Burner Device

This application is a national phase of international application No. PCT/DE2023/100230 filed on Mar. 23, 2023, and claims the benefit of German application No. 10 2022 106 816.1 filed on Mar. 23, 2022, which are incorporated herein by reference in their entirety and for all purposes.

The present disclosure concerns a burner device for combustion of at least one fuel with at least one oxidizer. Furthermore, the present disclosure concerns a combustion chamber device with a burner device, and furthermore a thermal exhaust gas cleaning system with a burner device.

Ever more stringent legal requirements impose, for example in thermal exhaust air cleaning systems, a trend towards ever lower NOx values which are difficult to achieve with the former combustion devices or burners, since sometimes very high combustion chamber temperatures prevail with a low mass stream. Also, in conventional low NOx jet burners, the burner jet enters the flow region very deeply after the burner head, whereby larger recirculation zones occur at the side of this jet. Accordingly, attempts are made to achieve rapid homogenization of fuel and oxidizer with complex injection geometry, but in larger burners this rapidly leads to high investment levels. Finally, the present burners not designed for the use of hydrogen.

The present disclosure is therefore based on the object of creating a burner device of the type cited initially which can be produced easily and cheaply, achieves an even and rapid mixing of fuel and oxidizer, causes lower NOx emissions and/or is prepared at least for the use of hydrogen/methane mixtures.

This object is achieved according to examples disclosed herein in that a burner device is provided for combustion of at least one fuel with at least one oxidizer, wherein the burner device comprises a central longitudinal axis and a main flow direction which is at least approximately parallel to the central longitudinal axis, and wherein the burner device comprises the following:

The burner head comprises the following:

wherein the at least one baffle plate is arranged downstream of the at least one injection device relative to the main flow direction; and/or

wherein the at least one baffle plate comprises multiple differently configured baffle openings; and/or

wherein the at least one injection device comprises multiple differently configured injection openings.

With the burner device according to examples disclosed herein, it may be advantageous that in comparison with conventional burner devices, significantly lower NOx values can be achieved with a more even combustion. A more even and faster mixing of fuel and oxidizer accelerates the corresponding thermal reactions, whereby the combustion chamber temperature can be reduced.

In particular, the use of the baffle plate preferably optimizes the recirculation zones, the flame anchoring and/or the stabilization. Preferably, also the injected fuel or oxidizer can be accelerated and/or an improved mixing of fuel and oxidizer achieved. As a result, as already stated, combustion can take place preferably at lower temperatures, whereby in particular the NOx emissions are lowered.

It is furthermore possible that each two adjacent baffle openings of the at least one baffle plate, and/or each two adjacent injection openings of the at least one injection device, are formed or arranged differently from one another in shape, dimensions and orientation relative to one another and/or relative to the main flow direction or central longitudinal axis.

It may also be provided that the arrangement of the at least one baffle plate on the at least one injection device means that these can be arranged in the immediate physical vicinity of one another relative to the main flow direction, without however thereby obstructing the flow of the oxidizer around the injection device through the baffle openings of the at least one baffle plate.

Furthermore, it is understood that the central longitudinal axis is preferably an axis of symmetry along the burner device, and the main flow direction, in particular parallel thereto, is an axial direction, i.e. any twist with respect to the main flow direction remains disregarded unless explicitly specified otherwise.

In an embodiment of examples disclosed herein, it is provided that the burner head furthermore comprises at least one swirl device for swirling the fuel and/or oxidizer supplied through the burner head, which device is arranged at least partially upstream of the at least one injection device relative to the main flow direction.

The through-flowing part of the oxidizer is thereby deflected only once for swirling and the flow speed can therefore preferably be used almost unchanged for mixing with the fuel. Injection of the fuel is preferably optimized by such a structure and optimally lower pressure losses and/or lower emissions are achieved.

In an embodiment of examples disclosed herein, it is provided that the at least one swirl device is connected to the at least one injection device or has a distance from the at least one injection device which is constant or variably adjustable.

It is conceivable that the at least one injection device is at least partially integrated in the at least one swirl device at a downstream end thereof relative to the main flow direction. However, a fixed distance between the at least one swirl device and the at least one injection device may also be advantageous. Furthermore, a variably adjustable distance allows reaction to changing peripheral conditions of the flow system of the burner device, so that the combustion process can be adapted in order to efficiently reduce the NOx emissions.

In an embodiment of examples disclosed herein, it is provided that the at least one swirl device is connected to the at least one baffle plate.

By connecting the at least one swirl device to the at least one baffle plate and the at least one injection device arranged between the two, advantageously a compact design of the burner device can be achieved.

In an embodiment of examples disclosed herein, it is provided that the swirl device comprises multiple swirl bodies which are each tilted relative to the main flow direction about a radial axis, relative to the central longitudinal axis, for swirling of the through-flowing fuel and/or oxidizer.

The swirl bodies may preferably have the form of straight or curved plates; however, wing profiles or similar are also conceivable.

It is advantageous if the swirl bodies are arranged equidistantly from one another in a circumferential direction relative to the central longitudinal axis, since this guarantees an even swirling of the through-flowing oxidizer, and no local pressure differences or losses occur at the swirl bodies.

