JP2014231977A - Gas turbine engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas turbine engine capable of preventing counter flow of air to a primary combustion field, preventing a combustion temperature from rising in the primary combustion field, and achieving NOx reduction.SOLUTION: A gas turbine engine includes a combustion chamber 5 in which combustion is performed in a fuel rich condition in an upstream primary combustion field 3 and combustion is performed in a fuel lean condition in a downstream secondary combustion field 4, and a throttle 10 having a narrower channel than that of the secondary combustion field 4 is arranged adjacent to an upstream side of the secondary combustion field 4. By flowing an inner fluid flowing in the primary combustion field 3 into the secondary combustion field 4 at a higher flow velocity, inhibiting a counter flow of additional combustion air supplied between the primary combustion field 3 and the secondary combustion field 4. This can inhibit contamination of the additional combustion air into the primary combustion field 3, conduct rich combustion in the primary combustion field 3, prevent temperature rise in the primary combustion field 3, and inhibit NOx generation.

Description

  The present invention relates to a gas turbine engine that supplies additional combustion air downstream of a primary combustion field of a combustion chamber and performs fuel lean combustion in a secondary combustion field downstream of the primary combustion field.

  Conventionally, the atmosphere is compressed by a compressor, the compressed air is introduced into the combustion chamber to burn the fuel in the combustion chamber, and the turbine is rotated using the combustion gas discharged from the combustion chamber to obtain mechanical power. There is a combustor for a gas turbine engine. This combustor includes a primary combustion chamber provided on the upstream side in the combustor casing and a secondary combustion chamber provided on the downstream side in the combustor casing (see, for example, Patent Document 1).

  The gas turbine combustor described in Patent Document 2 includes a liner that is connected downstream of the premixing duct and defines a combustion chamber. A primary combustion zone for burning the premixed gas generated in the premixing duct is formed in the liner, and diluting air for diluting the combustion gas as needed flows into the wall of the liner. Dilution holes are provided.

  The gas turbine described in Patent Document 3 includes a plurality of air nozzles, and the air nozzles are sequentially arranged at intervals on a concentric circle surrounding a fuel injection nozzle that injects fuel together with air. In this gas turbine, the amount of NOx generated is reduced by colliding the air passed through the air nozzle with the fuel injected from the fuel injection nozzle to form an air-fuel mixture having a uniform fuel distribution.

  In the gas turbine described in Patent Document 4, primary air is supplied on the upstream side of the combustor, secondary air is supplied at substantially the center of the combustor, and dilution air is supplied on the downstream side of the combustor. The combustion chamber described in Patent Document 5 is provided with an inlet for allowing air to flow into the combustion chamber on the wall surface of the primary combustion chamber on the upstream side, and a vortex generator for generating vortices in the air flow that flows, The thermal load on the wall of the fuel chamber is reduced by forming an air film.

JP-A-8-226648 JP 2002-295831 A JP 2005-90884 A JP-A-6-241455 JP-A-9-14603

  By the way, as a combustor of a gas turbine engine, while performing combustion in a fuel rich state, combustion in a fuel lean state is performed downstream thereof to suppress an increase in flame temperature, thereby partially reducing the amount of NOx emission. There are combustors that employ the Rich Burn Quick Quench Lean Burn method. In this RQL combustor, it is important that fuel and air are uniformly mixed to create a fuel rich state, and combustion gas and air are rapidly mixed to create a fuel lean state.

  An object of the present invention is to provide a gas turbine engine capable of preventing the backflow of air to the primary combustion field, preventing the increase of the combustion temperature in the primary combustion field, and reducing NOx. .

  The gas turbine engine of the present invention introduces compressed air and fuel into a combustion chamber, performs fuel rich combustion in the primary combustion field of the combustion chamber, and fuels in the secondary combustion field downstream of the primary combustion field. In a gas turbine engine that performs combustion in a lean state and blows the combustion gas discharged from the secondary combustion field to rotate the turbine, the upstream of the secondary combustion field is between the primary combustion field and the secondary combustion field. And a throttle portion having a flow path narrower than the flow path of the secondary combustion field is provided adjacent to the upstream side of the secondary combustion field, and the interior of the primary combustion field is provided. It is characterized by flowing the fluid into the secondary combustion field at a higher flow rate.

