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EP0900351A1 - Fuel injection method for a stepped gas turbine combustion chamber - Google Patents

Fuel injection method for a stepped gas turbine combustion chamber

Info

Publication number
EP0900351A1
EP0900351A1 EP97923092A EP97923092A EP0900351A1 EP 0900351 A1 EP0900351 A1 EP 0900351A1 EP 97923092 A EP97923092 A EP 97923092A EP 97923092 A EP97923092 A EP 97923092A EP 0900351 A1 EP0900351 A1 EP 0900351A1
Authority
EP
European Patent Office
Prior art keywords
fuel injection
fuel
combustion chamber
gas turbine
control
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.)
Granted
Application number
EP97923092A
Other languages
German (de)
French (fr)
Other versions
EP0900351B1 (en
Inventor
F. Richard Emmons
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rolls Royce Deutschland Ltd and Co KG
Original Assignee
Rolls Royce Deutschland Ltd and Co KG
BMW Rolls Royce GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Rolls Royce Deutschland Ltd and Co KG, BMW Rolls Royce GmbH filed Critical Rolls Royce Deutschland Ltd and Co KG
Publication of EP0900351A1 publication Critical patent/EP0900351A1/en
Application granted granted Critical
Publication of EP0900351B1 publication Critical patent/EP0900351B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • 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
    • F23R3/28—Continuous combustion chambers using liquid or gaseous fuel characterised by the fuel supply
    • F23R3/34—Feeding into different combustion zones
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C15/00—Apparatus in which combustion takes place in pulses influenced by acoustic resonance in a gas mass
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2205/00—Pulsating combustion
    • F23C2205/10—Pulsating combustion with pulsating fuel supply
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/86493—Multi-way valve unit
    • Y10T137/86549—Selective reciprocation or rotation

