DE2160675A1 - Combustion chamber for a gas turbine - Google Patents

Description

! Dokio, Japan
LJ

Under characters:

B _rhyme i5: _amtner for a gas turbine

Γ?. Dec 1971

The invention relates to a combustion chamber for a gas turbine .

The formation of smoke in the combustion chamber of a gas turbine is attributable to the fact that the fuel mixture is in the Load operation of the device is enriched or over-greased locally in the combustion chamber. Especially in load operation The injection cone angle is reduced in the combustion chamber as a result of an increase in pressure in the combustion chamber, and measurements actually carried out have shown that the amount of air, especially in the primary combustion zone near the center of the combustion chamber, decreases to less than $ 5. As a result, more carbon becomes in this area share that causes smoke to form.

To avoid smoke formation in the combustion chamber of a Gas turbine, therefore, improvements to the combustion chamber are required in order to meet the following conditions:

1. Supplying a sufficient amount of air to the close-by

a fuel injection valve located area, there here the mixture tends to be over-rich and that for

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The theoretical mixing ratio of 15.5J1 required in this area is not required for perfect combustion can be adhered to.

2. Favoring the mixing of the fuel particles with air in the areas near the axis of the combustion chamber.

3. Turbulence of the fuel parts and the air, there a pressure increase inside the combustion chamber to one

Reduction of the injection cone angle of the fuel particles and consequently increased smoke formation in the combustion chamber leads.

In view of the aforementioned conditions, the task of completely avoiding smoke development can be achieved do not solve the primary combustion zone in a Leitbleoh combustion chamber, in which it is impossible due to the design supply a sufficient amount of air. Rather, it is preferred to achieve this object, improvements to be carried out on a swirl insert combustion chamber. However, attempts are made to encourage smoke formation reduce the air circulation through the combustion chamber, the ignition properties of the combustion chamber are impaired, so that the so-called flame out can occur. In the conventional combustion chambers of Gas turbines used to have ignition stability on Costs of either the ignition properties or the roughing properties, i.e. to improve the smoke development of the combustion chamber, among other things.

The object of the invention is therefore primarily to create a fuel injection device or a combustion chamber for a gas turbine which is designed so that the Smoke development of the combustion chamber during operation with high loads is reduced without the. Ignitability of the

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To affect the combustion chamber. For this purpose are at the combustion chamber according to the invention has numerous small openings in an extension of a sprue of a swirl insert provided in such a way that they enclose a fuel injection opening which is through the extension

from the

of the sprue is set and enclosed in front of a / sprue Fuel injection valve is located, with im Operation of the combustion chamber with high load a large amount of the working fluid, such as air or steam, over the small openings is supplied, whereby the smoke development is reduced while the combustion chamber is in operation with no or low load, the amount of fuel through the small openings near the fuel injection port supplied working fluid is throttled, whereby the ignition and combustion properties of the combustion chamber be improved.

To achieve this object, the invention creates furthermore a combustion chamber for a gas turbine, which communicates with the outside of the combustion chamber Openings in a flange and in the sprue of a fuel -Injection valve enclosing swirl insert are provided on its air inlet side, with these openings Abzant- or supply means for the working fluid are in communication.

Furthermore, the invention aims to provide a combustion chamber for a gas turbine, in which numerous small Openings in an extension of a sprue of a swirl insert are designed in such a way that they are defined by the extension of the sprue and in front of a Fuel injection port located in the fuel injector enclose, with working fluid under high load through these openings during operation of the combustion chamber Boost pressure initiated around the fuel injection port is solved, ^ 8uroh the task mentioned at the beginning will.

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To achieve the stated object, the invention also creates a combustion chamber for a gas turbine, in which a perforated guide plate or a guide plate is provided.

The following are preferred embodiments of the invention explained in more detail with reference to drawings. Show it:

Fig. 1 is a vertical section through the injection side Part of a combustion chamber according to the invention for a gas turbine,

Fig. 2 is a vertical section through a modified embodiment the invention,

5 shows a vertical section through a further modified one Embodiment of the invention,

Fig. 4- a vertical section through an even further modified one Embodiment of the invention,

FIG. 5 shows a sectional view, on an enlarged scale, of part of the swirl insert according to FIG. 4,

Fig. Β is a vertical section through an even further modified Embodiment of the invention and

7 shows a vertical section through a further modification the combustion chamber according to the invention.

