JPH11101434A - Controller for combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of durability of a combustor due to back fire to elongate the life of the combustor and achieve the stabilized operation of an engine, by a method wherein the introducing amount of air from an external air source, which is introduced into a pre-evaporation and pre-mixing flow passage, is regulated in accordance with the operating condition of the engine, and the stabilized combustion range of the combustor is made changeable. SOLUTION: An annular sleeve 5 for regulating the flow rate of air, which is provided with air introducing port formed thereon, is engaged pivotally with the peripheral wall, on which the air introducing port 3a of a pre-evaporation pipe 3 is formed. A first fuel injection valve 6 for pre-evaporation and pre-mixing combustion, which injects fuel into the pre-evaporation pipe 3, is mounted on the upstream end unit of the pre-evaporation pipe 3, while a connecting unit to a combustion tube 4 or the downstream end unit of the pre- evaporation pipe 3 is provided with a second fuel injection valve 9 for diffusion combustion, which is mounted on a flame retainer 8 for retaining flame, which is supported by the central part of the pre-evaporation pipe 3 through a bracket 7. In this case, the flow rate of air, introduced into the pre-evaporation pipe 3 by extracting the same out of the outlet flow passage of a compressor in accordance with the operating condition of an engine, is regulated to restrain back fire or blow off and achieve the stabilized operation of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a combustor, and more particularly, to bleed air from a compressor outlet flow passage which is introduced into a pre-evaporation pre-mixing flow passage according to an operation state so that an operation point is in a stable combustion region. The present invention relates to a technique for suppressing the occurrence of flashback and blow-out in advance by adjusting the amount to realize smooth engine operation.

[0002]

2. Description of the Related Art As a conventional combustor for a gas turbine or the like, a combustor called a pre-evaporation premixing type as shown in FIG. there were.

[0003] The configuration of this prior art will be described with reference to FIG. The combustor 1 has two fuel injection valves, and appropriately distributes and injects a required fuel injection amount set according to an operation state to the first fuel injection valve 6 and the second fuel injection valve 9. Configuration.

Fuel is injected from a first fuel injection valve 6 into a pre-evaporation pipe 3 serving as a pre-evaporation pre-mixing passage of the combustor 1, and combustion air supplied via a compressor and a heat exchanger (not shown). Is introduced. In the pre-evaporation tube 3,
The injected fuel and combustion air are evaporated and mixed to form a premixed gas, which is supplied to a combustion cylinder 4 which is a main combustion part. Further, the remaining injection amount obtained by subtracting the injection amount of the first fuel injection valve 6 from the required fuel injection amount is directly injected into the combustion cylinder 4 from the second fuel injection valve 9 and supplied from the pre-evaporation pipe 3. The fuel is burned in the combustion cylinder 4 together with the air-fuel mixture. Further, dilution air is introduced into the combustion cylinder 4 in accordance with the amount of fuel injected from the two fuel injection nozzles, and the combustion is controlled in the combustion cylinder 4 to be in a certain lean state.

[0005] As described above, a part or all of the fuel injection amount is pre-evaporated and pre-mixed, and then the fuel is burned in a certain lean state in the combustion cylinder. Compared with the diffusion combustion type that directly injects fuel, there is an advantage that the emission amount of NOx can be greatly reduced and good exhaust characteristics can be obtained.

[0006] In such a pre-evaporation premix combustor, the flame in the combustor flows back to the pre-evaporation pre-mix passage.
If so-called flashback occurs, reduce the fuel supply,
Alternatively, a dedicated on-off valve is provided in the pre-evaporation pre-mixing flow path, and this valve is opened at the time of flashback to introduce combustion air into the pre-evaporation pre-mixing flow path to avoid flashback.

[0007]

However, in an actual operation involving sudden acceleration and sudden deceleration, flashback occurs frequently, and in such a system in which flashback avoidance control is performed after the occurrence of flashback, acceleration is not possible. In the case of a flashback, there is a problem that the operability of the engine deteriorates, for example, the fuel cannot be accelerated because the fuel is rapidly reduced, and the possibility of a misfire due to deceleration after acceleration increases.

