Fuel spray nozzle comprising axially projecting air guiding element for a combustion chamber of a gas turbine engine

Abstract

A combustion chamber assembly group includes a nozzle providing a fuel-air mixture at a nozzle exit opening. An end of a fuel guiding channel is bordered at the nozzle exit opening by a flow-off edge located radially outside, and an air guiding element of an air guiding channel of the nozzle located radially outside projects with respect to this flow-off edge in the axial direction with respect to a nozzle longitudinal axis such that: a reference angle present between the nozzle longitudinal axis and a straight boundary line extending through a point at the flow-off edge and tangentially to the axially projecting air guiding element, and/or a reference angle present between the nozzle longitudinal axis and a straight boundary line extending through a point at the flow-off edge and a point of the air guiding element that projects maximally beyond the flow-off edge in the axial direction is 50.

Claims

1. A combustion chamber assembly group, comprising: a burner seal that comprises a bearing section that extends along a nozzle longitudinal axis and has a passage opening, and a nozzle for a non-staged combustion chamber of an engine that is positioned inside a passage hole of the bearing section for providing a fuel-air mixture at a nozzle exit opening of the nozzle, wherein the nozzle has a nozzle main body that comprises the nozzle exit opening and that extends along the nozzle longitudinal axis, and the nozzle main body further comprises at least the following: an inner first air guiding channel that extends along the nozzle longitudinal axis for conveying air to the nozzle exit opening, a fuel guiding channel for conveying fuel to the nozzle exit opening, which is located radially further outside with respect to the nozzle longitudinal axis as compared to the inner first air guiding channel, and at least one further air guiding channel that is located radially outside with respect to the nozzle longitudinal axis with regard to the fuel guiding channel, wherein an air guiding element for guiding air flowing from the at least one further air guiding channel is provided at an end of the at least one further air guiding channel located in an area of the nozzle exit opening wherein: one end of the fuel guiding channel at the nozzle exit opening is bordered by a flow-off edge that is located radially outside of the fuel guiding channel and the air guiding element projects into an axial direction with respect to the nozzle longitudinal axis, such that at least one chosen from the following applies: a first reference angle that is present between the nozzle longitudinal axis and a first straight boundary line extending through a point at the flow-off edge and tangentially to the axially projecting air guiding element is less than or equal to 50, and a second reference angle that is present between the nozzle longitudinal axis and a second straight boundary line extending through the point at the flow-off edge and a point of the air guiding element that projects maximally beyond the flow-off edge in the axial direction is less than or equal to 50, wherein the burner seal has a radially widening flow guiding element in the area of the nozzle exit opening and an inner shell surface of the radially widening flow guiding element extends at an end of the burner seal at an angle to the nozzle longitudinal axis that substantially corresponds to, or is identical to, the at least one chosen from the first reference angle and the second reference angle.

2. The combustion chamber assembly group according to claim 1, wherein at least one chosen from the first straight boundary line and the second straight boundary line extends tangentially to the flow-off edge and tangentially to the air guiding element.

3. The combustion chamber assembly group according to claim 2, wherein the air guiding element has a radially inward pointing bulge and the at least one chosen from the first straight boundary line and the second straight boundary line extends through a point at the air guiding element that is located behind the radially inward pointing bulge of the air guiding element in the axial direction.

4. The combustion chamber assembly group according to claim 1, wherein the flow-off edge and the air guiding element abut at an outer shell surface of a virtual straight circular cone, with a cone point being located on the nozzle longitudinal axis and with an opening angle of the cone corresponding to twice the at least one chosen from the first reference angle and the second reference angle.

5. The combustion chamber assembly group according to claim 1, wherein the at least one further air guiding channel includes two further air guiding channels that are radially displaced with respect to each other, wherein one of the two further air guiding channels that is provided with the air guiding element forms a radially outermost one of the two further air guiding channels.

6. The combustion chamber assembly group according to claim 1, wherein, in the area of the nozzle exit opening, the burner seal forms an end that is substantially flush or is flush with a heat shield of the combustion chamber assembly group.

