JPH08177628A - Aircraft engine lobe mixer - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to a lobe mixer of an aircraft engine, and aims to improve engine performance by simultaneously increasing the mixing capacity and downsizing. As a lobe mixer for guiding a combustion gas flow from the inner side to the outer side and guiding an external air flow from the outer side to the inner side, a separation suppressing means is arranged near an inlet of a valley portion and is inserted as the separation suppressing means. A delta wing is applied that intersects the fluid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lobe mixer for an aircraft engine, and more particularly to a mixer ejector for a supersonic vehicle, which is intended to improve performance when a main flow and an external flow are mixed and exhausted. .

[0002]

2. Description of the Related Art A combined cycle engine (aircraft engine) as shown in FIG. 4 is being studied as an engine used for an aircraft that flies at a Mach number of 2.5 to 5. In FIG. 4, reference numeral 1 is an intake (air intake), 2 is an engine part, 3 is a casing, 4 is a lobe mixer, 5 is an ejector duct, and 6 is an external air introducing flap.

In this combined cycle engine,
The air taken in from the intake 1 is compressed to operate the engine part 2 by supplying fuel, and the combustion gas is guided to the lobe mixer 4 through the inside of the casing 3 to generate the combustion gas flow (core flow) A and the external air introduction flap. 6
As shown in FIG. 5, the external air flow B taken from
By mixing with the lobe mixer 4 and ejecting from the ejector duct 5, the exhaust gas flow is expanded to lower the temperature and reduce the level of ejection noise. In this case, the mixing efficiency can be improved by increasing the angle (lobe angle θ) formed by the fluid introduction direction and the fluid ejection direction by the casing 3.

[0004]

However, if the lobe angle θ is set to a value larger than the limit, such as 20 degrees or more, as shown in FIG. In some cases, the stagnant separation layer C may be generated and the desired mixing efficiency may not be obtained. On the other hand, when the lobe angle θ is set small (when the flow passage is set to be smooth), the lobe mixer 4 has a large size. Will be changed.

The present invention has been made in view of these circumstances, and realizes an increase in mixing capacity and a reduction in size at the same time,
The purpose is to improve engine performance.

[0006]

As means for solving such a problem, in the present invention, the combustion gas flow generated based on the operation of the engine section is guided from the inner side to the outer side and the external air flow is guided from the outer side to the inner side. As a lobe mixer for mixing by mixing, a separation suppressing means is arranged near the inlet of the valley portion, and a delta blade that intersects the insertion fluid is applied as the separation suppressing means. The delta vanes are installed in either or both of the trough on the combustion gas flow side and the trough on the external air flow side of the lobe mixer. The delta blades are arranged in an inclined state with respect to the inflow direction of the insertion fluid, a plurality of delta blades are arranged in the valley portion at intervals in the circumferential direction, and adjacent delta blades are symmetrical. It is set to have a shape. Further, as another separation suppressing means, a technique of arranging a slit formed in the valley portion in a penetrating state or a technique of adding a delta blade to this is adopted.

[0007]

The combustion gas flow generated based on the operation of the engine section is guided from the inner side to the outer side by the lobe mixer, and the external air flow is guided from the outer side to the inner side to mix the two fluids downstream of the lobe mixer. Planned. In this case, if the lobe angle is increased, the fluid easily separates in the valley portion of the lobe mixer, but the separation suppressing means is arranged near the inlet of the valley portion to suppress the occurrence of the fluid separation phenomenon. As a result, the size of the lobe mixer can be reduced.
When a delta blade is arranged as a separation suppressing means, the insertion fluid intersects with the delta blade, so that a vortex is generated in the valley based on the arrangement and shape of the delta blade, and part of the insertion fluid is guided to the valley. As a result, separation of the insertion fluid is suppressed. At that time, if the Delta blade is twisted in the circumferential direction, vortices are likely to be formed in the inclined portion, and if the Delta blade is arranged in the vicinity of the inlet of the trough, separation occurs due to the vortex spreading downstream thereof. Suppression is done. By arranging multiple delta blades in the valley part at intervals in the circumferential direction, vortices are generated at multiple points, and by adjoining delta blades being symmetrical, the diluting action of the mixed fluid by the vortex is made uniform. To do. As a peeling suppression means,
When a slit is formed in the valley that guides the external air flow, part of the high-pressure combustion gas flow is ejected to the external air flow, and the two fluids are mixed, so that the separation layer Formation will be suppressed and mixing will be promoted by the confluence and dilution of some of the combustion gas streams. If a delta wing is added downstream of the slit,
Mixing is performed by stirring the fluid in addition to the confluence.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a lobe mixer for an aircraft engine according to the present invention will be described below with reference to FIGS.

