JP7434858B2 - Flame holding device and engine - Google Patents

Description

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

Patent Document 1 listed below discloses an afterburner for a turbofan engine. This afterburner is provided with a flame stabilizer (flame holding plate) to suppress the flame from blowing out in the afterburner. This flame stabilizer (flame stabilizer plate) is a dogleg-shaped heat-resistant alloy member installed on the downstream side of the fuel injection nozzle. It forms a low speed region and holds the flame (flame holding) in this low speed region. In addition, in turbofan engines, a flame stabilizer (flame holding plate) is installed not only in the afterburner but also in the main combustor, which prevents the flame from blowing out due to the compressed air supplied from the compressor in the previous stage. There is.

International Publication No. 2015/178477

By the way, the flame stabilizer (flame stabilizer plate) in the above-mentioned background art acts as a resistance to the flow of combustion gas, and can reduce the flow velocity of combustion gas as a byproduct of flame stabilization performance. That is, the conventional flame stabilizer (flame stabilizer plate) obstructs the original functions of the afterburner and the main combustor in exchange for the flame stabilizing function.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a flame stabilizing device that can reduce the effect of reducing the flow velocity of combustion gas more than ever before.

In order to achieve the above object, the present invention is provided with a laser irradiator that irradiates a flame formed in a combustion field with a laser beam as a first solution related to a flame stabilizing device, and the laser irradiator is configured to A method is adopted in which a condensing optical system is provided to condense the laser beam onto the flame.

In the present invention, as a second solution related to a flame stabilizing device, in the first solution, when the flame is formed at a plurality of locations in the combustion field, the laser irradiator A method is adopted in which the laser beam is irradiated to each of the areas.

In the present invention, as a third solving means related to a flame stabilizing device, a means is adopted in which the condensing optical system is provided for each of the plurality of flames in the second solving means.

In the present invention, as a fourth solution related to the flame stabilizing device, a method is adopted in any of the first to third solutions, wherein the laser light is a laser pulse that repeats at a predetermined time interval. do.

In the present invention, as a fifth solution related to a flame stabilizing device, in any one of the first to fourth solutions, the laser irradiator focuses the laser beam on the surface of the object. adopt.

In the present invention, as a sixth solving means related to a flame stabilizing device, a means is adopted in which the combustion field is a combustor of a turbofan engine in any one of the first to fifth solving means.

In the present invention, as a seventh solving means related to a flame stabilizing device, a means is adopted in which the combustion field is a reheater of a turbofan engine in any one of the first to fifth solving means.

In the present invention, as a solving means related to the engine, a means of providing a flame holding device according to any one of the first to seventh solving means is adopted.

According to the present invention, it is possible to provide a laser flame stabilizing device that can reduce the flow velocity reduction effect of combustion gas more than ever before.

1 is a sectional view showing the configuration of a turbofan engine according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing the configuration of a flame stabilizing device according to an embodiment of the present invention. It is a schematic diagram which shows the structure of the flame stabilizing device based on the 1st modification of one Embodiment of this invention. It is a schematic diagram which shows the structure of the flame stabilization device based on the 2nd modification of one Embodiment of this invention.

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

This turbofan engine A has a substantially rotationally symmetrical shape around an axis L, and includes 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. , a shaft 8, a reheater 9 (afterburner), an exhaust nozzle 10, and a 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. This casing 1 has an opening on the front side serving as an intake la for taking air into the interior, and an exhaust nozzle 10 on the rear side.

Such a casing 1 has 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 the casing 1, in the radial direction. The core flow path 1b and the bypass flow path 1c are provided by dividing the inside of the casing 1 in the radial direction on the downstream side of the fan 2, as shown in FIG.

The core flow path 1b is a flow path that guides air to the combustor 5 and guides 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 path that guides air compressed from the fan 2 toward the reheater 9, bypassing the low pressure compressor 3, high pressure compressor 4, combustor 5, high pressure turbine 6, and low pressure turbine 7. It is a road.

The fan 2 is disposed at the most upstream side inside the casing 1. The fan 2 has a row of rotor blades fixed to a low-pressure shaft 8a, which will be described later, of a shaft 8, and a stator blade row fixed to a casing 1, which are alternately arranged in multiple stages. In such a fan 2, the rotor blades are rotated as the shaft 8 rotates, and the air taken in from the intake 1a is forcedly conveyed to the downstream side.

The low pressure compressor 3 is arranged at the most upstream side in the core flow path 1b. The low-pressure compressor 3 includes a row of rotor blades fixed to a low-pressure shaft 8a of a shaft 8 and a row of stator blades fixed to a casing 1, which are alternately arranged in multiple stages. In such a low-pressure compressor 3, the rotor blades are rotated as the shaft 8 rotates, and the rotor blades compress the air taken into the core flow path 1b while rectifying it with the stator blades.

