EP0833104B1 - Burner for operating a combustion chamber - Google Patents

Description

Technical field

The present invention relates to a burner according to the preamble of claim 1.

State of the art

From EP-0 704 657 a burner has become known, the upstream side consists of a swirl generator, the herein formed flow seamlessly transferred into a mixing section becomes. This is done using one at the beginning of the mixing section for this purpose formed transition geometry, which consists of Transition channels exist, which are sectoral, according to the Number of acting partial bodies of the swirl generator, the end face the mixing section and in the direction of flow twisted. Downstream of these transition channels the mixing section has a number of filming holes on what an increase in flow velocity ensure along the pipe wall. Then follows a combustion chamber, the transition between the mixing section and the combustion chamber through a cross-sectional jump is formed, in the plane of which is a backflow zone or Backflow bubble forms.

The swirl strength in the swirl generator is selected so that that the swirl does not burst within the mixing section, but continues downstream, as stated above in the area of the cross-sectional jump. The length of the mixing section is dimensioned so that an adequate Mixing quality is guaranteed for all types of fuel.

Although this burner compared to those from the previous one State of the art a significant improvement in terms of strengthening flame stability, deeper Pollutant emissions, lower pulsations, complete Burnout, large operating area, good cross-ignition between the various burners, compact design, improved Mixture, etc., it shows that a further strengthening flame stability as well as improved Adaptation of the flame to the given combustion chamber geometry for smooth operation at the highest level at the Premix combustion of the newer generation has become necessary is.

Presentation of the invention

The invention seeks to remedy this. The invention how it is characterized in the claims, the task lies based on precautions for a burner of the type mentioned propose which a strengthening of flame stability and an adaptation of the flame to the given one Combustion chamber geometry does this without the other advantages To diminish Brenners in any way.

For this purpose, the burner front is at the end of the mixing section in the plane of the cross-sectional jump on the combustion chamber side formed with a torus or torus-like notch. This configuration means that the Mixing section flowing combustion air to the in the torus creating flow, with which the swirl number of the main flow rises sharply. Enlarged compared to a current without a torus which are in the area of cross-sectional jump backflow bubble forming enormous. This enlargement is due to radial expansion and axial compactness characterized. This strengthens flame stability and the opportunity through appropriate training of the torus a targeted adaptation of the flame to the to carry out predetermined combustion chamber geometry.

Another embodiment of the invention relates to the relocation the head-side fuel nozzle opposite the inflow the combustion air in a conical shape Swirl generator with tangential air inlet slots. This misalignment leads to the mouth of the fuel nozzle upstream of the inflow area, so that Fuel spray from the fuel nozzle with a larger one Spray radius can be injected into the main flow. With This precaution is achieved in that the fuel spray first contact with the combustion air from a film has decayed into drops, and the conical surface of this Fuel sprays in this area increased by a factor has what improves the spread of the fuel spray and does not hinder the inflow of combustion air.

Does the fuel nozzle come through its setback in the Area of a solid casing can then be Provide openings around the mouth of the fuel nozzle what purge air in the cross section induced by the fuel nozzle flows in. The flow cross section of these purge air openings as well as the reset of the fuel nozzle chosen so that in gas operation through these openings flowing purge air is not sufficient to the above already to move said backflow bubble further downstream. in the The fuel spray has a practical effect on liquid fuel operation as jet pump, with which the purge air flow through the mentioned openings increased in such a way that a larger axial impulse arises which continues the backflow bubble shifts downstream.

Another advantage of the invention is that the purge air through the openings in the area of the mouth Fuel nozzle wetting the inner wall of the conical Swirl generator prevented.

Advantageous and expedient developments of the inventive Task solutions are in the further claims characterized.

In the following, exemplary embodiments are described with reference to the drawings the invention explained in more detail. All for the immediate Understand the invention are non-essential features been left out. The same elements are in the different Figures with the same reference numerals. The The direction of flow of the media is indicated by arrows.

