JP2021089101A - Flame holding device and engine - Google Patents

Abstract

To provide a laser flame holding device that can relax a flow rate reduction action of a combustion gas more than before.SOLUTION: A flame holding device includes light irradiation means 5c, 9b for irradiating a flame formed in a combustion field 5a with a laser beam. The light irradiation means 5c, 9b include a light condensing optical system for condensing a laser beam at a flame. When a flame is formed in multiple places in the combustion field 5a, the light irradiation means 5c, 9b irradiate the flames in the multiple places with a laser beam respectively. The light condensing optical system is installed for each of the flames in the multiple places.SELECTED DRAWING: Figure 2

Description

The present invention relates to a flame holding device and an engine.

Patent Document 1 below discloses an afterburner for a turbofan engine. This after-burner suppresses the extinguishing of flames in the after-burner by providing a flame-retaining device (flame-retaining plate). This flame retainer (flame retainer plate) is a "dogleg" -shaped heat-resistant alloy member provided on the downstream side of the fuel injection nozzle, and is locally localized in the high-speed exhaust gas supplied from the turbine in the previous stage. A low-speed region is formed, and the flame is held (held) in this low-speed region. In the turbofan engine, not only the afterburner but also the main combustor is equipped with a flame holder (flame holder plate) to suppress the extinction of the flame by the compressed air supplied from the compressor in the previous stage. There is.

International Publication No. 2015/178477

By the way, the flame holding device (flame holding plate) in the above background technique acts as a resistance to the flow of the combustion gas, and can reduce the flow velocity of the combustion gas as a by-product of the flame holding performance. That is, the conventional flame-retaining device (flame-retaining plate) obstructs the original functions of the afterburner and the main combustor as a compensation for the flame-retaining function.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flame holding device capable of alleviating the effect of reducing the flow velocity of combustion gas as compared with the conventional case.

In order to achieve the above object, in the present invention, as a first solution relating to a flame holding device, a laser irradiator that irradiates a flame formed in a combustion field with a laser beam is provided, and the laser irradiator is described as described above. A means of providing a condensing optical system that condenses the laser beam on the flame is adopted.

In the present invention, as a second solution relating to the flame holding device, when the flame is formed at a plurality of places in the combustion field in the first solution, the laser irradiator uses the flame at a plurality of places. The means of irradiating each of the laser beams is adopted.

In the present invention, as a third solution relating to the flame holding device, in the second solution, the condensing optical system is provided for each of the flames at a plurality of locations.

In the present invention, as a fourth solution for the flame holding device, in any of the first to third solutions, the laser beam is a laser pulse that repeats at predetermined time intervals. To do.

In the present invention, as a fifth solution relating to the flame holding device, in any one of the first to fourth solutions, the laser irradiator collects laser light on the surface of an object. adopt.

In the present invention, as a sixth solution relating to the flame holding device, in any of the first to fifth solutions, the means that the combustion field is a combustor of a turbofan engine is adopted.

In the present invention, as a seventh solution relating to the flame holding device, in any of the first to fifth solutions, the means that the combustion field is a reheater of a turbofan engine is adopted.

In the present invention, as a solution means for an engine, a means for providing a flame holding device according to any one of the first to seventh solutions is adopted.

According to the present invention, it is possible to provide a laser flame holding device capable of alleviating the effect of reducing the flow velocity of combustion gas as compared with the conventional case.

It is sectional drawing which shows the structure of the turbofan engine which concerns on one Embodiment of this invention. It is a schematic diagram which shows the structure of the flame holding device which concerns on one Embodiment of this invention. It is a schematic diagram which shows the structure of the flame holding device which concerns on 1st modification of 1 Embodiment of this invention. It is a schematic diagram which shows the structure of the flame holding device which concerns on the 2nd modification of one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, the configurations of the turbofan engine A and the flame holding devices B and C according to the present embodiment will be described with reference to FIGS. 1 and 2.

This turbofan engine A has a substantially rotationally symmetric shape centered on the shaft L, and has a casing 1, a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustor 5, a high-pressure turbine 6, and a low-pressure turbine 7. , Shaft 8, reheater 9 (afterburner), exhaust nozzle 10 and liner 11.