The high pressure compressor 4 is arranged downstream of the low pressure compressor 3 in the core flow path 1b. This high-pressure compressor 4 has a row of rotor blades fixed to a high-pressure shaft 8b, which will be described later, of a shaft 8, and a row of stator blades fixed to a casing 1, which are arranged alternately in multiple stages. Become. In such a high-pressure compressor 4, the rotor blades are rotated as the shaft 8 rotates, and the air compressed by the low-pressure compressor 3 is rectified by the stator blades and further compressed by the rotor 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 generates combustion gas by burning a mixture of compressed air and fuel generated by the high-pressure compressor 4.

As shown in FIG. 2(a), 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 has an internal space that is a substantially annular (doughnut-shaped) combustion field. Compressed air generated by the high-pressure compressor 4 flows into the combustor liner 5a as an oxidizer. Note that the term "combustion field" used in this embodiment means a space where a combustion phenomenon occurs.

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

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

The plurality of laser irradiators 5c are equipped with a condensing optical system and condense and irradiate pulsed laser light (laser pulses) that repeats at predetermined time intervals toward the fuel or flame. Each of the laser irradiators 5c includes a laser oscillator and a condensing optical system, and the laser pulses generated by the laser oscillators are condensed by the condensing optical system including a convex lens and irradiated onto fuel or flame. Such a plurality of laser irradiators 5c ignite the fuel injected from each fuel injection nozzle 5b, and also perform flame stabilization (maintenance of the flame) for each flame.

A plurality of these laser irradiators 5c are provided corresponding to the fuel injection nozzles 5b. That is, in this embodiment, eight laser irradiators 5c are provided at an angular pitch of 45 degrees for the approximately annular (doughnut-shaped) combustor 5. An assembly of such laser irradiators 5c constitutes a flame holding device B in this embodiment.

The high-pressure turbine 6 is arranged downstream of the combustor 5 in the core flow path 1b. The high-pressure turbine 6 includes a plurality of rows of rotor blades fixed to the high-pressure shaft 8b of the shaft 8 and rows of stator blades fixed to the casing 1, which are alternately arranged in multiple stages. In such a high-pressure turbine 6, the combustion gas generated in the combustor 5 is rectified by the stationary blades and received by the rotor blades, so that the rotor blades rotate, 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 includes a row of rotor blades fixed to the low-pressure shaft 8a of the shaft 8 and a row of stator blades fixed to the casing 1, which are alternately arranged in multiple stages. In such a low-pressure turbine 7, the combustion gas that has passed through the high-pressure turbine 6 is rectified by the stator blades and received by the rotor blades, so that the rotor blades rotate, thereby rotating the low-pressure shaft 8a of the shaft 8.

The shaft 8 includes a radially inner low-pressure shaft 8a and a radially outer high-pressure shaft 8b, and has a double-shaft structure in which the low-pressure shaft 8a and the high-pressure shaft 8b can independently rotate coaxially. . The rotor blades of the low pressure turbine 7, the rotor blades of the low pressure compressor 3, and the rotor blades of the fan 2 are fixed to the low pressure shaft 8a. Such a low-pressure shaft 8a transmits rotational power generated when the rotor blades of the low-pressure turbine 7 receive combustion gas and rotate to the rotor blades of the low-pressure compressor 3 and the rotor blades of the fan 2, and The rotor blades of the low pressure compressor 3 and the rotor blades of the fan 2 are rotated.

The rotor blades of the high-pressure turbine 6 and the rotor blades of the high-pressure compressor 4 are fixed to the high-pressure shaft 8b. Such a high-pressure shaft 8b transmits rotational power generated when the rotor blades of the high-pressure turbine 6 receive combustion gas and rotate to the rotor blades of the high-pressure compressor 4, and the rotor blades of the high-pressure compressor 4 Rotate.

Reheater 9 is arranged downstream of low pressure turbine 7. The reheater 9 increases thrust by re-burning the fuel using oxygen contained in the mixture of the combustion gas that has passed through the low-pressure turbine 7 and the air that has passed through the bypass passage 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 at predetermined angular pitches in the circumferential direction of the substantially annular casing 1.

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

The plurality of laser irradiators 9b are equipped with a condensing optical system and condense and irradiate pulsed laser light (laser pulses) that repeats at predetermined time intervals toward the fuel or flame. The laser irradiators 9b are each equipped with a laser oscillator and a condensing optical system, and the laser pulses generated by the laser oscillators are condensed by the condensing optical system including a convex lens, and irradiated onto fuel or flame. The plurality of laser irradiators 9b ignite the fuel injected from each fuel injection nozzle 9a, and also perform flame stabilization (maintenance of the flame) for each flame.

