JP2001318030A - Wind shield body for intake noise-suppressing chamber for jet engine test cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make air flow without generating deviation not to generate voltex in the upstream in the vicinity of a tested jet engine in an engine room, when the outside air of high flow velocity is taken in from an intake noise-suppressing chamber to conduct a test run. SOLUTION: In this wind shield body having an opening in its bottom and formed box-likely, arranged concentrically to the intake noise-suppressing chamber 11 with clearances with respect to the chamber 11 in the condition where an intake port gets into a boxlike hollow part from the opening in an upper part of the noise-suppressing chamber 11 of which the upper end is formed into the intake port, and constituted to make the outside air taken from the clearances into the chamber 11, the opening is formed to close the clearances Ga,Ga,Gb,Gb with respect to the noise-suppressing chamber 11 in portions corresponding to four corners of the chamber 11 in top view.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jet engine test cell which is a ground test facility for a jet engine, and performs a test operation by taking in external air flowing at a high flow rate of, for example, 18 m / s from an intake silencer. The present invention relates to a windshield for an intake silence chamber of a jet engine test cell that allows air to flow evenly upstream in the vicinity of a test jet engine in an engine room.

[0002]

2. Description of the Related Art A jet engine test cell accommodates a jet engine for an aircraft after maintenance or newly developed in an engine room and performs a test operation on the jet engine. This is a ground test facility for measuring and evaluating functions, and is generally provided in the airport area. This jet engine test cell has an intake muffler (intake muffler) on the intake side for taking in external air, and has an exhaust muffler (exhaust muffler) on the exhaust side. An intake chamber into which external air is taken in through an intake silencer, an engine chamber in which a test jet engine is installed, an exhaust duct chamber for guiding exhaust gas of the test jet engine backward, and an exhaust chamber. Are connected in series.

[0003] In a jet engine test cell, from the viewpoint of further improving the performance, safety and economy of an aircraft, the high-speed external air is supplied at a high atmospheric wind speed of 18 m / s. It is necessary to take a test drive from the intake silencer.

Accordingly, the present inventors have proposed such a flow rate 1
The influence of the external air having a large flow velocity of 8 m / s on the air flow distribution at the position upstream of the test jet engine in the engine room of the jet engine test cell was investigated. That is, a jet engine test cell model having a scale of 1/40 that of the actual machine was manufactured, and the influence investigation was conducted by an experiment using the test cell model.

FIG. 7 is a side view showing the structure of a jet engine test cell model. As shown in the figure, this jet engine test cell model has a rectangular tube shape in appearance, and has a plurality of sound absorbing splitters 11a extending vertically in a flat plate shape inside thereof (see FIG. 8 (a)). Silencer (intake silencer) 11 in which are arranged at intervals.
And an intake chamber 12 having a rectangular cross section which is provided below the intake muffler chamber 11 and through which external air is taken in. The test chamber is provided with the intake chamber 12 and extends horizontally. And an engine room 13 having a rectangular cross section for housing the engine room. Further, this jet engine test cell model is connected to the engine chamber 13 and has an exhaust duct chamber 14a having an exhaust duct 14a for guiding engine exhaust gas backward.
And an exhaust chamber 15 connected to the exhaust duct chamber 14 to receive the exhaust gas from the exhaust duct 14a, and a number of sound absorbing splitters (not shown) provided inside the exhaust chamber 15 and connected to the upper side of the exhaust chamber 15. An exhaust silencer (exhaust silencer) 16 for exhausting exhaust gas to the outside through a gap between the sound absorbing splitters is provided. The exhaust duct 14a
A secondary silencer 17 is surrounded on the upstream side of the muffler. The muffler 17 is configured to allow air taken in from the ceiling opening of the exhaust duct chamber 14 near the exhaust port of the test jet engine. This is to reduce the noise generated when being guided.

The jet engine test cell includes:
In order to improve the air flow distribution on the upstream side near the test jet engine in the engine room when conducting test operation by taking in external air with high flow rate from the intake silencer, a windshield for the intake silencer is provided. . FIG. 8 shows FIG.
It is a configuration explanatory view of a windshield for an intake silencing room in
(A) is the top view, (b) is BB sectional drawing of (a).