The present invention has been made in view of such a conventional problem. The stable combustion range of the combustor (the flashback limit, the blowing limit, etc.) is controlled by the amount of air introduced from the outside into the pre-evaporation premixing flow path. Using the fact that the extinguishing limit changes, the amount of air introduced into the pre-evaporation pre-mixing flow path is adjusted according to the operating conditions. An object of the present invention is to control the flashback and blowout beforehand by controlling, and to solve the above problems.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a first fuel injection valve disposed near a combustor inlet between a combustor inlet into which combustion air flows and a combustion cylinder. A pre-evaporation pre-mixing passage for evaporating the fuel injected from the fuel tank and mixing with the combustion air to guide the fuel to the combustion cylinder; The required fuel injection amount set according to the operating state is appropriately distributed and injected into the first fuel injection valve and the second fuel injection valve according to the normal fuel distribution setting means, and is injected into the combustion cylinder in the combustion cylinder. In a combustor configured to open an intake of the dilution air to be introduced and burn at a predetermined excess air rate in the combustion cylinder, an air introduction means for introducing external air into the pre-evaporation flow path; Temperature detection means for detecting the Engine speed detecting means for detecting a fuel injection amount, a fuel injection amount detecting means for detecting a fuel injection amount from the first fuel injection valve, and a predetermined operation map based on the engine speed are selected. Operating state judgment means for judging the current operating point on the operation map from the operation map and judging whether or not the operating point is in a stable combustion region during operation, and a preliminary operation when the operating point is not in the stable combustion region. The air flow rate setting means and the air flow rate setting means for increasing or decreasing the amount of air introduced into the evaporation passage, and for keeping the amount of air introduced into the pre-evaporation passage constant when the operating point is in the stable combustion region. An air flow control means for adjusting the air introduction amount based on the set air introduction amount.

Further, according to the present invention, when the operating point on the operation map is a point having a predetermined value from both the flashback area and the blowout area, the operating point is in the stable combustion area. It is characterized by having an operating state determining means for determining that:

Further, according to the present invention, in the control device for a combustor, when the value of the operating point on the operation map from the flashback region becomes equal to or less than a predetermined value, it is determined that the operating point is in the flashback notice region. It is characterized by having an operating state determining means for performing the operation.

Further, according to the present invention, in the control device of the combustor, when the value of the operating point on the operation map from the blowout area becomes equal to or less than a predetermined value, it is determined that the operating point is in the blowout notice area. It is characterized by having an operating state determining means for performing the operation.

Further, according to the present invention, in the control device for a combustor, when the operating state determining means determines that the operating point is in the stable combustion region, the operating amount determining means does not change the amount of air introduced into the pre-evaporation passage. It is characterized by having air flow control means for adjusting the flow rate.

Further, according to the present invention, in the control device for a combustor, when the operating state determining means determines that the operating point is in the flashback notice area, the amount of air introduced into the pre-evaporation passage is increased. And air flow control means for adjusting the flow rate.

Further, according to the present invention, in the control device for a combustor, when the operating state determining means determines that the operating point is in the blowing-out notice area, the air flow introduced into the pre-evaporation passage is reduced. And air flow control means for adjusting the flow rate.

Further, the present invention is characterized in that in the control device for a combustor, there is provided air introducing means for extracting air introduced into the pre-evaporation passage from a compressor outlet air passage.

Further, the present invention is characterized in that in the control device for the combustor, there is provided air introducing means for supplying air introduced into the pre-evaporation flow path from an external air source.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a control device for a combustor according to the present invention.