Definitions

  • the invention relates to a method for fuel injection into a staged gas turbine combustion chamber with separate fuel injection nozzles for each stage, at least one stage being switchable for certain operating states by interrupting the fuel supply.
  • the invention further relates to a fuel injection device for carrying out the fuel injection method according to the invention.
  • WO 95/17632 for the known prior art, reference is made only to WO 95/17632 by way of example.
  • Gas turbine combustion chambers in particular ring combustion chambers of gas turbines, which work with staged combustion or staged fuel injection, are becoming increasingly important.
  • a pilot combustion chamber and a main combustion chamber are usually provided, each of which form a so-called stage.
  • the first stage of the pilot combustion chamber has one or more pilot burners which, in the preferred application, have an annular combustion chamber arranged fuel injection nozzles exist, likewise the second stage, namely the main combustion chamber, has a plurality of main burners, likewise in the form of a plurality of injection nozzles preferably arranged in a ring again.
  • FIG. 2 A schematic diagram for such a stepped gas turbine combustor is shown in the attached FIG. 2.
  • the combustion chamber outer wall is designated by the reference number 20 and the combustion chamber inner wall by the reference number 21.
  • These two walls 20, 21 are also surrounded by envelope walls 20a, 21a, which ultimately also define the combustion chamber inlet 22a on the left side and the combustion chamber outlet 22b on the right side.
  • the center line 23 of this gas turbine combustion chamber which is designed as an annular combustion chamber, is shown.
  • a partition structure 24 is provided within the left half of this combustion chamber.
  • the so-called pilot combustion chamber 25a lies between this partition structure 24 and the central axis 23, while the so-called main combustion chamber 25b is located below this partition structure 24.
  • Pilot burners 26a are assigned to the pilot combustion chamber 25a, while main burners 26b are provided for the main combustion chamber 25b.
  • Fuel or a fuel-air mixture is introduced into the combustion chambers via these burners 26a, 26b, while a main air flow 27 reaches the individual combustion chambers 25a, 25b via the combustion chamber inlet 22a.
  • Fer ⁇ ner can admixed air 28 through apertures in the outer wall 20, in the inner wall 21, as well as in the partition wall structure 24 into the individual combustion chambers ⁇ 25a, 25b occur.
  • the fuel / air mixture burned in the pilot combustion chamber 25a or in the main combustion chamber 25b and in the combination of these two combustion chambers is finally discharged via the combustion chamber outlet 22b.
  • the pilot burners 26a are operated, which means that the injectors of the main burners 26b are not supplied with fuel.
  • the main burners 26b are operated, so that their injection nozzles are then supplied with fuel.
  • the pilot combustion chamber 25a which is also operated solely for starting the gas turbine and for starting up in idle mode, is usually operated in the entire operating map of the gas turbine, in particular the flight gas turbine, in order to provide an ignition source for the main burners 26b, which are only switched on as required to accomplish.
  • staged combustion is to minimize pollutant emissions, especially NO x . This is achieved in that the respective burner size can be better adapted to the respective power requirement.
  • the combustion temperature should be as low as possible, which can be achieved by targeted air supply (admixing air 28) into the combustion zone.
  • the respective stages, namely the pilot burner 26a or the main burner 26b, are designed for special air-fuel ratios.
  • the air-fuel ratio coming to the main burners 26b would be too high to be able to support a sensible combustion at all.
  • the main burners 26b are therefore only switched on at higher load points of the gas turbine.
  • FIG. 3 The strategy according to which the individual burners, namely the pilot burners 26a and the main burners 26b are supplied with fuel, is shown in FIG. 3.
  • the sum of the fuel flow for the two burners is plotted on the abscissa of this diagram, and the percentage of the pilot burner 26a and the main burner 26b in this is plotted on the ordinate Sum fuel flow.
  • the corresponding characteristic curve of the pilot burner 26a is designated by the letter A, that of the main burner 26b by the letter B. It can be seen that with initially only a small total fuel flow, ie only the one in the left-hand section of this diagram Pilot burners 26a are operated so that their share in the total fuel flow is 100%.
  • connection point Z In order to avoid instabilities in the immediate vicinity of this connection point Z, a control system which contains a hysteresis is proposed for this in the aforementioned WO 95/17632. With increasing thrust, the main burners are only switched on with a higher total fuel throughput than they are switched off with decreasing thrust.
  • the object of the invention is to achieve this another solution to the problems outlined above hang up with the connection of a second stage to a first stage.
  • At least the stage which can be switched off ie preferably the main combustion chamber 25b explained above, can be operated with pulsed fuel injection.
  • fuel injection is not continuous, but discontinuous.
  • the fuel is thus introduced into the combustion chamber in a virtually clocked manner, the pulsation frequency being in the range from a single Hz to a few 100 Hz.
  • this pulsed injection results in an equally pulsed combustion.
  • a favorable fuel-air ratio can be set for each injection pulse or for each so-called combustion pulse. Because fuel is no longer continuously injected, but only temporarily, at least in the case of low fuel quantities, significantly less fuel can be injected overall than is possible with conventional continuous injection when favorable fuel-air ratios are set.
  • the pulsation frequency which should preferably be variable in order to be able to set a favorable combustion in a large number of operating points, can preferably be above the characteristic frequencies of possible combustion chamber vibrations, so that there are no negative effects on the combustion efficiency or on the Thrust and noise generation are to be feared.
  • combustion can always be achieved with a favorable efficiency, since there is a favorable fuel-air ratio for each combustion or injection pulse.
  • pulsed fuel injection according to the invention is for everyone Fuel pulse, a larger fuel-air ratio can be achieved, so that a stable combustion or a series of stable combustion pulses can still be achieved by targeted selection of the pulsation frequency even with a significantly lower fuel supply.
  • the pulsation frequency of the discontinuous fuel injection can be varied in order to be able to adapt the total amount of fuel injected in a certain period of time to the respective operating point of the gas turbine.
  • the injection duration can be changed with a constant fuel quantity per unit of time
  • the fuel quantity introduced here can be changed with a constant injection duration.
  • the pulsation frequency can be adjusted so that the optimum fuel injection can be selected for each operating point of the gas turbine due to the many possible variations. It should be pointed out that at high-load operating points it is of course possible to switch from pulsed injection to continuous fuel injection.
  • a further advantage of pulsed fuel injection should also be pointed out.
  • the usual combustion frequencies can be controlled in such a way that the so-called "combustion hum" which can occur in the case of unstable combustion with low fuel throughput resulting from the characteristic frequencies of possible combustion chamber vibrations is minimized
  • the first stage or pilot combustion chamber which is usually not switched off in certain operating states, can or should work with a continuous fuel injection, in particular also for reliable ignition of the fuel - Ensure air mixture in the second stage or main combustion chamber.
  • An advantageous fuel injection device for carrying out such a pulsed fuel injection can consist of an electromagnetically and / or hydraulically actuated fuel injection valve, the opening time and duration of which can be specifically adjusted.
  • Fuel injection valves of this type are known from reciprocating piston internal combustion engines. Modified accordingly, fuel injection valves of this type can now be used either to inject the fuel directly into the combustion chamber of a gas turbine or they can be connected upstream of an essentially conventional fuel injection nozzle.
  • Another fuel injection device for carrying out a pulsed fuel injection according to the invention can consist of a suitable pulsation control valve which is connected upstream of a fuel injection nozzle which is conventional and opens into the combustion chamber.
  • a metering valve can be connected upstream of this injection nozzle, it being particularly advantageous to combine the pulsation control valve and the metering valve in one component, which is referred to below as the “pulse metering device”.
  • FIG. 1 A preferred exemplary embodiment of such a pulse dosing device is shown in a basic section in FIG. 1 and is explained in more detail below.
  • the reference number 1 denotes a cylinder of the pulse meter described, within which a control piston 2 is arranged to be rotatable about the cylinder axis 3 and to be displaceable in the direction of the cylinder axis 3.
  • Fuel can be introduced into the interior of the cylinder 1 via a cylinder wall opening 4 according to arrow 18a, and fuel can be removed from the interior of the cylinder according to arrow 18b via a further opening in the cylinder wall referred to as control window 5.
  • the cylinder wall opening 4 and the control window 5 are connected to the fuel supply system of a switchable stage of a stepped gas turbine combustion chamber, the fuel discharged via the control window 5 (arrow 18b) leading to the fuel injection nozzles of this switchable combustion chamber stage becomes.
  • the control piston 2 is hollow at least in sections, so that there is a piston interior 6, which is only shown in broken lines, in which as can be seen, fuel which, according to arrow 18a, flowed into the interior of the cylinder 1 via the wall opening 4.
  • This piston interior 6, which is designed here in the form of two bores, is thus connected to the fuel supply system of the gas turbine.
  • At least one control slot 7 is provided on the outer wall of the control piston 2 and communicates with the piston interior 6 or with the corresponding bores. Fuel that is brought in through the wall opening 4 can thus ultimately escape through the control slot 7.
  • the control window 5 already explained is located approximately in the height of the control slot 7 in the wall of the cylinder 1. If the control piston 2 is now rotated continuously about the cylinder axis 3, fuel which was brought in via the wall opening 4 is pulsed off via the control window 5 ⁇ led. Whenever the control slot 7 coincides with the control window 5 during rotation of the control piston 2, a partial fuel quantity can emerge through the control window 5 according to arrow 18b and ultimately reach the fuel injection nozzle of the combustion chamber stage. As soon as the rotating control slot 7 has passed the control window 5, this fuel flow is interrupted again. Only by rotating the control piston 2 in the cylinder 1 can a pulsed fuel injection into a gas turbine combustion chamber stage be achieved. The pulsation frequency is predetermined by the speed of rotation of the control piston 2 in the cylinder 1, so that a specific pulsation frequency can be set by specifically selecting the speed of rotation.
  • the amount of fuel discharged via the control window 5 can also be influenced by the rotational frequency of the control piston 2 or control slot 7. However, if a certain rotation frequency is desired in view of certain boundary conditions, a preferred setting is The amount of fuel delivered per fuel pulse can be adjusted by displacing the control piston 2 along the cylinder axis 3 in or against the direction of the arrow 14. In this way, the effective length I of the control slot 7, by means of which it comes into congruence with the control window 5, can be changed. With a larger value of length I, a larger amount of fuel is discharged via control window 5, with a smaller length I, a smaller amount of fuel.
  • the control piston 2 can be set in rotation about the cylinder axis 3 by the gearbox of the gas turbine, but also, for example, by an electric motor, of which only the output pinion 8 is shown, with which a gearwheel 9 meshes, which meshes with a stub shaft 10 with a so-called guide extension 11 of the control piston 2 is connected.
  • This guide extension 11 is also guided within the cylinder 1 and has an end face 12 ', on which acts with constant pressure a hydraulic medium which passes above this guide extension 11 via a control opening 13' into the interior of the cylinder 1.
  • a comparable control opening 13 is located below the control piston 2 in the cylinder 1, so that a hydraulic medium can also act on this lower end face 12.
  • a spring element 16 which acts on the control piston 2 via an adjusting rod 15a and via a spring plate 15b, an adjusting screw 17 also being provided which can also act on the spring plate 15b in such a way that it provides maximum fuel flow can be set via the control slot 7 and the control window 5.
  • this as well as a large number of details, in particular of a constructive type, can be designed quite differently from the exemplary embodiment shown, without departing from the content of the patent claims. Rather, it is essential that, in general, at least the stage which can be switched off in a stepped gas turbine combustion chamber can be operated with pulsed fuel injection.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Gas Burners (AREA)

Abstract

A gas turbine combustion chamber comprises pilot burners (26a) and main burners (26b), the latter being switched off when the fuel supply is interrupted. In particular to prevent problems during the transition from the mode in which the pilot burners are operating alone to the mode in which both the pilot burners and the main burners are operating, the main burners can be operated with pulsed fuel injection. By varying in a specific manner the pulsation frequency and the amount of fuel introduced with each injection pulse, the main burners can each be operated with the most favourable air-fuel ratio over a wide operating range. The invention further concerns a particularly advantageous pulse-metering device for producing this pulsed fuel injection.