In the first embodiment, lobe mixer 4
The separation suppressing means 10 is arranged near the entrance of each valley 4a formed between the pair of side wall parts 4b adjacent to each other based on the corrugated shape of the above. A pair of delta wings 11 for applying the crossing state is applied.

The delta wing 11 is formed in such a manner that a triangular plate material is integrated with the valley portion 4a of the lobe mixer 4 and has an inclination angle with respect to the inflow direction of the insertion fluid, for example, in the shape of "C". In addition to being arranged, the pair of delta vanes 11 are arranged symmetrically with a space in the circumferential direction. The inclination angle (twisting angle) α in this case is set to have a line-symmetrical shape of, for example, about 15 to 20 degrees as shown in FIG. Then, as shown in FIG. 1, the height of the delta wing 11 (top of the triangle) is set to project more than the separation layer C when the formation of the above-described separation layer C in the valley portion 4a is predicted. Is set. The slope β of the delta blade 11 shown in FIG. 1 is set in consideration of the installation position and the length of the delta blade 11. Further, the delta blades 11 are usually combined one by one so as to form an "C" shape, but a plurality of pairs may be arranged symmetrically with one valley portion 4a spaced circumferentially.

In the lobe mixer 4 having such a structure, the combustion gas flow A generated by the operation of the engine unit 2 is guided from the inside to the outside based on the shape of the lobe mixer 4, and the external air flow is generated. B is guided from the outside to the inside to mix both fluids downstream of the lobe mixer 4. However, if the lobe angle θ is set large, the fluids are separated near the valley 4a. Although it becomes easier, when the delta vane 11 is provided as the separation suppressing means 10, the delta vane 11 intersects the insertion fluid, and the inclined edge portion 11a of the delta vane 11 with respect to the flow of the insertion fluid is formed. Because of the twist, as shown in FIGS. 1 and 2, a mixing vortex V is generated downstream of the inclined edge portion 11a. When the mixing vortex V is generated, the insertion fluid is sent to the valley portion 4a, so that the insertion fluid is supplied to a portion where the peeling layer C is easily formed, and the formation of the peeling layer C is suppressed.

Therefore, the peeling suppressing means 10 is provided with the valley portion 4
When it is arranged in the vicinity of the inlet of a, a mixing vortex V is generated in the downstream thereof, which prevents the separation layer C from being formed in a portion that is downstream of the separation suppressing means 10, and prevents the combustion gas flow A and the outside. The mixing property of the air flow B is enhanced. When a plurality of delta vanes 11 of the same type are arranged in a symmetrical state, as shown in FIG. 2, the mixing vortex V in a symmetrical state is extended to the downstream side to uniformize the dilution action of the mixed fluid. become.

Next, a second embodiment of the lobe mixer for an aircraft engine according to the present invention will be described. In the second embodiment of the peeling suppressing means 10, as shown in FIG.
The valley 4a for guiding the external air flow B is roughly
A slit 12 having a penetrating state so that the combustion gas flow A is blown out along a is applied. In this case, it does not prevent the delta vane 11 from being provided side by side at the downstream position of the slit 12.

