JPH05213281A - Intake for supersonic air flow - Google Patents

Abstract

PURPOSE:To provide a supersonic air flow intake which dispenses with a complex control mechanism, and always functions self-stably, and can be used in a high mach domain (M>=2.5). CONSTITUTION:An external domain is provided with the first supersonic diffuser section 3 whose sectional area of a flow passage is decreased by decreasing the space of a side wall 2 in the direction of an air flow and moreover the second supersonic diffuser section 5 which is constant in the space of the side wall and decreased in the sectional area of the flow passage in the direction of the air flow by a ramp 4 on the inside of an upper wall 1. An internal domain is provided with a throat section 13 to minimize the sectional area of the flow passage near a cowl lip 14 and a subsonic diffuser section 15 to increase the sectional area of the flow passage. The supersonic air flow is precompressed to about Mach number 2-3 in the first supersonic diffuser section, and even when a vertical shock wave formed in the throat section moves forward, high rear static pressure is leaked downward for preventing the occurrence of nonstarting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supersonic air used for a high speed aircraft turbo engine, a ramjet engine, a heat exchanger or the like, which takes in a supersonic air flow, decelerates and compresses it to a subsonic speed. The present invention relates to a flow inlet, and particularly to a supersonic air flow inlet used in a high Mach region (M ≧ 2.5).

[0002]

2. Description of the Related Art In general, supersonic airflow inlets used in fighters and the like are vertically installed on the upper wall and both sides thereof, and have a receding angle with respect to the airflow direction flowing into the tip surface at supersonic speed. In the downward channel-shaped outer region (open channel section) consisting of the side wall and the side wall, the ramp cross section is gradually reduced in the air flow direction by the ramp on the inner surface of the upper wall with respect to the side wall with a constant spacing, and all supersonic compression is performed. In addition, in the inner region (closed flow passage section) which is connected to the outer region and the lower part between both side walls is closed by the cowl (bottom cover), the flow passage cross-sectional area provided near the cowl lip is minimized. By decelerating and compressing the air flow by the throat part so that it becomes almost sonic speed, and making a vertical shock wave at the throat part, and making the flow after that a subsonic speed, gradually increase the cross-sectional area of the flow path after the throat part. Subsonic Diffuse And it is configured to decelerate and compressing subsonic state until a predetermined Mach number by parts.

This type of air intake is called an external compression type because all supersonic compression is performed in the external region, but the practical Mach number upper limit is about 2.5 and is not suitable for the high Mach region.

This is because in order to effectively decelerate and compress the supersonic air flow, it is necessary to increase the deflection angle of the flow by the ramp (the flow is bent downward) with the increase of the Mach number, and the deflection angle is increased. If too much, it is necessary to inflate the cowl to a large extent correspondingly, and as a result, the cowl resistance increases rapidly in the high Mach region, making it unsuitable for use in this speed range.

For this reason, as shown in FIGS. 9 to 16, the inlet for the supersonic air flow conventionally used in the high Mach region is vertically provided on the upper wall 31 and both sides thereof, and the front end surface (see FIG. 9,
In the outer region of the downward channel, which is composed of the side wall 32 having a receding angle with respect to the air flow direction (the direction of the white arrow in FIGS. 9 and 10) that flows into the supersonic velocity at the left end face in FIG. The ramp 33 on the inner surface of the upper wall 31 with respect to the side wall of the upper wall 31 gradually reduces the flow passage cross-sectional area in the air flow direction to perform a part of the supersonic compression, and is provided in a continuous manner in the outer region, and the lower portion between the side walls 32 is In the inner region closed by the cowl 34, the remaining supersonic compression is performed, and the throat portion 36 from the cowl lip 35 is appropriately decelerated / compressed so that the air flow is almost sonic at the throat portion 36 having the smallest flow passage cross-sectional area. In addition, a vertical shock wave 37 is set up in the throat section 36 to make the flow thereafter subsonic, and to the subsonic diffuser section 38 in which the flow passage cross-sectional area after the throat section 36 is gradually increased. And it is configured to decelerate and compressing to a predetermined Mach number at the rear acoustic velocity state.