(First Embodiment) FIG. 1 is a diagram showing a first embodiment of a control device for a combustor according to the present invention. First, the configuration will be described with reference to FIG. A combustor 1 provided with an intake passage serves as a pre-evaporation premix passage surrounded by a cover 2 provided with a compressor (not shown) and an air introduction hole 2a for introducing combustion air supplied through a heat exchanger. It has a pre-evaporation tube 3 and a combustion tube 4 connected to the downstream end of the pre-evaporation tube 3.

A ring-shaped sleeve 5 for adjusting the air flow rate, which also has an air introduction hole (not shown), is rotatably fitted to the peripheral wall of the pre-evaporation tube 3 where the air introduction hole 3a is formed. . At the upstream end of the pre-evaporation pipe 3, a first fuel injection valve 6 for pre-evaporation, premix combustion for injecting fuel into the pre-evaporation pipe 3 is mounted, and is connected to the combustion cylinder 4. At the downstream end of the evaporating pipe 3, a second fuel injection valve 9 for diffusion combustion is provided, which is mounted on a flame holding flame holder 8 supported at the center of the pre-evaporating pipe 3 via a bracket 7. I have.

An air inlet 2 for introducing combustion air.
The part a is provided with a temperature sensor 31 as a temperature detecting means for detecting a combustor inlet temperature.

An ignition plug 11 is mounted on the combustion tube 4 with its tip facing the inside of the combustion tube 4. In addition, combustion cylinder 4
A first air intake 4a for introducing air for dilution into the combustion cylinder 4 and a second air intake 4b for introducing air for diffusion combustion into the combustion cylinder 4 are formed on the peripheral wall. Have been. Then, similarly to the pre-evaporation tube 3, the opening area of the first air inlet 4a is changed to adjust the opening of the ring-shaped first sleeve 12 and the opening area of the second air inlet 4b. A ring-shaped second sleeve 13 for adjusting the air to be taken in is rotatably fitted and mounted. Gears 14 and 15 are provided integrally with the sleeves 12 and 13, respectively.

The gear 14 of the first sleeve 12 is
A gear 17 provided at the tip of a rotary shaft 16 rotatably supported on the outer wall of the second shaft 13 meshes with the gear 15. The gear 15 on the second sleeve 13 side is rotatably fitted on the outer peripheral surface of the rotary shaft 16 and supported. And a gear 19 provided integrally with the formed cylindrical rotary shaft 18.

Connected to the base end of the rotating shaft 16 is a first actuator 22 for rotating the rotating shaft 16 to rotate the first sleeve 12 in order to adjust the air taken in from the first air intake 4a. ing. A second sleeve 13 is provided at the base end of the rotating shaft 18 to rotate the rotating shaft 18 to adjust the air taken in from the second air inlet 4b.
Is connected to the second actuator 23 that rotationally drives the actuator.

The air pipe 34 extracts the compressor outlet air from a compressor outlet air flow path (not shown).
It is a pipe for introducing into the pre-evaporation pipe 3, and includes an air flow control valve 35 for controlling the air flow and an air flow sensor 36 for measuring the air flow in the middle.

The control unit 20 for controlling the combustion of the combustor 1 is composed of, for example, a microcomputer. At normal time, the first operation is performed based on signals from the temperature sensor 31 and the accelerator opening sensor 21 as in the conventional case.
The drive control of the fuel injection valve 6 and the second fuel injection valve 9, the first actuator 22, and the second actuator 23 is performed to perform combustion in a predetermined lean state.

That is, based on the combustor inlet temperature Tin signal from the temperature sensor 31, a normal fuel distribution map in which the allowable fuel injection amount from the first fuel injection valve 6 that can evaporate in the pre-evaporation pipe 3 is set in advance. In addition to calculating the required fuel injection amount Gfset of the engine corresponding to the current operating state, the accelerator opening θ signal corresponding to the engine load from the accelerator opening sensor 21 is input.