Brief description of the drawings

Fig. 1

einen als Vormischbrenner ausgelegten Brenner mit einer Mischstrecke stromab eines Drallerzeugers,

Fig. 2

einen aus mehreren Schalen bestehenden Drallerzeuger in perspektivischer Darstellung, entsprechend aufgeschnitten,

Fig. 3

einen Querschnitt durch einen zweischaligen Drallerzeuger,

Fig. 4

einen Querschnitt durch einen vierschaligen Drall-erzeuger,

Fig. 5

eine Ansicht durch einen Drallerzeuger, dessen Schalen schaufelförmig profiliert sind,

Fig. 6

eine Ausgestaltung der Uebergangsgeometrie zwischen Drallerzeuger und Mischstrecke,

Fig. 7

eine schematische Darstellung des Drallerzeugers nach Fig. 2 mit zurückversetzter Brennstoffdüse,

Fig. 8-11

verschiedene torusähnliche Ausgestaltungen in der Brennerfront zur Stabilisierung der Rückströmblase.

It shows:

Fig. 1

a burner designed as a premix burner with a mixing section downstream of a swirl generator,

Fig. 2

a swirl generator consisting of several shells in a perspective view, cut open accordingly,

Fig. 3

a cross section through a double-shell swirl generator,

Fig. 4

a cross section through a four-shell swirl generator,

Fig. 5

2 shows a view through a swirl generator, the shells of which are profiled in a shovel shape,

Fig. 6

an embodiment of the transition geometry between the swirl generator and the mixing section,

Fig. 7

2 shows a schematic representation of the swirl generator according to FIG. 2 with the fuel nozzle set back;

Fig. 8-11

Various torus-like designs in the burner front to stabilize the backflow bubble.

WAYS OF CARRYING OUT THE INVENTION, INDUSTRIAL APPLICABILITY

Fig. 1 shows the overall structure of a burner. Is initially a swirl generator 100 effective, the design of which in the following Fig. 2-5 shown and described in more detail becomes. This swirl generator 100 is a conical structure, the tangential multiple of a tangential inflowing combustion air flow 115 is applied becomes. The flow that forms here is based on a transition geometry provided downstream of the swirl generator 100 transitioned seamlessly into a transition piece 200, in such a way that no separation areas can occur there. The configuration of this transition geometry is under Fig. 6 described in more detail. This transition piece is 200 downstream of the transition geometry through a mixing tube 20 extended, both parts of the actual mixing section Form 220. Of course, the mixing section 220 can consist of a single piece, i.e. then that the transition piece 200 and the mixing tube 20 into one contiguous structures merge, the characteristics of each part are preserved. Become a transition piece 200 and mixing tube 20 created from two parts, so are these are connected by a socket ring 10, the same Socket ring 10 on the head side as anchoring surface for the Swirl generator 100 is used. Such a sleeve ring 10 has it also the advantage that different mixing tubes are used can be. Downstream side of the mixing tube 20 is the actual combustion chamber 30, which is here is only symbolized by a flame tube. The Mixing section 220 largely fulfills the task that downstream of the swirl generator 100 provided a defined distance in which a perfect premix of fuels different types can be achieved. This mixing section, so primarily the mixing tube 20, further allows a loss-free flow, so that even in Active connection with the transition geometry initially none Backflow zone or backflow bubble can form, with which over the Length of the mixing section 220 to the mix quality for all Fuel types influence can be exerted. This mixing section 220 has yet another property, which is that in it itself the axial velocity profile has a pronounced maximum on the axis, so that the flame does not reignite from the combustion chamber is possible. However, it is true that with such Configuration this axial velocity towards the wall falls off. To prevent reignition in this area, becomes the mixing tube 20 in the flow and circumferential direction with a number of regularly or irregularly distributed Provide holes 21 of different cross-sections and directions, through which an amount of air into the interior of the mixing tube 20 flows, and along the wall like a film induce an increase in speed. A there is another possibility to achieve the same effect in that the flow cross section of the mixing tube 20 downstream of the transition channels 201, which the form the aforementioned transition geometry, a narrowing experiences what the overall speed level within of the mixing tube 20 is raised. Run in the figure these holes 21 at an acute angle to the Burner axis 60. Furthermore, the outlet corresponds to Transition channels 201 the narrowest flow cross section of the Mixing tube 20. Bridge the mentioned transition channels 201 accordingly the respective cross-sectional difference, without thereby negatively influencing the flow formed. If the selected precaution when guiding the pipe flow 40 an intolerable pressure loss along the mixing tube 20 can be remedied, not at the end of this mixing tube in the figure shown diffuser is provided. At the end of the mixing tube 20 then connects to a combustion chamber 30, with between the two flow cross-sections through a burner front 70 formed cross-sectional jump is present. First here forms a central backflow zone 50, which the Features of a disembodied flame holder. Forms within this cross-sectional jump during the Operation a flow boundary zone, in which by the negative pressure of the vortex prevailing there, this leads to an increased ring stabilization of the Backflow zone 50. Combustion chamber 30 has an end face Number of openings 31 through which an amount of air directly flows into the cross-sectional jump, and there bottom others contributes to the ring stabilization of the backflow zone 50 is strengthened. In addition, it should not go unmentioned that the creation of a stable backflow zone 50 is also sufficient requires a high number of twists in a tube. Is a such undesirable at first, so stable backflow zones by supplying small, strongly swirled air flows on the Pipe end, for example through tangential openings, be generated. It is assumed here that the Air volume required for this is approximately 5-20% of the total air volume is. As for the design of the burner front 70 in the end of the mixing tube 20 to stabilize the backflow zone or Backflow bladder 50 relates to the description below Fig. 8-11 referenced.