This type of air intake is called a mixed compression type because a part of supersonic compression is performed in the outer region and the rest is performed in the inner region.

[0007]

In this conventional mixed compression type supersonic air flow inlet, the vertical shock wave 37 is fixed in the throat portion 36 by controlling the static pressure at the main flow passage outlet 39 to an appropriate degree. Need to be present. Normally, this is always maintained by actively controlling the engine speed, the fuel injection amount, the air flow rate to the bypass passage, and the like.

If the static pressure at the main flow path outlet 39 is lower than the proper static pressure, the vertical shock wave 37 of the throat portion 36 moves rearward (to the right in FIGS. 9 and 10) to stabilize the pressure. Stops automatically at the point. In this way, the state in which the vertical shock wave 37 is swallowed backward is called a so-called starting state.

On the contrary, when the static pressure at the outlet 39 of the main flow path is higher than the proper static pressure, the vertical shock wave 37 tries to move to the front of the throat portion 36 (to the left in FIGS. 9 and 10).
When the vertical shock wave 37 starts to move forward due to some cause in the internal region, the Mach number immediately before the shock wave increases and the shock wave becomes stronger than before the movement. As a result, the static pressure immediately after the shock wave rises, and the force that pushes this out further acts. Therefore, the vertical shock wave 37 once becomes
After passing 6 and entering in front of it, the shock wave is immediately discharged to the external area, and when the discharged vertical shock wave 37 reaches the cowl lip 35, the flow path becomes an open flow path section, and the high static pressure behind the shock wave is downward. The shock wave stops moving at the position where the pressure naturally balances as it escapes. This is the so-called non-starting state.

As described above, since the state transition from the start to the non-start occurs instantaneously, it often causes the stall of the engine copressor, the blowout of the combustor, and the like. In addition, if the aircraft fails to start at a very high speed during flight, a new external shock wave is generated due to pressure leakage from the cowl lip 35, and the wave-making resistance increases rapidly. In the worst case, there is also the risk of falling out of control and crashing.

At the inlet of the mixed compression type supersonic air flow, in order to avoid or delay the occurrence of a non-start, a slot type or perforated wall type throat extraction hole 40 is provided, and a throat extraction hole 40 is provided at the rear of the shock wave. It adopts a structure that allows pressure to escape here. However, if the amount of air extracted from the throat air extraction hole 40 is increased, the margin until the occurrence of a non-start increases, but the air extraction resistance increases.
Further, this structure alone cannot completely prevent the non-startup, and a complicated mechanism for precisely controlling the static pressure at the main flow path outlet 39 is required.

Since the non-starting is also caused by the peeling due to the interference between the oblique shock wave 41 generated in the lamp 33 and the boundary layer, in order to suppress this, the porous wall type extraction is usually performed on the lamp surface or on the side wall. Pores 42, 43 are provided.

In FIG. 9, reference numeral 44 is a discharge port of the throat extraction hole 40, and 45 and 46 are discharge ports of the extraction holes 42 and 43.

Therefore, an object of the present invention is to provide a supersonic airflow intake port that does not require a complicated control mechanism, always operates in a self-stable manner, and can be used in a high Mach region.

[0015]

In order to solve the above-mentioned problems, the inlet of the supersonic airflow of the present invention is a supersonic airflow which takes in a supersonic airflow and decelerates / compresses it to a subsonic speed. A first supersonic diffuser portion having a flow passage cross-sectional area reduced due to a decrease in the distance between the side walls in the direction of the air flow flowing in at the supersonic speed, which is the intake port, is provided in the outer region of the side wall. A second supersonic diffuser portion, which has a constant interval and whose flow passage cross-sectional area is reduced in the air flow direction by a ramp on the inner surface of the upper wall, is provided so as to be continuous with the first supersonic diffuser portion, and is continuously provided for an external region, A throat part that minimizes the flow passage cross-sectional area is provided near the cowl lip in the inner area where the lower part is closed by a cowl, and a subsonic diffuser that increases the flow passage cross-sectional area is connected to the throat part. It is what is.