[0008] As shown in FIG. 8, a conventional wind shield for an intake silencer (hereinafter, simply referred to as a wind shield) 10 has a box shape with an entire bottom opening, and is larger than an inlet of an intake silencer 11. The opening has a cross-sectional area. This wind shield 10
Is supported and fixed to the intake silencer 11 by means of flanges and bolts (not shown) so that the intake silencer 11 enters the box-shaped hollow portion above the intake silencer 11 from below. 11 and are arranged concentrically with a gap. Here, in the wind shield 10, the gap distance between the wall of the intake silencer chamber 11 extending in the width direction of the engine room 13 in plan view is a, and the gap distance between the wall surface of the intake silencer chamber 11 extending in the longitudinal direction of the engine chamber 13 is b. .
In addition, the windshield 10 height direction (the engine room 13 height direction)
Is c and the height dimension of the wind shield 10 is d. As shown in FIG. 8 (b), a turning vane 18 extending in the width direction of the engine chamber 13 is provided in the intake chamber 12, and the turning vane 18 smoothly takes in the external air taken in at right angles. It serves as a guide that bends and leads to the engine room 13.

In this jet engine test cell model, the model jet engine EM
Is set, and compressed air is jetted from the test jet engine model EM toward the downstream side at the same total pressure as that of the actual jet engine. However,
Unlike an actual jet engine, intake (air intake) by a compressor of the engine and ejection of high-temperature gas after combustion are not performed, and the air flow distribution is investigated without being affected by both.

As shown in Table 1, the gap distances a, b, c, and
First, five windshields A to E having different d were manufactured. First, when the external air was a crosswind with a flow velocity of 18 m / s, the air flow velocity in the engine room 13 at an upstream position near the test jet engine model EM. The distribution was investigated.

FIG. 9 is a view for explaining the measurement position of the air flow velocity in the engine room on the upstream side near the test jet engine model EM, and FIG. 9A is a plan view thereof.
(B) is a side view thereof. Note that the dimension length in FIG. 9 is a dimension in terms of actual machine scale. The measurement of the air flow velocity was performed using a pitot tube 19 inserted into the engine room 13.

As shown in FIG. 9 (b), the flow velocity measurement position is set at 1.6 m upstream of the test jet engine model EM in the longitudinal direction of the engine room 13 (length in actual machine scale). 13 In the height direction, it is at the same height as the jet engine horizontal axis and 2m from the floor.
(Length on actual scale). The positions in the longitudinal and height directions were set as described above, and the air flow velocity distribution in the width direction of the engine compartment 13 was measured at a small pitch. Table 1 shows the experimental conditions.

[0012]

[Table 1]

The measurement results are shown in the graph of FIG. From the figure, the air flow velocity distribution in the width direction of the engine compartment in the engine compartment 13 is the same as that of the experiment no. In Experiment No. 5, although the distribution was almost symmetrical and the flow velocity was almost uniform, the experiment No. 5 was conducted under the condition of no windshield and a cross wind of 18 m / s. In No. 6, the distribution is such that the flow velocity fluctuates significantly. On the other hand, in Experiment No. In Experiment 3, 6
It has been found that the results of the above can be greatly improved.

Next, as shown in Table 2, the gap distance c between the wind shield and the intake silencer 11 in the wind shield height direction and the two wind shields F and G having different wind shield height dimensions d are shown in FIG. Using the wind shield C, the air flow distribution in the width direction of the engine compartment 13 in the engine compartment 13 was similarly examined under the condition that the external air was a crosswind having a flow velocity of 18 m / s.

[0015]

[Table 2]

The measurement results are shown in the graph of FIG. As shown in the figure, it was found that the gap distance c and the windshield height dimension d had a small effect on the quality of the air flow velocity distribution within the current setting range. Then, based on the wind shield C, which has a small but good air flow distribution, the experiment described later was performed using the wind shield C.

Next, the wind shield C is set, and when the external air is a head-on wind having a flow velocity of 18 m / s, the engine room 13
The air velocity distribution in the interior was investigated. As shown in FIG. 9B, the flow velocity measurement position is 1.6 m upstream of the test jet engine model EM in the longitudinal direction of the engine room.
(Length in actual machine scale), and in the engine compartment width direction, as shown in FIG. 9A, Y = 1/10, Y = 3/10, Y
= 5/10, Y = 7/10, and Y = 9/10. Here, the width direction position Y = 5/10 is the center position of the width of the engine room, and adjacent width direction positions (for example, Y = 1/10 and Y
= 3/10) is 1.46 m (length in actual machine scale). The positions in the longitudinal and width directions were set as described above, and the air velocity distribution in the height direction of the engine compartment was measured at a small pitch.