Description

Kraftstoffeinspritzung für eine gestufte Gasturbinen-BrennkammerFuel injection for a staged gas turbine combustor
Die Erfindung betrifft ein Verfahren zur Kraftstoff-Einspritzung in eine ge- stufte Gasturbinen-Brennkammer mit separaten Kraftstoff-Einspritzdüsen für jede Stufe, wobei zumindest eine Stufe für bestimmte Betriebszustände durch Unterbrechung der Kraftstoffzufuhr abschaltbar ist. Ferner betrifft die Erfindung eine Kraftstoffeinspritzvorrichtung zur Durchführung des erfin¬ dungsgemäßen Kraftstoff-Einspritzverfahrens. Zum bekannten Stand der Technik wird lediglich beispielshalber auf die WO 95/17632 verwiesen.The invention relates to a method for fuel injection into a staged gas turbine combustion chamber with separate fuel injection nozzles for each stage, at least one stage being switchable for certain operating states by interrupting the fuel supply. The invention further relates to a fuel injection device for carrying out the fuel injection method according to the invention. For the known prior art, reference is made only to WO 95/17632 by way of example.
Gasturbinen-Brennkammern, insbesondere Ring-Brennkammern von Gasturbinen, die mit gestufter Verbrennung bzw. gestufter Kraftstoff-Ein¬ spritzung arbeiten, gewinnen zunehmend an Bedeutung. Üblicherweise ist eine Pilot-Brennkammer sowie eine Haupt-Brennkammer vorgesehen, die jeweils eine sog. Stufe bilden. Selbstverständlich können neben diesen bei¬ den Stufen noch weitere Abstufungen bzw. Stufen vorgesehen sein. Die Pilot-Brennkammer besitzt als erste Stufe einen oder mehrere Pilot-Brenner, die im bevorzugten Anwendungsfall einer Ring-Brennkammer aus ringförmig angeordneten Kraftstoff-Einspritzdüsen bestehen, ebenso besitzt die zweite Stufe, nämlich die Haupt-Brennkammer, mehrere Haupt-Brenner, ebenfalls in Form mehrerer vorzugsweise wieder ringförmig angeordneter Einspritz¬ düsen.Gas turbine combustion chambers, in particular ring combustion chambers of gas turbines, which work with staged combustion or staged fuel injection, are becoming increasingly important. A pilot combustion chamber and a main combustion chamber are usually provided, each of which form a so-called stage. Of course, in addition to these two levels, further levels or levels can be provided. The first stage of the pilot combustion chamber has one or more pilot burners which, in the preferred application, have an annular combustion chamber arranged fuel injection nozzles exist, likewise the second stage, namely the main combustion chamber, has a plurality of main burners, likewise in the form of a plurality of injection nozzles preferably arranged in a ring again.
Eine Prinzipdarstellung für eine derartige gestufte Gasturbinen-Brennkam¬ mer zeigt die beigefügte Fig. 2. Hier ist die Brennkammer-Außenwand mit der Bezugsziffer 20 und die Brennkammer-Innenwand mit der Bezugsziffer 21 bezeichnet. Diese beiden Wände 20, 21 sind noch von Hüllwänden 20a, 21a umgeben, welche letztlich auch linksseitig den Brennkammer-Eintritt 22a und rechtsseitig den Brennkammer-Austritt 22b definieren. Ferner ist die Mittellinie 23 dieser als Ring-Brennkammer ausgebildeten Gasturbinen- Brennkammer dargestellt.A schematic diagram for such a stepped gas turbine combustor is shown in the attached FIG. 2. Here, the combustion chamber outer wall is designated by the reference number 20 and the combustion chamber inner wall by the reference number 21. These two walls 20, 21 are also surrounded by envelope walls 20a, 21a, which ultimately also define the combustion chamber inlet 22a on the left side and the combustion chamber outlet 22b on the right side. Furthermore, the center line 23 of this gas turbine combustion chamber, which is designed as an annular combustion chamber, is shown.
Innerhalb der linken Hälfte dieser Brennkammer ist eine Trennwandstruktur 24 vorgesehen. Zwischen dieser Trennwandstruktur 24 sowie der Mit¬ telachse 23 liegt die sog. Pilot-Brennkammer 25a, während sich unterhalb dieser Trennwandstruktur 24 die sog. Haupt-Brennkammer 25b befindet. Der Pilot-Brennkammer 25a sind Pilot-Brenner 26a zugeordnet, während für die Haupt-Brennkammer 25b Haupt-Brenner 26b vorgesehen sind. Über diese Brenner 26a, 26b wird Kraftstoff bzw. ein Kraftstoff-Luft-Gemisch in die Brennkammern eingeführt, während ein Hauptluftstrom 27 über den Brenn¬ kammer-Eintritt 22a in die einzelnen Brennkammern 25a, 25b gelangt. Fer¬ ner kann Zumischluft 28 über Durchbrüche in der Außenwand 20, in der Innenwand 21 , sowie in der Trennwandstruktur 24 in die einzelnen Brenn¬ kammern 25a, 25b eintreten. Das in der Pilot-Brennkammer 25a bzw. in der Haupt-Brennkammer 25b sowie in der Zusammenführung dieser beiden Brennkammern verbrannte Kraftstoff-Luft-Gemisch wird schließlich über den Brennkammer-Austritt 22b abgeführt. In niedrigeren Lastpunkten der Gasturbine werden lediglich die Pilot-Brenner 26a betrieben, was bedeutet, daß die Einspritzdüsen der Haupt-Brenner 26b nicht mit Kraftstoff versorgt werden. In höheren Lastpunkten der Gasturbine werden zusätzlich zu den Pilot-Brennern 26a die Haupt-Brenner 26b betrie¬ ben, so daß deren Einspritzdüsen dann mit Kraftstoff versorgt werden. Übli¬ cherweise wird die Pilot-Brennkammer 25a, die auch zum Starten der Gasturbine und zum Hochfahren in den Leerlauf alleinig betrieben wird, im gesamten Betriebskennfeld der Gasturbine, insbesondere Flug-Gasturbine betrieben, um eine Zündquelle für die nur bedarfsweise zugeschalteten Haupt-Brenner 26b zu schaffen. Der Zweck der gestuften Verbrennung liegt in der Minimierung von Schadstoffemissionen, insbesondere von NOx. Er¬ reicht wird dies dadurch, daß die jeweilige Brennergröße besser an den je¬ weiligen Leistungsbedarf angepaßt werden kann. So sollte zur NOx-Reduzie- rung die Verbrennungstemperatur möglichst gering sein, was durch gezielte Luftzufuhr (Zumischluft 28) in die Verbrennungszone erreichbar ist. Dabei sind die jeweiligen Stufen, nämlich die Pilot-Brenner 26a bzw. die Haupt- Brenner 26b auf spezielle Luft-Kraftstoff-Verhältnisse hin ausgelegt. Bei niedrigen Lastpunkten der Gasturbine, in denen insgesamt nur relativ wenig Kraftstoff verbrannt wird, wäre das den Haupt-Brennern 26b zukommende Luft-Kraftstoff-Verhältnis zu groß, um überhaupt eine sinnvolle Verbrennung unterstützen zu können. Daher werden die Haupt-Brenner 26b erst in höhe¬ ren Lastpunkten der Gasturbine zugeschaltet.A partition structure 24 is provided within the left half of this combustion chamber. The so-called pilot combustion chamber 25a lies between this partition structure 24 and the central axis 23, while the so-called main combustion chamber 25b is located below this partition structure 24. Pilot burners 26a are assigned to the pilot combustion chamber 25a, while main burners 26b are provided for the main combustion chamber 25b. Fuel or a fuel-air mixture is introduced into the combustion chambers via these burners 26a, 26b, while a main air flow 27 reaches the individual combustion chambers 25a, 25b via the combustion chamber inlet 22a. Fer¬ ner can admixed air 28 through apertures in the outer wall 20, in the inner wall 21, as well as in the partition wall structure 24 into the individual combustion chambers ¬ 25a, 25b occur. The fuel / air mixture burned in the pilot combustion