7. The combustion chamber assembly group according to claim claim 6, wherein, in the area of the nozzle exit opening, the burner seal forms an end that projects beyond the heat shield of the combustion chamber assembly group in the axial direction by a length a, for which the following applies with regard to a wall thickness d of the projecting end: a1.5 d.

8. An engine with the combustion chamber assembly group according to claim 1.

Description

(1) The attached Figures illustrate possible embodiment variants of the proposed solution by way of example.

(2) Herein:

(3) FIG. 1A shows, in sections, a first embodiment variant of a nozzle according to the invention in which a flow guidance inside the predefined flow cone is achieved by means of an air guiding element of a radially outermost air guiding channel that projects axially with a defined length;

(4) FIG. 1B shows, in a view corresponding to FIG. 1A, an alternative embodiment variant of the nozzle;

(5) FIG. 2 shows, in a cross-sectional view, a further embodiment variant of a nozzle according to the invention;

(6) FIGS. 3A-3F shows, in identical views and respectively in sections, alternative embodiments of the air guiding element;

(7) FIG. 4 shows, in a cross-sectional view and in sections, a combustion chamber assembly group with a burner seal that has a flow guiding element which is substantially flush with a heat shield and connects to the air guiding element of the nozzle along a straight boundary line in the radially outwards pointing direction;

(8) FIG. 5 shows, in sections and in a cross-sectional view, a further development of the embodiment variant of FIG. 4 with a burner seal with a widening flow guiding element of greater length;

(9) FIG. 6 shows, in a perspective view, a burner seal for an embodiment variant according to FIG. 5;

(10) FIG. 7A shows an engine in which the embodiment variants of FIGS. 1 to 6 are used;

(11) FIG. 7B shows, in sections and on an enlarged scale, the combustion chamber of the engine of FIG. 7A;

(12) FIG. 7C shows, in a cross-sectional view, the basic structure of a nozzle according to the state of the art and the surrounding components of the engine in the installed state of the nozzle;

(13) FIG. 7D shows a back view of a nozzle exit opening, also showing swirling elements that are provided in the radially outwardly located air guiding channels of the nozzle.

(14) FIG. 7A schematically illustrates, in a sectional view, a (turbofan) engine T in which the individual engine components are arranged in succession along a rotational axis or central axis M and the engine T is embodied as a turbofan engine. By means of a fan F, air is suctioned in along an entry direction at an inlet or an intake E of the engine T. This fan F, which is arranged inside a fan housing FC, is driven via a rotor shaft S that is set into rotation by a turbine TT of the engine T. Here, the turbine TT connects to a compressor V, which for example has a low-pressure compressor 11 and a high-pressure compressor 12, and where necessary also a medium-pressure compressor. The fan F supplies air to the compressor V in a primary air flow F1, on the one hand, and, on the other, to a secondary flow channel or bypass channel B in a secondary air flow F2 for creating a thrust. Here, the bypass channel B extends about a core engine that comprises the compressor V and the turbine TT, and also comprises a primary flow channel for the air that is supplied to the core engine by the fan F.

(15) The air that is conveyed via the compressor V into the primary flow channel is transported into the combustion chamber section BKA of the core engine where the driving power for driving the turbine TT is generated. For this purpose, the turbine TT has a high-pressure turbine 13, a medium-pressure turbine 14, and a low-pressure turbine 15. The turbine TT drives the rotor shaft S and thus the fan F by means of the energy that is released during combustion in order to generate the necessary thrust by means of the air that is conveyed into the bypass channel B. The air from the bypass channel B as well as the exhaust gases from the primary flow channel of the core engine are discharged via an outlet A at the end of the engine T. Here, the outlet A usually has a thrust nozzle with a centrally arranged outlet cone C.

(16) FIG. 7B shows a longitudinal section through the combustion chamber section BKA of the engine T. Here, in particular an (annular) combustion chamber 3 of the engine T can be seen. A nozzle assembly group is provided for injecting fuel or an air-fuel-mixture into a combustion space 30 of the combustion chamber 3. It comprises a combustion chamber ring R along which multiple (fuel/injection) nozzles 2 are arranged along a circular line about the central axis M. Here, the nozzle exit openings of the respective nozzles 2 that are positioned inside the combustion chamber 3 are provided at the combustion chamber ring R. Here, each nozzle 2 comprises a flange by means of which a nozzle 2 is screwed to an outer housing G of the combustion chamber section 3.

