RU2460892C1 - Method of adjusting supersonic air intake - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: method of adjusting mouth area and position of compression shocks by simultaneous turn of the front adjustable panel and rear adjustable panel. Axis of said front panel rotation is aligned with interaction of first and second steps of one of arrow-shape wedge, not perpendicular incident flow. Axis of said rear panel rotation is located in zone of rear edge of rear adjustable panel and is directed subject to location of the point of intersection with front panel rotational axis. In turn of both said panels, their side edges displace relative to channel shaped side surfaces with making clearances there between.

EFFECT: improved gas dynamic characteristics, stealth properties.

4 cl, 8 dwg

Description

The invention relates to aircraft, and in particular to the air intakes of the power plants of supersonic aircraft. The preferred field of application of the invention are aircraft with turbofan engines with a maximum Mach number of not more than 3.

The creation of an aircraft, which is hardly noticeable in the radar range, implies that the shape of all its elements contributes to a decrease in the level of the effective scattering area (EPR) of the aircraft. This also applies to the intake form of the engine intake. To achieve the desired result, all edges of the air intake should have a sweep and be parallel to any elements of the aircraft (the edges of the wing, plumage, etc.). The implementation of such an air intake, which has high internal characteristics in the entire operational range, is impossible without its regulation.

Adjustable, as a rule, are the braking surfaces of the air intake (for example, a wedge or cone). At supersonic speeds, a change in the angle of the solution of the braking surface leads to a change in the intensity of braking of the flow in the air intake, as well as a change in the area of its throat. In total, the effect of such regulation allows to obtain high characteristics of the air intake in the entire range of flight speeds of the aircraft on which it is installed.

A known method of regulating a supersonic flat (two-dimensional) air intake, the braking surface of which is represented by a multi-stage non-sweep wedge (N. Remeev, “Aerodynamics of the air intakes of supersonic aircraft.” TsAGI Publishing House, Zhukovsky, 2002, 178 pp.). In a known solution, the regulation of the air intake is carried out using rotary relative to the respective axes of the panels. The panels are located in the channel one after another. The front panel contains the steps of the brake wedge, except for the first. Its axis coincides with the line of intersection of the first and second steps of the wedge. The back panel is part of the channel and has a complex shape. The axis of the rear panel extends over its trailing edge. The absence of sweep of the edge and the steps of the braking wedge allows the use of panels parallel to the axis of rotation, perpendicular to the incoming flow. The disadvantage of the method of regulating a flat air intake in relation to an air intake with swept edges is the impracticability of its regulation by axes perpendicular to the direction of flow, because all elements of the air intake are sweep.

As a prototype of the invention, a method for controlling a supersonic air intake is adopted, in which the throat area and the position of the shock waves are changed (RU 2343297 C1). In the known solution, spatial flow inhibition is realized through the use of a V-shaped wedge (i.e., two arrow-shaped wedges adjoining each other, oriented towards each other in a front view at an obtuse angle). The air intake is made sweeping all edges of the entrance. The regulation of the air intake is carried out using two pairs of panels that rotate relative to the respective axes. The front panels of each pair are part of the braking surfaces. The rear panels are part of the channel. When adjusting each pair of panels, transverse slots arise between their adjacent end faces, and longitudinal slots arise between their lateral sides both at the joints with the side walls and at the joints with each other. This technical solution has the following disadvantages:

- the method of regulating the air intake does not provide the necessary throat area at subsonic and low supersonic flight speeds, because the amplitude of movement of the movable panels is small. Otherwise, the aforementioned longitudinal slots of unacceptable sizes arise. This means that the air intake does not provide the operation of the turbofan engine in the entire operational range of speeds and is not multi-mode;

- technically difficult implementation of the method of regulating the air intake.

The technical result to which the invention is directed is to provide the possibility of changing the angle of the steps of one of the arrow-shaped braking wedges and the minimum passage area of the air intake (throat) without the formation of undesirable longitudinal gaps and seizing of moving elements in its channel. Such regulation will allow, in turn, to ensure stable operation of the engine in all flight modes of the aircraft up to Mach number M = 3.0 with a coefficient of restoration of the total pressure at the engine inlet at a level not lower than typical for adjustable flat air intakes and the total flow heterogeneity below the maximum allowable quantities ("Aerodynamics, stability and controllability of supersonic aircraft", under the editorship of G. S. Byushgens. - M.: Science. Fizmatlit, 1998). At the same time, due to the parallelogram shape of the intake inlet in the front view and giving all of its edges a sweep, a decrease in the radar signature of the object on which it is installed is achieved. The greatest effect of reducing radar signature will be achieved when the edges of the air intake are parallel to some elements of the object (front or rear edges of the wing, plumage, etc.).

