JPH0893554A - Jet engine - Google Patents

Abstract

PURPOSE: To improve high thrust by improving combustion efficiency of an after burner through a process of improving mixing performance of combustion gas with air. CONSTITUTION: An annular mixer 14 wherein air guiding-out passages 18A for partially guiding air passages inward and combustion gas guiding-out passages 18B for partially guiding combustion gas passages outward are alternately formed in the peripheral direction is arranged in the confluence position of the air passage with the combustion gas passage, and swirling devices 20 for swirling an air flow A or a combustion gas flow B are provided on at least one of the air guiding-out passages 18A and the combustion gas guiding-out passages 18B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jet engine used in, for example, an aircraft engine.

[0002]

2. Description of the Related Art A gas turbine engine is one of the jet engines used for aircraft.

Conventionally, such a gas turbine engine has the following structure. As shown in FIG. 4, a gas turbine engine 1 includes a fan 2 that takes in air, a compressor 3 that compresses the taken-in air, and a combustor 4 that mixes fuel with the compressed air and burns it.
And an output turbine 5 that drives the fan 2 and the compressor 3 by the combustion gas generated in the combustor 4. This gas turbine engine 1
Then, thrust is obtained by ejecting the combustion gas rearward through the exhaust pipe 6. Further, an afterburner 7 is provided in the exhaust pipe 6 of the gas turbine engine 1, and the afterburner 7 completely burns unburned oxygen remaining in the combustion gas in the exhaust pipe 6 to perform combustion. It is designed to improve the thrust by increasing the gas ejection speed.

[0004]

However, the conventional gas turbine engine 1 as described above has the following problems. That is, in the gas turbine engine 1, in order to promote combustion by the afterburner 7,
A part of the air taken in by the fan 2 is guided directly into the exhaust pipe 6 without passing through the combustor 4, and here, with this air flow A,
The combustion gas flow B from the combustor 4 is merged, and these are mixed. However, this air flow A
Because the outer peripheral side of the combustion gas flow B flows substantially parallel to the combustion gas flow B, the air flow A and the combustion gas flow B do not mix well and remain in layers. Sometimes becomes. As a result, there is a problem in that the combustion efficiency cannot be improved and the thrust cannot be improved as intended. The present invention has been made in consideration of the above points. By improving the mixing property of combustion gas and air, the combustion efficiency of the afterburner can be improved and a high thrust can be obtained. The purpose is to provide.

[0005]

The invention according to claim 1 is
A jet engine having an annular air flow passage that allows an air flow to pass therethrough, and an annular combustion gas flow passage that is disposed inside the air flow passage and that allows a combustion gas flow from a combustor to pass therethrough, wherein: At the confluence position with the combustion gas flow passage, an air discharge flow passage for guiding the air flow passage partially inward and a combustion gas discharge passage for guiding the combustion gas flow passage partially outward were alternately formed in the circumferential direction. An annular mixer is arranged, and a swirler for swirling a passing air flow or combustion gas flow is provided in at least one of the air discharge flow path and the combustion gas discharge flow path. .

According to a second aspect of the present invention, in the jet engine according to the first aspect, a plurality of swirlers are provided for one of the air discharge passage or the combustion gas discharge passage in which the swirler is provided. It is characterized by

The invention according to claim 3 is the invention according to claim 1 or 2.
In the jet engine described in the above, the swirlers are respectively provided in the air derivation flow path and the combustion gas derivation flow path, and pass by the swirler of the air derivation flow path and the swirler of the combustion gas derivation flow path. It is characterized in that the swirling direction of the air flow or the combustion gas flow is reversed.

[0008]

According to the present invention, the air flow passing through the annular air flow passage and the combustion gas flow from the combustor passing through the annular combustion gas flow passage inside the air flow passage are mixed. In the mixer, a part of the air flow is guided inward, that is, in the combustion gas flow direction by the air discharge flow path, and a part of the combustion gas flow is guided in the outer direction, that is, in the air flow direction, by the combustion gas discharge flow path. Will be mixed downstream. Then, the swirling device provided in at least one of the air derivation flow path and the combustion gas derivation flow path swirls the air flow or the combustion gas flow passing through the swirl device to enhance the mixing property. become.