A plurality of these laser irradiators 9b are provided corresponding to the fuel injection nozzles 9a. That is, in this embodiment, as shown in FIG. 2(b), eight laser irradiators 9b are provided at an angular pitch of 45 degrees with respect to the substantially annular casing 1. An assembly of such laser irradiators 9b constitutes a flame holding device C in this embodiment.

The exhaust nozzle 10 is provided at the downstream end of the casing 1, and injects the combustion gas exhausted from the core passage 1b and the airflow exhausted from the bypass passage 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 with no fuel mixed and uncompressed flows from the bypass flow path 1c.

Next, the operations of the turbofan engine A and the flame stabilizing devices B and C according to this 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 air is distributed between the core flow path 1b and the bypass flow path 1c. Air flowing through the core flow path 1b is compressed by a low pressure compressor 3 and a high pressure compressor 4, and then supplied to a combustor 5.

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

Furthermore, the air flowing through the bypass flow path 1c bypasses the low pressure compressor 3, high pressure compressor 4, combustor 5, high pressure turbine 6, and low pressure turbine 7, and passes through the reheater 9 before exiting from the exhaust nozzle 10. Injected with combustion gas. In this way, thrust is obtained by ejecting the combustion gas from the exhaust nozzle 10 and the air flowing through the bypass flow path 1c from the exhaust nozzle 10.

Here, when the combustion gas flowing through the core flow path 1b passes through the high-pressure turbine 6, the rotor 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, thereby rotating the rotor blades of the high-pressure compressor 4. Furthermore, when the combustion gas flowing through the core flow path 1b passes through the low-pressure turbine 7, the rotor blades of the low-pressure turbine 7 are rotationally driven to generate rotational power.

In addition, 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 and re-burns it, so that new combustion gas is pumped into the casing 1. is generated. This new combustion gas is ejected from the exhaust nozzle 10, thereby increasing the thrust.

Although the overall operation of the turbofan engine A according to the present embodiment is as described above, the flame stabilizing devices B and C according to the present embodiment are capable of controlling the overall operation of the turbofan engine A. It works as follows.

That is, when the turbofan engine A is started, the flame stabilizing device B provided in the combustor 5 irradiates the fuel injected from the fuel injection nozzle 5b with laser pulses at a predetermined time interval (pulse period T1). ignite it by doing so. That is, the flame stabilizing device B locally heats a portion of the fuel and compressed air by concentrating and irradiating the fuel injected from each fuel injection nozzle 5b from each laser irradiator 5c with a laser pulse. to generate high-temperature plasma.

This high-temperature plasma brings the fuel and compressed air into a combustible state and generates a flame. Since such high-temperature plasma is generated for each fuel injection nozzle 5b, that is, for each laser irradiator 5c, fuel is ignited, that is, flame is generated, at eight locations in total within the combustor 5.

In addition, in such a steady state of operation after ignition, the flame stabilizing device B maintains the flame ( flame holding). That is, the flame holding device B performs flame holding (flame holding) by emitting laser pulses from each laser irradiator 5c at a pulse period T1 to generate high-temperature plasma at the pulse period T1.

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, the pulse period T1 is set to a time interval that maximizes flame holding performance through preliminary experiments using combustion conditions as parameters.

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

This high-temperature plasma brings the fuel and compressed air into a combustible state and generates a flame. Since such high-temperature plasma is generated for each fuel injection nozzle 9a, that is, for each laser irradiator 9b, fuel is ignited, that is, flame is generated, at eight locations in total in the reheater 9.

In addition, in such a steady state of operation after ignition, the flame stabilizing device C maintains the flame ( flame holding). That is, the flame holding device C irradiates laser pulses from each laser irradiator 9b with a pulse period T2, thereby generating high temperature plasma at the pulse period T2 and holding the flame (flame holding).

Here, the pulse period T2 is similar to the pulse period T1 in the flame stabilizing device B described above, and is determined by combustion conditions such as the operating state of the turbofan engine A, the properties of the fuel, and/or the compression degree of the compressed air (oxidizing agent). The optimum setting is made by considering the following. That is, the pulse period T2 is set so as to maximize the flame holding performance in the reheater 9 through preliminary experiments using the combustion conditions in the reheater 9 as parameters.

According to this embodiment, the flame stabilizing devices B and C perform flame stabilization using laser light, so that the flame stabilizing devices B and C exert a deceleration effect on the combustion gas generated by the turbofan engine A. Therefore, it is possible to reduce the effect of reducing the flow velocity of combustion gas more than before.