The casing 1 is a cylindrical member that houses a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustor 5, a high-pressure turbine 6, a low-pressure turbine 7, a shaft 8, and a reheater 9. The casing 1 has an intake 1a whose front opening is for taking in air inside, and an exhaust nozzle 10 is provided on the rear side.

In such a casing 1, a core flow path 1b, which is a flow path provided inside the casing 1 in the radial direction, and a bypass flow path 1c, which is a flow path provided outside in the radial direction, are formed inside. As shown in FIG. 1, the core flow path 1b and the bypass flow path 1c are provided by partitioning the inside of the casing 1 in the radial direction on the downstream side of the fan 2.

The core flow path 1b is a flow path that guides air to the combustor 5 and guides the combustion gas discharged from the combustor 5 toward the reheater 9 via the high-pressure turbine 6 and the low-pressure turbine 7. The bypass flow path 1c is a flow that guides the air pumped from the fan 2 toward the reheater 9 by bypassing the low-pressure compressor 3, the high-pressure compressor 4, the combustor 5, the high-pressure turbine 6 and the low-pressure turbine 7. The road.

The fan 2 is arranged on the most upstream side inside the casing 1. The fan 2 is formed by alternately arranging a moving blade array composed of moving blades fixed to the low-voltage shaft 8a described later of the shaft 8 and a stationary blade example consisting of stationary blades fixed to the casing 1 in a plurality of stages. In such a fan 2, the moving blades are rotated with the rotation of the shaft 8, and the air taken in from the intake 1a is pumped to the downstream side.

The low-pressure compressor 3 is arranged on the most upstream side in the core flow path 1b. The low-pressure compressor 3 is formed by alternately arranging a moving blade array composed of moving blades fixed to the low-pressure shaft 8a of the shaft 8 and a stationary blade array consisting of stationary blades fixed to the casing 1 in a plurality of stages. In such a low-pressure compressor 3, the moving blades are rotated with the rotation of the shaft 8, and the air taken into the core flow path 1b is rectified by the stationary blades and compressed by the moving blades.

The high-pressure compressor 4 is arranged downstream of the low-pressure compressor 3 in the core flow path 1b. In this high-pressure compressor 4, a moving blade array composed of moving blades fixed to the high-pressure shaft 8b described later of the shaft 8 and a stationary blade array consisting of stationary blades fixed to the casing 1 are alternately arranged in a plurality of stages. Become. In such a high-pressure compressor 4, the moving blades are rotated with the rotation of the shaft 8, and the air compressed by the low-pressure compressor 3 is rectified by the stationary blades and further compressed by the moving blades.

The combustor 5 is arranged downstream of the high-pressure compressor 4 in the core flow path 1b. The combustor 5 includes a fuel nozzle and an ignition device (not shown), and produces combustion gas by burning a mixture of compressed air and fuel generated by the high-pressure compressor 4.

As shown in FIG. 2A, such a combustor 5 includes a combustor liner 5a, a plurality of fuel injection nozzles 5b, and a plurality of laser irradiators 5c. The combustor liner 5a is a substantially annular (doughnut-shaped) container composed of a plurality of heat-resistant metal plates, and is a combustion field having a substantially annular (doughnut-shaped) internal space. The compressed air generated by the high-pressure compressor 4 flows into the combustor liner 5a as an oxidant. The term "combustion field" used in this embodiment means a space in which a combustion phenomenon occurs.

The plurality of fuel injection nozzles 5b are provided on the upstream side of such a combustor liner 5a, and inject fuel toward the downstream side in the combustor liner 5a. These fuel injection nozzles 5b are provided with a substantially annular (doughnut-shaped) combustor 5 at a predetermined angular pitch in the circumferential direction. In this embodiment, eight fuel injection nozzles 5b are provided at an angle pitch of 45 degrees.

Here, the fuel injected into the combustor liner 5a from each fuel injection nozzle 5b forms a flame in each of them by fueling in the presence of the oxidizing agent (compressed air). That is, in the present embodiment, flames are formed inside a substantially annular (doughnut-shaped) combustor liner 5a at an angle pitch of 45 degrees, that is, flames are formed at eight locations (plural locations) of the combustion field.