chamber 25a or in the main combustion chamber 25b and in the combination of these two combustion chambers is finally discharged via the combustion chamber outlet 22b. At lower gas turbine load points, only the pilot burners 26a are operated, which means that the injectors of the main burners 26b are not supplied with fuel. At higher load points of the gas turbine, in addition to the pilot burners 26a, the main burners 26b are operated, so that their injection nozzles are then supplied with fuel. The pilot combustion chamber 25a, which is also operated solely for starting the gas turbine and for starting up in idle mode, is usually operated in the entire operating map of the gas turbine, in particular the flight gas turbine, in order to provide an ignition source for the main burners 26b, which are only switched on as required to accomplish. The purpose of staged combustion is to minimize pollutant emissions, especially NO x . This is achieved in that the respective burner size can be better adapted to the respective power requirement. In order to reduce NO x, the combustion temperature should be as low as possible, which can be achieved by targeted air supply (admixing air 28) into the combustion zone. The respective stages, namely the pilot burner 26a or the main burner 26b, are designed for special air-fuel ratios. At low load points of the gas turbine, in which only a relatively small amount of fuel is burned overall, the air-fuel ratio coming to the main burners 26b would be too high to be able to support a sensible combustion at all. The main burners 26b are therefore only switched on at higher load points of the gas turbine.
Nach welcher Strategie die einzelnen Brenner, nämlich die Pilot-Brenner 26a sowie die Haupt-Brenner 26b hierbei mit Kraftstoff versorgt werden, ist in Fig. 3 dargestellt. Auf der Abszisse dieses Diagrammes ist der Summen-Kraft- stoff-Fluß für die beiden Brenner aufgetragen, auf der Ordinate der prozen¬ tuale Anteil der Pilot-Brenner 26a bzw. der Haupt-Brenner 26b an diesem Summen-Kraftstoff-Fluß. Die entsprechende Kennlinie des Pilot-Brenners 26a ist mit dem Buchstaben A bezeichnet, diejenige der Haupt-Brenner 26b mit dem Buchstaben B. Man erkennt, daß bei zunächst nur geringem Sum¬ men-Kraftstoff-Fluß, d. h. im linken Teilbereich dieses Diagrammes lediglich die Pilot-Brenner 26a betrieben werden, so daß deren Anteil am Summen- Kraftstoff-Fluß 100 % beträgt. Bei zunehmendem Summen-Kraftstoff-Fluß werden nun die Haupt-Brenner 26b zugeschaltet, und zwar im Zuschaltpunkt Z. Hierbei soll jedoch kein schlagartiger Leistungszuwachs erfolgen. Er¬ wünscht ist vielmehr ein sanfter Leistungszuwachs, so daß mit einer zu- nächst relativ geringen Versorgung der Haupt-Brenner 26b gleichzeitig die Pilot-Brenner 26a mit einer geringeren Kraftstoffmenge versorgt werden. Dieser Zuschaltpunkt Z ist hinsichtlich seiner Auslegung daher äußerst kri¬ tisch, da sowohl in den Pilot-Brennern 26a, als auch in den Haupt-Brennern 26b stets ein geeignetes Kraftstoff-Luftverhältnis vorliegen muß. Die gleichen Überlegungen gelten dabei auch bezüglich einer Leistungsrücknahme der Gasturbine, wenn also die zunächst betriebenen Haupt-Brenner 26b wieder abgeschaltet werden. Um Instabilitäten in der direkten Umgebung dieses Zuschaltpunktes Z zu vermeiden, wird in der eingangs genannten WO 95/17632 hierfür eine Steuerung vorgeschlagen, die eine Hysterese enthält. Bei zunehmendem Schub werden die Haupt-Brenner erst bei einem höheren Gesamt-Kraftstoffdurchsatz zugeschaltet, als sie bei abnehmendem Schub abgeschaltet werden.The strategy according to which the individual burners, namely the pilot burners 26a and the main burners 26b are supplied with fuel, is shown in FIG. 3. The sum of the fuel flow for the two burners is plotted on the abscissa of this diagram, and the percentage of the pilot burner 26a and the main burner 26b in this is plotted on the ordinate Sum fuel flow. The corresponding characteristic curve of the pilot burner 26a is designated by the letter A, that of the main burner 26b by the letter B. It can be seen that with initially only a small total fuel flow, ie only the one in the left-hand section of this diagram Pilot burners 26a are operated so that their share in the total fuel flow is 100%. With increasing total fuel flow, the main burners 26b are now switched on, specifically at the switching point Z. However, there should be no sudden increase in output. Rather, what is desired is a gentle increase in output, so that with a initially relatively low supply to the main burners 26b, the pilot burners 26a are simultaneously supplied with a smaller amount of fuel. This connection point Z is therefore extremely critical with regard to its design, since a suitable fuel-air ratio must always be present both in the pilot burners 26a and in the main burners 26b. The same considerations also apply to a reduction in the power of the gas turbine, that is to say when the main burners 26b initially operated are switched off again. In order to avoid instabilities in the immediate vicinity of this connection point Z, a control system which contains a hysteresis is proposed for this in the aforementioned WO 95/17632. With increasing thrust, the main burners are only switched on with a higher total fuel throughput than they are switched off with decreasing thrust.
Da es jedoch erwünscht ist, in einem definierten Lastpunkt bzw. Schubzu- stand der Gasturbine stets auch einen definierten Kraftstoffdurchsatz zu ha¬ ben - d. h. unabhängig davon, ob es sich um eine Schubzunahme oder um eine Schubrücknahme handelt -, hat sich die Erfindung die Aufgabe gestellt, eine andere Lösung für die oben geschilderte Problematik im Zusammen- hang mit dem Zuschalten einer zweiten Stufe zu einer ersten Stufe aufzuzei¬ gen.However, since it is desirable to always have a defined fuel throughput at a defined load point or thrust state of the gas turbine - ie regardless of whether it is an increase in thrust or a decrease in thrust - the object of the invention is to achieve this another solution to the problems outlined above hang up with the connection of a second stage to a first stage.
Gelöst wird diese Aufgabe dadurch, daß zumindest die abschaltbare Stufe mit gepulster Kraftstoff-Einspritzung betreibbar ist. Geeignete Kraftstoffein- spritzvorrichtungen zur Durchführung dieses erfindungsgemäßen Kraftstoff- Einspritzverfahrens sind in den Ansprüchen 5 und 6 beschrieben, während die weiteren Unteransprüche vorteilhafte Aus- und Weiterbildungen zum In¬ halt haben.This object is achieved in that at least the stage that can be switched off can be operated with pulsed fuel injection. Suitable fuel injection devices for carrying out this fuel injection method according to the invention are described in claims 5 and 6, while the further subclaims contain advantageous training and further developments.