(17) FIG. 7C now shows a cross-sectional view of the basic structure of a nozzle 2 as well as the surrounding components of the engine T in the installed state of the nozzle 2. Here, the nozzle 2 is part of a combustion chamber system of the engine T. The nozzle 2 is located downstream of a diffuser DF and during mounting is inserted through an access hole L through a combustion chamber head 31, through a heat shield 300 and a head plate 310 of the combustion chamber 3 up to the combustion space 30 of the combustion chamber 3, so that a nozzle exit opening formed at a nozzle main body 20 reaches all the way into the combustion space 30. Here, the nozzle 2 is positioned at the combustion chamber 3 via a longitudinal section 41 of the burner seal 4 and is held inside a passage hole of the longitudinal section 41. The nozzle 2 further comprises a nozzle neck 21 which substantially extends radially with respect to the central axis M and inside of which a fuel supply line 210 conveying fuel to the nozzle main body 20 is accommodated. Further formed at the nozzle main body 20 are a fuel chamber 22, fuel passages 220, heat shields 23 as well as air chambers for insulation 23a and 23b. In addition, the nozzle main body 20 forms a (first) inner air guiding channel 26 extending centrally along a nozzle longitudinal axis DM and, positioned radially further outside with respect to the same, a (second and third) outer air guiding channels 27a and 27b. These air guiding channels 26, 27a and 27b extend in the direction of the nozzle exit opening of the nozzle 2.

(18) Further, also at least one fuel guiding channel 26 is formed at the nozzle main body 20. This fuel guiding channel 25 is located between the first inner air guiding channel 26 and the second outer air guiding channel 27a. The end of the fuel guiding channel 25, via which fuel flows out in the direction of the air from the first inner air guiding channel 26 during operation of the nozzle 2, is locatedwith respect to the nozzle longitudinal axis DM and in the direction of the nozzle exit openingin front of an end of the second air guiding channel 27a from which air from the second, outer air guiding channel 27a flows out in the direction of a mixture of air from the first, inner air guiding channel 26 and fuel from the fuel guiding channel 25.

(19) Swirling elements 270a, 270b for swirling the air supplied through the air guiding channels 27a and 27b are provided in the outer air guiding channels 27a and 27b. Further, the nozzle main body 20 also comprises an outer, radially inwardly oriented air guide element 271b at the end of the third outer air guiding channel 27b. In the nozzle 2, which may e.g. be a pressure-assisted injection nozzle, the ends of the second and third radially outwardly located air guiding channels 27a and 27b followwith respect to the nozzle longitudinal axis DM and in the direction of the nozzle exit openingthe end of the fuel guiding channel 25 from which fuel is supplied to the air from the first inner centrally extending air guiding channel 26 during operation of the engine T, according to FIG. 7C. Air that is swirled by means of the swirling elements 270a, 270b is transported to the nozzle exit opening form these second and third air guiding channels 27a and 27b. As is shown in the back view of FIG. 7D with a view of the nozzle exit opening along the nozzle longitudinal axis DM, these swirling elements 270a, 270b are arranged inside the respective air guiding channel 27a, 27b in a circumferentially distributed manner.

(20) A sealing element 28 is also provided at the nozzle main body 20 at its circumference for sealing the nozzle 2 towards the combustion space 30. This sealing element 28 forms a counter-piece to a burner seal 4. This burner seal 4 is floatingly mounted between the heat shield 300 and the head plate 310 to compensate for radial and axial movements between the nozzle 2 and the combustion chamber 3 and to ensure reliable sealing in different operational states.

(21) The burner seal 4 usually has a flow guiding element 40 towards the combustion space 30. In connection with the third outer air guiding channel 27b at the nozzle 2, this flow guiding element 40 ensures a desired flow guidance of the fuel-air mixture that results from the nozzle 2, more precisely the swirled air from the air guiding channels 26, 27a and 27b, as well as the fuel guiding channel 25.