The plurality of laser irradiators 5c include a condensing optical system, and condense and irradiate a pulsed laser beam (laser pulse) that repeats at predetermined time intervals toward a fuel or a flame. The laser irradiator 5c is provided with a laser oscillator and a condensing optical system, respectively, and the laser pulse generated by the laser oscillator is condensed by a condensing optical system including a convex lens or the like to irradiate the fuel or flame. Such a plurality of laser irradiators 5c ignite the fuel injected from each fuel injection nozzle 5b and retain the flame (maintain the flame) for each flame.

A plurality of these laser irradiators 5c are provided corresponding to the fuel injection nozzles 5b. That is, in the present embodiment, eight laser irradiators 5c are provided at an angle pitch of 45 degrees for the combustor 5 having a substantially annular shape (doughnut shape). The aggregate of such a laser irradiator 5c constitutes the flame holding device B in the present embodiment.

The high-pressure turbine 6 is arranged downstream of the combustor 5 in the core flow path 1b. The high-pressure turbine 6 is formed by alternately arranging a moving blade array composed of moving blades fixed to the high-pressure shaft 8b of the shaft 8 and a stationary blade array consisting of stationary blades fixed to the casing 1 in a plurality of stages. In such a high-pressure turbine 6, the moving blades rotate by receiving the combustion gas generated by the combustor 5 with the moving blades while rectifying the combustion gas with the stationary blades, thereby rotating the high-pressure shaft 8b of the shaft 8.

The low-pressure turbine 7 is arranged downstream of the high-pressure turbine 6 in the core flow path 1b. The low-pressure turbine 7 is formed by alternately arranging a moving blade array composed of moving blades fixed to the low-pressure shaft 8a of the shaft 8 and a stationary blade array consisting of stationary blades fixed to the casing 1 in a plurality of stages. In such a low-pressure turbine 7, the moving blades rotate by receiving the combustion gas that has passed through the high-pressure turbine 6 with the moving blades while rectifying the combustion gas with the stationary blades, thereby rotating the low-pressure shaft 8a of the shaft 8.

The shaft 8 includes a low-pressure shaft 8a on the inner side in the radial direction and a high-pressure shaft 8b on the outer side in the radial direction, and the low-pressure shaft 8a and the high-pressure shaft 8b have a dual shaft structure that can be rotated coaxially individually. .. The moving blades of the low-pressure turbine 7, the moving blades of the low-pressure compressor 3, and the moving blades of the fan 2 are fixed to the low-pressure shaft 8a. Such a low-pressure shaft 8a transmits the rotational power generated by rotating the moving blades of the low-pressure turbine 7 in response to the combustion gas to the moving blades of the low-pressure compressor 3 and the moving blades of the fan 2. The moving blades of the low-pressure compressor 3 and the moving blades of the fan 2 are rotated.

The moving blades of the high-pressure turbine 6 and the moving blades of the high-pressure compressor 4 are fixed to the high-pressure shaft 8b. Such a high-pressure shaft 8b transmits the rotational power generated by the rotor blades of the high-pressure turbine 6 receiving the combustion gas and rotating to the rotor blades of the high-pressure compressor 4, and the rotor blades of the high-pressure compressor 4 To rotate.

The reheater 9 is arranged downstream of the low pressure turbine 7. The reheater 9 enhances the thrust by reburning the fuel using the combustion gas that has passed through the low-pressure turbine 7 and the oxygen contained in the air-fuel mixture that has passed through the bypass flow path 1c. , A plurality of fuel injection nozzles 9a, a plurality of laser irradiators 9b, and the like.

The plurality of fuel injection nozzles 9a inject fuel toward the downstream side of the casing 1. That is, the plurality of fuel injection nozzles 9a supply new fuel to the exhaust gas of the low pressure turbine 7. These fuel injection nozzles 9a are provided with a substantially annular casing 1 at a predetermined angular pitch in the circumferential direction.

In this embodiment, eight fuel injection nozzles 9a are provided at an angle pitch of 45 degrees. The area near the downstream side of the fuel injection nozzle 9a is a combustion field where the fuel burns. That is, in the present embodiment, flames are formed at eight locations (plural locations) in the combustion field of the reheater 9.