Note that the present invention is not limited to the above-described embodiment, and for example, the following modifications can be considered.
(1) In the above embodiment, the laser pulse is focused in the atmosphere where fuel and 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 includes a combustor 5A in place of the combustor 5 described above, and a reheater in place of the reheater 9 described above. A heating device 9A is provided.

The combustor 5A includes a laser irradiator 5d instead of the laser irradiator 5c described above. This laser irradiator 5d focuses and irradiates laser pulses on the tip of the fuel injection nozzle 5b as the target. The flame stabilizing device B1 including such a laser irradiator 5d generates high-temperature plasma on the surface of the target (object), so it is expected to have better flame stabilizing performance than the flame stabilizing device B described above.

The reheater 9A includes a protrusion 9c as a new component, and a laser irradiator 9d instead 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 part that protrudes from the inner surface of the casing 1 toward the center to a predetermined height. Such a protrusion 9c is provided for each fuel injection nozzle 9a, and is exposed to the fuel injected from the fuel injection nozzle 9a.

The laser irradiator 9d focuses and irradiates laser pulses on such a protrusion 9c as a target. The flame stabilizing device C1 equipped with such a laser irradiator 9d generates high-temperature plasma on the surface of the protrusion 9c which is a target (object), so it is expected to have improved flame stabilizing performance compared to the flame stabilizing 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 applied only to one place (one point) in the air where fuel and compressed air exist. Although the pulses are focused, the present invention is not limited thereto. That is, the laser pulse may be focused at multiple locations. For example, as shown in FIG. 4, a turbofan engine A2 according to a second modification of the present embodiment includes a combustor 5B instead of the combustor 5 described above, and a reheater 5B instead of the reheater 9 described above. A heating device 9B is provided.

The combustor 5B includes two laser irradiators 5e and 5f instead of the laser irradiator 5c described above. One laser irradiator 5e focuses and irradiates a position closer to the fuel injection nozzle 5b with laser pulses in the atmosphere where fuel and compressed air are present. The other laser irradiator 5f focuses and irradiates laser pulses onto a distant position using the fuel injection nozzle 5b in the atmosphere where fuel and compressed air are present.

The flame stabilizing device B2 including such two laser irradiators 5e and 5f condenses and irradiates the fuel injected from each fuel injection nozzle 5b at two locations with laser pulses, so that high-temperature plasma is applied to the two locations. can be generated. Therefore, according to this flame stabilizing device B2, it is expected that the flame stabilizing performance will be improved more than the flame stabilizing device B mentioned above.

The reheater 9B includes two laser irradiators 9e and 9f instead of the laser irradiator 9b described above. One laser irradiator 9e focuses laser pulses and irradiates a position closer to the fuel injection nozzle 9a in the atmosphere where fuel and compressed air are present. The other laser irradiator 9f focuses and irradiates laser pulses to a distant position using the fuel injection nozzle 9a in the atmosphere where fuel and compressed air are present.

According to the flame stabilizing device C2 including such two laser irradiators 9e and 9f, since the laser pulse is focused and irradiated at two locations for the fuel injected from each fuel injection nozzle 9a, the laser pulses are focused and irradiated at two locations. It is possible to generate high temperature plasma. Therefore, according to this flame stabilizing device C2, it is expected that the flame stabilizing performance will be improved more than the flame stabilizing device C mentioned above.

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

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

A, A1, A2 Turbofan engine B, B1, B2, C, C1, C2 Flame holding device 1 Casing 1a Intake 1b Core passage 1c Bypass passage 2 Fan 3 Low pressure compressor 4 High pressure compressor 5 Combustor 5a Combustor Liner 5b Fuel injection nozzle 5c to 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 to 9f Laser irradiator 9c Projection 10 Exhaust nozzle 11 Liner

Claims (5)

Equipped with a laser irradiator that irradiates the flame formed in the combustion field of the reheater of the turbofan engine with laser light,
The laser irradiator includes a plurality of condensing optical systems that converge the laser beam at a plurality of flames formed in the reheater at a predetermined angular pitch ,
The focusing optical system focuses the laser pulse at a position closer to the fuel injection nozzle and a position farther from the fuel injection nozzle,
The focusing position of the laser beam at the farther position is further from the injection center of the fuel injected by the fuel injection nozzle into the combustion field than the focusing position of the laser beam at the closer position. Characteristic flame holding device. The flame stabilizing device according to claim 1 , wherein the condensing optical system is provided for each of the plurality of flames . 3. The flame stabilizing device according to claim 1 , wherein the laser beam is a laser pulse that repeats at predetermined time intervals . The flame stabilizing device according to any one of claims 1 to 3 , wherein the laser irradiator focuses laser light on the surface of an object . An engine comprising the flame stabilizing device according to any one of claims 1 to 4.

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