In the embodiment of the invention shown in Fig. 1 are arranged in one on the air inlet side of a swirl insert Sprue openings formed, the swirl blades supplied air is partly introduced into the sprue via these openings in order to keep the combustion chamber in operation under load conditions around the opening of a fuel injection valve to be blown in, whereby the smoke development is automatically suppressed in load operation. According to Fig. 1, the air serving as the working fluid flows, as indicated by the arrows 2, through a radial

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sohaufel swirl insert 1, which has a sprue 3, an extension 4 and several air outlet openings 5 which are formed around a fuel injection opening defined by the extension 4 of the sprue 3. Furthermore are in! Ig. 1 a fuel injection valve 6, a stand piece 7 ,. air 8 to be mixed with the fuel, an annular diaphragm 9 for sealing the gap between the extension 4 of the sprue and the side wall of the injection valve 6 at a point opposite its center line inward of the air outlet openings 5 and several air inlet openings formed in the sprue of the swirl insert Openings 10 shown. The force (material flow is indicated with A, in the air supply with B.

In this combustion chamber, the diameter of the sprue 3 of the swirl insert 1 is expediently enlarged, the radial blades of the swirl insert 1 being attached to the sprue without a casing ring attached to their tips. As a result, sweeps a guided over the surface of the gate 5, a turbulent air stream away of the end of a spark plug over and the spark plug stable vortices are also backward generated so that a fuel enrichment on the surface of ä injection cone takes place and can be achieved very stable ignition and combustion. In addition, since the blade angle of attack can be kept small, the ignition properties can be improved without increasing the degree of pitting.

At the in J? Ig. 1 shown combustion chamber can Air outlet openings 5 have any convenient size. At the beginning of the ignition, when the amount and pressure of the combustion chamber supplied air have not yet reached sufficiently high values, the injection cone is fed through the opening practically no air supplied, so that the Zündigensohaften

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2180675

the combustion chamber is not impaired at the start of operation will.

In the further course of the combustion, when the amount and pressure of the air supplied by a compressor increase with increasing If the load on the combustion chamber or the gas turbine is increased, on the other hand, air is sent through the opening towards the fuel-rich area on the centerline of the injector 6 blown in, as indicated by the arrows 8; this reduces smoke formation.

) Experiments carried out according to the invention have shown that at an internal pressure of the combustion chamber of 20 kg / cm the degree of building up by 0.5 B.S.NV (Baoara Smoke Number = in Term used all over the world to determine a smoke level by comparing the blackness of the surface of a filter paper during a unit of time during which a. Combustion exhaust gas flows through the filter paper, adhering carbon with IForm heating values from 0 to 9) can be decreased. In the further course of combustion, when the internal pressure has a value of 6-7 kg / cm reached, the rough level can consequently be in a larger ratio be lowered.

As mentioned, in the illustrated embodiment of the invention it is possible to improve the ignition properties and the combustion stability to improve and at the same time to reduce smoke formation during load operation of the combustion chamber.

In the embodiment of the invention shown in FIG. 2, the working fluid under charging pressure is is blown into the central area of the same, located on the axis of the combustion chamber, near the injection valve, where the mixture tends to become excessively rich in high-load operation The degree of roughness in the combustion chamber is thereby reduced. In FIG. 2 are those of the embodiment of FIG. 1

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corresponding parts are denoted by the same reference numerals.

According to S ¹ Ig. 2, an inlet 17 formed in the spacer 7 for working fluid under supercharging pressure, a distributor 12, with the aid of which the working fluid is evenly distributed to each of the various combustion chambers, and a supercharging pressure control valve 13, which is provided by a regulates the boost pressure supplied directly by the supercharger or the blower driven by the gas turbine in such a way that the pressure gradient between the compressed working fluid and the interior of the combustion chamber is approximately 1-2 kg / cm.

The working fluid is discharged through a number of air outlet openings 5 of each about 2 - 3 mm Durohmesser in the Discharged way that it flows axially and without swirl component and has a differential pressure of 1-2 kg / om or in the same sifting as the swirled fuel particles and flows with tangential swirl components. In this embodiment, the pre-diluted, with a small differential pressure compared to the internal pressure of the combustion chamber Working fluid supplied via inlet 17 by zero. the control valve 13 regulated with respect to pressure and flow rate. If the degree of smoke formation is to be reduced, the control valve 13 is opened in order to reduce the amount of smoke through the inlet 17 flowing working fluid by 0 through the openings 5 in the Let the combustion chamber flow in, so that the degree of smoke formation can be reduced to about) B.S.] J5J * 3. In this embodiment the smoke level can therefore be set to a desired value at any point in time.

In the embodiments shown in Fig. 3 to 5 is on the outlet side of the swirl insert at its sprue a conical baffle is provided, the opening side of which Combustion chamber is facing and in which small openings are trained; in this way it is in high load operation

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a large amount of working fluid is supplied to the combustion chamber in the vicinity of the injection opening defined by the extension of the extension and located in front of the injection valve, in order to reduce smoke development. Combustion chamber, however, the amount of working fluid is reduced in order to improve the ignition properties of the combustion chamber. In FIGS. 3 % β 5, parts corresponding to the previously described embodiments according to FIGS. 1 and 2 are denoted by the same reference numerals.