The measurement results are shown in the graph of FIG. From the figure, it can be seen that the flow velocity on the floor in the engine room 13 is small and the position Y
At = 1/10, it was found that a region where the flow velocity was 0 m / s was present and a large vortex of air was generated. On the other hand, the engine room 13
The flow velocity is extremely large near the height of 4 m inside the
At 1/10, it was found that the flow velocity was about 12 m / s.

As described above, when the test operation is performed by taking in the external air having a large flow velocity of 18 m / s from the intake silencer, the conventional wind shield has the air upstream of the engine room near the test jet engine. Was found to occur. When such a vortex is generated, there is a fear that the air intake fan of the test jet engine may be damaged.

Therefore, an object of the present invention is to prevent a vortex from being generated on the upstream side near the test jet engine in the engine room when a test operation is performed in a jet engine test cell by taking in high-speed external air from the intake silencer. An object of the present invention is to provide a windshield for an intake silence room of a jet engine test cell, in which air flows evenly in the air.

[0021]

In order to achieve the above object, the invention according to claim 1 is characterized in that it has a box-like shape having an opening at the bottom and an upper portion above an intake silencer chamber having an intake port. The air inlet is inserted through the opening into the box-shaped hollow portion, and is arranged concentrically with the air intake silence chamber with a gap provided between the air intake silence chamber and external air taken into the air intake silence chamber through the gap. In the windshield for an intake silencer of a jet engine test cell, the opening is formed such that a gap between the silencer and the intake silencer in a plan view is closed at portions corresponding to four corners of the intake silencer. This is a windshield for an intake silencing chamber of a jet engine test cell, characterized in that the windshield is formed.

According to a second aspect of the present invention, in the windshield for an intake silencing chamber of the jet engine test cell according to the first aspect, a triangular or quadrangular plate-like member is provided at four bottom corners to form the opening. It is characterized by having.

FIGS. 5A and 5B are diagrams for explaining the operation of the wind shield, FIG. 5A is a diagram for explaining the operation of the conventional wind shield, and FIG. 5B is a diagram for explaining the operation of the wind shield of the present invention. FIG. In the above-described conventional windshield 10, when the external air flowing at a high flow velocity is taken into the intake silencing chamber 11 (the intake port of the silencing chamber), as shown in FIG. The airflow concentrates on the downstream (leeward) corner of the wind body 10, and flows unevenly near the downstream (leeward) wall surface in the intake noise reduction chamber 11.

On the other hand, in the windshield 1 of the present invention, the four corners at the bottom are closed by, for example, a triangular plate-like member 1a, so that a gap between the air-absorbing silencer 11 and the air intake silencer 11 in plan view is increased. Since the portions corresponding to the four corners of the noise reduction chamber 11 (the suction noise reduction chamber suction port) are closed, the external air flows downstream (downwind side) in the suction noise reduction chamber 11 as shown in FIG. ) Can be prevented from being concentrated near the wall surface and flowing unevenly, and can flow toward the center. As a result, in the engine room following the intake muffling chamber and the intake chamber, air can flow evenly so that eddies are not generated.

As described above, in the wind shield according to the present invention, the gap between the air intake silencer 11 and the intake silencer 11 in plan view is different.
Since the part corresponding to the four corners of 1 is closed, the wind direction of the external air is determined as “lateral wind” from the left and right directions, “direct wind” from the front, and “back wind” from behind. Can be supported.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. The parts other than the windshield in the jet engine test cell are the same as the conventional ones, and the same reference numerals as those in FIGS.

FIG. 1 is a view showing a windshield for an intake silencer according to a first embodiment of the present invention. FIG. 1 (a) is a partially cutaway plan view, FIG. 1 (b) is a side view, and FIG. FIG. 1A is a sectional view taken along line AA of FIG.