The plurality of laser irradiators 9b include a condensing optical system, and condense and irradiate a pulsed laser beam (laser pulse) that repeats at predetermined time intervals toward a fuel or a flame. The laser irradiator 9b is provided with a laser oscillator and a focusing optical system, respectively, and the laser pulse generated by the laser oscillator is focused by a focusing optical system including a convex lens or the like to irradiate the fuel or flame. Such a plurality of laser irradiators 9b ignite the fuel injected from each fuel injection nozzle 9a and retain the flame (maintain the flame) for each flame.

A plurality of these laser irradiators 9b are provided corresponding to the fuel injection nozzles 9a. That is, in the present embodiment, as shown in FIG. 2B, eight laser irradiators 9b are provided at an angle pitch of 45 degrees with respect to the substantially annular casing 1. Such an aggregate of the laser irradiators 9b constitutes the flame holding device C in the present embodiment.

The exhaust nozzle 10 is provided at the downstream end of the casing 1 and injects the combustion gas exhausted from the core flow path 1b and the air flow exhausted from the bypass flow path 1c rearward. The liner 11 is a cylindrical partition wall provided in the reheater 9, and forms a flow path through which low-temperature air that is not mixed with fuel and is not compressed flows from the bypass flow path 1c.

Next, the operations of the turbofan engine A and the flame holding devices B and C according to the present embodiment will be described in detail.

In this turbofan engine A, air is taken in from the outside through the intake 1a of the casing 1 by driving the fan 2, and the taken-in air is distributed to the core flow path 1b and the bypass flow path 1c. The air flowing through the core flow path 1b is compressed by the low-pressure compressor 3 and the high-pressure compressor 4 and then supplied to the combustor 5.

Then, in the combustor 5, a flame is formed by burning the compressed air generated by the high-pressure compressor 4 as an oxidant, and at the same time, combustion gas is generated. This combustion gas flows in the order of the core flow path 1b, the high-pressure turbine 6, the low-pressure turbine 7, and the reheater 9, and is finally ejected from the exhaust nozzle 10.

Further, the air flowing through the bypass flow path 1c bypasses the low-pressure compressor 3, the high-pressure compressor 4, the combustor 5, the high-pressure turbine 6 and the low-pressure turbine 7, passes through the reheater 9, and then from the exhaust nozzle 10. It is injected with the combustion gas. Thrust is obtained by ejecting the combustion gas and the air flowing through the bypass flow path 1c from the exhaust nozzle 10 from the exhaust nozzle 10 in this way.

Here, when the combustion gas flowing through the core flow path 1b passes through the high-pressure turbine 6, the moving blades of the high-pressure turbine 6 are rotationally driven to generate rotational power. This rotational power is transmitted to the high-pressure compressor 4 through the high-pressure shaft 8b of the shaft 8, whereby the moving blades of the high-pressure compressor 4 rotate. Further, when the combustion gas flowing through the core flow path 1b passes through the low-pressure turbine 7, the moving blades of the low-pressure turbine 7 are rotationally driven to generate rotational power.

When a large thrust is required, the reheater 9 supplies fuel to the combustion gas that has passed through the high-pressure turbine 6 and the low-pressure turbine 7 to reburn the combustion gas, so that new combustion gas is introduced into the casing 1. Is generated by. The thrust is enhanced by ejecting this new combustion gas from the exhaust nozzle 10.

The overall operation of the turbofan engine A according to the present embodiment is as described above, but the flame holding devices B and C according to the present embodiment have a relation to the overall operation of the turbofan engine A. It works as follows.

That is, the flame holding device B provided in the combustor 5 irradiates the fuel injected from the fuel injection nozzle 5b with laser pulses at predetermined time intervals (pulse period T1) when the turbofan engine A is started. Ignite by doing. That is, the flame holding device B locally heats a part of the fuel and the compressed air by irradiating the fuel injected from each fuel injection nozzle 5b from each laser irradiator 5c by condensing the laser pulse. To generate high temperature plasma.

Then, the fuel and the compressed air are in a combustion state by this high temperature plasma, and a flame is generated. Since such high-temperature plasma is generated for each fuel injection nozzle 5b, that is, for each laser irradiator 5c, the fuel is ignited, that is, a flame is generated at a total of eight places in the combustor 5.