Erfindungsgemäß ist zumindest die abschaltbare Stufe, d. h. bevorzugt die oben erläuterte Haupt-Brennkammer 25b, mit gepulster Kraftstoff-Ein¬ spritzung betreibbar. Dies bedeutet, daß dann keine kontinuierliche, sondern eine diskontinuierliche Kraftstoff-Einspritzung erfolgt. Der Kraftstoff wird somit quasi getaktet in die Brennkammer eingeführt, wobei die Pulsations- frequenz im Bereich zwischen einzigen Hz bis zu einigen 100 Hz liegen kann. Diese gepulste Einspritzung hat zumindest theoretisch eine ebenso gepulste Verbrennung zur Folge. Für jeden Einspritzimpuls bzw. für jeden sog. Verbrennuπgs-Impuls ist dabei ein günstiges Kraftstoff-Luft- Verhältnis einstellbar. Dadurch, daß zumindest bei niedrigen Kraftstoffmengen nicht mehr kontinuierlich, sondern nurmehr zeitweise Kraftstoff eingespritzt wird, kann somit bei Einstellung günstiger Kraftstoff-Luft-Verhältnisse insgesamt deutlich weniger Kraftstoff eingespritzt werden, als dies bei einer herkömmli¬ chen kontinuierlichen Einspritzung möglich ist. Insbesondere sind aufgrund der gepulsten Einspritzung im sog. Zuschaltpunkt Z auch keine Instabilitäten zu befürchten, so daß zum einen ein weicher Übergang beim Zuschalten der zweiten Stufe erzielbar ist und zum anderen tatsächlich für jeden Be¬ triebspunkt bzw. Schubwert eine definierte Kraftstoffmenge in die Brenn¬ kammer eingeführt wird, unabhängig davon, ob es sich nun um eine Schub¬ zunahme oder um eine Schubrücknahme handelt. Die Pulsationsfrequenz, die bevorzugt variierbar sein soll, um in einer Viel¬ zahl von Betriebspunkten eine jeweils günstige Verbrennung einstellen zu können, kann bevorzugt oberhalb der charakteristischen Frequenzen von möglichen Brennkammer-Schwingungen liegen, so daß keine negativen Auswirkungen auf den Verbrennungswirkungsgrad bzw. auf den Schub sowie die Lärmerzeugung zu befürchten sind. Vielmehr ist stets eine Ver¬ brennung mit einem günstigen Wirkungsgrad erreichbar, da für jeden Ver- brennungs- bzw. Einspritzimpuls ein günstiges Kraftstoff-Luft-Verhältnis vorliegt. Während bei der heute üblichen kontinuierlichen Kraftstoff-Ein¬ spritzung in die (abschaltbare) Hauptbrennkammer der Minimalwert des Kraftstoffdurchsatzes durch die Instabilität der Verbrennung durch ein zu mageres Kraftstoff-Luft-Gemisch bestimmt ist, ist bei einer erfindungsge¬ mäßen gepulsten Kraftstoff-Einspritzung für jeden Kraftstoffimpuls ein größe¬ res Kraftstoff-Luft-Verhältnis realisierbar, so daß durch gezielte Auswahl der Pulsationsfrequenz auch bei deutlich geringerer Kraftstoff-Summenzufuhr noch eine stabile Verbrennung bzw. eine Reihe von stabilen Verbrennungs- Impulsen erzielbar ist.According to the invention, at least the stage which can be switched off, ie preferably the main combustion chamber 25b explained above, can be operated with pulsed fuel injection. This means that fuel injection is not continuous, but discontinuous. The fuel is thus introduced into the combustion chamber in a virtually clocked manner, the pulsation frequency being in the range from a single Hz to a few 100 Hz. At least theoretically, this pulsed injection results in an equally pulsed combustion. A favorable fuel-air ratio can be set for each injection pulse or for each so-called combustion pulse. Because fuel is no longer continuously injected, but only temporarily, at least in the case of low fuel quantities, significantly less fuel can be injected overall than is possible with conventional continuous injection when favorable fuel-air ratios are set. In particular, no instabilities are to be feared due to the pulsed injection in the so-called switch-on point Z, so that on the one hand a smooth transition can be achieved when the second stage is switched on and on the other hand a defined amount of fuel into the fuel for each operating point or thrust value chamber is introduced, regardless of whether it is an increase in thrust or a decrease in thrust. The pulsation frequency, which should preferably be variable in order to be able to set a favorable combustion in a large number of operating points, can preferably be above the characteristic frequencies of possible combustion chamber vibrations, so that there are no negative effects on the combustion efficiency or on the Thrust and noise generation are to be feared. Rather, combustion can always be achieved with a favorable efficiency, since there is a favorable fuel-air ratio for each combustion or injection pulse. While in the continuous fuel injection into the main combustion chamber which can be switched off today, the minimum value of the fuel throughput is determined by the instability of the combustion due to an excessively lean fuel / air mixture, pulsed fuel injection according to the invention is for everyone Fuel pulse, a larger fuel-air ratio can be achieved, so that a stable combustion or a series of stable combustion pulses can still be achieved by targeted selection of the pulsation frequency even with a significantly lower fuel supply.
Wie bereits erläutert, kann die Pulsationsfrequenz der diskontinuierlichen Kraftstoff-Einspritzung variiert werden, um die in einer gewissen Zeitspanne eingespritzte Kraftstoff-Summenmenge an den jeweiligen Betriebspunkt der Gasturbine anpassen zu können. Es ist aber auch erwünscht, die mit jedem Einspritz-Impuls einbringbare Kraftstoff menge variieren zu können, wobei hierfür mehrere Möglichkeiten existieren. Zum einen kann bei einer konstan¬ ten Kraftstoffmenge je Zeiteinheit die Einspritzdauer geändert werden, zum anderen kann bei einer konstanten Einspritzdauer die hierbei eingebrachte Kraftstoffmenge verändert werden. Selbstverständlich ist es auch möglich, diese beiden Strategien miteinander zu kombinieren, ebenfalls wie zusätzlich die Pulsationsfrequenz angepaßt werden kann, so daß insgesamt durch die vielen Variationsmöglichkeiten für jeden Betriebspunkt der Gasturbine die jeweils optimale Kraftstoff-Einspritzung gewählt werden kann. Dabei sei darauf hingewiesen, daß in Hochlast-Betriebspunkten selbstverständlich von der gepulsten Einspritzung auf eine kontinuierliche Kraftstoff-Einspritzung umgeschaltet werden kann.As already explained, the pulsation frequency of the discontinuous fuel injection can be varied in order to be able to adapt the total amount of fuel injected in a certain period of time to the respective operating point of the gas turbine. However, it is also desirable to be able to vary the amount of fuel that can be introduced with each injection pulse, and there are several possibilities for this. On the one hand, the injection duration can be changed with a constant fuel quantity per unit of time, on the other hand, the fuel quantity introduced here can be changed with a constant injection duration. Of course, it is also possible to combine these two strategies, as well as in addition the pulsation frequency can be adjusted so that the optimum fuel injection can be selected for each operating point of the gas turbine due to the many possible variations. It should be pointed out that at high-load operating points it is of course possible to switch from pulsed injection to continuous fuel injection.
