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.
FIG. 3 shows an embodiment including a circumferential guide vane 5 having a reflection curved surface 2 and a variable guide vane 6. In this practical example, a circumferential guide vane 5 and a variable guide vane 6 are provided between the duct inlet 1 and the fan rotor blade 3. The circumferential guide vanes 5 attached to the struts are curved toward the rear end of the engine as shown in FIG. 2, and the microwave incident from the duct inlet 1 is diffusely reflected and diffused before entering the fan rotor blade 3. It has a structure. Further, since the movable guide vane swings and closes around its front end shaft at the time of low thrust as in the previous embodiment, this effect is further enhanced.
[0018]
According to the present embodiment, the effect of suppressing the reflection of microwaves from the fan rotor blade 3 can be obtained without bending the duct as in the conventional example shown in FIG. Since the outer peripheral shape of the duct is not changed, separation of air in the duct during supersonic flight can be suppressed, and air can be sent to the fan rotor blade 3 with more uniform pressure.
Therefore, it has the outstanding characteristic that a stealth property and flight performance can be improved with a compact and minimum component structure.
[0019]
A preferred embodiment of the present invention will be described with reference to FIG.
In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.
In FIG. 4, a circumferential guide vane 5 having a reflection curved surface 2 and a variable guide vane 6 are provided, and the outer periphery of the duct is changed in accordance with the shape of the circumferential guide vane. In this practical example, a circumferential guide vane 5 and a variable guide vane 6 are provided between the duct inlet and the fan rotor blade 3. The circumferential guide vane fixed to the strut 4 is curved toward the rear end of the engine as shown in FIG. 4, and the microwave incident from the duct inlet 1 is diffusely reflected and diffused before entering the fan rotor blade. It has a structure.
Moreover, since the movable guide vane 6 swings and closes around its front end shaft at the time of low thrust as in the previous embodiment, this effect is further enhanced.
[0020]
According to the present embodiment, the effect of suppressing the reflection of microwaves from the fan rotor blade 3 can be obtained without bending the duct as in the conventional example shown in FIG. Since the duct is not bent, the separation of air in the duct during supersonic flight can be reduced, and the air can be sent to the fan rotor blade with a more uniform pressure. Further, by offsetting the outer periphery of the duct to the shape of the outer circumferential guide vane outside the outermost diameter, the cross-sectional area against microwave intrusion is reduced. For this reason, there is a possibility that the effect of suppressing the reflection of microwaves is further improved.
Therefore, it has the outstanding characteristic that a stealth property and flight performance can be improved with a compact and minimum component structure.
[0021]
In the above invention, the microwaves that enter the fan rotor blade are shielded and diffused by the outer peripheral shape of the strut, the circumferential guide vane, the movable guide vane, and the duct, but the same function is added to other engine components, etc. Of course, various modifications can be made without departing from the scope of the present invention.
[0022]
【The invention's effect】
As can be seen from the above description, according to the present invention, the effect of suppressing the reflection of microwaves from the fan rotor blade 3 can be obtained without bending the duct. Since the outer shape of the duct is not significantly changed, the separation of air in the duct during supersonic flight can be reduced, and air can be sent to the fan blades with more uniform pressure.
Therefore, it is possible to exert an excellent effect that stealth and flight performance can be improved with a compact and minimal component configuration.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view when a reflection curved surface is a strut.
FIG. 2 is a partial cross-sectional view of a strut portion.
FIG. 3 is a cross-sectional view when the reflection curved surface is a circumferential guide vane.
FIG. 4 is a cross-sectional view when the reflection curved surface is a circumferential guide vane and a duct outer periphery.
FIG. 5 is an embodiment when the shape of a conventional engine duct is changed.
FIG. 6 is a partial cross-sectional view in the vicinity of a conventional engine duct.
FIG. 7 is a partial cross-sectional view of a strut portion in the vicinity of a conventional engine duct.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Entrance duct 2 Reflecting curved surface 3 Fan rotor blade 4 Strut 5 Circumferential guide vane 6 Movable guide vane 10 Gas turbine engine

Claims (4)

A plurality of reflecting curved surfaces dividing the inlet duct (1) in the form radiate against the duct central axis of a gas turbine engine (10), the reflection curved surface, the inlet duct (1) from the fan blades (3 ) Shielding and diffusing the microwaves that enter the surface, suppressing the reflection of the microwaves by the fan blades ,
A plurality of struts (4) mounted radially in the inlet duct have the reflective curved surface,
Each of the struts has one side surface and the other side surface in the circumferential direction around the duct central axis,
Both the one side surface and the other side surface extend from the upstream side of the air flow in the inlet duct to the downstream side of the air flow inclining from the direction of the duct central axis to the same one side in the circumferential direction. The microwave reflection control device according to claim 1 , wherein the reflection reflection curved surface is used. The gas turbine engine (10) has a plurality of reflection curved surfaces that concentrically divide the inside of the inlet duct (1) with respect to the central axis of the duct, and the reflection curved surfaces are provided to the fan rotor blade (3) from the inlet duct (1). Shields and diffuses intruding microwaves, suppresses reflection of microwaves by the fan blades ,
A strut (4) is mounted in the inlet duct, and a circumferential guide vane extending in the circumferential direction around the duct central axis is spaced apart from the strut in a direction perpendicular to the duct central axis. There are several installed,
Each circumferential guide vane has one side surface facing the duct central axis side, and the other side surface facing the one side surface,
Both the one side surface and the other side surface are inclined in a direction perpendicular to the duct central axis and away from the duct central axis from the air flow upstream side to the air flow downstream side in the inlet duct. A microwave reflection control device characterized in that the reflection curved surface is formed by extending . The reflection curved surface, the a circumferential guide vanes (5), micro according to claim 2, characterized by comprising a duct, by having the same shape across the outermost peripheral shape and spacing of the peripheral direction guide vanes A microwave reflection control device characterized by suppressing wave reflection. The microwave according to any one of claims 1 to 3, wherein the reflection curved surface includes movable guide vanes (6) concentrically or radially attached in a duct. Reflection control device.

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