According to the second aspect of the present invention, since a plurality of swirlers are provided for one of the air discharge passage or the combustion gas discharge passage, the air flow or the combustion gas flow passing through the swirler is swirled at a plurality of locations. It is possible to improve the mixing property.

According to the third aspect of the invention, the air flow and the combustion gas flow, which are alternately formed in the circumferential direction, pass through the respective swirlers in opposite directions. Since it is swirled, it is possible to further improve the mixing property.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. 1 to 3 show an embodiment of a jet engine according to the present invention. In these figures, the same parts as those shown in FIG. 4 shown as a conventional example are designated by the same reference numerals to simplify the description. As shown in FIG. 1, a gas turbine engine (jet engine)
As in the conventional gas turbine engine 1 shown in FIG. 4, a cylindrical casing 10a includes a fan 2 for taking in air and a compressor 3 for compressing the taken-in air.
A combustor 4 that mixes fuel with the compressed air and burns it; and an output turbine 5 that drives the fan 2 and the compressor 3 by the combustion gas generated in the combustor 4.
And an exhaust pipe 6 for ejecting combustion gas to the rear, and an afterburner 11 is arranged in the exhaust pipe 6 to have a schematic configuration.

In the casing 10a, a cylindrical inner cylinder 12 having a diameter smaller than that of the casing 10a is arranged coaxially with the casing 10a. The output turbine 5 is arranged inside thereof. In such a gas turbine engine 10, the airflow taken by the fan 2 is
At the upstream end 12a of the inner cylinder 12, a bypass flow (air flow) that is guided to the outside of the inner cylinder 12 and passes through an annular bypass flow path (air flow path) 13A formed by the inner cylinder 12 and the casing 10a. A and the combustor 4 guided to the inside of the inner cylinder 12
And a core flow (combustion gas flow) B passing through an annular core flow path (combustion gas flow path) 13B inside the inner cylinder 12, and thereafter, the bypass flow A and the core flow B are separated from each other. It is supposed to meet again inside.

At the downstream end 12b of the inner cylinder 12 located immediately before the bypass flow A and the core flow B merge,
A mixer 14 as shown below is attached. The mixer 14 has an annular configuration along the same axis as the axis of the gas turbine engine 10, and is formed in an annular shape such that one end 14 a thereof is continuous with the downstream end 12 b of the inner cylinder 12. Then, as shown in FIGS. 1 to 3, on the other end 14b side, the convex portions 15 projecting outward in the radial direction and the concave portions 16 projecting inward are alternately arranged at regular intervals along the circumferential direction. Is formed. These convex portion 15 and concave portion 1
6 is formed such that the height difference thereof gradually increases from one end 14a to the other end 14b. In this way, the mixer 14 has a configuration in which the convex portions 15 and the concave portions 16 are continuously formed alternately in the circumferential direction.

In such a mixer 14, the convex portion 1
The inner part of 5 is a combustion gas outlet passage 18B that guides a part of the core passage 13B outward in the radial direction. A part of the core flow B is indicated by an arrow in FIG. 2 by the combustion gas outlet passage 18B. Thus, it is guided radially outward, that is, to the bypass flow path 13A side. In addition, the inner portion of the recess 16 serves as an air outlet passage 18A that guides a part of the bypass passage 13A inward in the radial direction, and a portion of the bypass flow A is indicated by an arrow in FIG. As shown by, it is guided inward in the radial direction, that is, to the core flow path 13B side.

As shown in FIG. 3, in the mixer 14, two swirlers 20 are attached to all the air discharge passages 18A and the combustion gas discharge passages 18B.
The swirler 20 is arranged so that the air outlet passage 18A or the combustion gas outlet passage 18B extends substantially along the passage direction.
A or a cylindrical casing 21 arranged in a part on the outlet side of the combustion gas derivation flow path 18B, a shaft portion 22 coaxially provided therein, and an inner peripheral surface of the casing 21 and the shaft portion 22. A plurality of blade portions 23 are arranged between the outer circumferential surface and the outer circumferential surface and are fixed at equal pitches in the circumferential direction. The vane portion 23 may have a shape (not shown) slightly twisted with respect to the direction of the air outlet passage 18A or the combustion gas outlet passage 18B in which the swirler 20 is provided. Then, all the blade portions 23 in one swirler 20 are twisted in the same manner, whereby the bypass flow A
Alternatively, the core flow B is made to flow downstream while being swung in a predetermined direction with the shaft portion 22 of the swirler 20 as the swirling center. In the air outlet flow passage 18A, the inner swirler 20 is larger than the radial outer swirler 20 in the mixer 14 in accordance with the shape thereof, and in the combustion gas outlet flow passage 18B, the shape thereof. Accordingly, the inner swirler 20 is smaller than the outer swirler 20 in the radial direction.