Ferner sei noch auf einen weiteren Vorteil der gepulsten Kraftstoff-Ein¬ spritzung hingewiesen. Durch gezielte Auswahl der Pulsationsfrequenz kön- nen nämlich die üblichen Verbrennungsfrequenzen derart gesteuert werden, daß das sog. „Verbrennungs-Brummen", das bei instabiler Verbrennung bei geringem Kraftstoffdurchsatz auftreten kann aus den charakteristischen Fre¬ quenzen von möglichen Brennkammer-Schwingungen resultiert, minimiert werden kann. Im übrigen sei noch darauf hingewiesen, daß bevorzugt die erste Stufe oder Pilotbrennkammer, welche üblicherweise nicht in bestimm¬ ten Betriebszuständen abgeschaltet wird, mit einer kontinuierlichen Kraft¬ stoff-Einspritzung arbeiten kann bzw. sollte, insbesondere auch um eine sichere Zündung des Brennstoff-Luft-Gemisches in der zweiten Stufe oder Hauptbrennkammer zu gewährleisten.A further advantage of pulsed fuel injection should also be pointed out. By specifically selecting the pulsation frequency, the usual combustion frequencies can be controlled in such a way that the so-called "combustion hum" which can occur in the case of unstable combustion with low fuel throughput resulting from the characteristic frequencies of possible combustion chamber vibrations is minimized It should also be pointed out that preferably the first stage or pilot combustion chamber, which is usually not switched off in certain operating states, can or should work with a continuous fuel injection, in particular also for reliable ignition of the fuel - Ensure air mixture in the second stage or main combustion chamber.
Eine vorteilhafte Kraftstoffeinspritzvorrichtung zur Durchführung einer derar¬ tigen gepulsten Kraftstoff-Einspritzung kann aus einem elektromagnetisch und/oder hydraulisch betätigten Kraftstoff-Einspritzventil bestehen, dessen Öffnungszeitpunkt und Öffnungsdauer gezielt einstellbar ist. Derartige Kraft- stoff-Einspritzventile sind von Hubkolben-Brennkraftmaschinen her bekannt. Entsprechend abgewandelt können derartige Kraftstoff-Einspritzventile nun dazu verwendet werden, entweder direkt den Kraftstoff in die Brennkammer einer Gasturbine einzuspritzen oder sie können einer im wesentlichen übli¬ chen Kraftstoff-Einspritzdüse vorgeschaltet sein. Eine weitere Kraftstoff-Einspritzvorrichtung zur Durchführung einer erfin¬ dungsgemäßen gepulsten Kraftstoff-Einspritzung kann aus einem geeigne¬ ten Pulsations-Steuerventil bestehen, das einer an sich üblichen, in der Brennkammer mündenden Kraftstoff-Einspritzdüse vorgeschaltet ist. Zusätz¬ lich zum Pulsations-Steuerventil kann dieser Einspritzdüse ein Dosierventil vorgeschaltet sein, wobei es besonders vorteilhaft ist, das Pulsations- Steuerventil sowie das Dosierventil in einem Bauelement zusammenzufas¬ sen, welches im folgenden als „Puls-Dosierer" bezeichnet wird.An advantageous fuel injection device for carrying out such a pulsed fuel injection can consist of an electromagnetically and / or hydraulically actuated fuel injection valve, the opening time and duration of which can be specifically adjusted. Fuel injection valves of this type are known from reciprocating piston internal combustion engines. Modified accordingly, fuel injection valves of this type can now be used either to inject the fuel directly into the combustion chamber of a gas turbine or they can be connected upstream of an essentially conventional fuel injection nozzle. Another fuel injection device for carrying out a pulsed fuel injection according to the invention can consist of a suitable pulsation control valve which is connected upstream of a fuel injection nozzle which is conventional and opens into the combustion chamber. In addition to the pulsation control valve, a metering valve can be connected upstream of this injection nozzle, it being particularly advantageous to combine the pulsation control valve and the metering valve in one component, which is referred to below as the “pulse metering device”.
Ein bevorzugtes Ausführungsbeispiel für einen derartigen Puls-Dosierer ist in Fig. 1 in einem Prinzipschnitt dargestellt und wird im folgenden näher erläu¬ tert.A preferred exemplary embodiment of such a pulse dosing device is shown in a basic section in FIG. 1 and is explained in more detail below.
Mit der Bezugsziffer 1 ist ein Zylinder des beschriebenen Puls-Dosierers be¬ zeichnet, innerhalb dessen ein Steuerkolben 2 um die Zylinderachse 3 ver¬ drehbar sowie in Richtung der Zylinderachse 3 verschiebbar angeordnet ist. Über einen Zylinder-Wanddurchbruch 4 ist in den Innenraum des Zylinders 1 Kraftstoff gemäß Pfeil 18a einleitbar, über einen weiteren als Steuerfenster 5 bezeichneten Durchbruch in der Zylinderwand ist Kraftstoff aus dem Zylin¬ der-Innenraum gemäß Pfeil 18b abführbar. Der Zylinder-Wanddurchbruch 4 sowie das Steuerfenster 5 sind mit dem Kraftstoff-Versorgungssystem einer abschaltbaren Stufe einer gestuften Gasturbinen-Brennkammer verbunden, wobei der über das Steuerfenster 5 abgeführte Kraftstoff (Pfeil 18b) zu den Kraftstoff-Einspritzdüsen dieser abschaltbaren Brennkammer-Stufe hinge¬ führt wird.The reference number 1 denotes a cylinder of the pulse meter described, within which a control piston 2 is arranged to be rotatable about the cylinder axis 3 and to be displaceable in the direction of the cylinder axis 3. Fuel can be introduced into the interior of the cylinder 1 via a cylinder wall opening 4 according to arrow 18a, and fuel can be removed from the interior of the cylinder according to arrow 18b via a further opening in the cylinder wall referred to as control window 5. The cylinder wall opening 4 and the control window 5 are connected to the fuel supply system of a switchable stage of a stepped gas turbine combustion chamber, the fuel discharged via the control window 5 (arrow 18b) leading to the fuel injection nozzles of this switchable combustion chamber stage becomes.
Der Steuerkolben 2 ist zumindest abschnittsweise hohl ausgebildet, so daß ein lediglich gestrichelt dargestellter Kolben-Innenraum 6 vorliegt, in welchen wie ersichtlich Kraftstoff, der gemäß Pfeil 18a über den Wanddurchbruch 4 in das Innere des Zylinders 1 einströmte, gelangen kann. Somit ist dieser Kol¬ ben-Innenraum 6, der hier in Form zweier Bohrungen ausgebildet ist, mit dem Kraftstoffversorgungssystem der Gasturbine verbunden ist. An der Außenwand des Steuerkolbens 2 ist zumindest ein Steuerschlitz 7 vorgese¬ hen, der mit dem Kolben-Innenraum 6 bzw. mit den entsprechenden Boh¬ rungen in Verbindung steht. Somit kann Kraftstoff, der über den Wanddurch¬ bruch 4 herangeführt wird, letztlich über den Steuerschlitz 7 austreten.The control piston 2 is hollow at least in sections, so that there is a piston interior 6, which is only shown in broken lines, in which as can be seen, fuel which, according to arrow 18a, flowed into the interior of the cylinder 1 via the wall opening 4. This piston interior 6, which is designed here in the form of two bores, is thus connected to the fuel supply system of the gas turbine. At least one control slot 7 is provided on the outer wall of the control piston 2 and communicates with the piston interior 6 or with the corresponding bores. Fuel that is brought in through the wall opening 4 can thus ultimately escape through the control slot 7.