  This gas turbine engine includes a combustion chamber that performs fuel rich combustion in an upstream primary combustion field and performs fuel lean combustion in a downstream secondary combustion field, upstream of the secondary combustion field. Is provided with an inlet for supplying additional combustion air between the primary combustion field and the secondary combustion field. The throttle portion having a flow path narrower than the flow path of the secondary combustion field is disposed adjacent to the upstream side of the secondary combustion field and flows through the primary combustion field (combustion gas generated in the primary combustion field, Unburned fuel and remaining compressed air) are passed between the primary combustion field and the secondary combustion field because they pass through the secondary combustion field at a flow rate higher than the flow rate of the internal fluid of the secondary combustion field. The backflow of the added additional combustion air is suppressed. Thereby, it is possible to suppress the addition of additional combustion air to the primary combustion field, keep the primary combustion field rich, prevent the combustion temperature from rising, and suppress the generation of NOx.

  It is preferable that the guide portion that protrudes inward of the combustion chamber from the wall surface of the combustion chamber extends downstream from the portion of the wall surface that is upstream of the suction port and adjacent to the suction port. According to the gas turbine engine of this configuration, the additional combustion air that has flowed in from the suction port is guided downstream by the guide portion, so that the air that flows back to the primary combustion field can be further suppressed. Generation of NOx can be suppressed by preventing an increase in the combustion temperature in the primary combustion field.

  ADVANTAGE OF THE INVENTION According to this invention, the gas turbine engine which can prevent the backflow of the air to a primary combustion field, can prevent the raise of the combustion temperature in a primary combustion field, and can aim at reduction of NOx can be provided. .

It is sectional drawing which shows the combustion chamber of the gas turbine engine which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the combustion chamber of the gas turbine engine which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the combustion chamber of the gas turbine engine which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the combustion chamber of the gas turbine engine which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the combustion chamber of the gas turbine engine which concerns on 5th Embodiment of this invention.

  Hereinafter, embodiments of a gas turbine engine according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the gas turbine engine 1 includes a combustor 2 that employs a partially rich fuel combustion system. The combustor 2 is in a fuel rich state (rich state) in an upstream primary combustion field 3. Combustion chamber 5 for performing combustion in a lean state (lean state) in the secondary combustion field 4 on the downstream side.

  The gas turbine engine 1 can be used as, for example, an aircraft jet engine, compresses the atmosphere with a compressor provided upstream of the combustor 2, and introduces compressed air into the combustion chamber 5 of the combustor 2. Then, the fuel supplied into the combustion chamber 5 is combusted, the combustion gas discharged from the combustion chamber 5 is used to rotate a turbine provided downstream of the combustor 2 to obtain mechanical power, and combustion Thrust is obtained from the high-speed combustion gas discharged from the chamber 5.

  A fuel injection nozzle 6 is provided at the upstream end of the combustion chamber 5, and an intake port 5 a for introducing compressed air into the combustion chamber 5 is provided around the fuel injection nozzle 6. The fuel injected from the fuel injection nozzle 6 is mixed with compressed air in the combustion chamber 5 to generate an air-fuel mixture. Combustion in a fuel rich state is performed in the primary combustion field 3, and the combustion gas and the unburned mixed gas that are the internal fluid flowing through the primary combustion field are introduced into the downstream secondary combustion field 4.

  The combustion chamber 5 is an annular combustion chamber (annular combustion chamber), and the inner side is the side where the center of the ring exists, and the cylindrical inner case 7 is disposed outside the inner case 7. An outer case 8 is provided. Between these inner case 7 and outer case 8, a flow path through which the internal fluid flows is formed. The combustion chamber 5 is not limited to the annular type, and may be a combustion chamber having another structure such as a can type or a cannular type.

