JP2010270601A - Noise reduction device and method for aircraft jet engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise reduction device and a method for an aircraft jet engine capable of reducing jet noise without causing an engine thrust loss at the time of takeoff while being reduced in a remodeled section of the air craft jet engine. <P>SOLUTION: The device includes a compressed air injection pipe 12 attached to an engine exhaust nozzle N of the aircraft jet engine 1 and injecting compressed air to exhaust gas flowing in the engine exhaust nozzle, an auxiliary engine 14 generating compressed air, an compressed air bleed pipe 16 bleeding compressed air and supplying the air to the compressed air injection pipe from the auxiliary engine, and a compressed air changeover valve 18 disposed in a middle of the compressed air bleed pipe and exclusively changing over the compressed air to the compressed air injection pipe and a cabin. The compressed air changeover valve 18 is changed over to the compressed air injection pipe 12 side and noise is reduced by injecting compressed air from the compressed air injection pipe at the time of takeoff. The compressed air changeover valve 18 is changed over to a cabin side and the compressed air is supplied to the inside of the cabin at a time except for a time of takeoff. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an aircraft jet engine noise reduction apparatus and method.

  In recent years, environmental compatibility of aircraft has been strongly demanded, and noise reduction of aircraft jet engines is one of them. Aircraft jet engine noise is not a major problem during high altitude cruises, but is most problematic during takeoff and landing. In particular, since noise caused by an exhaust jet becomes a problem during takeoff, various noise reduction means only during takeoff have been proposed (for example, Patent Documents 1 to 3).

Patent Document 1 “JET NOISE SUPPRESSION AND METHOD” extracts a part of fluid from the compressor part of the propulsion engine and expels it near the nozzle lip to promote mixing of the high-speed jet and the surrounding atmosphere. Jet noise is reduced.
“APPARATUS AND METHODS FOR ACTIVE FLOW CONTROL OF A NOZZLE EXHAUST PLUME” of Patent Document 2 is basically the same as Patent Document 1 described above. Jet noise is reduced by spraying around the lip.
Patent Document 3 “Apparatus for Reducing Jet Engine Exhaust Noise Using Vibrating Jet” includes a vibrating jet coupled to an engine exhaust, and injects gas in a state having a vibrating flow from the vibrating jet, The noise is reduced by mixing with the exhaust gas flowing through the engine exhaust.
In addition, the oscillating flow here is a flow in which a fluid is ejected at a predetermined frequency / repetition, for example, a flow in which the fluid is ejected in a pulse shape.

US Pat. No. 6,571,549, “JET NOISE SUPPRESSION AND METHOD” US Pat. No. 6,308,898, “APPARATUS AND METHODS FOR ACTIVE FLOW CONTROL OF A NOZZLE EXHAUST PLUME” Japanese Patent Application Laid-Open No. 2005-195019, “Apparatus for reducing jet engine exhaust noise using a vibrating jet”

  In the conventional noise reduction means described above, both Patent Documents 1, 2, and 3 extract a part of the working fluid of the engine and use it for jet noise reduction. Therefore, thrust loss due to a reduction in the amount of working fluid occurs. .

Further, in Patent Documents 2 and 3, a conventional aircraft jet engine is used as it is, and a microjet is pulsed by a pulse generator, or a vibration jet is coupled to an engine exhaust portion to extract air extracted from a compressor. Unlike the patent document 1, the microjet is made to vibrate instead of a steady flow to increase the jet noise reduction effect and to obtain the jet noise reduction effect with a smaller amount of extraction. Even so, thrust loss due to reduced working fluid is inevitable.
Hereinafter, the noise reduction means using a microjet having a steady flow state or an oscillating flow state in Patent Documents 1, 2, and 3 will be referred to as “noise reduction means using a microjet”.

  FIG. 1 is a schematic diagram showing a conventional noise reduction means using a microjet. In this figure, reference numeral 1 denotes an aircraft jet engine, which includes a compressor C, a combustor B, and a turbine T. The exhaust gas exiting the turbine T is injected as an exhaust jet from the exhaust nozzle N to the rear of the engine, and at that time, jet noise is generated.

In FIG. 1, as a noise reduction means, a micro jet nozzle 2 provided around the lip of the exhaust nozzle N and a micro jet pipe 3 for extracting compressed air from between the compressor C and the combustor B are provided. The jet noise is reduced by injecting the fluid (microjet) from the microjet nozzle 2 to the vicinity of the nozzle lip.
However, the above-described noise reduction means by the micro jet injects a part of the working fluid (compressed air) of the jet engine from the periphery of the lip of the exhaust nozzle N, and is accompanied by a thrust loss due to a decrease in the amount of engine working fluid It will be.
For this reason, a drop in thrust especially during takeoff has a problem that causes an increase in engine size and an increase in aircraft size.

  The present invention has been developed to solve the above-described problems. That is, an object of the present invention is to provide an aircraft jet engine noise reduction apparatus and method that can reduce the jet noise without reducing engine thrust loss during takeoff, with few modifications of the aircraft jet engine. is there.