Etwa in Höhe des Steuerschlitzes 7 befindet sich in der Wand des Zylinders 1 das bereits erläuterte Steuerfenster 5. Wird nun der Steuerkolben 2 um die Zylinderachse 3 kontinuierlich gedreht, so wird über das Steuerfenster 5 Kraftstoff, der über den Wanddurchbruch 4 herangeführt wurde, gepulst ab¬ geführt. Jedesmal, wenn der Steuerschlitz 7 bei Rotation des Steuerkolbens 2 mit dem Steuerfenster 5 zur Deckung kommt, kann nämlich eine Kraftstoff¬ teilmenge gemäß Pfeil 18b durch das Steuerfenster 5 austreten und letztlich zur Kraftstoff-Einspritzdüse der Brennkammer-Stufe gelangen. Sobald je¬ doch der rotierende Steuerschlitz 7 das Steuerfenster 5 passiert hat, wird dieser Kraftstoff-Fluß wieder unterbrochen. Allein durch Rotation des Steuerkolbens 2 im Zylinder 1 ist somit eine gepulste Kraftstoff-Einspritzung in eine Gasturbinen-Brennkammer-Stufe erzielbar. Dabei ist die Pulsations¬ frequenz durch die Drehgeschwindigkeit des Steuerkolbens 2 im Zylinder 1 vorgegeben, so daß mit gezielter Auswahl der Drehgeschwindigkeit eine bestimmte Pulsationsfrequenz einstellbar ist.The control window 5 already explained is located approximately in the height of the control slot 7 in the wall of the cylinder 1. If the control piston 2 is now rotated continuously about the cylinder axis 3, fuel which was brought in via the wall opening 4 is pulsed off via the control window 5 ¬ led. Whenever the control slot 7 coincides with the control window 5 during rotation of the control piston 2, a partial fuel quantity can emerge through the control window 5 according to arrow 18b and ultimately reach the fuel injection nozzle of the combustion chamber stage. As soon as the rotating control slot 7 has passed the control window 5, this fuel flow is interrupted again. Only by rotating the control piston 2 in the cylinder 1 can a pulsed fuel injection into a gas turbine combustion chamber stage be achieved. The pulsation frequency is predetermined by the speed of rotation of the control piston 2 in the cylinder 1, so that a specific pulsation frequency can be set by specifically selecting the speed of rotation.
Die Menge des über das Steuerfenster 5 abgeführten Kraftstoffes kann zwar auch durch die Rotationsfrequenz des Steuerkolbens 2 bzw. Steuerschlitzes 7 beeinflußt werden. Ist jedoch im Hinblick auf gewisse Randbedingungen eine gewisse Rotationsfrequenz erwünscht, so ist eine bevorzugte Einstel- lung der je Kraftstoff-Impuls abgegebenen Kraftstoffmenge dadurch möglich, daß der Steuerkolben 2 längs der Zylinderachse 3 in bzw. gegen Pfeilrich¬ tung 14 verschoben wird. Hierdurch kann die wirksame Länge I des Steuer¬ schlitzes 7, über welche dieser mit dem Steuerfenster 5 zur Deckung kommt, verändert werden. Bei einem größeren Wert der Länge I wird eine größere Menge Kraftstoff über das Steuerfenster 5 abgeführt, bei einer kleineren Länge I eine geringere Kraftstoffmenge.The amount of fuel discharged via the control window 5 can also be influenced by the rotational frequency of the control piston 2 or control slot 7. However, if a certain rotation frequency is desired in view of certain boundary conditions, a preferred setting is The amount of fuel delivered per fuel pulse can be adjusted by displacing the control piston 2 along the cylinder axis 3 in or against the direction of the arrow 14. In this way, the effective length I of the control slot 7, by means of which it comes into congruence with the control window 5, can be changed. With a larger value of length I, a larger amount of fuel is discharged via control window 5, with a smaller length I, a smaller amount of fuel.
In Rotation um die Zylinderachse 3 versetzt werden kann der Steuerkolben 2 von der gearbox der Gasturbine, aber auch beispielsweise von einem Elek¬ tromotor, von dem lediglich das Abtriebsritzel 8 dargestellt ist, mit welchem ein Getrieberad 9 kämmt, das über einen Achsstummel 10 mit einem sog. Führungsfortsatz 11 des Steuerkolbens 2 verbunden ist. Dieser Führungs¬ fortsatz 11 ist ebenfalls innerhalb des Zylinders 1 geführt und weist eine Stirnseite 12' auf, auf die mit konstantem Druck ein Hydraulikmedium, wel¬ ches oberhalb dieses Führungsfortsatzes 11 über eine Steueröffnung 13' in den Innenraum des Zylinders 1 gelangt, einwirkt. Eine vergleichbare Steueröffnung 13 findet sich unterhalb des Steuerkolbens 2 im Zylinder 1 , so daß auch auf diese untere Stirnseite 12 ein Hydraulikmedium einwirken kann. Wird nun der Hydraulikdruck in der Steueröffnung 13 gegenüber demjenigen in der Steueröffnung 13' erhöht, so wird der Steuerkolben 2 gemäß Pfeilrichtung 14 nach oben verschoben. Eine Erniedrigung des Druckes in der Steueröffnung 13 gegenüber demjenigen in der Steueröff¬ nung 13' hingegen bewirkt eine Verschiebung des Steuerkolbens gegen Pfeilrichtung 14 nach unten. Diese beschriebene Verschiebebewegung in bzw. gegen Pfeilrichtung 14 kann im übrigen auch das Getrieberad 9 bezüg¬ lich des Abtriebsritzels 8 durchführen, da letzteres deutlich breiter ausgebil¬ det ist, als das Getrieberad 9. Vorgesehen ist ferner ein über eine Stellstange 15a sowie über einen Feder¬ teller 15b auf den Steuerkolben 2 einwirkendes Federelement 16, wobei zu¬ sätzlich eine Einstellschraube 17 vorgesehen ist, die ebenfalls auf den Fe¬ derteller 15b einwirken kann, derart, daß er maximale Kraftstoffdurchfluß über den Steuerschlitz 7 sowie das Steuerfenster 5 eingestellt werden kann. Jedoch kann dies sowie eine Vielzahl von Details, insbesondere konstrukti¬ ver Art durchaus abweichend von diesem gezeigten Ausführungsbeispiel gestaltet sein, ohne den Inhalt der Patentansprüche zu verlassen. Wesent¬ lich ist vielmehr, daß ganz allgemein zumindest die abschaltbare Stufe einer gestuften Gasturbinen-Brennkammer mit gepulster Kraftstoff-Einspritzung betreibbar ist. The control piston 2 can be set in rotation about the cylinder axis 3 by the gearbox of the gas turbine, but also, for example, by an electric motor, of which only the output pinion 8 is shown, with which a gearwheel 9 meshes, which meshes with a stub shaft 10 with a so-called guide extension 11 of the control piston 2 is connected. This guide extension 11 is also guided within the cylinder 1 and has an end face 12 ', on which acts with constant pressure a hydraulic medium which passes above this guide extension 11 via a control opening 13' into the interior of the cylinder 1. A comparable control opening 13 is located below the control piston 2 in the cylinder 1, so that a hydraulic medium can also act on this lower end face 12. If the hydraulic pressure in the control opening 13 is now increased compared to that in the control opening 13 ', the control piston 2 is shifted upward in the direction of the arrow 14. A lowering of the pressure in the control opening 13 compared to that in the control opening 13 ', however, causes the control piston to move downward in the direction of the arrow 14. This described displacement movement in or against the direction of the arrow 14 can also carry out the gear wheel 9 with respect to the output pinion 8, since the latter is significantly wider than the gear wheel 9. Also provided is a spring element 16 which acts on the control piston 2 via an adjusting rod 15a and via a spring plate 15b, an adjusting screw 17 also being provided which can also act on the spring plate 15b in such a way that it provides maximum fuel flow can be set via the control slot 7 and the control window 5. However, this, as well as a large number of details, in particular of a constructive type, can be designed quite differently from the exemplary embodiment shown, without departing from the content of the patent claims. Rather, it is essential that, in general, at least the stage which can be switched off in a stepped gas turbine combustion chamber can be operated with pulsed fuel injection.