In order to better understand the structure of the swirl generator 100 it is advantageous if, at the same time as FIG. 2, at least FIG. 3 is used. Furthermore, this Fig. 2 is not unnecessary to be confusing, they are those according to the Figure 3 schematically shown guide plates 121a, 121b only hinted been recorded. In the following, the Description of Fig. 2 as required on the figures mentioned pointed out.

The first part of the burner according to FIG. 1 forms the swirl generator 100 shown in FIG. 2. This consists of two hollow, conical partial bodies 101, 102 which are nested one inside the other. The number of conical partial bodies can of course be greater than two, as shown in FIGS. 4 and 5; This depends on the mode of operation of the entire burner, as will be explained in more detail below. In certain operating constellations, it is not excluded to provide a swirl generator consisting of a single spiral. The offset of the respective central axis or longitudinal symmetry axes 201b, 202b of the tapered partial bodies 101, 102 to one another creates a tangential channel, that is to say an air inlet slot 119, 120 (FIG. 3), through which the combustion air 115 in Interior of the swirl generator 100, ie flows into the cone cavity 114 of the same. The conical shape of the partial bodies 101, 102 shown in the flow direction has a specific fixed angle. Of course, depending on the operational use, the partial bodies 101, 102 can have an increasing or decreasing cone inclination in the flow direction, similar to a trumpet or. Tulip. The last two forms are not included in the drawing, since they can be easily understood by a person skilled in the art. The two tapered partial bodies 101, 102 each have a cylindrical starting part 101a, 102a, which, similarly to the conical partial bodies 101, 102, also run offset from one another, so that the tangential air inlet slots 119, 120 are present over the entire length of the swirl generator 100. In the area of the cylindrical initial part, a nozzle 103 is preferably accommodated for a liquid fuel 112, the injection 104 of which coincides approximately with the narrowest cross section of the conical cavity 114 formed by the conical partial bodies 101, 102. The injection capacity and the type of this nozzle 103 depend on the given parameters of the respective burner. Of course, the swirl generator 100 can be designed in a purely conical manner, that is to say without cylindrical starting parts 101a, 102a. The tapered partial bodies 101, 102 further each have a fuel line 108, 109, which are arranged along the tangential air inlet slots 119, 120 and are provided with injection openings 117, through which a gaseous fuel 113 is preferably injected into the combustion air 115 flowing through there, such as arrows 116 symbolize this. These fuel lines 108, 109 are preferably placed at the latest at the end of the tangential inflow, before entering the cone cavity 114, by an optimum
Obtain air / fuel mixture. As mentioned, the fuel 112 brought in through the nozzle 103 is normally a liquid fuel, and it is readily possible to form a mixture with another medium. This fuel 112 is injected into the cone cavity 114 at an acute angle. A conical fuel spray 105 is thus formed from the nozzle 103 and is enclosed by the rotating combustion air 115 flowing in tangentially. In the axial direction, the concentration of the injected fuel 112 is continuously reduced by the inflowing combustion air 115 to mix in the direction of evaporation. If a gaseous fuel 113 is introduced via the opening nozzles 117, the fuel / air mixture is formed directly at the end of the air inlet slots 119, 120. If the combustion air 115 is additionally preheated or, for example, enriched with a recirculated flue gas or exhaust gas, this provides lasting support the vaporization of the liquid fuel 112 before this mixture flows into the downstream stage. The same considerations also apply if liquid fuels should be supplied via lines 108, 109. When designing the conical partial bodies 101, 102 with regard to the cone angle and the width of the tangential air inlet slots 119, 120, strict limits have to be observed so that the desired flow field of the combustion air 115 can be set at the outlet of the swirl generator 100. In general, it can be said that a reduction in the size of the tangential air inlet slots 119, 120 already favors the faster formation of a backflow zone in the region of the swirl generator. The axial speed within the swirl generator 100 can be changed by a corresponding supply, not shown, of an axial combustion air flow. A corresponding swirl generation prevents the formation of flow separations within the mixing tube downstream of the swirl generator 100. The design of the swirl generator 100 is furthermore particularly suitable for changing the size of the tangential air inlet slots 119, 120, with which a relatively large operational bandwidth can be recorded without changing the overall length of the swirl generator 100. Of course, the partial bodies 101, 102 can also be displaced relative to one another in another plane, as a result of which an overlap thereof can even be provided. It is also possible to interleave the partial bodies 101, 102 in a spiral manner by counter-rotating movement. It is thus possible to vary the shape, the size and the configuration of the tangential air inlet slots 119, 120 as desired, with which the swirl generator 100 can be used universally without changing its overall length.

