EP0035869B1 - Chambre de combustion pour turbine à gaz - Google Patents

Chambre de combustion pour turbine à gaz Download PDF

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Publication number
EP0035869B1
EP0035869B1 EP81300903A EP81300903A EP0035869B1 EP 0035869 B1 EP0035869 B1 EP 0035869B1 EP 81300903 A EP81300903 A EP 81300903A EP 81300903 A EP81300903 A EP 81300903A EP 0035869 B1 EP0035869 B1 EP 0035869B1
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EP
European Patent Office
Prior art keywords
air
group
combustion chamber
combustor
port
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
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EP81300903A
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German (de)
English (en)
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EP0035869A1 (fr
Inventor
Isao Sato
Yohji Ishibashi
Yoshimitsu Minakawa
Takashi Ohmori
Zensuke Tamura
Yoshihiro Uchiyama
Ryoichiro Ohshima
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Hitachi Ltd
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Hitachi Ltd
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Priority claimed from JP2663080A external-priority patent/JPS56124834A/ja
Priority claimed from JP8788580A external-priority patent/JPS5714125A/ja
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Publication of EP0035869A1 publication Critical patent/EP0035869A1/fr
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
    • F23R3/00—Continuous combustion chambers using liquid or gaseous fuel
    • F23R3/02—Continuous combustion chambers using liquid or gaseous fuel characterised by the air-flow or gas-flow configuration
    • F23R3/04—Air inlet arrangements
    • F23R3/10—Air inlet arrangements for primary air
    • F23R3/12—Air inlet arrangements for primary air inducing a vortex
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
    • F23R3/00—Continuous combustion chambers using liquid or gaseous fuel
    • F23R3/02—Continuous combustion chambers using liquid or gaseous fuel characterised by the air-flow or gas-flow configuration
    • F23R3/04—Air inlet arrangements
    • F23R3/06—Arrangement of apertures along the flame tube