* In the embodiment according to FIG. 3, there is an inner guide plate 11 is provided in which a number of small openings 12 are formed. Furthermore, the combustion chamber has a Bell dome 13 and air inlet openings H, while the air flow along the bell dome 13 is indicated at E.

In this embodiment, the inner guide plate 11 is on inner end of the sprue of the swirl insert blades 1 welded on and with a number of on equal? Large stocks distributed small openings 12 provided. The air supplied via the opening 10 is at the end of the injection valve mixed with the injected fuel particles.

Since the swirl insert Sohaufein 1 at an angle to Axial Riohtung the combustion chamber are arranged, forms the Pressurized air flow 2 eddies around the injector 6 around, which swirls the atomized fuel particles move or give them a swirl energy. The injection cone angle is therefore not decreased, either when the internal pressure of the combustion chamber rises, so that associated with an increase in the internal pressure increases Smoke ratio can be kept small.

The inner baffle 11 is arranged so that it the eddy currents favored, while stable turbulence flows form on its rear side. This can

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licit improved ignition properties and stability of the Combustion can be guaranteed.

The small openings penetrating the inner baffle If 12 are used to reduce the development of black tint when the combustion chamber is under load, when air is higher Throughput and high: pressure is supplied without the improving the ignition properties at the start of operation To affect the effect of the inner Leitbleehs 11. While the flow rate and the air pressure at the start of operation are still low, only a very small amount of air flows through the small openings 12, and there these small Openings 12 also distributed on appropriate peripheral stands are, the turbulence flows behind the baffle. 11 not destroyed

The amount of air emerging from the small openings 12 in the direction of the injection cone gradually increases with increasing amount of view and increasing pressure of the Air, so that the air / fuel mixture ratio seeps increases in the height of the RLnspritzventils and smoke formation is reduced «

This effect becomes even more noticeable with increasing exposure, i.e. the pressure-dependent accumulation-to-increase ratio decreases. Experiments have confirmed ^ dafi at

ty

an internal pressure of the combustion chamber of 3 kg / cm, the BrSJST. number is _{reduced by Q t} 6 - 1.0 and the ignition properties of the combustion chamber are significantly improved at the beginning of its operation

As mentioned, the ignition properties, the combustion stability and the degree of smoke generation can be improved at the same time are simply installed by installing the perforated inner baffle in a conventional combustion chamber with a swirl insert will. By using a twist insert with internal

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Guide plate, as in the illustrated Ausführungsforra, can the burnability can be improved and can in particular, completely switching off the so-called flame failure} this effect is so emphasized that the flame does not tears off or is blown out, even if the air supply is interrupted after ignition.

The door directions according to FIGS. 4 and 5 are modified embodiments of the combustion chamber according to FIG. 3 ₅ , an outer guide plate 15 and a casing ring 16 being provided. The combustion chamber shown in Figs. 4 and 5 operates in the same manner as the combustion chamber shown in Fig. 3 _f but serves here conical, at the tips of the swirl insert Sehauf a 1 angesehweißte outer guide plate 15 as a guide for the cooling air to (Rockendem 13 , while at the same time it enables the air flow B to form turbulence flows behind this outer baffle, which stabilize the flame Swipe past and stream along the bell dome 13.

The outer guide plate 15 of the swirl insert can be removed just like the swirl insert according to FIG makes dismantling and checking the combustion chamber easier will. In addition, the jacket ring 16 provided at the tips of the swirl insert can be made narrower or even be left out. 5 are also the Biabauwtttkel <* »the brewing insert and the diameter D of the swirl insert sprue.

The embodiment shown in FIG. 6 is a modification of the embodiment according to FIG. 2, in which an inner guide plate 11 is fastened in an inclined position on the inner end of the twist-insert sprue 3. This baffle

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is penetrated by a number of small openings 11 ', over which the swirl insert blades 1 flowing through Working fluid is automatically expelled. The others Construction details correspond to the embodiment according to FIG. 2, and the fig. 2 corresponding parts are with given the same reference numbers.

In this embodiment, with increasing load, ie air flow rate and pressure, the combustion chamber automatically compressed working fluid is supplied to the fuel-enriched area via the small openings 11- 'of the guide tube 11, whereby the smoke development to about BS Ή. 2 can be reduced.

Although in the embodiments according to FIGS. 2 and 3, the sealing member 9 is provided in order to allow the working fluid to be blown out To facilitate via the small openings 5, this sealing member is not absolutely necessary. In some In some cases, it is even advantageous to omit this sealing member in order to prevent carbon deposits on the fuel injection opening to prevent.