The geometric configuration of FIG Baffles 121a, 121b. They have a flow initiation function these, according to their length, the respective End of the tapered partial body 101, 102 in the direction of flow extend towards the combustion air 115. The Channeling the combustion air 115 into the cone cavity 114 can by opening or closing the guide plates 121a, 121b by one in the area of the entry of this channel into the Cone cavity 114 placed pivot point 123 can be optimized, this is particularly necessary if the original gap size of the tangential air inlet slots 119, 120 dynamic should be changed. Of course you can dynamic arrangements can also be provided statically by required guide plates with a fixed component form the tapered partial bodies 101, 102. The can also Swirl generator 100 can also be operated without baffles, or other aids can be provided for this.

4 shows that the swirl generator 100 now made up of four partial bodies 130, 131, 132, 133 is. The associated longitudinal symmetry axes for each partial body are marked with the letter a. About this configuration can be said that because of the generated lower twist strength and in cooperation with one suitably suitably enlarged slot width, the bursting of the vortex flow on the downstream side of the To prevent swirl in the mixing tube, making the mixing tube can best fulfill the role intended for him.

Fig. 5 differs from Fig. 4 in so far as here the partial bodies 140, 141, 142, 143 have a blade profile shape, which is intended to provide a certain flow becomes. Otherwise, the mode of operation of the swirl generator stayed the same. The admixture of fuel 116 in the combustion air flow 115 happens from the inside the blade profiles out, i.e. the fuel line 108 is now integrated in the individual blades. Also here are the longitudinal axes of symmetry to the individual partial bodies marked with the letter a.

6 shows the transition piece 200 in a three-dimensional view. The transition geometry is for a swirl generator 100 with four partial bodies, corresponding to FIG. 4 or 5, built up. Accordingly, the transition geometry points as natural extension of the upstream parts four transition channels 201 on, making up the cone quarter area the partial body mentioned is extended until it hits the wall of the mixing tube cuts. The same considerations apply also if the swirl generator is based on a principle other than that described under Fig. 2 is constructed. The down surface of the individual transition channels running in the direction of flow 201 has a spiral shape in the flow direction running shape, which has a crescent shape describes, according to the fact that present the flow cross section of the transition piece 200 in the flow direction flared. The twist angle of the transition channels 201 in the flow direction is selected so that the Pipe flow then up to the cross-sectional jump on Combustion chamber entrance still has a sufficiently large distance, for a perfect premix with the injected To accomplish fuel. It also increases through above-mentioned measures also the axial speed the mixing tube wall downstream of the swirl generator. The transition geometry and the measures in the area of the mixing tube cause a significant increase in the axial speed profile towards the center of the mixing tube so that the Danger of early ignition is decisively counteracted.