Definitions

  • the present invention relates to a combustor arrangement and, more particularly to an arrangement for reducing nitrogen oxides and carbon monoxides in exhaust gases of a combustor of a gas turbine.
  • Exhaust gases from a gas turbine contain air pollutants in the form of nitrogen oxides (NOx) and carbon monoxide (CO).
  • NOx nitrogen oxides
  • CO carbon monoxide
  • the source of the NOx and CO pollutants is the combustor and, to eliminate the pollutants, it has been proposed to suppress the production of the pollutants within the combustor or to mount a so-called post-processor, such as denitrifier, for removing NOx and CO in the exhaust gas. While the installation of the post-processor results in increasing the operating costs of the gas turbine and somewhat adversely affects the performance, the provision of a post-processor is nevertheless the best expedient for reducing NOx and CO in the exhaust gases from the combustor.
  • the rate of production of NOx can be determined by the following equation: wherein:
  • One known type of gas turbine combustor shown in, for example GB-A-845971, includes a combustor outer pipe, a combustor inner pipe which is constructed as a head combustion chamber and a rear combustion chamber larger in diameter than the head combustion chamber, and a fuel nozzle arranged at the head combustion chamber end of the combustor inner pipe.
  • Several groups of ports are provided in the combustor inner pipe for radially feeding air to the head and rear combustion chambers. Two different combustion systems have been proposed for this type of combustor with the aim of lowering the NOx in the exhaust gases.
  • a first combustion system proposes enriching the fuel in the head combustion chamber and thinning the fuel in the rear combustion chamber.
  • this proposed combustion system it becomes possible to some extent to lower NOx by eliminating high-NOx combustion at a stoichiometric mixture; however with a combustion process in the combustor at a high air ratio, a region in which a stoichiometric mixture is established appears inevitably in the course of the combustion process and hinders the effective reduction of NOx.
  • a gas turbine combustor in which the residence time of the gas is short, there is an increase in the quantity of carbon produced in the head combustion chamber.
  • a disadvantage of the increased carbon production resides in the fact that the carbon does not burn up and the combustion emits black smoke or soot.
  • the second combustion chamber is supplied with excess air.
  • a first group of air swirling and feeding ports for swirling and supplying air in an axial direction are disposed around the fuel nozzle, with a second group of air swirling and feeding ports, whose respective ports are open in substantially a tangential direction of an inner peripheral surface of the combustion chamber for swirling and supplying air in a radial direction, are disposed in a side wall of the head combustion chamber on a side of the fuel nozzle.
  • a group of air feeding ports for cooling the temperature of the combustion gas down to a turbine inlet temperature are disposed in the rear combustion chamber.
  • NOx are mainly produced within the head combustion chamber, and the so-called excess air, i.e. quantity of air greater than the required minimum quantity of air (theoretical amount of air) for complete combustion of the fuel, is supplied into the head combustion chamber so as to perform low-temperature combustion and to achieve the reduction of NOx.
  • the quality of air including the quantity of air to be supplied into the rear combustion chamber corresponds to approximately 1.7 times the amount of theoretical air for the fuel at the related load of the gas turbine.
  • a low-NOx combustor provided with the head combustion chamber can attain a NOx reduction of approximately 70% as compared with a combustor which has the same diameter and which is not provided with the head combustion chamber.
  • a combustor wherein a group of air feeding ports are circumferentially disposed on a downstream side of the side wall of the head combustion chamber and in an enlarged portion between the head combustion chamber and the rear combustion chamber.
  • the intense air flow from the group of air feeding ports disposed at the enlarged portion gives rise to a pull-in or suction flow which draws in the ambient air.
  • the air flow forms a flame recess in the swirling air flow from the head combustion chamber somewhat downstream of the enlarged portion, and although the production of CO on the wall surface of the rear combustion chamber can be suppressed, a new low-temperature region is formed on substantially an extension of the inside diameter of the head combustion chamber, which new low-temperature region generates a large quantity of CO. Additionally, a low temperature region is formed in a vicinity of the inner wall surface of the head combustion chamber due to the fact that the excess air is drawn because of the power or strength of the swirling air flow along the vicinity of the inner wall surface. The above-noted phenomena become even more evident when a gaseous fuel rather than a liquid fuel is used.
  • the extinguishing of and the fluctuation of the length of the combustion flames may be called the "flame instability phenomenon".
  • a decrease in the fuel quantity of air lengthens the combustion flames, and moreover, the temperature of lengthened combustion flames suppresses the appearance of the low-temperature regions.
  • the fuel component diffuses into the excess air immediately after its inflow from the fuel nozzle because the gaseous fuel does not involve the vaporization process and the mixing between the air and the fuel is carried out very smoothly. Accordingly, when air in an amount equal to that of the liquid fuel is applied, the entire combustion gas is undercooled, and the quantity of production of CO increases remarkably. Even when the quantity of excess air is decreased, the temperature of the flames becomes lower than that when liquid fuel is used. Moreover, the flame instability phenomenon becomes greater than that when the liquid fuel is used. The flames become so short as to burn violently on the upper stream side of the head combustion chamber, that is, on the side of the fuel nozzle. Thus, with gaseous fuel, the generation of low-temperature regions is promoted.
  • gaseous fuel such as, for example, natural gas or coal gas
  • the gaseous fuel smoothly mixes with air, there is difficulty in the formation of hot spots such as could occur with high temperature so that only small amounts of NOx are produced.
  • gaseous fuel is lower in the N 2 content and, therefore, smaller in the amount of production of the so-called fuel NOx than liquid fuel. For these reasons, a low-NOx gas turbine combustor which does not undergo the "flame instability phenomenon" even with a gaseous fuel, and which has the function of suppressing the production of CO is ernestly desired.
  • NOx are principally produced in the combustion process within the head combustion chamber, and especially the uniform mixing between the fuel and the air streams through the air feeding ports is greatly influential on the reduction of NOx.
  • high NOx concentration parts exist in a vicinity of an axial part within a head combustion chamber and in an enlarged portion between the head combustion chamber and the rear combustion chamber.
  • NOx concentration in the axial part near to the fuel nozzle within the head combustion chamber is high, and this axial part greatly governs the generation of NOx.
  • the air stream from the air feeding ports mix with the fuel injected from the fuel nozzle, but the uniform mixing between the fuel and the air streams in the vicinity of the axial part is not effectively carried out, so an effective low-temperature combustion cannot be attained and the vicinity of the axial part is not at a high temperature. Thus, considerable amounts of NOx are produced.