  The combustion chamber 5 includes an upstream portion 9 disposed on the upstream side of the combustion chamber 5, a connecting portion 10 that continues downstream of the upstream portion 9, and a downstream portion 11 that continues downstream of the connecting portion. The upstream portion 7 a of the inner case 7 and the upstream portion 8 a of the outer case 8 are arranged in parallel to each other along the flow direction of the internal fluid in the combustion chamber 5. A primary combustion field 3 is formed in the flow path between the upstream portion 7 a of the inner case 7 and the upstream portion 8 a of the outer case 8.

  The connecting portion 10 bent from the downstream end of the upstream portion 9 has a pair of wall surfaces 10a directed to the downstream side. The connecting portion 7b of the inner case 7 and the connecting portion 8b of the outer case 8 are inclined so as to be separated from each other toward the downstream side, and the flow path between the inner case 7 and the outer case 8 is widened.

  The joint portion 7b of the inner case 7 and the joint portion 8b of the outer case 8 have combustion air inlets 12 for supplying additional combustion air between the primary combustion field 3 and the secondary combustion field 4. Is provided. The shape of the combustion air inlet 12 may be circular or slit. A plurality of combustion air inlets 12 may be arranged in a direction inclined with respect to the flow direction of the internal fluid. Further, the axial direction of the combustion air inlet 12 may be arranged parallel to the axial direction of the combustion chamber 5, or may be arranged inclined with respect to the axial direction of the combustion chamber 5.

  The downstream portion 11 bent from the downstream end of the joint portion 10 in the flow direction has a downstream portion 7c of the inner case 7 and a downstream portion 8c of the outer case 8, and these downstream portions 7c, 8c. Are arranged parallel to each other along the flow direction of the internal fluid. A secondary combustion field 4 is formed in the flow path between the downstream portion 7 c of the inner case 7 and the downstream portion 8 c of the outer case 8.

  The combustion chamber 5 includes the connecting portion 10 as a constricted portion adjacent to the upstream side of the secondary combustion field 4 and having a flow path narrower than the flow path of the secondary combustion field 4. The gap between the case 8 and the connecting portion 8b becomes narrower from the downstream side toward the upstream side. The upstream end portion 10b of the connecting portion 10 is narrowed by the inner case 7 and the outer case 8 being closest to each other at the throttle portion.

  At the downstream end of the combustion chamber 5, an exhaust port 5 b for discharging combustion gas generated by combustion in the combustion chamber 5 is formed. The combustion gas is jetted toward the turbine provided downstream of the combustion chamber 5 to rotate the turbine. The rotary impeller of the compressor arranged at the front stage of the combustor 2 includes a rotation shaft common to the turbine at the rear stage of the combustor 2, and the rotary impeller rotates and compresses the air as the turbine rotates. The introduced air is introduced into the combustor 2.

Next, the operation of the gas turbine engine 1 configured as described above will be described.
In the gas turbine engine 1, the sucked air is compressed by a compressor and supplied to the combustor 2. The compressed air is introduced into the combustion chamber 5 through the intake port 5a. The compressed air introduced into the combustion chamber 5 and the fuel injected from the fuel injection nozzle 6 are mixed to generate an air-fuel mixture.

  The air-fuel mixture burns in the fuel rich state in the primary combustion field 3, and the combustion gas and the unburned gas mixture pass through the connecting portion 10 and flow into the downstream portion 11. The additional combustion air that has flowed into the combustion chamber 5 through the combustion air inlet 12 flows into the downstream portion 11 together with the combustion gas and the unburned mixed gas. Additional combustion air is supplied to dilute the unburned gas mixture, combustion in a lean fuel state in the secondary combustion field 4 is performed, and NOx emissions are reduced by suppressing an increase in combustion temperature. . The combustion gas generated in the combustion chamber 5 is discharged from the exhaust port 5b on the downstream side of the combustion chamber 5 and blown to the turbine on the downstream side of the combustion chamber 5 to rotate the turbine and generate a propulsive force.