According to the present invention, a compressed air injection pipe which is attached to an engine exhaust nozzle of an aircraft jet engine and injects compressed air into exhaust gas flowing through the engine exhaust nozzle;
An auxiliary engine for generating the compressed air;
A compressed air bleed pipe for extracting and supplying compressed air from the auxiliary engine to the compressed air injection pipe;
A compressed air switching valve provided in the middle of the compressed air bleed pipe and capable of exclusively switching the compressed air to a compressed air injection pipe and a cabin;
At the time of takeoff, the compressed air switching valve is switched to the compressed air injection pipe side to reduce noise by injecting compressed air from the compressed air injection pipe,
There is provided an aircraft jet engine noise reduction device characterized in that the compressed air switching valve is switched to a cabin side at a time other than takeoff to supply compressed air into the cabin.

  According to a preferred embodiment of the present invention, the compressed air injection pipe injects compressed air in a state having a steady flow or an oscillating flow.

According to the present invention, a compressed air injection pipe that is attached to an engine exhaust nozzle of an aircraft jet engine and injects compressed air into exhaust gas flowing through the engine exhaust nozzle;
An auxiliary engine for generating the compressed air;
A compressed air bleed pipe for extracting and supplying compressed air from the auxiliary engine to the compressed air injection pipe;
A compressed air switching valve provided in the middle of the compressed air bleed pipe and capable of exclusively switching the compressed air to a compressed air injection pipe and a cabin;
At the time of takeoff, the compressed air switching valve is switched to the compressed air injection pipe side to reduce noise by injecting compressed air from the compressed air injection pipe,
There is provided a method for reducing noise in an aircraft jet engine, wherein the compressed air switching valve is switched to a cabin side at a time other than takeoff to supply compressed air into the cabin.

According to the above-described apparatus and method of the present invention, the number of remodeled portions of the aircraft jet engine is small because only the compressed air injection pipe is attached to the engine exhaust nozzle.
In addition, since the auxiliary engine and the compressed air bleed pipe are provided separately from the aircraft jet engine, jet noise can be reduced without engine thrust loss during takeoff.
In addition, it is equipped with a compressed air switching valve to reduce noise by switching to the compressed air injection pipe side at takeoff, and can switch to the cabin side other than at takeoff to supply compressed air into the cabin. Can be used as an auxiliary power unit (APU). In this case, since there is an advantage that the APU loaded at the rearmost part of the airframe in the conventional airframe is not necessary, an increase in weight due to the microjet compressor can be avoided.

It is a schematic diagram which shows the noise reduction means by the conventional microjet. It is a schematic diagram of the aircraft provided with the noise reduction apparatus by this invention. 1 is an overall configuration diagram of a noise reduction device and an aircraft propulsion engine according to the present invention. It is explanatory drawing at the time of the actual action | operation of the noise reduction apparatus of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 2 is a schematic diagram of an aircraft equipped with a noise reduction device according to the present invention. In this figure, reference numeral 1 denotes an aircraft jet engine, which is mounted as a main engine of the aircraft 4.
In this figure, the aircraft jet engine 1 is mounted below the main wing, but the present invention is not limited to this and may be mounted at other positions.

  The noise reduction device 10 of the present invention is installed in the vicinity of the aircraft jet engine 1. The distance between the noise reduction device 10 and the aircraft jet engine 1 is set close enough (for example, inside the main wing) so that the weight and pressure loss of an air pipe (described later) provided therebetween do not affect the engine performance. Has been. However, if it is determined that these effects do not have a significant effect on the entire airframe system, it can be operated at other positions such as the rearmost part of the airframe where the conventional APU is mounted.

  FIG. 3 is an overall configuration diagram of a noise reduction apparatus and an aircraft propulsion engine according to the present invention. In this figure, the noise reduction device 10 of the present invention includes a compressed air injection pipe 12, an auxiliary engine 14, a compressed air bleed pipe 16, and a compressed air switching valve 18.

  The aircraft jet engine 1 is mounted as a propulsion jet engine for the aircraft 4 and includes a compressor C, a combustor B, and a turbine T. The exhaust gas exiting the turbine T is injected as an exhaust jet from the exhaust nozzle N to the rear of the engine, and at that time, jet noise is generated.

The compressed air injection pipe 12 is, for example, an exhaust nozzle lip, is attached to the engine exhaust nozzle N of the aircraft jet engine 1, and injects compressed air into the exhaust gas flowing through the engine exhaust nozzle N. The compressed air injection pipe 12 injects compressed air in a state having a steady flow or an oscillating flow, mixes the compressed air into the exhaust gas, and reduces jet noise.
In the present application, the compressed air injection pipe 12 is not limited to this configuration, and may be the same as the noise reduction means by the micro jet in Patent Document 3 as long as the jet noise can be reduced by the compressed air, but other configurations. There may be.

