JP2000318696A - Ground test facility for aircraft engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate installation of an exhaust duct of a low-frequency noise generating source to provide a noise-suppressed type facility for an engine ground test of simple structure excellent in noise-suppressing effect, in the noise-suppressed type facility for conducting the engine ground test in the condition where an aircraft is parked on the ground. SOLUTION: This facility is a noise-suppressed type facility for an engine ground test while parking an aircraft on the ground. The facility has a deck plate 12 disposed to be positioned with a space on the rear side of an exhaust port of an aircraft engine E set for the ground test, arranged inclinedly from its lower side upto its upper side to form an exhaust passage for guiding exhaust of the engine E to the upper side, and provided with plural holes, a sound insulation wall 2 arranged in a backface side of the deck plate 12 to keep a space with respect to the plate 12, and a sound insulation layer executed with an anisotropic material such as a porous material and a crushed stone in a floor between the deck plate 12 and the sound insulation wall 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound-deadening aircraft engine ground test facility for performing an engine ground test while an aircraft is parked.

[0002]

2. Description of the Related Art A muffled test facility is provided at an airport or the like to perform an engine ground test while an aircraft after inspection and maintenance is parked. Conventionally, various types of aircraft engine ground test facilities have been provided. As an example, as shown in FIG. 6, there is a configuration in which a sound insulation wall is simply installed on the rear side of an aircraft on which an engine ground test is performed.

[0003] This is a so-called blast fence type in which a sound insulation fence 01 for blocking noise from an aircraft engine is provided on the rear side of the engine ground test machine. In this type of aircraft engine ground test facility, a blast fence 02 made of a wire mesh or the like must be installed in front of the sound insulation fence 01 in order to block high heat and high-speed flow of the exhaust jet from the aircraft engine. In this blast fence-type facility, sound is reduced by the diffraction effect of the flat sound insulation fence 01, so that the sound reduction is small.

Further, there is an aircraft engine ground test facility called a splitter type shown in FIG. This has a structure in which exhaust gas from an aircraft engine to be subjected to an engine ground test is guided to a splitter type silencer 011 by an exhaust duct 010 to muffle the sound. The splitter type silencer 011 is
It has a flow passage partitioned in a honeycomb shape by a sound absorbing panel.

In this splitter type aircraft engine ground test facility, an exhaust duct 010 for introducing exhaust of an aircraft engine into the splitter type silencer is required. A specific frequency noise is generated. For this reason, it is necessary to additionally provide a splitter-type silencer for silencing the noise generated by the exhaust duct 010, and this splitter-type equipment is inevitably a heavy load having a complicated structure.

[0006] As another conventional aircraft engine ground test facility using a splitter type silencer, there is a so-called semi-hanger type. Although the sound-insulating wall surrounds the aircraft on which the engine ground test is performed, it has the same disadvantages as the equipment shown in FIG. 7 in that it has a problem associated with the installation of the splitter type silencer. .

Further, as another aircraft engine ground test facility using a splitter type silencer, there is a so-called hashed house (completely closed) type shown in FIG. This is a building type that covers an aircraft on which an engine ground test is performed on the entire circumference, and an intake port 022 for flowing intake air to an engine is provided on a front surface of the aircraft. In FIG.
Reference numeral 021 denotes a splitter type silencer, and 020 denotes an exhaust duct for guiding engine exhaust to the splitter type silencer 021. Although this facility is excellent in sound insulation, it has the same problems as described for the facility in FIG. 7 because it is provided with a splitter type silencer.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the conventional silencing type equipment for performing an engine ground test while an aircraft is parked, and therefore, a source of low-frequency noise. It is an object of the present invention to provide a muffler for engine ground tests with a simple structure and excellent muffling effect without using a splitter muffler which requires installation of an exhaust duct.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem in a sound deadening type facility for performing an engine ground test while an aircraft is parked. A deck plate provided with a plurality of holes, which is installed so as to be spaced from the exhaust port of the engine and is inclined upward from below so as to form an exhaust path for guiding the exhaust of the engine upward, and the deck plate. An aircraft engine ground test facility having a structure including a sound insulation wall disposed on the back side of the deck plate at a distance from the deck plate and a sound deadening layer installed on a floor surface between the deck plate and the sound insulation wall.

[0010] In the aircraft engine ground test facility according to the present invention, the sound deadening layer may be made of an anisotropic material such as a porous material or crushed stone.