  • a gas turbine combustor which is effectively supplied with air to a high temperature portion of the combustor in a vicinity of an axial part in a head combustion chamber and reduced to a lower temperature so as to obtain a sharp reduction in the production of NOx.
  • a gas turbine combustor having a combustor inner pipe means defining a head combustion chamber means and a rear combustion chamber means having a diameter larger than the diameter of the head combustion chamber means
  • a combustor generally designated by the reference numeral 2 is located between a compressor 4 and a turbine 6.
  • the combustor 2 is principally constructed of an outer cylindrical member or pipe 8 and an inner cylindrical member or pipe 10.
  • a fuel nozzle 12 is fixedly mounted to a cover 14 of the outer pipe 8.
  • the fuel nozzle 12 extends through the cover 14 and opens into one end of the inner pipe 10.
  • the fuel nozzle 12 supplies, for example, gasified LNG to the combustor 2.
  • the inner pipe 10 is formed of a head or main combustion chamber 16 located on the side of the fuel nozzle 12, and a rear or secondary combustion chamber 18 located on the side of the turbine 6.
  • the diameter of the rear combustion chamber 18 is larger than the diameter of the head combustion chamber 16.
  • An enlarged portion 20 forms a transition area between the combustion chambers 16 and 18 with the enlarged portion 20 having a changing diameter.
  • a group of air swirling and feeding ports 22 are disposed in an area of the head combustion chamber 16 into which the fuel nozzle 12 opens. These ports 22 may also be termed “swirler” or “turbulence imparting means”.
  • a further group of air swirling and feeding ports 24 are circumferentially disposed in a side wall of an end part of the head combustion chamber 16. As shown most clearly in Figure 2, each of the air swirling and feeding ports 24 opens tangentially so that the supplied air swirls in the head combustion chamber 16.
  • a group of air feeding ports 28 are similarly circumferentially disposed in a sidewall 26 of the head combustion chamber 16 on a down- stream side of the air swirling and feeding ports 24 that is, towards the rear combustion chamber 18. As shown in Figure 3, the group of air feeding ports 28 are disposed so that the respective ports open in radial directions. The distance between the group of air swirling and feeding ports 24 and the group of air feeding ports 28 is substantially equal to the inside diameter of the head combustion chamber 16.
  • a further group of air swirling and feeding ports 30, as shown in Figure 1, are similarly circumferentially disposed as the air swirling and feeding ports 24. The air swirling and feeding ports 30 are disposed in the side wall 26 of the head combustion chamber 16 on the down- stream side of the group of air feeding ports 28.
  • the group of air swirling and feeding ports 30 are located at an end portion of the head combustion chamber 16 on the side of the enlarged portion 20 of the inner pipe 10 facing the fuel nozzle 12.
  • a group of air feeding ports 34 are circumferentially disposed in the side wall 32 of the rear combustion chamber 18 in the vicinity of the enlarged portion 20 on the side thereof facing the turbine 6.
  • Another group of air feeding ports 36 are disposed in the side wall 32 downstream of the air feeding ports 34.
  • the opening directions of the air feeding ports 34 and 36 coincide with the radial opening directions of the ports 28.
  • the supplying of air through the swirling and feeding ports 22 results in a swirling air flow 38 indicated in Figure 1.
  • the swirling air flow 38 is in the air flow affected by the air swirling and feeding.
  • the turbine combustor 2 operates in the following manner:
  • a recirculating flow 48 is induced in the vicinity of the longitudinal axis of the combustor 2 due to the suction of the swirling air flow 46 with the recirculating flow 48 assisting in holding or stabilizing the shape of the flames 44.
  • a portion of the air flowing from the group of air feeding ports 28 is used for the recirculating flow 48. Further, the inflowing air from the air feeding ports 28 cools high-temperature flames formed in a central part of the head combustion chamber 16 and suppresses the production of NOx.
  • the direction of the air inflow from the group of air swirling and feeding ports 30 is substantially tangential along the inner wall surface. Therefore, the velocity component of the inflowing air in the axial direction is small thereby lengthening the time the combustion gas stays in the combustor.
  • a recirculating flow 50 develops with a portion of the inflowing air from the group of air feeding ports 34 being used for the recirculating flow 50.
  • This inflowing air from the air feeding ports 34 cools high-temperature flames which continue to be formed in the central part of the combustor 2 behind the enlarged portion 20 so that the production of NOx is suppressed.
  • the high-temperature flames are involved by the recirculating flow 50, no low-temperature region due to supercooling is generated thereby further ensuring a suppression of the production of CO. In this manner, the flames 44 are stably held at suitable temperatures. Eventually, the temperature of the combustion gas 52 is lowered to an optimum turbine-inflow temperature by the air inflow from the group of air feeding ports 36 and the combustion gas 52 goes out of the combustor 2.
  • the groups of air swirling and feeding ports or air feeding ports are disposed in six places.
  • the total open area of all the groups of air feeding ports as well as the percentages of the total attributed to each of the respective groups of air feeding ports, hereinafter simply termed "opening percentages" are determined in the following manner.
  • the group of air swirling and feeding ports 22 are set at an opening percentage of 10%, the group of air swirling and feeding ports 24 at 18%, the group of air feeding ports 28 at 16%, the group of air swirling and feeding ports 30 at 9%, the group of air feeding ports 34 at 20%, and the group of air feeding ports 36 at 27%.
  • the stability of the flames is mostly determined by the opening percentage of the group of air swirling and feeding ports 22.
  • Figure 5 diagrammatically illustrates the results obtained by observing the limitation at which the combustion flames vanished, as the opening percentage of the group of air swirling and feeding ports 22 was varied.
  • the opening percentage of the group of air feeding ports 36 was varied with that of the group of air swjrling and feeding ports 22, but all the opening percentages of the other groups of air feeding ports were selected to the optimum ranges.
  • the ordinate represents a flame flow velocity (U Bo (m/s)) in an axial flow direction within the head combustion chamber 16 at the vanishing of the combustion flame, with the abscissa representing the opening percentage of the air swirling and feeding ports 22.
  • the opening percentage of the air swirling and feeding ports 22 may be greater so that a larger quantity of air can be supplied from the group of air swirling and feeding ports 22 in order to make a stable combustion possible.
  • the region in which U BO is greater than the characteristic curve in Figure 5 is an incombustible region in which the axial flow velocity becomes too high and a blow-off phenomenon of the combustion flames takes place thereby making it impossible to sustain the combustion process.