The specified technical result is achieved by the fact that in the method of controlling a supersonic air intake, in which the throat area and the position of the shock waves are changed, the throat area and the position of the shock waves are changed by simultaneously turning the front adjustable panel, the rotation axis of which coincides with the intersection line of the first and second stage one of the arrow-shaped wedges, not perpendicular to the incoming flow, and the rear adjustable panel, the rotation axis of which is located in the zones e of the trailing edge of the rear adjustable panel and is oriented based on the condition of a point of intersection with the axis of rotation of the front adjustable panel, while turning the front and rear adjustable panels, their side edges move relative to the profiled side surfaces of the channel without creating gaps between them.

In addition, when the front and rear adjustable panels are rotated, the orientation of the transverse gap between them in the top view does not change, and its position coincides with the straight line passing through the intersection of the rotation axes of the front and rear adjustable panels, while the gap has a shape close to rectangular for any possible position of the adjustable panels.

In addition, when the front and rear adjustable panels of the panel are rotated, the curtains are rotated relative to its axis of rotation and are oriented in such a way that they have a common point of intersection between themselves and the axis of rotation of the rear adjustable panel.

In addition, when the front and rear adjustable panels are rotated, the position of the kinematically associated rotary sash that closes the transverse gap located on the unregulated braking wedge in the throat area changes.

The invention is illustrated by drawings, where figure 1 shows an adjustable supersonic air intake - bottom view; figure 2 - adjustable supersonic air intake - side view; figure 3 - adjustable supersonic air intake - front view; figure 4 is a section aa of figure 1; figure 5 - braking diagram in a supersonic adjustable air intake at the calculated flight mode; figure 6 is a top view of a supersonic air intake and control panels; Fig.7 is a side view of a supersonic air intake and its control panel; Fig.8 is a section bB in Fig.6.

The supersonic adjustable air intake contains the following elements:

1 - the edge of the brake wedge 7,

2 - the edge of the stationary braking wedge 22,

3, 4 - the edges of the shell,

5 - channel air intake

6 - cylindrical section,

7 - a brake wedge containing a front adjustable panel 11,

8 - zone of the possible location of the flaps of the feed,

9 - the axis of rotation of the front adjustable panel 11,

10 - axis of rotation of the rear adjustable panel 12,

11 - front adjustable panel in the position of the maximum neck (the position of the minimum neck is shown by the dashed line),

12 - rear adjustable panel in the position of the maximum neck (the position of the minimum neck is shown by the dashed line),

13 - front adjustable panel 11 in the minimum throat position,

14 - rear adjustable panel 12 in the minimum throat position,

15 is a transverse gap between the front and rear adjustable panels for draining the boundary layer,

16 is a fracture line between the first and second steps of the braking wedge containing a front adjustable panel,

17 is a fracture line between the first and second steps of the stationary braking wedge 22,

18 is a fracture line between the second and third steps of the braking wedge containing a front adjustable panel,

19 - trimming of the dihedral angle formed by the shell,

20 - rounding of the entrance at the junction of the braking wedge containing the front adjustable panel and the shell,

21 - trimming of the dihedral angle formed by the stationary braking wedge 22 and the shell,

22 - stationary braking wedge,

23 - a sash regulating an additional transverse gap in the throat area on a stationary braking wedge 22,

24 - supersonic diffuser (braking system),

25 - subsonic diffuser,

26 - oblique shock compaction from the first stages of swept wedges,

27 - oblique shock seal from the second stages of swept wedges,

28 - oblique shock seal from the third stages of swept wedges,

29 - closing direct shock seal,

30 - the bypass area for oblique and direct shock waves to increase the range of air flow through the air intake, which ensures its stable operation,

31 - the first stage of the wedge containing the front adjustable panel 11,

32, 33, 34 - axis of rotation of the curtain 45,

35 - the intersection of the axis of rotation of the blind 43 and the axis of the rear adjustable panel 12,

36 - the point of intersection of the axes of rotation of the front and rear adjustable panels 11 and 12,

37 is a line along which the transverse gap is oriented between the adjustable panels 11 and 12,

38 - mounting points of the drive rear adjustable panel 12,

39 - unloading holes in the rear adjustable panel 12,

40 - axis of rotation of the sash 23,

41 - tight sewing over the rear adjustable panel 12,

42 - control mechanism of the lateral rotary shutter 23,

43 - traction drive front adjustable panel 11,

44 - circuit channel

45 - curtain

46 - compartment control mechanism of the rear adjustable panel 12,

47 - profiled side surfaces of the channel 5.

As the main elements of the air intake, it is possible to distinguish a supersonic throat diffuser 24, a subsonic diffuser 25, front 11 and rear 12 adjustable panels that rotate around axes 9 and 10, respectively.