When the slit 12 is arranged at the upstream position in the valley portion 4a of the lobe mixer 4, etc., the combustion gas flow A
Is relatively high with respect to the flow rate of the external air flow B, the pressure is high, and the kinetic energy is high, a part of the combustion gas flow A is, as shown by a chained arrow in FIG.
The two fluids are mixed by being jetted to the outside through the slit 12 and joining with the external air flow B. Therefore, a new flow is formed in the vicinity of the valley 4a, and the peeling layer C
Suppress the formation of. Further, a part of the combustion gas flow A joins and the external air flow B is diluted, whereby the mixing of both fluids is promoted.

[0015]

The lobe mixer for an aircraft engine according to the present invention has the following excellent effects. (1) By adopting the configuration in which the separation suppressing means is arranged near the entrance of the valley portion, it is possible to suppress the generation of the separation layer when the lobe angle is increased, and increase the mixing capacity. (2) By applying a delta blade that intersects the insertion fluid as the separation suppressing means, it is possible to easily generate a mixing vortex downstream thereof, reduce the size of the lobe mixer, and increase the mixing efficiency. (3) By arranging the delta blades so as to be inclined with respect to the inflow direction of the insertion fluid, it is possible to effectively generate a mixing vortex, reduce the size of the lobe mixer, and improve engine performance. (4) By arranging a plurality of delta vanes in a circumferentially spaced state and in a symmetrical shape, the mixed vortices can be generated over a long distance, and the arbitrariness of the shape of the lobe mixer can be improved. (5) As a separation suppressing means, by applying a slit formed in the valley portion in a penetrating state, in addition to suppressing the formation of a separation layer, promote the mixing of a part of the combustion gas flow and the external air flow. You can

[Brief description of drawings]

FIG. 1 is a front sectional view showing a first embodiment of a lobe mixer for an aircraft engine according to the present invention.

FIG. 2 is a plan sectional view showing a first embodiment of a lobe mixer for an aircraft engine according to the present invention.

FIG. 3 is a front sectional view showing a second embodiment of the lobe mixer of the aircraft engine according to the present invention.

FIG. 4 is a perspective view showing an example of the structure of an aircraft engine with a part of the description omitted.

5 is a front sectional view showing a fluid mixing state of the lobe mixer shown in FIG. 4;

6 is a front cross-sectional view showing a state of a peeling layer generated in the lobe mixer of FIG.

[Explanation of symbols]

 2 engine part 3 casing 4 lobe mixer 4a valley part 4b side wall part 10 separation suppressing means 11 delta blade 11a inclined edge part 12 slit A combustion gas flow B external air flow C separation layer V mixed vortex

Claims (4)

[Claims] 1. A lobe mixer (4) for guiding a combustion gas flow (A) generated based on the operation of an engine part (2) from the inside to the outside and guiding an external air flow (B) from the outside to the inside for mixing. The separation suppressing means (10) is arranged in the vicinity of the inlet of the valley (4a), and a delta wing (11) intersecting the insertion fluid is applied as the separation suppressing means. A lobe mixer for an aircraft engine. 2. A lobe mixer for an aircraft engine according to claim 1, wherein the delta vanes (11) are arranged in an inclined state with respect to the inflow direction of the insertion fluid. 3. A plurality of delta wings (11) are provided with valleys (4).
The lobe mixer for an aircraft engine according to claim 1 or 2, wherein the lobe mixers are arranged in a circumferentially spaced manner in a) and in a symmetrical shape. 4. A lobe mixer (4) for guiding a combustion gas flow (A) generated based on the operation of an engine section (2) from the inside to the outside and guiding an external air flow (B) from the outside to the inside to mix them. In addition, the peeling suppressing means (10) is arranged in the vicinity of the entrance of the valley (4a), and the peeling suppressing means has a slit (12) formed in a penetrating state in the valley.
A lobe mixer for an aircraft engine, characterized in that