  • an optimum opening percentage of the group of air swirling and feeding ports 22 for stabilizing the combustion flames 4 lies in the range of 4-12%. Since the opening percentage of the group of air swirling ports 22 of the above-described embodiment of the present invention of 10% falls within this range a satisfactory effect is demonstrated for the stabilization of the combustion flames.
  • the air from the group of air swirling and feeding ports 24 flows in along the inner wall surface of the head combustion chamber 16 from outside the group of air swirling and feeding ports 22 mixes with the gaseous fuel well and forms the main flames so it is also greatly influential on the reduction of NOx and the reduction of CO.
  • Figure 6 diagramatically illustrates the results obtained by observing the reduction effects of NOx and CO upon a varying of the opening percentage of the group of air swirling and feeding ports 24.
  • the opening percentage of the group of air feeding ports 36 was varied with that of the group of air swirling and feeding ports 24, but all the opening percentages of the other groups of air feeding ports were selected to the optimum ranges.
  • the ordinates represent the achievement ratio of the reduction of NOx and that of the reduction of CO with the abscissa representing the opening percentage of the air swirling and feeding ports 24.
  • a curve A represents an achievement ratio of NOx reduction and a curve B shows an achievement ratio of CO reduction.
  • Both curves represent the ratios of the effects of the combustor 2 of the present invention relative to the respective effects of a combustor, using a gaseous fuel, which is presently in operation in a gas turbine plant.
  • the combustor presently in operation which was used for comparative purposes includes an inner pipe having a uniform diameter and is not constructed of the two combustion chambers as in the embodiment of the invention described hereinabove.
  • the inner pipe and the rear combustion chamber 18 of the above-described embodiment were made equal in diameter.
  • ports corresponding to the group of air swirling and feeding ports 22 and the groups of air feeding ports 34 and 36 in the above-described embodiment are disposed in the same positions, and a group of air feeding ports for supplying secondary air as shown in Figure 3 are disposed at substantially the same distance in the axial direction as that of the group of air feeding ports 28 in the present invention, whereas ports corresponding to the groups of air swirling and feeding ports 24 and 30 in the present embodiment are not disposed in the inner pipe.
  • the main cause for the increase in CO concentration is that the supercooling effect, due to the swirling air flow, increases suddenly. This tendency is conspicuous especially under low turbine load conditions, for example, in cases where the flow rate of supply for combustion has decreased with the inflow of air to the combustor is kept constant.
  • the opening percentage of the group of air swirling and feeding ports 24 needs to be set at 12% or more.
  • the optimum opening percentage of the group of air swirling and feeding ports 24 for the reduction of NOx and the reduction of CO is in the range of between 12-20%. Since the opening percentage of the air swirling and feeding ports 24 of the above-described embodiment of the present invention of 18% falls within this range the effects are satisfactorily demonstrated.
  • the group of air feeding ports 28 accomplish the stabilization of the combustion flames and contribute greatly to the reduction of NOx.
  • Figure 7 diagrammatically illustrates results obtained by observing the stability of the combustion flames and the effect of reducing NOx with a varying of the opening percentage of the group of air feeding ports 28.
  • the opening ratio of the group of air feeding ports 36 was varied with that of the group of air feeding ports 28, but all the opening percentages of the other groups of air feeding ports were selected to the optimum ranges.
  • the opening percentage of the air feeding ports 28 exceeds 32%, the inflow of air through the air feed ports 28 is too intense so that the combustion flames are split into pre- stage combustion flames within the head combustion chamber 16 and post-stage combustion flames within the rear combustion chamber 18 substantially in the area of the group of air feeding ports 28. These split combustion flames interfere with each other, and both the combustion flames fluctuate in an axial direction to give rise to a so-called vibrating combustion phenomenon.
  • the opening percentage of the air feeding ports 28 is below 10%, the air flow from the group of air feeding ports 28 is too weak that the penetration of air leading to the central part of the head combustion chamber 16 does not occur, and the action of cooling the center of the combustion flames becomes almost null; therefore, it is impossible to attain the reduction of NOx.
  • the quantity of air supply to the recirculating flow 48 decreases, the fuel concentration becomes high, resulting in an unstable combustion process. Therefore, the optimum opening percentage of the group of air feeding ports 28 for reducing NOx and for stabilizing the combustion flames lies in the range of 10-32%. Since the opening percentage of the air feeding ports 28 of the above-described embodiment of the present invention of 16% falls within this range, the effects are satisfactorily demonstrated.
  • the group of air swirling and feeding ports 30 strengthen the swirling air flow 46 again so as to thereby avoid an appearance of the low-temperature region and to suppress the production of CO, in addition to functioning to reburn CO in the stage even when it is reduced.
  • Figure 8 diagramatically illustrates the effect of reducing CO in terms of the achievement ratio similar to that described above in connection with the group of air swirling and feeding ports 24, with the opening part of the group of air swirling and feeding ports 30 varied.
  • the opening percentage of the group of air feeding ports 36 was varied with that of the group of air swirling and feeding ports 30, but all the opening percentages of the other groups of air feeding ports are selected to the optimum ranges.
  • the optimum opening percentage of the group of air swirling and feeding ports 30 is in the range of between about 8-11 %. Since the opening percentage of the above-described embodiment of the present invention of 9% falls within this range the effect is satisfactorily demonstrated.
  • the CO concentration ought to be suppressed to be, at least, lower than the CO concentration in the combustion gas of the aforementioned combustor presently in operation.
  • the opening percentage of the group of air swirling and feeding ports 30 be in a range of between 6-12%.
  • the table below lists the effects achieved by the entire combustor with the opening percentages of the respectives groups of air feeding ports described above.
  • the quantity of inflowing air to the head combustion chamber 16 was principally varied, and the quantity of inflowing air to the rear combustion chamber 18 was also varied in order to suppress the pressure loss of the whole combustor to between 3-4%.
  • the comparisons were simplified by maintaining the opening percentage of the group of air feeding ports 34 constant.
  • the symbol @ represents the best results for reduction in the concentration of NOx and CO and/or flame stability obtained for the listed opening percentages of the groups of air and feeding ports, with the symbol A representing better results than previously proposed combustors, the symbol O representing results which are approximately the same as previously proposed combustors, and the symbol X representing poor results with respect to combustion flame stability.