Then, the ratio of fuel injection from the first fuel injection valve 6 and the second fuel injection valve 9 to the required fuel injection amount is calculated from a predetermined "engine speed-fuel injection amount" map, and the calculated value is calculated. As the injection amount, fuel injection is performed from the first fuel injection valve 6 and the second fuel injection valve 9, and both pre-evaporation, premixed combustion and diffusion combustion are used. Simultaneously with these fuel injection controls, the first actuator 22 for driving the first sleeve 12, the second sleeve 13 and the second actuator in accordance with the fuel injection amount assigned to the first fuel injection valve 6 and the second fuel injection valve 9. 23 is controlled so that the supply amounts of the combustion air and the dilution air are appropriately controlled so that the combustion in the combustion cylinder 4 is performed in a lean combustion state within a predetermined range.

Further, the control unit 20 is configured as shown in FIG.
As shown in the flowchart of FIG. 7, an operation map for determining the current operation state is selected from a plurality of maps based on the rotation speed signal N of the engine rotation sensor 32,
The combustor inlet temperature Tin from the temperature sensor 31 and the first
The operating point on the operation map is determined based on the fuel injection amount Gf of the first fuel injection valve from a fuel injection amount sensor (not shown) of the fuel injection valve 6.

Further, a stable combustion (operation) range (flashback limit, blowout limit) on the map with respect to the flow rate of air introduced into the pre-evaporation pipe 3 during operation is determined, and an operation point for the stable combustion (operation) range is determined. Judge the position.

If the operating point is not at a position having a predetermined value from the flashback limit, it is determined that the operating point is in an area where flashback is likely to occur (flashback warning area), and air is introduced into the pre-evaporation pipe. If the operating point is not at a position having a predetermined value from the blowout limit, the operating point is in an area where blowout is likely to occur (a blowout notice area). Judgment is performed, and the amount of air introduced into the pre-evaporation tube is controlled to be reduced by a predetermined flow rate ΔGap.

Here, the control unit 20 is provided with the functions of the operating state determination means, the air flow rate setting means, and the air flow rate control means as software as shown in the flowchart of FIG.

Next, with reference to the flowchart shown in FIG. 2, each control operation of the operation state determination, air flow adjustment, and air flow control of the combustor control device according to the first embodiment will be specifically described. I do.

In step S 1, an air flow Ga extracted from the compressor outlet air flow path and introduced into the pre-evaporation pipe 3.
p is set to a predetermined flow rate Gap0. In step S2, the fuel injection amount Gfp of the first fuel injection valve is read based on the signal from the first fuel injection valve fuel injection amount sensor.

In step S3, the combustor inlet temperature Tin is read based on the signal from the temperature sensor 31. In step S4, the engine speed N is read from the engine speed sensor 32 by a signal.

In step S5, an operation map corresponding to the engine speed N is selected. The operation map is a diagram showing a relationship between the combustor inlet temperature Tin and the fuel injection amount Gfp of the first fuel injection valve 6, as shown in FIG. It is. An operation map closest to the engine rotation speed during operation is selected from the plurality of operation maps corresponding to the engine rotation speed N.
(See Fig. 4)

In step S6, the air flow sensor 36
From the air flow Ga
Read p.

In step S7, a flashback limit and a blowout limit on the operation map selected in step S5 are selected in accordance with the air flow rate Gap detected in step S6. In each operation map, a flashback limit and a blow-off limit are set so as to be selectable in accordance with a change in the air flow rate Gap. The disappearance limit can be selected. (See Fig. 5)

In step S8, the current operating point position on the operation map is determined from the fuel injection amount Gfp and the combustor inlet temperature Tin. (See FIG. 6) Steps S5, S7, and S8 correspond to the function of the operating state determination means.

In step S9, the operating point (fuel injection amount G
fp) is the flashback limit on the operation map (flashback limit fuel flow rate G
fp (fb1)) by a predetermined value (fuel flow rate ΔGfp)
It is determined whether or not the point is equal to or less than the point obtained by subtracting. “G
If it is determined that “fp ≦ Gfp (fb1) −ΔGfp”, it is determined that the operating point has a sufficient value from the flashback limit and the possibility of flashback is low, and the process proceeds to step S10.
> Gfp (fb1)-. DELTA.Gfp ", the operating point is in an operation region where there is a high possibility of flashback (flashback warning region), and it is determined that the possibility of flashback is high, and step S11 is performed. Proceed to.

