Flow arrangement for placing in a hot gas duct of a turbomachine

Abstract

The invention relates to a flow arrangement for placing in the hot gas duct of a turbomachine, having a first surrounding-flow structure and a second surrounding-flow structure, the surrounding-flow structures each having, in reference to the surrounding flow in the hot gas duct, a leading edge and, downstream thereof, a trailing edge, wherein the second surrounding-flow structure is provided as a deflecting blade with a suction side and a pressure side and has a lesser profile thickness than the first surrounding-flow structure, which is arranged on the suction side of the second surrounding-flow structure, and wherein, although the second surrounding-flow structure has a partial axial overlap with the first surrounding-flow structure referred to a longitudinal axis of the turbomachine, the trailing edge of the second surrounding-flow structure is, at the same time, displaced axially downstream relative to the trailing edge of the first surrounding-flow structure.

Claims

1. A flow arrangement fora hot gas duct of a turbomachine, comprising: a first surrounding-flow structure; a second surrounding-flow structure; the first surrounding-flow structure and the second surrounding-flow structure each having, in reference to a surrounding flow in the hot gas duct, a leading edge and, downstream thereof, a trailing edge; wherein the second surrounding-flow structure is configured and arranged as a deflecting blade with a suction side and a pressure side and has a lesser profile thickness than the first surrounding-flow structure, the first surrounding-flow structure is arranged on the suction side of the second surrounding-flow structure; wherein, the second surrounding-flow structure has a partial axial overlap with the first surrounding-flow structure with respect to a longitudinal axis of the turbomachine, the trailing edge of the second surrounding-flow structure is displaced axially downstream relative to the trailing edge of the first surrounding-flow structure, and wherein the trailing edge of the second surrounding-flow structure is displaced axially downstream relative to the trailing edge of the first surrounding-flow structure by at least 0.5 times and at most 4.0 times an axial length of a blading of a rotor that is arranged directly downstream of the second surrounding-flow structure.

2. The flow arrangement according to claim 1, in which the first surrounding-flow structure is configured and arranged as a support strut or cladding or fairing thereof.

3. The flow arrangement according to claim 1, wherein the second surrounding-flow structure has a maximum curvature at a place where the second surrounding-flow structure has axial overlap with the first surrounding-flow structure.

4. The flow arrangement according to claim 1, wherein the leading edge of the second surrounding-flow structure is displaced axially downstream relative to the leading edge of the first surrounding-flow structure, namely, by at least 0.4 times and at most 1.2 times an axial length of the first surrounding-flow structure.

5. The flow arrangement according to claim 1, wherein the second surrounding-flow structure has a chord length that constitutes at least 1 times and at most 8 times a chord length of the blading of the rotor that is arranged directly downstream of the second surrounding-flow structure.

6. The flow arrangement according to claim 1, further comprising a third surrounding-flow structure, which is provided as a deflecting blade with a suction side and a pressure side and has a lesser profile thickness than the first surrounding-flow structure, and the second surrounding-flow structure and the third surrounding-flow structure are hereby differently formed, wherein the first surrounding-flow structure is configured and arranged on the pressure side of the third surrounding-flow structure.

7. The flow arrangement according to claim 6, wherein the third surrounding-flow structure has a shorter chord length than the second surrounding-flow structure.

8. The flow arrangement according to claim 6, wherein the third surrounding-flow structure has a lesser curvature than the second surrounding-flow structure.

9. The flow arrangement according to claim 1, wherein the flow arrangement includes a plurality of adjacent first surrounding-flow structures, and wherein, between two nearest of the plurality of adjacent first surrounding-flow structures, in a direction of rotation, at least two additional surrounding-flow structures are each provided as a deflecting blade with a suction side and a pressure side and are each arranged in a peripheral direction.

10. The flow arrangement according to claim 1, wherein the flow arrangement is configured and arranged in a mid turbine frame.

11. The flow arrangement according to claim 1, wherein the flow arrangement is configured and arranged for use in an aircraft engine.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention will be explained in detail below on the basis of an exemplary embodiment, wherein the individual features in the scope of the independent claims may also be essential to the invention in other combinations, and also no distinction is made in detail between the different claim categories.

(2) Shown in detail are:

(3) FIG. 1a is a jet engine in a section;

(4) FIG. 1b is a schematic detail view relating to FIG. 1a;

(5) FIG. 2 shows a flow arrangement according to the invention in a mid turbine frame of the jet engine in accordance with FIG. 1a; and

(6) FIG. 3 shows the position of the subchannels with acceleration (nozzle) as well as the suction field of the deflecting blades.

DESCRIPTION OF THE INVENTION

(7) FIG. 1a shows a turbomachine 1 in section, specifically a jet engine. FIG. 1b shows a schematic detailed view thereof. The following comments relate to both figures. In functional terms, the turbomachine 1 is composed of the compressor 1a, the combustion chamber 1b, and the turbine 1c. Both the compressor 1a and the turbine 1c are each constructed from a plurality of stages and each stage is composed, as a rule, of a guide vane ring and a ring of rotating blades. During operation, the ring of rotating blades rotates around the longitudinal axis 2 of the turbomachine 1. The turbomachine shaft 3 is guided in a bearing 4, which is held by support struts 5 (shown partly by dashes) in the rest of the turbomachine 1. In the region of the hot gas duct, each of the support struts 5 is clad for aerodynamic and also thermal reasons, namely, by a first surrounding-flow structure 6, which represents a cladding and is also referred to as a fairing. This segment is a so-called mid turbine frame. In the turbomachine according to the invention, the segment is constructed integrally with the following guide vane ring.