7 shows a schematic illustration of a swirl generator 100a, that closer to the previous Fig. 2-5 has been described. 7 is essential Representation of the fuel nozzle 103a placed in the middle, which compared to the beginning 125 of the conical flow cross-section is set back upstream, the distance 126 from depends on the chosen spray angle 105, and it is approx long as the diameter of the cross section there. By this displacement comes the mouth 104 of the fuel nozzle 103a in the area of the fixed casing 101a on the head side, 102a to stand. This is due to the reset of the fuel nozzle 103a fuel spray 105 occurs with a larger cone radius in that of the main flow of the combustion air covered in the interior 114 of the burner Area so that the fuel spray 105 is in this Area no longer behaves as a solid compact body, but has already crumbled into drops and is therefore light is penetrable. The inflow of combustion air 115 in the fuel spray 105 is no longer hindered, which is has a positive impact on the quality of the mixture, in that the fuel spray 105 more easily through the combustion air can be penetrated. In addition, in The area of the plane of the fuel spray orifice 104 are radial or quasi-radially arranged openings 124 are provided, through which a purge air in the size of the fuel nozzle 103a induced cross-section flows. The flow cross section of these openings 124 is chosen such that in gas operation the air mass flow flowing through these openings not sufficient to cover the backflow zone (see Fig. 1) to move further downstream. In liquid fuel mode the fuel spray 105 acts practically as a jet pump, with which the air mass flow through the openings mentioned 124 increased. This causes a larger axial momentum the backflow zone moves further downstream, which is good Measures against flame reignition are effective. On the schematically shown conical partial bodies 101, 102 is discussed in more detail in Fig. 2-5. There will also be configuration and mode of operation of the tangential air inlet slots 119, 120 discussed in more detail.

Fig. 8 shows how at the end of the mixing tube 20, along the radial end edge, which forms the burner front 70, On the combustion chamber side, a torus 71 is left out. Basically the size of this torus depends on the main flow 40 within the mixing tube 20 belonging to the mixing section: the Torus 71 is selected so that the main flow 40 turns on creates a torus flow 72 formed by it, with which the Swirl number increases sharply. At the same time results from this Creation of an inclined to the burner axis 60 deflected main flow 73, which is tangential to the Torus flow 72 developed. This is caused by the torus 71 induced flow dynamics is responsible for that the backflow bladder 50 against a flow without Torus increased enormously, as this is indicated in Fig. 1 is, and from this an increase in flame stabilization induced in this area. The one from this FIG. 8 visible torus 71 describes a semicircle, starting on the inner edge of the mixing tube 20. The remaining End edge 70 in the radial direction remains over the course of the semicircular torus 71 unchanged.

9 shows a further embodiment of the torus. This is now of quarter circle 74 and then goes in a radial terminating edge 75 over which of the original Burner front 70 is deposed according to FIG. 8. Here too there is a strong increase in the number of twists, and from above reasons set out to strengthen the backflow bladder 50.

Already from these two examples it can be seen that the Training of the toruses can be various. Important is that the torus flow 72 through the main flow 40 is driven, and then the latter in the sense of Images is redirected.

10 corresponds, as far as the course of the torus 71 is concerned, the design according to Fig. 8. The further development concerns here the torus flow 72, which is in addition to the main flow 40 still driven by a secondary flow 76 becomes. This secondary flow 76 also forms a cooling air flow for the end edge forming the burner front 70.

FIG. 11 is another embodiment of FIG. 10, wherein here a basic possibility is shown, as in A pilot stage in connection with the formation of the torus flow 72 77 can be integrated. One to pilot level 77 proper and axially extending channel brings fuel in the torus flow 72 and ensures fuel piloting, this channel roughly at the highest point of the Toruses 71 flows into.

Reference list

10th

Beech ring

20th

Mixing tube, part of the mixing section 220

21

Holes, openings

30th

Combustion chamber

31

Openings

40

Flow, pipe flow in the mixing pipe, main flow

50

Backflow zone, backflow bubble

60

Burner axis

70

End edge, burner front

71

Course of the torus

72

Torus flow

73

Redirected main flow

74

Course of the torus

75

Set back edge

76

Secondary flow, cooling air

77

Fuel piloting, pilot stage

100

Swirl generator

100a

Swirl generator

101, 102

Partial body

101a, 102b

Cylindrical starting parts

101b, 102b

Longitudinal symmetry axes

103

Fuel nozzle

103a

Fuel nozzle

104

Fuel injection

105

Fuel spray (fuel injection profile)

108, 109

Fuel lines

112

Liquid fuel

113

Gaseous fuel

114

Cone cavity

115

Combustion air (combustion air flow)