Further, in such a steady operation state after ignition, the flame holding device B holds the flame by irradiating the fuel of each fuel injection nozzle 5b by condensing the laser pulse from each laser irradiator 5c. Hold the flame). That is, the flame holding device B irradiates a laser pulse from each laser irradiator 5c with a pulse cycle T1 to generate a high temperature plasma in the pulse cycle T1 to hold the flame (flame holding).

Here, the pulse period T1 is optimally set by considering combustion conditions such as the operating state of the turbofan engine A, the properties of the fuel, and / or the degree of compression of the compressed air (oxidizing agent). That is, as the pulse period T1, the time interval for maximizing the flame retention performance is set by a preliminary experiment or the like with the combustion conditions as parameters.

On the other hand, the flame holding device C provided in the reheater 9 applies laser pulses at a predetermined time interval (pulse period T2) to the fuel injected from the fuel injection nozzle 9a when the reheater 9 is started. Ignite by irradiating. That is, the flame holding device C locally heats a part of the fuel and the compressed air by concentrating and irradiating the fuel injected from each fuel injection nozzle 9b from each laser irradiator 9b with a laser pulse. To generate high temperature plasma.

Then, the fuel and the compressed air are in a combustion state by this high temperature plasma, and a flame is generated. Since such high-temperature plasma is generated for each fuel injection nozzle 9a, that is, for each laser irradiator 9b, the reheater 9 ignites the fuel, that is, generates a flame at a total of eight places.

Further, in such a steady operation state after ignition, the flame holding device C holds the flame by concentrating and irradiating the fuel of each fuel injection nozzle 9a from each laser irradiator 9b with each laser pulse. Hold the flame). That is, the flame holding device C irradiates a laser pulse from each laser irradiator 9b with a pulse cycle T2 to generate a high temperature plasma in the pulse cycle T2 to hold the flame (flame holding).

Here, the pulse period T2 is the combustion conditions such as the operating state of the turbofan engine A, the properties of the fuel, and / or the degree of compression of the compressed air (oxidizing agent), similarly to the pulse period T1 in the flame holding device B described above. It is optimally set by considering. That is, the pulse period T2 is set so as to maximize the flame holding performance of the reheater 9 by a preliminary experiment or the like with the combustion conditions of the reheater 9 as a parameter.

According to the present embodiment, since the flame holding devices B and C perform flame holding using the laser beam, that is, the flame holding devices B and C have a deceleration action on the combustion gas generated by the turbofan engine A. Since it does not exert any effect, it is possible to relax the effect of reducing the flow velocity of the combustion gas as compared with the conventional case.

The present invention is not limited to the above embodiment, and for example, the following modifications can be considered.
(1) In the above embodiment, the laser pulse is focused in the air where the fuel and the compressed air are present, but the present invention is not limited to this. For example, a laser pulse may be focused on a predetermined target (object). That is, as shown in FIG. 3, the turbofan engine A1 according to the first modification of the present embodiment is provided with a combustor 5A instead of the combustor 5 described above, and is reheated in place of the reheater 9 described above. It is equipped with a combustor 9A.

The combustor 5A includes a laser irradiator 5d instead of the above-mentioned laser irradiator 5c. The laser irradiator 5d collects and irradiates the laser pulse with the tip of the fuel injection nozzle 5b as the target. Since the flame holding device B1 provided with such a laser irradiator 5d generates high-temperature plasma on the surface of the target (object), the flame holding performance is expected to be improved as compared with the flame holding device B described above.

The reheater 9A includes a protrusion 9c as a new component, and also includes a laser irradiator 9d in place of the laser irradiator 9b described above. The protrusion 9c is located on the downstream side of the fuel injection nozzle 9a, and is a portion that protrudes from the inner surface of the casing 1 toward the center to a predetermined height. Such protrusions 9c are provided for each fuel injection nozzle 9a, and are exposed to the fuel injected from the fuel injection nozzle 9a.

The laser irradiator 9d focuses and irradiates the laser pulse with such a protrusion 9c as a target. Since the flame holding device C1 provided with such a laser irradiator 9d generates high-temperature plasma on the surface of the protrusion 9c which is a target (object), the flame holding performance is expected to be improved as compared with the flame holding device B described above. ..