  • Figure 9 shows another embodiment of the present invention and, according to this figure a group of air swirling and feeding ports 54 which supply turbulent air into the head combustion chamber 16 are disposed in the vicinity of a central part of the side end of the head combustion chamber 16.
  • a fuel nozzle 12 is provided on the outer periphery of the group of air swirling and feeding ports 54.
  • Fuel 56 is injected into the head combustion chamber 16 through a fuel feeding passage 58 of the fuel nozzle 12.
  • a group of air swirling and feeding ports 60 are provided in the outer periphery of the fuel nozzle 12. The air from the group of air swirling and feeding ports 60 is mixed with fuel and injected into the head combustion chamber 16.
  • the group of air swirling and feeding ports 60 introduce cooling air, obtained by partial extraction from a compressor 4, through an air passage 62, so as to cool a vicinity of the axial port 64 of the head combustion chamber 16. Air flow from the ports 54 and air from the ports 60 swirls in the same direction. A recirculating flow 66 is generated in the vicinity of the axial port 64 by swirling flows 68 from the air swirling and feeding ports 60 and 24. Since the circulating flow 66 involves a combustion gas at a high-temperature, the temperature of the vicinity of the axial port 64 becomes high, and particularly, a part 70 of the swirling flow 68 from the ports 60 reaches a high temperature.
  • the swirling flow 72 from the air swirling and feeding ports 54 is supplied between the recirculating flow 66 and the mixed swirling flow 68 of fuel and air, whereby the recirculating flow 66 can be further promoted and besides the high temperature part 70 can be effectively cooled, so that the generation of NOx can be suppressed.
  • the cooling air from the ports 54 swirls, and desirably it has the same swirling angle as that of the ports 60.
  • Figure 10 provides a diagrammatic illustration of results obtained by testing NOx- reducing effects in the cases where the cooling air is supplied from the ports 54 and in cases where there is no supply of cooling air from the ports 54.
  • the ordinates represent the concentration of NOx in ppm and the concentration of CO in ppm while the abscissa represents a ratio of the flow rate of fuel to the flow rate of air for the turbine load.
  • the tests were conducted under the conditions that the temperature of the air for combustion was 180°C and the pressure within the combustor was 4 atm.
  • the curves E, F in phantom lines indicate variations of the CO concentrations and the curves G, and H, in solid lines indicate variations of the NOx concentrations.
  • the symbols A represent conditions in the combustors with a swirling air flow 72 by the ports 54 shown in Figure 9
  • the symbols O represent conditions obtained with the combustor shown in Figure 1 of the present invention.
  • an air flow rate regulating valve 74 is provided for reducing the flow rate of cooling air with a decrease of the turbine load so as to enable a low concentration of NOx as well as a suppression of the concentration of generation of CO over the whole range of turbine loads.
  • the reduction of NOx can be sharply achieved by lowering the temperature, therefore it is effective to increase the flow rate of cooling air or to further lower the temperature of the cooling air.
  • a heat exchanger 76 is provided as means for cooling the air extracted from the compressor 4 to lower the temperature.
  • a lowering of the temperature of the cooling air to, for example, approximately 100°C results in a lowering of the NOx concentration to about 1/3rd.
  • the flame temperature may be maintained at a suitable temperature in substantially the whole region within the inner pipe including the enlarged portion so as to achieve both a reduction in the production of NOx and a reduction in the production of CO. Further, the swirling air flow is again intensified so as to lengthen and stabilize the flames.
  • a further advantage resides in the fact that, due to the use of the gaseous fuel, even when a quantity of air to be fed is made smaller than the quantity of air fed when using a liquid fuel, a radial inflowing air from the group of intermediate air feeding ports on the side wall of the head combustion chamber properly cools the central flames at tne nigh temperature and hence, the production of NOx can be suppressed.
  • the air flowing into the head combustion chamber spreads the flames sufficiently at least three times into the head combustion chamber, and further spreads them sufficiently onto the succeeding inner walls of the enlarged portion and the rear combustion chamber. Accordingly, a flame recess in a vicinity of the enlarged portion as occurs in previously proposed combustion is not formed. Thus, the production of CO is suppressed.
  • Another advantage resides in the fact that, since the group of air swirling and feeding ports are provided on the fuel nozzle side of the side wall of the head combustion chamber, the air flow through the ports induces a suction. Therefore a strong recirculation flow is induced in a vicinity of the longitudinal axis of the combustor. Furthermore, since the intermediate air feeding ports are provided between the two groups of air swirling and feeding ports, the air supplied into the strong recirculation flow and the central portion of the combustor is cooled by the air.
  • the distance between the intermediate air feeding ports and the fuel nozzle side end of the head combustion chamber is substantially equal to the inside diameter of the head combustion chamber.
  • the inventors have experimentally confirmed that this position of the intermediate air feeding ports does not disturb the swirl of the flames and that it is the most suitable for forming the recirculating flow and for cooling the central flames.
  • the group of central air feeding ports supply air to the recirculating flow which is induced by the group of air swirling and feeding ports situated upstream. If the position of the group of central air feeding ports is too close to these groups of air swirling and feeding ports, the inflowing air from the group of central air feeding ports must penetrate the intense swirling air flow, to ultimately, suppress the swirling air flow.
  • the air through the central air feeding ports does not cause the suppression of the swirling air flow, and can ensure an air penetration distance up to the longitudinal axis of the combustor in the radial direction.
  • a still further advantage resides in the fact that, since a group of air swirling and feeding ports are provided at the rearmost part of the head combustion chamber, a low-temperature region which arises downstream of the head combustion chamber is cancelled by the high-temperature eddy flow which is intensified by the swirling air flowing in a tangential from the group of air swirling and feeding ports. Moreover, this swirling air flow expands along the enlarged portion of the inner pipe without fail. Eventually, the low-temperature region appears neither in the head combustion chamber nor in the vicinity of the enlarged portion.
  • Another advantage resides in the fact that, by virtue of the provision of another group of air feeding ports disposed immediately behind the enlarged portion and on the side wall of the rear combustion chamber, the inventors have experimentally confirmed that this position of the feeding ports is the most suitable for not only forming the recirculating flows at the enlarged portion and in the rear combustion chamber but also for stabilizing the flames.
  • a group of air swirling and feeding ports are provided in the inner and outer peripheries of a group of fuel nozzles, the air through the ports cools the portion in the vicinity of longitudinal axis of the combustor where NOx is generated. As a result, the NOx concentration can be reduced and the combustion flames can be stabilized.