The front intake inlet form - a parallelogram or its special case - a rectangle, with an arbitrary ratio of its height and the length of the corresponding side. It is possible to perform trimming, for example 19 and 21, or rounding corners, for example 20, of the inlet of the air intake, with the exception of the angle formed by arrow-shaped wedges. The edges of the air intake inlet lie in a plane oriented to the direction of flow at an acute angle. Thus, all edges of the entrance have a sweep.

The supersonic diffuser 24 is a flow braking system consisting of a pair of swept wedges 7 and 22, forming a dihedral angle and shells (3, 4 - the edges of the shell). Arrow-shaped wedges 7 and 22 have at least one step, while the number of steps on these wedges may not coincide. As an example, Figures 1, 2, 3, 4 show an air intake, in which there are three steps on one swept wedge and two on the second. The fractures of the corresponding steps 16, 17, 18 of the arrow-shaped wedges 7 and 22 intersect at a point lying on the intersection line of the surfaces of the corresponding steps of the wedges forming a dihedral angle. The sweep angles of the steps on each of the sweep wedges may differ from the sweep angle of the edges of the corresponding wedge, as well as between themselves. The solution angles of the steps of swept wedges are determined when constructing the braking system from the condition that each pair of corresponding steps of the wedges creates a single oblique shock wave of a given intensity, i.e. the principles of gas-dynamic design are used (Schepanovsky VA, Gutov BI “Gas-dynamic design of supersonic air intakes”. Nauka, Novosibirsk, 1993). Perforation may be performed on some steps of the swept wedges.

The shell as well as swept wedges 7 and 22 forms a dihedral angle. A characteristic feature is the shell orientation in which it additionally inhibits the flow, i.e. the shell is not oriented along streamlines behind the shock waves from swept wedges. The angle of undercut of the shell may be variable. In the area of the dihedral angle formed by the shell, it is possible to organize a cutout in the edge of the inlet of the air intake, and in the shell itself, the placement of holes of arbitrary shape is possible.

In the subsonic diffuser 25, air recharge valves 8 may be provided, providing an external flow of air flowing around the air intake into the subsonic diffuser 25. The recharge valves 8 help to improve the characteristics of the air intake at low speeds (takeoff and flight modes at high angles of attack).

The method of controlling the above-described air intake is as follows. The front adjustable panel 11, containing the steps of one of the arrow-shaped wedges 7, except the first, rotates relative to the axis 9 located at the intersection of the first and second steps of the wedge 7. The response rear adjustable panel 12 is part of the subsonic diffuser 25 and rotates around the spatially located axis 10. If the axis 9 of the front adjustable panel is set unambiguously, then the choice of the orientation of the axis 10 of the rear adjustable panel passing over its trailing edge is determined from the condition of the intersection of the axis 10 of the rear adjustable panel iruemoy panel with axis 9 adjustable front panel 11.

When regulating the air intake between the front 11 and rear 12 adjustable panels, it is possible to form a transverse slit 15 to drain the boundary layer. With the selected method of setting the axes of the adjustable panels, the transverse gap between them has a shape close to rectangular.

The front adjustable panel 11 is connected to the rear adjustable panel 12 via rods 43.

When regulating the air intake, the front 11 and rear 12 adjustable panels, turning, simultaneously change their position in accordance with a given law. When the panels 11 and 12 are rotated, the area of the throat of the air intake, the opening angle of the movable steps of the swept wedge 7, the size of the transverse drain slit 15 between the panels 11 and 12 change, while the lateral edges of the panels 11 and 12 move relative to the profiled side surfaces of the channel 47 without the formation of cracks.

On a fixed swept wedge 22 in the throat region, it is possible to place an additional transverse drainage slit of the boundary layer closed by the sash 23. The sash can be controlled by a mechanism synchronized with the control of the panels 11, 12. For example, a kinematic mechanism 42 can be applied, connecting the rotary by means of rods and rocking sash and axis 9 of the front adjustable panel 11.

Mentioned transverse slots and perforations on the wedges contribute to improving the characteristics of the air intake at supersonic flight speeds.

On the rear adjustable panel 12, discharge openings 39 are made for equalizing the pressure in the channel and in the cavity above the rear adjustable panel 12. The cavity above the adjustable panels 11, 12 is divided into two halves by a curtain 45, made in the form of a folding partition, and serves to separate air with different the pressure that entered the subpanel space through the perforation, the transverse drain slit 15 between the adjustable panels and the discharge openings 39. The shutter 45 is a pivotally connected two flat panels - the top th and lower. The upper panel is pivotally mounted on the design of the compartment 46 of the control mechanism of the rear adjustable panel, the lower is pivotally mounted on the rear adjustable panel. To ensure the kinematic operability of the curtain 45, its rotation axes 32, 33, 34 are oriented in space in such a way that they have one intersection point 35 lying on the rotation axis 10 of the rear adjustable panel 12.