[0016]

In the above means, even if the vertical shock wave formed in the throat moves forward, the high static pressure behind it leaks downward due to the open flow path in front of the cowl lip, so that there is no sudden change in behavior. , The shock wave naturally stops at the position where the pressure is properly balanced, and the supersonic airflow flowing in at a high Mach number is up to about Mach number 2-3 due to the oblique shock wave formed by the side wall in the first supersonic diffuser section. Pre-compressed.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIGS. 1, 2 and 3 are a side view, a bottom view and a front view of a supersonic airflow inlet according to an embodiment of the present invention.

A rectangular plate-shaped upper wall 1 having a uniform thickness and vertically extending on both sides of the upper wall 1 have a tip surface (left end surface in FIGS. 1 and 2).
A downward channel-shaped exterior consisting of a side wall 2 having a receding angle θ with respect to the direction of the air flow flowing in at a supersonic velocity of a high Mach number (M ≧ 2.5) (the direction of the white arrow in FIGS. 1 and 2). In the region (open channel section), the first supersonic diffuser section 3 has a channel cross-sectional area reduced by gradually reducing the distance between the side walls 2 in the air flow direction (see FIGS. 4 and 5). Is provided, the distance between the side walls 2 is made constant (see FIG. 6), and the ramp 4 having a required gradient provided on the inner surface of the upper wall 1 gradually reduces the flow passage cross-sectional area in the air flow direction. Further, the second supersonic diffuser portion 5 is provided in series with the first supersonic diffuser portion 3.

In addition, in order to prevent the boundary layer developed on the inner surfaces of the side wall 2 and the upper wall 1 of the first supersonic diffuser portion 3 from being sucked into the second supersonic diffuser portion 5 in the outer region, a diverter structure is provided. Has been adopted.

That is, partition walls 6 are provided on the lower surface of the lamp 4 so as to be slightly separated from both side walls 2, and each partition wall 6 is provided.
And the respective side walls 2 are communicated with each other through the side diverter air discharge ports 7 which are open to the outside of the side walls 2 and the side diverter flow paths 8 (see FIG. 7) formed in each side wall 2. On the other hand, the upper wall 1 in front of the lamp 4 is provided with a slot-type upper diverter air outlet 9. Further, if necessary, a porous wall-type lamp extraction hole 10 is provided on the lamp 4 of the second supersonic dephasor unit 5, and the lamp extraction hole 10 is communicated with the lamp extraction port 11 provided on the upper wall 1, The interference between the boundary layer on the surface of the lamp 4 and the shock wave may be kept low.

In the outer region, an inner region (closed flow passage section) in which lower end portions of both side walls 2 are closed by a cowl 12 is provided in series. A throat portion 13 having a minimum flow passage cross-sectional area is provided in the vicinity of the cowl lip 14 in the internal region, and the flow passage cross-sectional area is gradually increased in the air flow direction in a continuous manner with the throat portion 13. A subsonic diffuser portion 15 is provided, and the subsonic diffuser portion 15 is communicated with an engine (not shown) and the like via a main flow path outlet 16 (see FIG. 8). The upper wall 1 of the throat portion 13 is provided with a slot type or perforated wall type throat extraction hole 18 in order to hold the upper end of the vertical shock wave 17 therein, and the throat extraction hole 18 is
Throat bleed air discharge port 20 opened above the upper wall 1 through a throat bleed air flow passage 19 (see FIG. 7) formed in the upper wall 1.
It is in communication with.