In step S10, the operating point (fuel injection amount Gfp) is equal to or higher than the point obtained by adding a predetermined value (fuel flow rate ΔGfp) from the blowout limit (blowoff limit fuel flow rate Gfp (bo1)) on the operation map. It is determined whether it is a point. If it is determined that “Gfp ≧ Gfp (bo1) + ΔGfp”, it is determined that the operating point has a sufficient value from the blowout limit and the possibility of blowout is low, and the process returns to step S1. When it is determined that “Gfp <Gfp (bo1) + ΔGfp”, it is determined that the operating point is in an operation area where a blow-out is likely to occur (a blow-out notice area), and that the possibility of a blow-out is high. Proceed to S12.

In step S11, the air flow rate Gap is
The amount is increased to an amount obtained by adding a predetermined increment ΔGap to the air flow rate Gap detected in step S6, and the process returns to step S2. In step S12, the air flow rate Gap is changed to the air flow rate Gap detected in step S6 by a predetermined decrement ΔGap.
, And returns to step S2. Steps S9 to S12 correspond to the function of the air flow rate setting means.

As described above, flashback and blowout are suppressed in advance by adjusting the flow rate of air extracted from the compressor outlet flow path and introduced into the pre-evaporation pipe in accordance with the operation state, and stable. Engine operation can be realized.

(Second Embodiment) First, the configuration of the second embodiment will be described. In the first embodiment, the air in the compressor outlet air flow path is extracted and introduced into the pre-evaporation pipe. In the second embodiment, air is supplied from an external air source independent of the engine. Then, it is configured to be introduced into the pre-evaporation tube. FIG. 7 shows the configuration.

The basic control flow is the same as in the first embodiment, and a description thereof will be omitted.

[0046]

As described above in detail, according to the present invention, the amount of air introduced from the external air source introduced into the pre-evaporation pre-mixing flow path is adjusted according to the engine operating conditions, and In this way, flashback and blowout of the combustor are prevented and suppressed in advance by varying the stable combustion range of the combustion chamber. by this,
It is possible to prevent a decrease in durability of the combustor due to flashback, prolong the life of the combustor, and realize stable operation of the engine.

Further, by minimizing the amount of air introduced into the pre-evaporation pre-mixing channel, the combustion performance, heat efficiency,
A decrease in engine performance such as exhaust performance can be minimized.

Each embodiment has the following effects in addition to the above-mentioned common effects. In the first embodiment, the air introduced into the pre-evaporation pre-mixing channel is
By adopting a configuration in which air is extracted from the compressor outlet flow path, there is an effect that the configuration can be simplified and the cost can be reduced.

Further, in the second embodiment, by adopting a configuration in which air is introduced from an external air source, it becomes possible to introduce air near normal temperature, so that drivability is improved without lowering engine performance. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a pre-evaporation-premix combustor according to a first embodiment of a combustor control device according to the present invention.

FIG. 2 is a flowchart illustrating a control operation according to the first embodiment.

FIG. 3 is a diagram (operation map) illustrating a control operation according to the first embodiment.

FIG. 4 is a diagram (a schematic diagram (1)) illustrating a control operation according to the first embodiment.

FIG. 5 is a diagram (a schematic diagram (2)) illustrating a control operation according to the first embodiment.

FIG. 6 is a diagram (a schematic diagram (3)) illustrating a control operation according to the first embodiment.

FIG. 7 is a diagram illustrating a configuration of a pre-evaporation-premix combustor according to a second embodiment.