The method of regulation of the air intake with swept edges is as follows.

At subsonic flight speeds, the adjustable air intake panels 11 and 12 are in the maximum throat position (retracted position, main line in the drawings), providing its area at which there are no supersonic flow velocities in the channel.

At supersonic flight speeds, the efficiency of an aircraft power plant is related to the efficiency of flow inhibition in the air intake. The supersonic flow in the air intake is inhibited in the shock waves 26, 27, 28, which are formed during the flow around the wedges of the braking system. With increasing supersonic flight speed, the adjustable panels 11 and 12 synchronously deviate from the position corresponding to subsonic flight. The synchronization of the deflection of the panels 11, 12 is ensured by mechanical coupling between the front and rear adjustable panels 11, 12 using rods 43. Thus, by turning the rear adjustable panel 12 by means of the mechanism, the front adjustable panel 11 is simultaneously driven. When the adjustable front panel 11 is rotated in the direction of increasing the angle of the solution of the wedge steps, the intensity of the flow inhibition in the shock waves from these steps increases. In this case, the rear panel 12, turning, reduces the area of the throat of the air intake. An increase in braking intensity and a decrease in throat area have a positive effect on the characteristics of the air intake.

The deceleration of the flow to subsonic speed is carried out in a direct shock of the seal 29, which is located at the entrance to the air intake. Finally, the subsonic flow is inhibited in the subsonic diffuser 25 and consumed by the engine.

Stable operation of the air intake in all flight modes and engine operation is ensured by the presence of the air bypass region 30 in oblique shock waves, as well as the drainage system of the boundary layer in the form of perforation on the steps of the wedges of the braking system and the transverse gap 15 between the front 11 and rear 12 adjustable panels.

The transverse gap 15 is formed when the position of the adjustable panels 11 and 12 is different from the removed. In the retracted position of the panels 11 and 12, the gap 15 is absent. This was achieved by choosing the orientation of the rotation axes 9 and 10 of the adjustable panels in space so that they have a point of intersection 36.

The drainage of the boundary layer is additionally possible through an additional transverse gap located in the throat area on the stationary braking wedge 22 (with fixed steps) and adjustable by the sash 23.

An additional transverse gap opens mainly at supersonic flight modes when the position of the adjustable panels 11 and 12 is different from the removed one. When the adjustable panels 11 and 12 are in the retracted position, said additional transverse slit is closed by the sash 23.

When the panels are released, the shutter 45 begins to open at the same time, separating the air that enters the cavity above the rear adjustable panel 12 through the discharge openings 39 and the air that enters the cavity above the front adjustable panel 11 through the perforation and the transverse drain slot 15 between the adjustable panels 11 and 12.

The proposed control method provides high internal gas-dynamic characteristics of the air intake, the configuration of which at the same time helps to reduce its radar signature due to the parallelogram shape of the entrance in the front view and the sweep of all the edges of the entrance and the steps of the braking wedges. The choice of orientation of the mentioned elements forming the input allows you to orient their design in relation to the direction of the X-ray radiation in such a way as to deviate the radio signal reflected from the structure from this direction, and also to exclude the presence of corner reflectors.

Claims (4)

1. A method of controlling a supersonic air intake, in which the throat area and the position of the shock waves are changed, characterized in that the throat area and the position of the shock waves are changed by simultaneously turning the front adjustable panel, the axis of rotation of which coincides with the intersection line of the first and second stages of one of arrow-shaped wedges, not perpendicular to the incoming flow, and the rear adjustable panel, the axis of rotation of which is located in the rear edge of the rear and the second panel is oriented from the condition of having intersection points with the rotation axis of the front panel adjustable, wherein when turning the front and rear panels of controlled their side edges are moved relative profiled side channel surfaces without the formation of gaps between them. 2. The method according to claim 1, characterized in that when the front and rear adjustable panels are rotated, the orientation of the transverse gap between them in the top view does not change, and its position coincides with the straight line passing through the intersection point of the rotation axes of the front and rear adjustable panels, this slot has a shape close to rectangular at any possible position of the adjustable panels. 3. The method according to claim 1, characterized in that when the front and rear adjustable panels of the panel are rotated, the curtains are rotated relative to the axis of its rotation and are oriented in such a way that they have a common intersection point with each other and the axis of rotation of the rear adjustable panel. 4. The method according to claim 1, characterized in that when the front and rear adjustable panels are rotated, the position of the kinematically associated rotary shutter that closes the transverse gap located on the unregulated braking wedge in the throat area changes.

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