In Fig. 7, finally, a further embodiment of the invention is shown in which an air bleed or charging device is provided, with the help of which the ignition properties at the start of operation, i.e. when starting, can be further improved and the smoke development in load operation can be freely regulated.

In Fig. 7, the parts corresponding to the previously described embodiments are given the same reference numerals designated. For the following description, reference is therefore made to the previously explained embodiments, in particular to those of FIGS. 3 and 4 are referred to.

The embodiment according to FIG. 7 has a passage 18 communicating with passage 17, an air inlet 19,

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trained in the rear wall of the Dralleinsatζ sprue Openings 19 ', an air charger line 20, a manifold 21, with which the lines from the individual combustion chambers are connected, as well as electromagnetic valves 22 and 23 on.

In this embodiment, when the gas turbine is started, the valve 23 is closed and the valve 22 is fully opened and the combustion chamber is further adjusted so that the one stroking through the Bralleinsatz-Sohaufeln 1 Air flow through the openings 19 'and the passages 17, "18 is partially diverted to the outside air. As a result, the air fed into the combustion chamber becomes partially outside air diverted so that ignition can proceed satisfactorily. After ignition has taken place, valve 22 closed and the valve 23 opened in response to a signal indicating that the ignition has taken place and for the turbine outlet temperature or the turbine speed is representative. The working fluid is thereupon under supercharging pressure via the passages 17, 18 in the primary The combustion area or zone is blown into the combustion chamber.

fc By increasing the degree of opening of the electromagnetic Valve 23 with increasing turbine speed, the smoke development can be reduced with increasing load.

The amount of at the beginning of the ignition via the openings 19 ' and air diverted to the outside through passages 17, 18 is approximately 10% of the total amount of air supplied to the combustion chamber.

The effect of improving the ignition properties by reducing the amount of air fed in at the time of ignition as well as the effect of reducing smoke formation

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degrees by increasing the air volume in load operation are already has been explained in connection with the previously described embodiments and therefore need not be described again to become.

Although the invention is described above for the case that air is used as the pre-compressed working fluid is, the effect achieved according to the invention of lowering the degree of smoke formation when charged with steam is even greater. This is due to the fact that the fuel parts pass through the Energy generated by the water droplets contained in the steam as they evaporate in the primary combustion zone is released, further broken down so that a more homogeneous air: fuel mixture can be achieved.

The same effect occurs when water droplets are injected into the primary combustion zone through a nozzle.

In this context it should also be noted that the swirl insert blades 1 according to Pig. 1, 2,), 6 and 7 of the so-called B-type, in which the blade width increases continuously from the root or sprue to the tip, while the blades according to FIGS. 4 and 5 of the so-called A-type in which the blade width remains the same over the blade length.

Although the invention is in preferred embodiments above is shown and described, these embodiments are of course only intended to be illustrative own and in no way limit the invention, since numerous changes and modifications are possible for the person skilled in the art, without departing from the scope of the invention.

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Claims (7)

Patent claims 1.) Combustion chamber for a gas turbine, characterized by a number of small openings (5) in an extension (4) of a sprue (3) of a swirl insert (1) are designed in such a way that they are defined by the sprue extension and in front of a by the sprue enclosed fuel injection valve (6) enclose the fuel injection opening, so that in operation of the combustion chamber with high load, i. e. high air flow and pressure, a working fluid through the small openings (5) in the vicinity of the fuel injection opening can be initiated. 2. Combustion chamber according to claim 1, characterized in that in a flange and in a sprue of the swirl insert (1) Openings communicating with the outside of the combustion chamber are formed on its inlet side and that a working fluid discharge communicating with these openings or feed device is provided. 3. Combustion chamber according to claim 1, characterized in that that the small openings (5) are connected in one with the sprue (3) of the swirl insert (1) on its outlet side conical baffle (11) are formed, the opening side of which faces the combustion chamber 4. Combustion chamber according to claim 1, characterized in that a number of small openings are formed in the sprue on the inlet side of the swirl insert, the same as the former communicate with small openings. 5. Combustion chamber according to claim 1, characterized in that a working fluid charging device with the small openings communicates. 209827/0631 - 15 - 6. Combustion chamber according to claim 1, characterized in that that an inner baffle, which is provided with a number of small openings, in an inclined position with the The inner end of the swirl insert sprue is connected in such a way that the fluid flowing through the swirl insert automatically via the small openings provided in the inner guide plate in the direction of the injection cone can be blown in. 7. Combustion chamber according to claim 6, characterized in that a working fluid charging device with the small openings communicates. 209827/0631 . A. Blank ite