  According to such a gas turbine engine 1, the connecting portion 10 is provided as a constricted portion having a flow path narrower than the flow path of the secondary combustion field 4, and the connecting part 10 is an internal fluid flowing through the primary combustion field 3 ( Combustion gas generated in the primary combustion field, unburned mixed gas, and remaining compressed air) can flow into the secondary combustion field 4 at a higher flow rate. Thereby, the backflow of the additional combustion air supplied from the combustion air inlet 12 of the joint portion 10 is suppressed, and the additional combustion air is suppressed from being mixed into the primary combustion field 3 and the primary combustion. Since rich combustion is possible in the field 3 and an increase in the combustion temperature is suppressed, the generation of NOx in the primary combustion field can be reduced.

  In this gas turbine engine 1, combustion in a fuel rich state is performed in the primary combustion field 3 upstream of the secondary combustion field 4, so that generation of NOx can be suppressed while realizing combustion stability.

(Second Embodiment)
The gas turbine engine 21 will be described with reference to FIG. The description of the same configuration as the above embodiment is omitted. The combustor 22 of the gas turbine engine 21 includes a combustion chamber 25 having a shape different from that of the combustion chamber 5 of the first embodiment. Specifically, the shape of the upstream portion 29 of the combustion chamber 25 is different from that of the first embodiment.

  The combustion chamber 25 includes a cylindrical inner case 27 and a cylindrical outer case 28 disposed outside the inner case 27.

  The inner case 27 includes an upstream portion 27a disposed along the flow direction on the upstream side, an inclined portion 27b bent inward from a downstream end of the upstream portion 27a, and a downstream side of the inclined portion 27b. It has the connection part 27c bent from the edge part to the back of the flow direction, and arrange | positioned along the flow direction.

  The outer case 28 includes an upstream portion 28a disposed along the flow direction on the upstream side, an inclined portion 28b bent inward from the downstream end of the upstream portion 28a, and a downstream portion of the inclined portion 28b. It has the connection part 28c bent from the edge part to the back of a flow direction, and is arrange | positioned along the flow direction.

  The flow path in the combustion chamber 25 is throttled by the inclined portions 27 b and 28 b on the downstream side of the upstream portion 29, maintained by the connecting portions 27 c and 28 c, expanded by the connecting portion 10, and connected to the downstream portion 11.

  In such a gas turbine engine 21 of the second embodiment, the flow path is throttled on the downstream side of the upstream portion 29 of the combustion chamber 25, and the internal fluid flowing in the primary combustion field 3 is high downstream of the subsequent connecting portion 10. Can flow out at a flow rate. As a result, like the gas turbine engine 1 of the first embodiment, the backflow of the additional combustion air is suppressed, rich combustion is possible in the primary combustion field 3, and the combustion temperature in the primary combustion field 3 is increased. It is suppressed and generation of NOx in the primary combustion field 3 can be reduced.

(Third embodiment)
The gas turbine engine 31 will be described with reference to FIG. The description of the same configuration as the above embodiment is omitted. The combustor 32 of the gas turbine engine 31 includes a combustion chamber 35 having a different shape from the combustion chambers 5 and 25 of the above embodiment. Specifically, the shape of the upstream portion 39 of the combustion chamber 35 is different from the above embodiment.

  The combustion chamber 35 includes a cylindrical inner case 37 and a cylindrical outer case 38 disposed outside the inner case 37. The upstream portion 37a of the inner case 37 and the upstream portion 38a of the outer case 38 are inclined so as to approach each other toward the downstream.

  In such a gas turbine engine 31 of the third embodiment, the flow path is throttled at the upstream portion 39 of the combustion chamber 35, and the internal fluid flowing through the primary combustion field 3 flows out at a high flow rate downstream of the connecting portion 10. The As a result, as with the gas turbine engines 1 and 21 of the above-described embodiment, the backflow of additional combustion air is suppressed, rich combustion is possible in the primary combustion field 3, and the combustion temperature in the primary combustion field 3 is increased. And the generation of NOx in the primary combustion field 3 can be reduced.