In the aircraft engine ground test facility of the present invention having the above-described structure, a large noise reduction effect can be obtained by the diffractive action of the deck plate for guiding the exhaust gas emitted from the aircraft engine upward. Further, since the deck plate is provided with a plurality of holes, the rise of the contact jet pressure caused by the exhaust of the aircraft engine directly contacting the deck plate is suppressed, and the noise of the exhaust jet is absorbed.

Further, since a sound insulating wall is provided on the back side of the deck plate and a sound absorbing layer is provided on the floor between the deck plate and the sound insulating wall, jet noise of engine exhaust is absorbed. In addition, the presence of the sound absorbing layer alleviates the wave flow caused by the contact back pressure of the exhaust jet acting from the hole of the deck plate to the air layer between the deck plate and the sound insulating wall on the back surface.

As described above, the aircraft engine ground test facility of the present invention reduces jet noise of an aircraft engine without using a splitter-type silencer or an exhaust duct for communicating the muffler and an exhaust port of the aircraft engine. be able to.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An aircraft engine ground test facility according to the present invention will be specifically described below with reference to an embodiment shown in the drawings. In FIGS. 1 and 2, reference numeral 2 denotes a soundproof wall.
It is provided so as to surround the aircraft on which the engine ground test is performed, and an opening that can be opened and closed by the soundproof door 4 is formed on the nose side. The soundproof wall 2 is also provided on the ceiling, and is configured as a completely closed type.

On the nose side of the soundproof wall 2 on the ceiling, an intake opening 6 for supplying an intake air flow 5 to an aircraft engine E for performing a ground test is provided, and the intake opening 6 has a plurality of sound absorbing plates 8.
Is provided. The soundproof wall 2 has an air layer 10 inside as shown in the figure.
Is formed to enhance the noise reduction effect.

A deck plate 12 is provided in front of the soundproof wall 2 behind the exhaust port of the engine E for performing a ground test. The aircraft engine E includes a center engine provided at the center of the fuselage and a wing engine mounted on the wings. The deck plate 12 is provided with a one-piece structure as shown in FIG.
2-1, 12-2, and 12-3.

The deck plate 12 forms an exhaust passage (flue) 16 for guiding the exhaust of the jet engine E upward upward, as schematically shown in FIG. 4 for the center engine. Soundproof wall 2 from below to above
It is gradually established along the road. The deck plate 12 is made of a metal that can withstand the contact of the engine exhaust jet with the high-temperature and high-speed fluid, and is provided at a position spaced a predetermined distance from the engine exhaust port. The deck plate 12
It has a perforated structure in which a plurality of holes of an appropriate size are provided.

A large air layer 18 is formed between the deck plate 12 and the soundproof wall 2 behind the deck plate 12, and the floor of the large air layer 18 has an anisotropic shape such as porous material or crushed stone. A silencing layer 20 made of a material is provided. An exhaust wall 22 rises from the ceiling so as to form an inner surface of the exhaust passage 16, but this is not indispensable and the installation may be omitted.

Deck plate 12, ceiling and exhaust wall 22
The actual shape of the exhaust passage (flue) 16 formed by this is as shown in FIG. The flue surface forming the soundproof wall 2 and the exhaust passage 16 has a concrete sound absorbing type sound insulating structure configured to absorb sound with a porous material. Reference numeral 24 denotes an exhaust recirculation prevention plate provided on the ceiling to prevent engine exhaust directed to the exhaust path 16 from recirculating toward the engine intake.

The aircraft engine ground test facility of the present embodiment has the above-described structure, and the exhaust jet discharged from the exhaust port of the aircraft engine in the ground test hits the deck plate 12 to the upper exhaust path 16. The noise reduction effect is obtained by the diffraction effect of being guided and turning the direction of the noise upward. Further, since a plurality of holes are provided in the deck plate 12, even when the engine exhaust jet directly contacts the deck plate 12, the rise of the contact jet pressure is suppressed, and the reflection of the jet is suppressed, so that the exhaust jet Softens the flow, and low-frequency noise due to jet velocity difference is not generated. The plurality of holes exhibit a sound absorbing effect.

On the other hand, the wave flow caused by the contact back pressure of the engine exhaust jet flowing through the holes of the deck plate 12 and acting on the large air layer 18 on the rear side of the deck plate 12 is provided on the floor of the large air layer 18. Mitigated by the noise reduction layer
In addition, sound waves propagating through the deck plate 12 are absorbed. Further, the large air layer 18 and the soundproof wall 2 on the rear side of the deck plate 12 effectively reduce engine exhaust jet noise.