At the supersonic airflow inlet having the above-mentioned structure, the air flowing in at a supersonic velocity of a high Mach number has an oblique shock wave formed by the side walls 2 in the first supersonic diffuser portion 3 in the outer region (see FIG. 2) by Mach number
After being decelerated and pre-compressed to about 3, the second supersonic diffuser section 5 decelerates and compresses to almost the sonic speed, and
Decelerate to subsonic speed by vertical shock wave 17 set up in 3
Compressed. Then, the air that has passed through the throat portion 13 is further decelerated / compressed to a required Mach number in the subsonic state in the subsonic diffuser portion 15 and supplied to the engine or the like.

When the static pressure at the outlet 16 of the main flow path rises for some reason during deceleration / compression of the supersonic air flow, even if the vertical shock wave 17 moves forward, the throat portion 13 is in the vicinity of the cowl lip 14. Since there is an open channel in front of it, a high static pressure behind the shock wave leaks downward so that no sudden behavior change occurs, and the vertical shock wave 17 naturally stops at a position where the pressure is properly balanced. ..

In the above embodiment, the case where the gradient of the lamp 4 is fixed has been described, but the present invention is not limited to this, and a ramp angle varying mechanism is provided to make the gradient of the lamp 4 variable. You may do it.

[0026]

As described above, according to the supersonic airflow intake of the present invention, even if the vertical shock wave formed in the throat moves forward, the high static pressure behind it causes the cowl lip to have a high static pressure. Since the open flow path in the front leaks downward, there is no sudden behavior change, and the shock wave naturally stops at the position where the pressure is properly balanced, so there is no need for a complicated control mechanism as in the past, and self-control is always possible. It can be operated stably.

Further, the supersonic airflow flowing in at a high Mach number is pre-compressed to a Mach number of about 2 to 3 by the oblique shock wave formed by the side wall in the first supersonic diffuser portion, so that in the high Mach region. Can be used.

[Brief description of drawings]

FIG. 1 is a side view of an inlet for supersonic airflow according to one embodiment of the present invention.

FIG. 2 is a bottom view of the supersonic airflow inlet of one embodiment of the present invention.

FIG. 3 is a front view of an inlet for supersonic airflow according to an embodiment of the present invention.

4 is a sectional view taken along line IV-IV in FIG.

5 is a sectional view taken along line VV in FIG.

6 is a sectional view taken along line VI-VI in FIG.

7 is a sectional view taken along line VII-VII in FIG.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9 is a side view of a conventional supersonic airflow inlet.

FIG. 10 is a bottom view of a conventional supersonic airflow inlet.

FIG. 11 is a front view of a conventional supersonic airflow inlet.

12 is a sectional view taken along line XII-XII in FIG.

13 is a sectional view taken along line XIII-XIII in FIG.

14 is a sectional view taken along line XIV-XIV in FIG.

15 is a sectional view taken along line XV-XV in FIG.

16 is a sectional view taken along line XVI-XVI in FIG.

[Explanation of symbols]

 1 Upper Wall 2 Side Wall 3 First Supersonic Diffuser Part 4 Lamp 5 Second Supersonic Diffuser Part 12 Cowl 13 Throat Part 14 Cowl Lip 15 Subsonic Diffuser Part 17 Vertical Shock Wave

Claims (1)

[Claims] 1. An inlet for a supersonic air flow that takes in a supersonic air flow, decelerates and compresses it to a subsonic speed.
In the downward channel-shaped outer region, there is provided a first supersonic diffuser portion having a reduced flow passage cross-sectional area due to a decrease in the side wall spacing in the direction of the airflow flowing at supersonic speed, and the side wall spacing is kept constant, and The second supersonic diffuser part, whose flow passage cross-sectional area is reduced by the ramp on the inner surface of the upper wall, is provided so as to be connected to the first supersonic diffuser part, is provided so as to be connected to the outer region, and the lower part is closed by a cowl. In the inner region, a throat portion that minimizes the flow passage cross-sectional area is provided near the cowl lip, and a subsonic diffuser portion that is connected to the throat portion and has an increased flow passage cross-sectional area is provided. Intake of supersonic airflow.