(8) FIG. 2 shows a part of the flow arrangement 20 according to the invention, which is arranged in the mid turbine frame in the hot gas duct. Shown is a section, where the sectional surface lies radially in the middle of the hot gas duct and is parallel to the longitudinal axis 2. In addition to the first surrounding-flow structures 6 (fairings), two second surrounding-flow structures 21 and third surrounding-flow structures 22 can be seen, each of which is designed as a deflecting blade with a suction side (at the top in the figure) and a pressure side (at the bottom in the figure). The profile thickness of the thin deflecting blades is only about 30% of the profile thickness of the first surrounding-flow structures 6 (in the schematic illustration in accordance with FIG. 2, the thin deflecting blades are depicted for simplicity as lines without a profile thickness).

(9) The surrounding-flow structures 6, 21, 22 each have a leading edge 6a, 21a, 22a and, downstream thereof, a respective trailing edge 6b, 21b, 22b. Although the thin deflecting blades are provided axially with an overlap with respect to the first surrounding-flow structures 6, they are also displaced further to a certain extent. The trailing edges 21b, 22b of the second and third surrounding-flow structures 21, 22 are displaced axially downstream with respect to the trailing edges 6b of the first surrounding-flow structures 6. In addition, the second surrounding-flow structure 21 has its greatest curvature in the region of the axial overlap with the first surrounding-flow structure 6. As a result, a stronger suction is accordingly produced and the flow from the trailing edge 6b of the aerodynamically rather unfavorable surrounding-flow structure 6 is accelerated away. The trailing flow is finer and more uniform; compare also what has been presented in the introduction of the description.

(10) On the bottom side of the first surrounding-flow structure 6 (on the bottom in the figure), the flow has to be deflected more strongly than on the top side, because the bottom lateral surface extends essentially axially into the trailing edge 6b as a consequence of the larger wedge angle or the greater thickness. For this reason, the second surrounding-flow structure 21 is more strongly curved than the third surrounding-flow structure 22 and it has a longer chord length. The first surrounding-flow structure 6 is arranged on the pressure side of the third surrounding-flow structure 22; the flow at the trailing edge 6b is thereby forced further downward to a certain extent and thus the load on the trailing edge 6b is relieved.

(11) FIG. 3 shows an enlarged illustration of the configuration from FIG. 2 with the suction field 23 on the top side of the thin deflecting blade 21. The two deflecting blades 21, 22, together with the surrounding-flow structure 6, form narrowing flow channels 24, 25 in their intake area, which lead to a further load relief of the flow at the trailing edge 6b. Downstream of the trailing edge 6b, another narrowing flow channel is adjoined up to the narrowed distance 26 and this produces, together with the blade curvature, the suction field. Thus, surrounding-flow structures 6 with a greater thickness and position of maximum thickness x.sub.d/L>50% become possible and can accommodate more and larger supply lines and support elements. A reduction in the number of blades, frictional loss, and weight is possible.

(12) In this example, the flow arrangement 20 is overall (over the entire rotation) composed of 9 first, second, and third surrounding-flow structures 6, 21, 22 in each case and therefore has 18 thin deflecting blades. In addition, it is also possible to provide a fourth surrounding-flow structure, which is likewise designed as a thin deflecting blade, so that, therefore, between two first surrounding-flow structures 6, three different thin deflecting blades would be arranged in each case (in this case, a total of 27 thin deflecting blades would be provided); compare also the description in the introduction. Regardless thereof in detail, a groupwise combination of the surrounding-flow structures 6, 21, 22 in multiple segments is preferred. In this regard, the axial displacement can be advantageous in terms of production engineering or, conversely, it would consequently be substantially more complicated to achieve the same flow guidance at the trailing edge 6b of the first surrounding-flow structure 6 by way of a first surrounding-flow structure 6 elongated to the rear.

(13) The axial displacement between the trailing edges 21b, 22b of the second and third surrounding-flow structures 21, 22 with respect to the trailing edges 6b of the first surrounding-flow structures 6 corresponds to about 1.5 axial lengths of a following rotor 30, specifically the blading 31 thereof. The described refinement of the flow and making it more uniform is also of advantageous for the operation of the rotor 30.

(14) Although the present invention has been described in detail on the basis of the exemplary embodiments, it is obvious to the person skilled in the art that the invention is not limited to these exemplary embodiments, but rather that modifications are possible in such a way that individual features are omitted or other types of combinations of features can be realized, without leaving the scope of protection of the appended claims. In particular, the present disclosure encompasses all combinations of the individual features shown in the different examples of embodiment, so that individual features that are described only in conjunction with one exemplary embodiment can also be used in other exemplary embodiments, or combinations of individual features that are not explicitly shown can also be employed.