(22) A combustion chamber assembly group corresponding to FIG. 7C as it is known from the state of the art can be disadvantageous with respect to the generation of soot emissions. Thus, air flow from the third air guiding channel 27b that is guided radially inwardly via the air guiding element 271b may possibly fail to lead to a desired homogenous distribution of the fuel directly downstream of the nozzle exit opening. Areas with too much excessive fuel can be created in particular in the area directly downstream of the fuel guiding channel 25, which in turn lead to the generation of soot emissions. This can be remedied by the proposed solution, of which different embodiment variants are shown in FIG. 1A to 6.

(23) Here, it is respectively provided that a flow-off edge 250 that borders the end of the fuel guiding channel 25 radially outside at the nozzle exit opening, and the air guiding element 271b that projects with respect to this flow-off edge 250 in the axial direction x along the nozzle longitudinal axis DM are formed and adjusted with respect to each other in such a manner for influencing an air flow LS from the third air guiding channel 271b, that a reference angle which is present between the nozzle longitudinal axis DM and a straight boundary line 6 is less than or equal to 50. This straight boundary line 6 extends through a (first) point at the flow-off edge 250 (e.g. through a point at a flow-off edge of the flow-off edge 250) and tangentially to the axially projecting air guiding element 271b, in particular tangentially to the flow-off edge 250 and tangentially to the air guiding element 271b that initially guides the air flow LS radially inward. Alternatively or additionally, the straight boundary line 6 extends through a point at the flow-off edge 250 and a (reference) point 2712b of a combustion-space-side end of the air guiding element 271b that projects maximally beyond the flow-off edge 250 in the axial direction x.

(24) For example, in the nozzle 2 shown in FIG. 1A, the air guiding element 271b projects beyond the flow-off edge 250 of the fuel guiding channel 25 in the axial direction x with a predefined length so that the straight boundary line 6, as a tangent at the flow-off edge 250 and a radially inwardly pointing bulge 2711b of the air guiding element 271b, encloses an angle 50 with respect to the centrally extending nozzle longitudinal axis DM. The air flow LS coming from the third air guiding channel 27b is thus guided at an inner contour 2710b of the axially projecting air guiding element 271b in the radially outwards pointing direction inside a spray cone 5, which is approximated to a naturally resulting spray cone of the injected fuel from the fuel guiding channel 25 and thus to the created fuel-air-mixture. The air flow LS from the third air guiding channel 27b is thus guided at the nozzle exit opening into a virtual straight circular cone by means of the air guiding element 271b that is thus arranged with respect to the flow-off edge 250 of the fuel guiding channel 25, with its cone point being located on the nozzle longitudinal axis DM and with its opening angle being 2. Thus, in FIG. 1 the straight boundary line 6 indicates the course of an outer shell surface of this straight circular cone at which the flow-off edge 250 and the air guiding element 271b (in the area of its bulge 2711b) abut.

(25) Through the design of the nozzle 2 thus chosen, a flow path with a flow-off angle of 50 is imposed on the air flow LS, so that the air from the third air guiding channel 27b is guided without conditions to the radially outwardly flowing spray which results from the fuel from the fuel guiding channel 25 and the swirled air from the first, inner air guiding channel 26 and the second air guiding channel 27a.

(26) In the embodiment variant of FIG. 1B, the axial projection of the air guiding element 271b is reduced as compared to the embodiment variant of FIG. 1A. Here, the air guiding element 271b projects with its convex inward pointing bulge 2711b with a smaller length l.sub.2 with respect to the flow-off edge 250 of the fuel guiding channel 25 (l.sub.2l.sub.1). However, also here, the length and geometry of the flow-off edge 250 and of the air guiding element 271b of the third air guiding channel 27b are chosen and adjusted to each other in such a manner for influencing the air flow LS in a targeted manner that, together with the nozzle longitudinal axis DM, the straight boundary line 6, as a tangent at the flow-off edge 250 and the bulge 2711b of the air guiding element 271b, encloses an angle 50. The straight boundary line 6 thus also runs through a point at the flow-off edge 250 (of a so-called pre-filmer) and a point that is located on a tangent at the inner contour 2710b of the air guiding element 271b that is facing towards the combustion space 30.