In this example, the auxiliary engine 14 includes a compressor C, a combustor B, and a turbine T, and has a bleed point 14a for taking out compressed air compressed by the compressor C to the outside. The auxiliary engine 14 drives the hydraulic pump L with the output of the turbine T and is used as auxiliary power for the aircraft 4.
The auxiliary engine 14 is not limited to the gas turbine engine system, and may be a combination of a reciprocating engine, a fuel cell, and a motor as long as it can be used as an auxiliary power source and can generate compressed air.

  The compressed air extraction pipe 16 is a pipe connecting the extraction point 14 a of the auxiliary engine 14 and the inlet of the compressed air injection pipe 12, and supplies compressed air from the auxiliary engine 14 to the compressed air injection pipe 12.

The compressed air switching valve 18 is a three-way valve that can be operated remotely. The compressed air switching valve 18 is provided in the middle of the compressed air bleed pipe 16, and the compressed air extracted from the bleed point 14a and the compressed air injection pipe 12 and a cabin (not shown). It is possible to switch exclusively.
When switched to the cabin side, the extracted compressed air can be used for air conditioning in the machine.

  FIG. 4 is an explanatory diagram at the time of actual operation of the noise reduction device of the present invention. In this figure, (A) shows the time of takeoff, and (B) shows the time other than the time of takeoff. Except when taking off is when climbing, cruising, descending, etc. In the compressed air switching valve 18, white indicates an open state (open) and black indicates a closed state (close).

  As shown in this figure, in the noise reduction method of the present invention, at the time of takeoff (A) of the aircraft 4, the compressed air switching valve 18 is switched to the compressed air injection pipe 12 side, and compressed air is supplied from the compressed air injection pipe 12. Spray to reduce noise. That is, at the time of takeoff (A), the auxiliary engine 14 is operated, the compressed air switching valve 18 is opened on the compressed air injection pipe 12 side, the cabin side is closed, and the compressed air injection pipe 12 (exhaust gas) is passed through the compressed air bleed pipe 16. Compressed air (microjet) is sprayed onto the nozzle lip.

  Further, when the aircraft 4 is not taking off (B), the compressed air switching valve 18 is switched to the cabin side to supply the compressed air to the cabin. That is, except during takeoff (B), the auxiliary engine 14 is operated, the compressed air switching valve 18 is closed on the compressed air injection pipe 12 side, the cabin side is opened, and compressed air is supplied to the cabin through the compressed air bleed pipe 16 To do.

According to the above-described apparatus and method of the present invention, the aircraft jet engine 1 is modified only by attaching the compressed air injection pipe 12 to the engine exhaust nozzle N.
In addition, since the auxiliary engine 14 and the compressed air bleed pipe 16 are provided separately from the aircraft jet engine 1, jet noise can be reduced without engine thrust loss during takeoff.
In addition, a compressed air switching valve 18 is provided to reduce noise by switching to the compressed air injection pipe 12 side at takeoff, and to switch to the cabin side other than at takeoff to supply compressed air into the cabin. Except for minutes, it can be used as an auxiliary power unit.

  In addition, this invention is not limited to embodiment mentioned above, is shown by description of a claim, and also includes all the changes within the meaning and range equivalent to description of a claim.

1 Aircraft jet engine,
2 Microjet nozzle,
3 Microjet piping, 4 aircraft,
10 noise reduction device, 12 compressed air injection pipe,
14 auxiliary engine, 14a bleed point,
16 Compressed air extraction pipe, 18 Compressed air switching valve

Claims (3)

A compressed air injection pipe which is attached to an engine exhaust nozzle of an aircraft jet engine and injects compressed air into exhaust gas flowing through the engine exhaust nozzle;
An auxiliary engine for generating the compressed air;
A compressed air bleed pipe for extracting and supplying compressed air from the auxiliary engine to the compressed air injection pipe;
A compressed air switching valve provided in the middle of the compressed air bleed pipe and capable of exclusively switching the compressed air to a compressed air injection pipe and a cabin;
At the time of takeoff, the compressed air switching valve is switched to the compressed air injection pipe side to reduce noise by injecting compressed air from the compressed air injection pipe,
A noise reduction device for an aircraft jet engine, wherein the compressed air switching valve is switched to a cabin side and compressed air is supplied into the cabin other than during takeoff.   The noise reduction device according to claim 1, wherein the compressed air injection pipe injects compressed air in a state of having a steady flow or an oscillating flow. A compressed air injection pipe which is attached to an engine exhaust nozzle of an aircraft jet engine and injects compressed air into exhaust gas flowing through the engine exhaust nozzle;
An auxiliary engine for generating the compressed air;
A compressed air bleed pipe for extracting and supplying compressed air from the auxiliary engine to the compressed air injection pipe;
A compressed air switching valve provided in the middle of the compressed air bleed pipe and capable of exclusively switching the compressed air to a compressed air injection pipe and a cabin;
At the time of takeoff, the compressed air switching valve is switched to the compressed air injection pipe side to reduce noise by injecting compressed air from the compressed air injection pipe,
A method for reducing noise in an aircraft jet engine, wherein the compressed air switching valve is switched to a cabin side and compressed air is supplied into the cabin other than during take-off.

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