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Claims (13)

1. Chambre de combustion pour turbine à gaz comportant
des moyens (10) formant conduite intérieure de la chambre de combustion et définissant une partie (16) formant chambre de combustion avant et une partie (18) formant chambre de combustion arrière et possédant un diamètre supérieur au diamètre de la partie (16) formant chambre de combustion avant,
des moyens (8) formant conduite extérieure de la chambre de combustion et entourant les moyens formant conduite intérieure (10),
des moyens (12) formant injecteur de combustible disposés sur une partie d'extrémité de la partie formant chambre de combustion avant et servant à envoyer le combustible auxdits moyens formant conduite intérieure de la chambre de combustion,
un premier groupe de moyens en forme d'orifices (22) disposés autour desdits moyens formant injecteur de combustible et servant à envoyer de l'air à l'intérieure dudit moyen formant conduite intérieure de la chambre de combustion et agencés de telle sorte que l'air pénétrant à travers eux, possède une composante de vitesse dirigée axialement le long desdits moyens formant conduite intérieure de la chambre de combustion,
un second group de moyens en forme d'orifices (24) disposés dans une paroi latérale (26) de ladite partie formant chambre de combustion avant pour l'envoi d'air dans lesdits moyens formant conduite intérieure de la chambre de combustion,
un troisième groupe de moyens en forme d'orifices (30) disposé dans la paroi latérale de ladite partie formant chambre de combustion avant, à proximité de la partie formant chambre de combustion arrière, afin d'envoyer de l'air dans lesdits moyens formant conduite intérieure de la chambre de combustion, et
un quatrième groupe de moyens en forme d'orifices (28) disposés dans la paroi latérale de la partie formant chambre de combustion avant, dans une position intermédiaire entre lesdits second et troisième groupes de moyens en forme d'orifices, afin d'envoyer de l'air à l'intérieure desdits moyens formant conduite intérieure de la chambre de combustion, lesdits second, troisième et quatrième groupes de moyens en forme d'orifices étant tous disposés de manière que l'air pénétrant à travers eux possède une composante de vitesse dirigée radialement dans lesdits moyens formant conduite intérieure de la chambre de combustion,