(27) In the variant of FIG. 2, the straight boundary line 6 also extends tangentially and thus through a point at the flow-off edge 250 of the fuel guiding channel 25. However, at the air guiding element 271b, the straight boundary line 6 extends through an axially outermost reference point 2712b. Here too, the geometry and the arrangement of the air guiding element 271b are chosen in such a manner with regard to the flow-off edge 250 of the fuel guiding channel 25 that, in order to influence the air flow LS from the third air guiding channel 27b, the flow-off edge 250 and the inner contour 2710b abut at an outer shell surface of a virtual reference or circular cone 7 downstream of the (inner) bulge 2711b, with the cone point 70 of the circular cone 7 being located on the nozzle longitudinal axis DM and having an opening angle of 2, with 50.

(28) FIGS. 3A to 3F illustrate different geometries of the air guiding element 271b in particular with respect to a course of an inner contour 2710b that is defined by means of the radially inward pointing bulge 2711b and the axial length of the air guiding element 271b.

(29) In the combustion chamber assembly group shown in FIG. 4, in which a nozzle 2 according to the previously described FIGS. 1A to 3F is used, the burner seal 4 is designed to be substantially flush with the heat shield 300 with its combustion-space-side flow guiding element 40. Thus, the radially widening flow guiding element 40 projects beyond the heat shield 300 or rather beyond an edge section of the heat shield 300 that is bordering the opening for the burner seal 4 only with a length a, which is less than 1.5 times a wall thickness d of the flow guiding element 40.

(30) For an optimized guiding of the fuel-air mixture, an inner shell surface of the flow guiding element 40 of the [burner seal] 4 further extends at the same reference angle to the nozzle longitudinal axis DM and thus connects to the air guiding element 271b in the radially outwards pointing direction along the straight boundary line 6.

(31) Moreover, in the present case the burner seal 4 that is floatingly mounted at the bearing position 311 is provided with a close fit between the flow guiding element 40 and the heat shield 300, so that, in the event of a maximal axial displacement of the burner seal 4 as it occurs during operation of the engine T, a radial distance between the burner seal 4 and the heat shield 300 does not exceed a predefined threshold value of 0.2 mm. Besides, a close fit between the burner seal 4 and the heat shield 300 in the area of the end of the flow guiding element 40 avoids the entry of combustion products into a cavity between the burner seal 4 and the heat shield 300.

(32) In the variant shown in FIG. 5, the continuously widening flow guiding element 41 is formed with an inner shell surface that is less inclined as compared to the variant of FIG. 4. However, here it is also provided that the flow guiding element 40 is substantially flush or is flush with a burner seal 300, and that the inner shell surface of the flow guiding element 40 extends at a reference angle to the nozzle longitudinal axis DM.

(33) FIG. 6 illustrates a perspective view of a possible design of the burner seal that is shown schematically in FIG. 5, including the flow guiding element 40 that widens towards the combustion space 30.

PARTS LIST

(34) 11 low-pressure compressor 12 high-pressure compressor 13 high-pressure turbine 14 medium-pressure turbine 15 low-pressure turbine 2 nozzle 20 nozzle main body 21 neck 210 fuel supply line 22 fuel chamber 220 fuel passage 23 heat shield 24a, 24b air chamber 25 fuel guiding channel 250 flow-off edge 26 first air guiding channel 270a, 270b swirling element 271b air guiding element 2710b inner contour 2711b bulge 2712b reference point 27a second air guiding channel 27b third air guiding channel 3 sealing element 30 combustion chamber 300 combustion space 300 heat shield 31 combustion chamber head 310 head plate 311 bearing position 4 burner seal 40 flow guiding element 41 longitudinal section 5 spray cone 6 tangent/straight boundary line 7 reference cone/circular cone 70 cone point A outlet a length B bypass channel BKA combustion chamber section C outlet cone D wall thickness DF diffuser DM nozzle longitudinal axis E inlet/intake F fan F1, F2 fluid flow FC fan housing G outer housing L access hole l.sub.1, l.sub.2 length LS air flow M central axis/rotational axis R combustion chamber ring S rotor shaft T (turbofan) engine TT turbine V compressor x direction reference angle