Here, in the present embodiment, all the swirlers 20 provided in the air outlet passage 18A swirl the bypass flow A in the same direction, and the combustion gas outlet passage 18B.
All the swirlers 20 installed in the
And the swirler 20 of the air outlet flow path 18A
The swirler 20 of the combustion gas outlet passage 18B swirls the bypass flow A and the gas flow B in opposite directions. That is, as shown by the arrow in FIG. 3, all the swirlers 20 of the air outlet flow path 18A flow the downstream side while swirling the bypass flow A counterclockwise as viewed from the outlet side.
All of the swirlers 20 in the combustion gas outlet passage 18B are arranged to swirl the core flow B clockwise while seeing it from the outlet side and to flow the core flow B downstream. The swirler 20 can be manufactured separately from the mixer 14, and can be attached later by welding or the like.

Next, the operation of the gas turbine engine 10 having the above structure will be described. As shown in FIG. 1, in such a gas turbine engine 10,
At the upstream end 12a of the inner cylinder 12, the air flow taken in by the fan 2 is split into a bypass flow A passing through the bypass flow passage 13A and a core flow B passing through the combustor 4 and the core flow passage B. . Then, after the core flow B is compressed by the compressor 3, the fuel is mixed with the core flow B in the combustor 4 and the core flow B is burned. At this time, in the combustor 4,
Since the amount of fuel is smaller than the amount of inflowing air, the combustion gas after being combusted in the combustor 4 contains unburned components.

The core flow B (that is, the combustion gas flow from the combustor 4) is then passed through the output turbine 5, passes through the core flow passage 13B, and then flows in the exhaust pipe 6 downstream of the mixer 14. , The bypass flow A (that is, the air flow containing no fuel) that has passed through the bypass flow path 13A is joined again. At this time, the core flow B flows inside the mixer 14, and the bypass flow A flows outside from the upstream. Then, the core flow B flows through the combustion gas outlet passage 18B, and a part of the core flow B is guided along the convex portion 15 of the mixer 14 from the inner side to the outer side in the radial direction of the flow. On the other hand, part of the bypass flow A is guided from the outer side to the inner side in the flow radial direction along the recess 16 of the mixer 14 while flowing through the air outlet flow path 18A. Then, by the swirler 20, the mixer 14
The bypass flow A and the core flow B from the inside of the exhaust pipe 6 on the downstream side of the mixer 14 are swirled in the opposite directions,
It will be mixed so as to intersect in the radial direction.

As described above, the bypass flow A and the core flow B
And are mixed efficiently. Then, the afterburner 11 supplies more fuel to this mixed gas.
By being mixed and burned, the unburned oxygen remaining in the combustion gas is completely burned. As a result, the ejection speed of the combustion gas from the exhaust pipe 6 is increased, and the thrust of the gas turbine engine 10 is improved.

As described above, in this embodiment, the core flow B from the combustor 4 passing through the core flow passage 13B and the bypass flow passing through the bypass flow passage 13A arranged outside the core flow passage 13B. Since A and A are swung by the mixer 14 so as to intersect in the radial direction and are swirled by the swirler 20, the mixing property can be improved. Moreover, the air outlet passage 18A and the combustion gas outlet passage 18
Since two swirlers 20 are provided for one of the swirlers B, the bypass flow A or the core flow B passing through the swirler 20 can be swirled at a plurality of places, and the mixing property can be further enhanced. In addition, the bypass flow A or the core flow B passing through the respective swirlers 20 is swirled in the opposite direction in the air discharge flow passage 18A and the combustion gas discharge flow passage 18B that are alternately formed in the circumferential direction. The mixability can be further enhanced. Therefore, in the gas turbine engine 10 having such a configuration, the combustion of the combustion gas in the exhaust pipe 6 is promoted, the ejection speed thereof is increased, and as a result, the thrust of the gas turbine engine 10 can be improved.