116

Fuel injection from lines 108, 109

117

Fuel nozzles

119, 120

Tangential air inlet slots

121a, 121b

Baffles

123

Pivot point of the guide plates

124

Openings

125

Inner cone tip

126

Displacement of fuel nozzle 103a from 125

130, 131, 132, 133

Partial body

131a, 131a, 132a, 133a

Longitudinal symmetry axes

140, 141, 142, 143

Vane-shaped partial body

140a, 141a, 142a, 143a

Longitudinal symmetry axes

200

Transition piece, part of the mixing section 220

201

Transition channels

220

Mixing section

Claims (18)

1. Burner for operating a combustion chamber, essentially comprising a swirl generator for a combustion-air flow and means for injecting a fuel into the combustion-air flow, a mixing section (220) being arranged downstream of the swirl generator, which mixing section (220) has a number of transition passages (201) inside a first part of the section in the direction of flow for passing a flow formed in the swirl generator into a mixing tube (20) arranged downstream of these transition passages and merging into a burner front, characterized in that the burner front (70) is formed with at least one torus-like notch (71, 74) on the combustion-chamber side.
2. Burner according to Claim 1, characterized in that the torus-like notch (71) in the burner front (70) describes a semicircle.
3. Burner according to Claim 1, characterized in that the torus-like notch (74) in the burner front (70) describes a quadrant, which then merges into an end edge (75) offset from the burner front (70).
4. Burner according to Claim 1, characterized in that the profile of the torus-like notch (71, 74) begins at the transition between the inner wall of the mixing tube (20) and the burner front (70).
5. Burner according to Claim 1, characterized in that the torus-like notch (71, 74) is provided at least with one passage, leading into a torus flow (72) formed there, for the inflow of secondary air (76) and/or a fuel (77).
6. Burner according to Claim 1, characterized in that the number of transition passages (201) in the mixing section (220) corresponds to the number of partial flows formed by the swirl generator (100, 100a).
7. Burner according to Claim 1, characterized in that the mixing tube (20) arranged downstream of the transition passages (201) is provided in the direction of flow and in the peripheral direction with openings (21) for injecting an air flow into the interior of the mixing tube (20).
8. Burner according to Claim 7, characterized in that the openings (21) run at an acute angle relative to the burner axis (60) of the mixing tube (20).
9. Burner according to Claim 1, characterized in that the cross section of flow of the mixing tube (20) downstream of the transition passages (201) is less than, equal to or greater than the cross section of the flow (40) formed in the swirl generator (100, 100a).
10. Burner according to Claim 1, characterized in that a combustion chamber (30) is arranged downstream of the mixing section (220), in that there is a jump in cross section between the mixing section (220) and the combustion chamber (30), which jump in cross section induces the initial cross section of flow of the combustion chamber (30), and in that a backflow zone (50) can take effect in the region of this jump in cross section.
11. Burner according to Claim 1, characterized in that there is a diffuser and/or a venturi section upstream of the burner front (70).
12. Burner according to Claim 1, characterized in that the swirl generator (100, 100a) comprises at least two hollow, conical sectional bodies (100, 102; 130, 131, 132, 133; 140, 141, 142, 143) which are nested one inside the other in the direction of flow, in that the respective longitudinal symmetry axes (101b, 102b; 130a, 131a, 132a, 133a; 140a, 141a, 142a, 143a) of these sectional bodies run mutually offset in such a way that the adjacent walls of the sectional bodies form ducts (119, 120), tangential in their longitudinal extent, for a combustion-air flow (115), and in that at least one fuel nozzle (103, 103a) is arranged in the interior space (114) formed by the sectional bodies.
13. Burner according to Claim 12, characterized in that further fuel nozzles (117) are arranged in the region of the tangential ducts (119, 120) in their longitudinal extent.
14. Burner according to Claim 12, characterized in that the sectional bodies (140, 141, 142, 143) have a blade-shaped profile in cross section.
15. Burner according to Claim 12, characterized in that the sectional bodies have a fixed cone angle, or increasing conicity, or decreasing conicity in the direction of flow.
16. Burner according to Claim 12, characterized in that the sectional bodies are nested spirally one inside the other.
17. Burner according to Claim 12, characterized in that the fuel nozzle (103) is shifted back relative to the start of the tangential ducts (119, 120) by a distance (126).
18. Burner according to Claim 17, characterized in that the distance (126) has radial or quasi-radial passages (124) for the inflow of secondary air.

Images