As described above, the present invention has been specifically described based on the illustrated embodiments. However, the present invention is not limited to these embodiments, and specific structures within the scope of the present invention shown in the claims are set forth. Needless to say, various changes may be made to the configuration.

For example, in the above-described embodiment, the ceiling is also covered with the soundproof wall 2 so as to be completely enclosed. However, depending on the location, the soundproof wall may not be provided on the ceiling. Also,
In the above-described embodiment, the configuration in which the intake opening 6 is provided in the ceiling is adopted, but the intake may be taken in from the front, and there is no limitation to providing the intake opening in the ceiling. It is not something to be done.

[0024]

As described above, the aircraft engine ground test equipment according to the present invention is installed behind the exhaust port of the engine to be subjected to the ground test so as to be spaced apart from the exhaust port, and controls the engine exhaust. A deck plate provided with a plurality of holes, which is arranged to be inclined upward from below so as to form an exhaust path leading upward, a sound insulation wall disposed at a distance from the deck plate on the back side of the deck plate, and It has a sound absorbing layer constructed on the floor between the deck plate and the sound insulating wall.

Therefore, in the aircraft engine ground test facility of the present invention, in addition to the noise reduction function by such an arrangement that forms an exhaust path for guiding exhaust gas emitted from the aircraft engine upward, the diffusion of noise due to upward exhaustion Depending on the function, a great silencing effect can be obtained. Also, the deck plate is provided with a plurality of holes, and while suppressing the rise of the contact jet pressure caused by the exhaust of the aircraft engine directly contacting the deck plate,
Absorbs the noise of the exhaust jet.

Further, in the aircraft engine ground test facility according to the present invention, since the sound insulation wall is provided on the back side of the deck plate, and the sound deadening layer is provided on the floor between the deck plate and the sound insulation wall, the engine exhaust gas is exhausted. Jet noise is absorbed. In addition, the presence of the sound absorbing layer alleviates the wave flow caused by the contact back pressure of the exhaust jet acting from the hole of the deck plate to the air layer between the deck plate and the sound insulating wall on the back surface.

As described above, the aircraft engine ground test facility of the present invention reduces jet noise of an aircraft engine without using a splitter-type muffler or an exhaust duct for communicating the muffler and the exhaust port of the aircraft engine. be able to.

[Brief description of the drawings]

FIG. 1 is a perspective view of an aircraft engine ground test facility according to an embodiment of the present invention, which is cut off in a vertical direction.

FIG. 2 is a plan view showing an exhaust path portion in the test facility of FIG.

FIG. 3 is a longitudinal sectional view showing a shape of an exhaust path formed by a deck plate in the test facility of FIG.

FIG. 4 is an explanatory diagram showing a configuration of a deck plate portion in the test facility of FIG. 1;

FIG. 5 is a plan view of the explanatory diagram shown in FIG. 4;

FIG. 6 is an explanatory view showing a conventional blast fence type aircraft engine ground test facility.

FIG. 7 is an explanatory view showing a conventional exhaust engine silencing splitter type aircraft engine ground test facility.

FIG. 8 is an explanatory diagram showing a conventional hashed house type aircraft engine ground test facility.

[Explanation of symbols]

 Reference Signs List 2 soundproof wall 4 soundproof door 6 intake opening 8 sound absorbing plate 10 air layer 12 deck plate 14 exhaust flow 16 exhaust path 18 large air layer 20 noise reduction layer 22 exhaust wall 24 exhaust recirculation prevention plate

Claims (2)

[Claims] 1. An aircraft engine ground test facility for performing an engine ground test while an aircraft is parked, wherein the aircraft engine ground test facility is positioned behind the exhaust port of the aircraft engine to be ground-tested and spaced from the engine exhaust port. A deck plate with a plurality of holes, which is arranged so as to be inclined upward from below so as to form an exhaust passage that guides the exhaust of the engine upward, and is spaced from the deck plate on the back side of the deck plate An aircraft engine ground test facility, comprising: a sound insulation wall arranged in a vertical direction; and a sound deadening layer constructed on a floor surface between the deck plate and the sound insulation wall. 2. The aircraft engine ground test facility according to claim 1, wherein said sound deadening layer is made of a porous material or an anisotropic material such as crushed stone.