(Fourth embodiment)
The gas turbine engine 41 will be described with reference to FIG. The description of the same configuration as the above embodiment is omitted. The gas turbine engine 41 is different from the gas turbine engine 1 of the first embodiment in that the gas turbine engine 41 includes a guide portion 13 that projects from the wall surface 10a of the combustion chamber 5 to the inside of the combustion chamber 5.

  The guide portion 13 has a plate shape and protrudes from the end portion 10 b on the upstream side of the connecting portion 10 to the inside of the combustion chamber 5. The guide part 13 protrudes from both the inner case 7 and the outer case 8, and the guide parts 13 on both sides of the flow path are disposed so as to approach each other toward the downstream side.

  In the gas turbine engine 41 of the fourth embodiment, the additional combustion air flowing in from the combustion air inlet 12 is guided toward the downstream side by the guide portion 13, so that the air that flows backward to the primary combustion field is used. It is possible to further suppress the occurrence of NOx by preventing an increase in the combustion temperature in the primary combustion field 3.

  In addition, the guide part 13 may be provided in the combustion chambers 25 and 35 of the gas turbine engines 21 and 31 of 2nd and 3rd embodiment. Moreover, the guide part 13 is not limited to what protrudes from the upstream edge part 10b of the connection part 10, and may protrude from the position shifted | deviated downstream from the upstream edge part 10b of the connection part 10. Further, it may project from a position shifted upstream from the downstream end of the upstream portion 9.

(Fifth embodiment)
The gas turbine engine 51 will be described with reference to FIG. The description of the same configuration as the above embodiment is omitted. The gas turbine engine 51 is different from the gas turbine engine 51 of the fourth embodiment in that the inner case 57 of the combustion chamber 5 is arranged linearly without changing its shape along the flow direction. In this way, the inner case 57 is linearly arranged, and the outer case 8 disposed opposite to the flow path is deformed to change the gap between the inner case 57 and the outer case 8, thereby changing the flow path. It may be narrowed. Similarly, the flow path may be narrowed by arranging the outer case linearly and deforming the inner case.

  The present invention is not limited to the embodiment described above. For example, in the above embodiment, the gas turbine engine 1 that can be used as an aircraft jet engine is described. However, the gas turbine engines 1, 21, 31, 41, and 51 of the present invention are not limited to aircraft jet engines. It can be used for other applications such as a generator for thermal power generation and a generator for cogeneration.

  In the above embodiment, the flow path is narrowed by changing the outer shape of the combustion chambers 5, 25, 35. However, the flow path may be narrowed by forming another wall surface in the flow path.

  1, 2, 31, 41, 51 ... Gas turbine engine, 3 ... Primary combustion field, 4 ... Secondary combustion field, 5, 25, 35 ... Combustion chamber, 12 ... Combustion air inlet, 13 ... Guide part.

Claims (2)

Compressed air and fuel are introduced into the combustion chamber, and fuel rich combustion is performed in the primary combustion field of the combustion chamber, and fuel lean combustion is performed in the secondary combustion field downstream of the primary combustion field. In the gas turbine engine for rotating the turbine by blowing the combustion gas discharged from the secondary combustion field,
An inlet for supplying additional combustion air between the primary combustion field and the secondary combustion field is provided upstream of the secondary combustion field,
The throttle portion having a flow path narrower than the flow path of the secondary combustion field is adjacent to the upstream side of the secondary combustion field, and the internal fluid of the primary combustion field is transferred to the secondary combustion field at a higher flow rate. A gas turbine engine which is made to flow.   The guide portion that protrudes inward of the combustion chamber from the wall surface of the combustion chamber extends downstream from a portion of the wall surface that is upstream of the suction port and adjacent to the suction port. The gas turbine engine according to claim 1.

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