caractérisé en ce que lesdits premier, second et troisième groupes de moyens en forme d'orifices (22, 24, 30) sont tous disposés de telle manière que l'air pénétrant à travers eux possède en outre une composante de vitesse dirigée circonférentiellement autour desdits moyens formant conduite intérieure de la chambre de combustion de manière à faire tourbillonner le fluide situé dans lesdits moyens formant conduite intérieure de la chambre de combustion, et que le quatrième groupe desdits moyens en forme d'orifices (28) sont disposés de telle manière que l'air pénétrant à travers eux ne possède aucune composante substantielle de vitesse dirigée circonférentiellement autour desdits moyens formant conduite intérieure de la chambre de combustion.
2. Chambre de combustion pour turbine à gaz selon la revendication 1, dans laquelle ledit second groupe de moyens en forme d'orifices (24) et/ou ledit troisième groupe de moyens en forme d'orifices (30) s'ouvrent suivant une direction essentiellement tangente à une surface périphérique intérieure de ladite partie formant chambre de combustion avant.
3. Chambre de combustion pour turbine à gaz selon la revendication 1 ou 2, dans laquelle la distance entre lesdits second et quatrième groupes de moyens en forme d'orifices (24, 28) est sensiblement égale au diamètre intérieur de la partie (16) formant la chambre de combustion avant.
4. Chambre de combustion pour turbine à gaz selon l'une quelconque des revendications précédentes, comportant en outre un cinquième groupe de moyens en forme d'orifices (34) disposés dans une paroi latérale (32) de la partie (18) formant chambre de combustion arrière, dans une position proche de la partie (16) formant chambre de combustion avant, afin d'envoyer de l'air dans la partie formant chambre de combustion arrière, un sixième groupe de moyens en forme d'orifices (30) disposés dans la paroi latérale de la chambre de combustion arrière sur le côté aval du cinquième groupe en forme de moyens d'orifices, afin d'envoyer de l'air dans la partie formant chambre de combustion arrière.
5. Chambre de combustion pour turbine à gaz, selon la revendication 4, dans lequel ledit cinquième groupe de moyens en forme d'orifices (34) sont disposés de telle manière que l'air entrant à travers eux possède une composante de vitesse dirigée radialement entre lesdits moyens formant conduite intérieure de la chambre de combustion, mais aucune composante substantielle de vitesse, dirigée circonférentiellement autour desdits moyens formant conduite intérieure de la chambre de combustion.
6. Chambre de combustion pour turbine à gaz selon l'une quelconque des revendications précédentes, dans lequelle la surface totale ouverte dudit premier groupe des moyens en forme d'orifices (22) se situe dans une gamme comprise entre 4 et 12% de la surface totale ouverte de l'ensemble des groupes des moyens en forme d'orifices.
7. Chambre de combustion pour turbine à gaz selon l'une quelconque des revendications précédentes, dans laquelle la surface totale ouverte dudit second groupe de moyens en forme d'orifices (24) se situe dans la gamme de 12-20% de la surface totale ouverte de l'ensemble des groupes d'orifices.
8. Chambre de combustion pour turbine à gaz selon l'une quelconque des revendications précédentes, dans laquelle la surface totale ouverte dudit troisième groupe de moyens en forme d'orifices (3) se situe dans une gamme comprise entre 6-12% de la surface totale ouverte de l'ensemble des groupes des moyens en forme d'orifices.
9. Chambre de combustion pour turbine à gaz selon l'une quelconque des revendications précédentes, dans lequel la surface totale ouverte desdits quatrième groupes de moyens en forme d'orifices (28) se situe dans une gamme comprise entre 10-32% de la surface totale ouverte de l'ensemble des groupes des moyens en forme d'orifices.
10. Chambre de combustion pour turbine à gaz selon la revendication 1, dans laquelle un autre groupe de moyens en forme d'orifices (54) servant à faire tourbillonner et à envoyer de l'air dans la chambre de combustion avant (16) sont disposés au voisinage de la région centrale de la partie d'extrémité de la chambre de combustion de tête et dans une zone périphérique intérieure desdits moyens en forme d'injecteur à combustible (12), ledit autre groupe de moyens en forme d'orifices (54) et ledit premier groupe de moyens en forme d'orifices (22) étant construits de telle manière que l'air provenant de ces deux groupes d'orifices possède la même direction de tourbillonnement.
11. Chambre de combustion pour turbine à gaz selon la revendication 10, comportant des moyens formant compresseur (4) servant à envoyer de l'air audit premier groupe de moyens en forme d'orifices (22), et dans lequel des moyens (74) sont prévus pour extraire une partie de l'air comprimé envoyé par les moyens formant compresseur et pour envoyer cet air audit autre groupe de moyens en forme d'orifices (54).
12. Chambre de combustion pour turbine à gaz selon la revendication 11, comprenant en outre des moyens d'échange de chaleur (74) servant à refroidir l'air comprimé, et dans lequel ladite partie de l'air comprimé est envoyée audit autre groupe de moyens en forme d'orifices (54) par l'intermédiaire desdits moyens d'échange de chaleur.
13. Chambre de combustion pour turbine à gaz, selon la revendication 11 ou 12, dans laquelle des moyens en forme de valves de régulation de débit (74) sont prévus pour commander le débit envoyé audit autre groupe de moyens en forme d'orifices.
EP81300903A 1980-03-05 1981-03-04 Chambre de combustion pour turbine à gaz Expired EP0035869B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP26630/80 1980-03-05
JP2663080A JPS56124834A (en) 1980-03-05 1980-03-05 Gas-turbine combustor
JP87885/80 1980-06-30
JP8788580A JPS5714125A (en) 1980-06-30 1980-06-30 Gas turbine burner