FIG. 8 is a diagram showing a configuration of a conventional pre-evaporation premix combustor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustor 2 Cover 2a Air introduction hole 3 Pre-evaporation tube 3a Air introduction hole 4 Combustion cylinder 4a First air intake 4b Second air intake 5 Sleeve 6 First fuel injection valve 7 Bracket 8 Flame stabilizer 9 Second fuel Injection valve 11 Spark plug 12 First sleeve 13 Second sleeve 14, 15, 17, 19 Gear 16, 18 Rotation axis 20 Control unit 21 Accelerator opening sensor 22 First actuator 23 Second actuator 31 Temperature sensor 32 Engine rotation sensor 34 Air piping 35 Air flow control valve 36 Air flow sensor

Claims (9)

[Claims] 1. A fuel injected from a first fuel injection valve disposed near a combustor inlet between a combustor inlet into which combustion air flows and a combustion tube, and mixed with the combustion air. Having a pre-evaporation pre-mixing passage leading to the combustion cylinder,
A second fuel injection valve for diffusion combustion is provided at a connection between the pre-evaporation pre-mixing passage and the combustion cylinder, and a required fuel injection amount set in accordance with an operation state is set to the first fuel injection amount according to the normal fuel distribution setting means. The fuel injection valve and the second fuel injection valve are appropriately distributed and injected, and the combustion cylinder is provided with an intake port for dilution air to be introduced into the combustion cylinder. In the combustor configured to burn in, air introduction means for introducing external air into the pre-evaporation flow path, temperature detection means for detecting the combustor inlet temperature, and engine speed detection means for detecting the engine speed A fuel injection amount detecting means for detecting a fuel injection amount from the first fuel injection valve, a predetermined operation map is selected from the engine speed, and a current operating point on the operation map based on the combustor inlet temperature and the fuel flow rate. Judge, Operating state determining means for determining whether or not the operating point is in a stable combustion area during operation; and increasing or decreasing the amount of air introduced into the pre-evaporation flow path when the operating point is not in the stable combustion area, When the point is in the stable combustion region, to keep the amount of air introduced into the pre-evaporation flow path constant,
A control device for a combustor, comprising: an air flow rate setting means; and an air flow rate control means for adjusting an air introduction amount based on an air introduction amount set by the air flow rate setting means. 2. The control device for a combustor according to claim 1, wherein the operating point on the operation map is a point having a predetermined value from both the flashback region and the blowout region, and the operating point is in a stable combustion region. A control device for a combustor, comprising: an operating state determination unit that determines that the combustion condition is present. 3. The control device for a combustor according to claim 1, wherein when the value of the operating point on the operation map from the flashback area is equal to or less than a predetermined value, the operating point is in the flashback notice area. A control device for a combustor, comprising: an operating state determination unit for determining that: 4. The control device for a combustor according to claim 1, wherein when the value of the operating point from the blowout area on the operation map is equal to or less than a predetermined value, the operating point is in the blowout notice area. A control device for a combustor, comprising: an operating state determination unit for determining that: 5. The combustor control device according to claim 1, wherein the operating state determining means does not change the amount of air introduced into the pre-evaporation flow path when the operating point determines that the operating point is in the stable combustion region. A combustor control device having an air flow control means for adjusting the flow rate as described above. 6. The control device for a combustor according to claim 1, wherein the operating state determining means increases the amount of air introduced into the pre-evaporation flow path when the operating point determines that the operating point is in the flashback notice area. A control device for a combustor, characterized by having an air flow rate control means for adjusting the flow rate so as to adjust the flow rate. 7. The control device for a combustor according to claim 1, wherein the operating state determining means reduces the flow rate of the air introduced into the pre-evaporation flow path when the operating point determines that the operating point is in the blow-out notice area. A control device for a combustor, characterized by having an air flow rate control means for adjusting the flow rate so as to adjust the flow rate. 8. The control device for a combustor according to claim 1, further comprising air introduction means for extracting air introduced into the pre-evaporation flow passage from an air flow passage at a compressor outlet. . 9. The control device for a combustor according to claim 1, further comprising air introduction means for supplying air introduced into the pre-evaporation flow path from an external air source.