Claims

Patentansprüche claims
1. Verfahren zur Kraftstoff-Einspritzung in eine gestufte Gasturbinen- Brennkammer mit separaten Kraftstoff-Einspritzdüsen für jede Stufe, wobei zumindest eine Stufe für bestimmte Betriebszustände durch Unterbrechung der Kraftstoffzufuhr abschaltbar ist, dadurch gekennzeichnet, daß zumindest die abschaltbare Stufe mit gepulster Kraftstoff-Einspritzung betreibbar ist.1. A method for fuel injection in a staged gas turbine combustion chamber with separate fuel injection nozzles for each stage, at least one stage for certain operating states can be switched off by interrupting the fuel supply, characterized in that at least the switchable stage can be operated with pulsed fuel injection is.
2. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, daß die Pulsationsfrequenz der diskontinu¬ ierlichen Kraftstoff-Einspritzung variierbar ist.2. The method according to claim 1, characterized in that the pulsation frequency of the discontinuous fuel injection is variable.
3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die mit jedem Einspritz-Impuls einbring¬ bare Kraftstoffmenge variierbar ist. 3. The method according to claim 1 or 2, characterized in that the quantity of fuel which can be introduced with each injection pulse can be varied.
4. Verfahren nach einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, daß von diskontinuierlicher, gepulster Kraftstoff-Einspritzung auf kontinuierliche Einspritzung umgeschaltet werden kann.4. The method according to any one of the preceding claims, characterized in that it can be switched from discontinuous, pulsed fuel injection to continuous injection.
5. Kraftstoff-Einspritzvorrichtung zur Durchführung des Verfahrens nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß ein elektromagnetisch und/oder hy- draulisch betätigtes Kraftstoff-Einspritzventil zum Einsatz kommt, des¬ sen Öffnungszeitpunkt und Öffnungsdauer gezielt einstellbar ist.5. Fuel injection device for performing the method according to one of claims 1 to 4, characterized in that an electromagnetically and / or hydraulically actuated fuel injection valve is used, the opening time and duration of which opening can be specifically adjusted.
6. Kraftstoff-Einspritzvorrichtung zur Durchführung des Verfahrens nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß einer in der Brennkammer mündenden6. Fuel injection device for performing the method according to one of claims 1 to 4, characterized in that one opening into the combustion chamber
Kraftstoff-Einspritzdüse ein Pulsations-Steuerventil und/oder ein Do¬ sierventil vorgeschaltet ist.Fuel injection nozzle is connected upstream of a pulsation control valve and / or a metering valve.
7. Kraftstoff-Einspritzvorrichtung nach Anspruch 6, dadurch gekennzeichnet, daß das Pulsations-Steuerventil und das7. Fuel injection device according to claim 6, characterized in that the pulsation control valve and the
Dosierventil in einem Bauelement in Form eines sog. Puls-Dosierers zusammengefaßt sind.Metering valve are combined in one component in the form of a so-called pulse metering device.
8. Kraftstoff-Einspritzvorrichtung nach Anspruch 7, dadurch gekennzeichnet, daß der Puls-Dosierer einen in einem Zylin¬ der (1 ) verdrehbar sowie in Zylinderachsrichtung (3) verschiebbar an¬ geordneten Steuerkolben (2) aufweist, dessen Außenwand einen mit dem Kolbeninnenraum (6), der mit dem Kraftstoffversorgungssystem der Brennkammer verbunden ist, verbundenen Steuerschlitz (7) auf- weist, der mit einem Steuerfenster (5) im Zylinder (1), welches eben¬ falls mit dem Kraftstoff-Versorgungssystem verbunden ist, zur Deckung bringbar ist.8. Fuel injection device according to claim 7, characterized in that the pulse meter has a in a Zylin¬ (1) rotatable and in the cylinder axis direction (3) displaceably arranged control piston (2), the outer wall of which with the piston interior ( 6), which is connected to the fuel supply system of the combustion chamber, connected control slot (7) has a control window (5) in the cylinder (1), which is also connected to the fuel supply system, to cover.
9. Kraftstoff-Einspritzvorrichtung nach Anspruch 8, gekennzeichnet durch zumindest eines der folgenden Merkmaie:9. Fuel injection device according to claim 8, characterized by at least one of the following features:
der Steuerkolben (2) wird von einem Elektromotor oder von der gear¬ box der Gasturbine in Rotation versetzt - der Steuerkolben (2) wird durch auf zumindest eine seiner Stirnseitenthe control piston (2) is set in rotation by an electric motor or by the gearbox of the gas turbine - the control piston (2) is moved to at least one of its end faces
(12, 12') einwirkenden Hydraulikdruck in Zyiinderachsrichtung (3) po¬ sitioniert. (12, 12 ') hydraulic pressure acting in the cylinder axis direction (3).
EP19970923092 1996-05-23 1997-05-15 Fuel injection method for a stepped gas turbine combustion chamber Expired - Lifetime EP0900351B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE1996120874 DE19620874A1 (en) 1996-05-23 1996-05-23 Fuel injection for a staged gas turbine combustor
DE19620874 1996-05-23
PCT/EP1997/002511 WO1997044622A1 (en) 1996-05-23 1997-05-15 Fuel injection method for a stepped gas turbine combustion chamber

Publications (2)

Publication Number Publication Date
EP0900351A1 true EP0900351A1 (en) 1999-03-10
EP0900351B1 EP0900351B1 (en) 2001-11-21

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US (1) US6381947B2 (en)
EP (1) EP0900351B1 (en)
DE (2) DE19620874A1 (en)
ES (1) ES2165057T3 (en)
WO (1) WO1997044622A1 (en)

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Also Published As

Publication number Publication date
WO1997044622A1 (en) 1997-11-27
US6381947B2 (en) 2002-05-07
ES2165057T3 (en) 2002-03-01
EP0900351B1 (en) 2001-11-21
US20010027639A1 (en) 2001-10-11
DE59706046D1 (en) 2002-02-21
DE19620874A1 (en) 1997-11-27

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