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EP0035869A1 EP0035869A1 (fr) 1981-09-16
EP0035869B1 true EP0035869B1 (fr) 1984-07-11

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GB2118710B (en) * 1981-12-31 1985-05-22 Secr Defence Improvements in or relating to combustion chamber wall cooling

Citations (1)

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Publication number Priority date Publication date Assignee Title
FR1282150A (fr) * 1960-12-09 1962-01-19 Tanins Rey Brûleur à gaz

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Publication number Priority date Publication date Assignee Title
DE1039785B (de) * 1957-10-12 1958-09-25 Maschf Augsburg Nuernberg Ag Brennkammer mit hoher Waermebelastung, insbesondere fuer Verbrennung heizwertarmer, gasfoermiger Brennstoffe in Gasturbinenanlagen
GB845971A (en) * 1958-07-21 1960-08-24 Gen Electric Improvements relating to combustion chambers for gas turbine engines
US3859787A (en) * 1974-02-04 1975-01-14 Gen Motors Corp Combustion apparatus
JPS5857655B2 (ja) * 1976-08-27 1983-12-21 株式会社日立製作所 ガスタ−ビン用燃焼器
JPS53104019A (en) * 1977-02-23 1978-09-09 Hitachi Ltd Gas turbine combustor

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1282150A (fr) * 1960-12-09 1962-01-19 Tanins Rey Brûleur à gaz

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EP0035869A1 (fr) 1981-09-16

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