In a preferred embodiment, the swirl bodies extend only up to the inside of the flame tube. However, in a possible further embodiment, the swirl bodies may extend radially to the central longitudinal axis through slot-like openings of the flame tube, whereby firstly a compact design is possible and secondly, because of the portion of the swirl body radially protruding beyond the flame tube, the possibility of swirling is also made available for a particular region outside the flame tube.

In an embodiment of examples disclosed herein, it is provided that the swirl bodies have a protrusion at their upstream edges relative to the main flow direction.

It may be favorable with such protrusions that the through-flow region is exposed to variable flame heights, i.e. the flame height is influenced in the main flow direction depending on the concrete embodiment of the protrusion.

In an embodiment of examples disclosed herein, it is provided that the flame tube forms at least one diffuser at its downstream end relative to the main flow direction.

It may be advantageous if the diffuser promotes the recirculation of the inner flow, and/or because of the diffuser the geometry of the flame tube is stabilized, for example the corresponding end of the flame tube has increased stiffness in comparison with a cylindrical design. The diffuser preferably causes a spreading of the secondary part of the oxidizer or secondary air flowing along the outside of the flame tube. Spreading or widening of this part of the oxidizer may be particularly important for rapid mixing of fuel and oxidizer, which preferably leads to improved cleaning of exhaust air.

In an embodiment of examples disclosed herein, it is provided that the diffuser has a constant cross-sectional widening downstream relative to the main flow direction.

The necessary or desired speed of mixing can be set amongst others by the opening angle and the course of the cross-sectional widening, so that a constant cross-sectional widening is regarded as merely particularly advantageous.

The opening angle of the cross-sectional widening may be constant. It is however also possible that the opening angle of the cross-sectional widening increases or decreases.

If the diffuser is produced by means of an additive manufacturing process such as 3D printing, it is possible that steps are formed due to production. This stepped contour, which is not usually very pronounced, on the outside and/or inside of the diffuser should also be regarded as a constant cross-sectional widening.

In an embodiment of examples disclosed herein, it is provided that the at least one injection device has first injection openings, the central axes of which point at least approximately in the main flow direction.

Thus the fuel and/or oxidizer is injected into the combustion chamber at least approximately parallel to the main flow direction, wherein the central axis of an injection opening means its main outflow direction.

It is however also conceivable that the central axes of the injection openings and the main flow direction enclose an angle of more than zero, since it may be advantageous not to orient the injection openings in the direction of the main flow direction but, depending on further adjustable elements of the burner device, to specify an angle relative to the main flow direction, for example in order to optimize the mixing of the injected fuel and through-flowing oxidizer.

In an embodiment of examples disclosed herein, it is provided that at least one of the first injection openings has an injection nozzle protruding in the main flow direction.

It is favorable here that injection nozzles at the injection openings, depending on profile or geometry along the central axis, can increase the speed with which the fuel emerges from the injection opening.

In an embodiment of examples disclosed herein, it is provided that the at least one injection device has second injection openings, the central axes of which each enclose an angle of between 0 degrees and 90 degrees to the main flow direction.

In particular, it may be advantageous if the second injection openings enclose an angle different from zero with the first injection openings.

Additional injection openings which are not oriented in the main flow direction preferably allow local premixed combustion, or at least an increase in local mixing of fuel and oxidizer, and thereby overall, as well as an increased available fuel volume, the homogenization of the mixture is accelerated.

In a further possible embodiment of examples disclosed herein, it may be provided that the first and second injection openings are controllable independently of one another, i.e. either the first, the second or both the first and second injection openings can be activated or deactivated, whereby the volume flow of fuel can be adjusted. Furthermore, it is possible that different fuels can be injected via the first and the second injection openings. The first and the second injection openings of the at least one injection device may be arranged alternately or in groups.

In an embodiment of examples disclosed herein, it is provided that the at least one injection device is a tube ring, a star-shaped closed tube arrangement, a tube ring with a fluidically connected internal tube cross, or a tube cross.

In the context of examples disclosed herein, the injection devices are not restricted to a specific embodiment. Rather, depending on concrete application, a design different from a tube ring may be preferable. Thus e.g. the variant of a tube ring with fluidically connected internal tube cross offers the possibility of injecting more fuel into a central region via the additional injection openings.

A tube cross is an arrangement in which the number of cross webs and, associated therewith, the angle prevailing between the webs depends on the application. A tube cross in particular means also an arrangement of at least three tube portions which are arranged substantially as a jet around a common center point, preferably with an enclosed angle of 120° between each two adjacent tube portions. The three tube portions are connected fluid-conductively with at least one supply. The supply may be arranged both in the center and also at least partly surrounding the tube cross of the tube portions.

In an embodiment of examples disclosed herein, it is provided that the at least one injection device has a round or angular cross-section.

Round or rounded cross-sections include circular, oval and elliptical cross-sections.

In an embodiment of examples disclosed herein, it is provided that the at least one injection device is formed undulating relative to a plane perpendicular to the central longitudinal axis.

An undulating or zigzag design of an injection device preferably allows an influence on the flame height, whereby additionally it may be provided that the orientation of the injection opening of such an injection device, relative to the main flow direction, may differ between the valleys and the peaks of the wave form.

In an embodiment of examples disclosed herein, it is provided that the at least one baffle plate has first baffle openings and second baffle openings.

Preferably, the first and second baffle openings are configured and/or arranged differently in form, dimensions and/or orientation relative to one another and/or relative to the main flow direction or central longitudinal axis, whereby the stabilization of the flames can be influenced.