As shown in FIGS. 1 and 2, the wind shield 1 according to this embodiment has a box shape with an opening at the bottom, and is supported and fixed to the intake silencing chamber 11 by flanges and bolts (not shown). Thus, the intake muffler 11 is placed above the intake muffler 11 having the upper end serving as the intake, and the intake muffler 11 enters the box-shaped hollow portion from below.
It is provided concentrically with the intake silence chamber 11 with a gap. The windshield 1 is provided with four triangular plate members 1a at the four corners of the bottom of the windshield and closing the four corners, as shown in FIG. 1 (a). Ga, Ga, G between
The opening is formed so that b and Gb are trapezoidal and are closed at portions corresponding to the four corners of the intake silencer 11.

In the wind shield 1 configured as described above,
In a jet engine test cell, the flow velocity is 18 m / s
When the test operation is performed by taking in the external air having such a high flow velocity from the intake silencing chamber 11, the above-described FIG. 5 (b)
As shown in (2), it is possible to prevent the outside air from concentrating near the wall surface on the downstream side (leeward side) in the intake silencing chamber 11 and preventing the outside air from flowing unevenly. As a result, the engine room 1 following the intake muffling room 11 and the intake room 12
In 3, air can be made to flow evenly so as not to generate a vortex.

Using the wind shield 1 according to the first embodiment,
In the case where the external air was a head-on wind having a flow velocity of 18 m / s, the air flow velocity distribution in the engine room height direction in the engine room 13 was investigated. For the flow velocity measurement position, refer to FIG.
2 is the same as the case of 2. In the windshield 1, a
= 1112 mm, b = 1140 mm, c = 1600 mm
And d = 2100 mm.

The results are shown in the graph of FIG. As shown in FIG. 6, as compared with FIG. 12 of the related art, the flow velocity on the floor surface (0 m in height) of the engine room 13 has been considerably improved by eliminating the flow velocity of 0 m / s, and the flow rate has been reduced to the extent that no vortex is generated. The air can be made to flow evenly. In addition,
In FIG. 6, at Y = 5/10, which is the center position in the width direction of the engine room 13, the flow velocity decreases near the position of 2 m in height, as described above. This is because, unlike the engine model EM, intake is not performed by the compressor of the engine, and the influence of the blockage of the engine model EM appears.

FIGS. 3A and 3B are views showing a windshield for an intake silencer according to a second embodiment of the present invention. FIG. 3A is a partially cutaway plan view and FIG. 3B is a side view.

The points different from the first embodiment will be described. In the wind shield 1 'of the second embodiment, square plate members 1'a are respectively attached to the four corners of the bottom of the wind shield, and the four corners are formed. By closing, the gaps Ga ′, Ga ′, Gb ′, Gb ′ between the intake silencer 11 and the intake silencer chamber in the plan view are rectangular as shown in FIG. The openings corresponding to the four corners of the intake silence chamber 11 are formed so as to be closed.

Also in the windshield 1 'thus constructed, similarly to the windshield 1 according to the first embodiment, in the jet engine test cell, external air having a high flow rate of 18 m / s is supplied to the intake silence chamber 11. At the time of performing the test operation by taking in more air, the air can be made to flow evenly so that no vortex is generated on the upstream side near the test jet engine in the engine room 13.

FIG. 4 is a view showing a windshield for an intake silencer according to a third embodiment of the present invention, and FIG.
(B) is a side view thereof.

As shown in FIG. 4, the windshield 1 ″ according to this embodiment has a box shape with the entire bottom open, and is supported and fixed to the intake noise reduction chamber 11 by flanges and bolts (not shown), thereby reducing the noise of the intake air. Above the chamber 11, the suction muffling chamber 11 is provided concentrically with the suction muffling chamber 11 with a gap between the suction muffling chamber 11 and the air inlet opening from below into the box-shaped hollow portion. The wind shield 1 "
By forming into a box shape having an octagonal cross section and an open bottom, as shown in FIG. 4 (a), a gap G between the intake air silencer 11 and the air intake silencer 11 in plan view.
The openings are formed so that a ″, Ga ″, Gb ″, and Gb ″ have a trapezoidal shape and are closed at portions corresponding to the four corners of the intake silencer 11. In the windshield 1 ″ thus configured as well, similarly to the windshield 1 according to the first embodiment, the flow rate of the jet engine test cell is 18 m.
/ S of external air having a high flow velocity such as
In conducting the test operation by taking in more, the engine room 13
The air can flow evenly so that no vortex is generated on the upstream side near the test jet engine in the inside.