The present invention is not limited to the above embodiment,
It is also possible to make the following changes or to combine the following changes. The core flow and the bypass flow are swirled in the same direction by providing similar swirlers in the air discharge flow path and the combustion gas discharge flow path, respectively.
The number of swirlers should be three or more per channel. One swirler is installed in each of the air discharge passage and the combustion gas discharge passage. At this time, the radial position of the mixer may be outside, middle, or inside. The swirler is partially provided in the air discharge passage and the combustion gas discharge passage. For example, it may be provided only on one side of the air derivation flow path and the combustion gas derivation flow path, or one or a plurality of them may be arranged on this one side. It is also possible to arrange them at random.

[0022]

As described above, according to the jet engine of the first aspect, the air flow passing through the annular air passage and the combustion passing through the annular combustion gas passage inside the air passage. In the mixer, a part of the air flow is guided inward by the air discharge flow path, that is, in the combustion gas flow direction, and a part of the combustion gas flow is discharged by the combustion gas discharge flow path, that is, the air. By being guided in the flow direction, it will be mixed on the downstream side of the mixer. Then, the swirling device provided in at least one of the air derivation flow path and the combustion gas derivation flow path swirls the air flow or the combustion gas flow passing through the swirl device to enhance the mixing property. become. As a result, combustion of the combustion gas in the combustion duct is promoted, the ejection speed thereof is improved, and as a result, the thrust of the jet engine can be improved.

According to the second aspect of the present invention, since a plurality of swirlers are provided for one of the air discharge passage or the combustion gas discharge passage, the air flow or the combustion gas flow passing through the swirler is swirled at a plurality of locations. It is possible to improve the mixing property. Therefore, the thrust of the jet engine can be further improved.

According to the third aspect of the present invention, the air flow and the combustion gas flow, which are alternately formed in the circumferential direction, pass through the respective swirlers in opposite directions. Since it is swirled, the mixing property is further enhanced. Therefore, the thrust of the jet engine can be further improved.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an example of a jet engine according to the present invention.

FIG. 2 is a front view showing an example of a mixer provided in the jet engine, in which a swirler is omitted for convenience of explanation.

FIG. 3 shows an example of a mixer included in the jet engine, and is a partially enlarged view including a swirler.

FIG. 4 is a side sectional view showing an example of a conventional jet engine.

[Explanation of symbols]

 4 Combustor 10 Gas Turbine Engine (Jet Engine) 13A Bypass Flow Path (Air Flow Path) 13B Core Flow Path (Combustion Gas Flow Path) 14 Mixer 18A Air Outflow Flow Path 18B Combustion Gas Outflow Flow Path 20 Swirler A Bypass Flow (Air flow) B core flow (combustion gas flow)

Claims (3)

[Claims] 1. An annular air flow passage for passing an air flow,
A jet engine having an annular combustion gas flow passage which is disposed inside the air flow passage and allows a combustion gas flow from a combustor to pass therethrough, wherein an air flow is provided at a confluence of the air flow passage and the combustion gas flow passage. An annular mixer in which an air derivation flow passage that guides a part of the passage inward and a combustion gas derivation flow passage that guides a part of the combustion gas passage to the outside are alternately formed in the circumferential direction is arranged, A jet engine comprising a swirler for swirling a passing air flow or a combustion gas flow in at least one of a discharge flow path and a combustion gas discharge flow path. 2. The jet engine according to claim 1, wherein a plurality of the swirlers are provided for one of the air discharge passage or the combustion gas discharge passage in which the swirler is provided. 3. The swirler is provided in each of the air outlet passage and the combustion gas outlet passage, and the air passing through the swirler in the air outlet passage and the swirler in the combustion gas outlet passage. The jet engine according to claim 1 or 2, wherein the swirling direction of the flow or the combustion gas flow is reversed.