(2) In the above embodiment, for each fuel injection nozzle 5b in the combustor 5 and each fuel injection nozzle 9a in the reheater 9, the laser is used only at one place (one point) in the air where fuel and compressed air are present. The pulse was focused, but the invention is not limited to this. That is, the laser pulse may be focused at a plurality of places. For example, as shown in FIG. 4, the turbofan engine A2 according to the second modification of the present embodiment includes a combustor 5B instead of the combustor 5 described above, and is reheated in place of the reheater 9 described above. It is equipped with a combustor 9B.

The combustor 5B includes two laser irradiators 5e and 5f in place of the above-mentioned laser irradiator 5c. On the other hand, the laser irradiator 5e concentrates and irradiates the laser pulse at a position closer to the fuel injection nozzle 5b in the air where the fuel and the compressed air are present. The other laser irradiator 5e irradiates the laser pulse by condensing the laser pulse at a distant position by the fuel injection nozzle 5b in the air where the fuel and the compressed air are present.

Since the flame holding device B2 provided with the two laser irradiators 5e and 5f irradiates the fuel injected from the respective fuel injection nozzles 5b by concentrating the laser pulses at two locations, high-temperature plasma is applied to the two locations. Can be generated. Therefore, according to the flame holding device B2, the flame holding performance is expected to be improved as compared with the flame holding device B described above.

The reheater 9B includes two laser irradiators 9e and 9f in place of the above-mentioned laser irradiator 9b. On the other hand, the laser irradiator 9e concentrates and irradiates the laser pulse at a position closer to the fuel injection nozzle 9a in the air where the fuel and the compressed air are present. The other laser irradiator 9e irradiates the laser pulse by condensing the laser pulse at a distant position by the fuel injection nozzle 9a in the air where the fuel and the compressed air are present.

According to the flame holding device C2 provided with the two laser irradiators 9e and 9f, the laser pulses are focused and irradiated at two points for the fuel injected from each fuel injection nozzle 9a, so that the laser pulses are focused at two points. It is possible to generate high temperature plasma. Therefore, according to the flame holding device C2, the flame holding performance is expected to be improved as compared with the flame holding device C described above.

(3) In the above embodiment, the case where the flame holding device according to the present invention is applied to the turbofan engine A has been described, but the present invention is not limited to this. That is, the flame holding device according to the present invention can be applied to various types of engines. For example, it can be applied to a ramjet engine or a scramjet engine.

(4) In the above embodiment, the case where a laser pulse is used as the laser beam has been described, but the present invention is not limited to this. In particular, in the case of ignition, continuous laser light may be adopted instead of the laser pulse.

A, A1, A2 Turbofan engine B, B1, B2, C, C1, C2 Flame retaining device 1 Casing 1a Intake 1b Core flow path 1c Bypass flow path 2 Fan 3 Low pressure compressor 4 High pressure compressor 5 Combustor 5a Combustor Liner 5b Fuel injection nozzle 5c-5f Laser irradiator 6 High-pressure turbine 7 Low-pressure turbine 8 Shaft 8a Low-pressure shaft 8b High-pressure shaft 9 Reheater 9a Fuel injection nozzle 9b, 9d-9f Laser irradiator 9c Projection 10 Exhaust nozzle 11 Liner

Claims (8)

Equipped with a laser irradiator that irradiates the flame formed in the combustion field with laser light
The laser irradiator is a flame holding device including a condensing optical system that condenses the laser beam on the flame. When the flame is formed in a plurality of places in the combustion field,
The flame holding device according to claim 1, wherein the laser irradiator irradiates the flames at a plurality of locations with the laser light. The flame holding device according to claim 2, wherein the condensing optical system is provided for each of the flames at a plurality of locations. The flame holding device according to any one of claims 1 to 3, wherein the laser beam is a laser pulse that repeats at predetermined time intervals. The flame holding device according to any one of claims 1 to 4, wherein the laser irradiator concentrates laser light on the surface of an object. The flame holding device according to any one of claims 1 to 5, wherein the combustion field is a combustor of a turbofan engine. The flame holding device according to any one of claims 1 to 5, wherein the combustion field is a reheater of a turbofan engine. An engine comprising the flame holding device according to any one of claims 1 to 7.

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