[0037]

As described above, according to the windshield for an intake silencer of a jet engine test cell according to the present invention,
Since the gap between the suction muffling chamber and the space corresponding to the four corners of the suction muffling chamber is closed in plan view, for example, the outside that flows at a high flow velocity such as a flow velocity of 18 m / s. When air is introduced into the intake silencer from the gap, the external air can be prevented from being concentrated near the wall surface on the downstream side (leeward side) in the intake silencer and unevenly flowing, and can be made to flow toward the center. . Therefore, air is not biased so that vortices that may cause damage to the air intake fan of the test jet engine and the like are not generated on the upstream side near the test jet engine in the engine room following the intake muffler chamber and the intake chamber. It can be flowing.

[Brief description of the drawings]

FIG. 1 is a diagram showing a windshield for an intake silencer according to a first embodiment of the present invention, wherein (a) is a partially cutaway plan view thereof;
(B) is a side view thereof.

FIG. 2 is a cross-sectional view taken along line AA of FIG.

3A and 3B are views showing a windshield for an intake silencer according to a second embodiment of the present invention, wherein FIG.
(B) is a side view thereof.

FIGS. 4A and 4B are views showing a windshield for an intake silencer according to a third embodiment of the present invention, wherein FIG. 4A is a plan view and FIG. 4B is a side view.

5A and 5B are diagrams for explaining the operation of a windshield for an intake silencer, wherein FIG. 5A is a diagram for explaining the operation of a conventional windshield, and FIG. It is a figure for explaining.

FIG. 6 is a graph showing the air flow velocity distribution in the height direction of the engine compartment in the engine compartment when the outside air is a head-on wind having a flow velocity of 18 m / s, using the windshield for the intake silencing room according to the first embodiment. is there.

FIG. 7 is a side view showing a configuration of a jet engine test cell model.

FIGS. 8A and 8B are explanatory views of the configuration of the conventional air-shielding member for an intake silencer in FIG. 7, in which FIG. 8A is a plan view and FIG.
FIG. 7 is a sectional view taken along line BB of FIG.

9A and 9B are diagrams for explaining a measurement position of an air flow velocity in the engine room near and upstream of the test jet engine model EM, where FIG. 9A is a plan view and FIG. 9B is a side view thereof. is there.

FIG. 10 is a graph showing the air flow velocity distribution in the width direction of the engine compartment in the engine compartment when a conventional wind shield for an intake air silencer is used and the external air is a cross wind having a flow velocity of 18 m / s.

FIG. 11 is a graph showing the air flow velocity distribution in the width direction of the engine compartment in the engine compartment when the conventional air shield for the air intake silencing chamber is used and the external air is a cross wind having a flow velocity of 18 m / s.

FIG. 12 is a graph showing an air flow velocity distribution in a height direction of an engine room in an engine room in a case where a conventional windshield for an intake silence room is used and external air is a head-on wind having a flow velocity of 18 m / s.

[Explanation of symbols]

1, 1 ', 1 "... Insulation silencer 1a ... Triangular plate member 1'a ... Square plate member 10 ... Insulation silencer windshield 11 ... Intake silencer room 11a ... Sound absorption splitter 12 ... intake room 13 ... engine room 14a ... exhaust duct 14 ... exhaust duct room 15 ... exhaust room 16 ...
Exhaust silencer 17 Secondary silencer 18 Turning vane 19 Pitot tube EM Test jet engine model Ga, Ga ', Ga ", Gb, Gb', Gb" Gap

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Toshio Yoshimura 1-3-18 Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo F-term (reference) 2G087 AA04 BB26 CC15 EE26 3L080 AE02

Claims (2)

[Claims] 1. An air intake system according to claim 1, wherein said intake port is formed into a box-like shape having an opening at a bottom portion, and above said intake silence chamber having an upper end serving as an intake port. A sound-absorbing silencer is arranged concentrically with the silencer with a gap,
In a windshield for an intake silencer of a jet engine test cell in which external air is taken into the intake silencer from the gap, the gap between the intake silencer and the four corners of the intake silencer in plan view. As if it were closed
A windshield for an intake silencer of a jet engine test cell, wherein the opening is formed. 2. A windshield for an intake silencer of a jet engine test cell according to claim 1, wherein a triangular or square plate member is provided at four bottom corners to form said opening.