Abstract:
A turbo engine, particularly a gas turbine aircraft engine, has compressor components, turbine components, and at least one combustion chamber. At least one support rib is in flow channel between two turbine components, connected one behind the other. Each support rib diverts a flow through the flow channel. A preferably cylindrical guide element runs within each support rib. Each support rib has a suction side with a greater thickness toward a radially inner flow channel wall as well as toward a radially outer flow channel wall, when viewed in the radial direction. Each support rib has a pressure side with a greater thickness toward a radially inner flow channel wall as well as toward a radially outer flow channel wall, when viewed in the radial direction. The front edge and the rear edge of each support rib are inclined in the meridian direction.

Description:
The invention relates to a turbo engine, in particular a gas turbine aircraft engine, according to the preamble of claim  1 . 
     A multi-shaft gas turbine aircraft engine provides a plurality of compressor components, at least one combustion chamber and a plurality of turbine components. Thus, a two-shaft gas turbine aircraft engine provides a low-pressure compressor, a high-pressure compressor, at least one combustion chamber, a high-pressure turbine as well as a low-pressure turbine. A three-shaft gas turbine aircraft engine provides a low-pressure compressor, an intermediate-pressure compressor, a high-pressure compressor, at least one combustion chamber, a high-pressure turbine, an intermediate-pressure turbine and a low-pressure turbine. 
       FIG. 1  shows a very schematized excerpt taken from a multi-shaft gas turbine aircraft engine known from the prior art in the region of a rotor  20  of a high-pressure turbine  21  as well as a rotor  22  of a low-pressure turbine  23 . A flow channel  24  extends between high-pressure turbine  21  and low-pressure turbine  23 , in order to introduce the flow that leaves high-pressure turbine  21  into low-pressure turbine  23 , at least one support rib  25  being positioned in flow channel  24 . Support rib  25  involves a stator-side component, which diverts the flow that flows through flow channel  24 . Such a flow-diverting support rib  25  provides a front edge  27 , which is also called a flow inlet edge, a rear edge  28 , which is also called a flow outlet edge, a suction side as well as a pressure side. Support rib  25  diverting the flow on the suction side is illustrated in  FIG. 1  by arrows  26 . Such a support rib  25  is typically designed as a hollow rib, wherein a preferably cylindrical guide element typically runs in the radial direction in an inside space or hollow space of support rib  25 , in order to guide, e.g., supply lines from radially inside to radially outside, or vice versa, from radially outside to radially inside. In addition, on the right side of  FIG. 1 , a section through support rib  25  is shown along the intersecting line A-A, wherein it can be derived from  FIG. 1  that in the case of turbo engines known from the prior art, such a support rib  25  in the region of suction side  29  as well as in the region of pressure side  30  is contoured in such a way that this rib has an approximately unchanged thickness, viewed in the radial direction. 
     In the case of the turbo engine shown in the excerpt in  FIG. 1  and known from the prior art, strong three-dimensional flow effects (see arrows  26 ), which can lead to considerable flow losses, occur in the region of support rib  25 . There is the need for a turbo engine in which a more balanced flow and smaller flow losses occur. 
     Proceeding from this, the problem of the present invention is based on creating a novel turbo engine, in particular a gas turbine aircraft engine, with smaller flow losses. 
     This problem is solved by a turbo engine according to claim  1 . According to the invention, the turbo engine comprises at least the following features: a) the suction side of the support rib or of each support rib is contoured in such a way that, viewed in the radial direction, a thickness of the respective support rib is enlarged or increases in the direction onto a radially inner boundary wall of the flow channel, as well as onto a radially outer boundary wall of the flow channel; b) the pressure side of the support rib or of each support rib is contoured in such a way that, viewed in the radial direction, the thickness of the respective support rib is enlarged or increases at least directly in the region of the radially inner boundary wall of the flow channel as well as directly in the region of the radially outer boundary wall of the flow channel; c) the front edge and the rear edge of the support rib or of each support rib are inclined in the meridian direction. 
     In the case of the turbo engine according to the invention, due to the special design of the flow-diverting support rib or of each support rib, which is positioned in a flow channel between two turbines, flow losses can be considerably reduced, i.e., on an order of magnitude between 20% and 40%. 
     Preferred enhancements of the invention are taken from the subclaims and the following description. Embodiment examples of the invention will be explained in more detail based on the drawing, but are not limited thereto. Here: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a very schematic, excerpted longitudinal section through a turbo engine known from the prior art; 
         FIG. 2  shows a very schematic, excerpted longitudinal section through a turbo engine according to the invention; 
         FIG. 3  shows an enlarged detail of  FIG. 2 ; 
         FIG. 4  shows a first intermediate design stage of a support rib for further clarification of the invention; 
         FIG. 5  shows a second intermediate design stage of a support rib for further clarification of the invention; 
         FIG. 6  shows a third intermediate design stage of a support rib for further clarification of the invention; 
         FIG. 7  shows a detail for the third intermediate design stage of  FIG. 6 ; 
         FIG. 8  shows another detail for the third intermediate design stage of  FIG. 6 ; 
         FIG. 9  shows a first diagram for further clarification of the invention; 
         FIG. 10  shows a second diagram for further clarification of the invention; 
         FIG. 11  shows a third diagram for further clarification of the invention; and 
         FIG. 12  shows a fourth diagram for further clarification of the invention; 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2  shows a schematic excerpt from a turbo engine according to the invention in the region of a rotor  31  of a high-pressure turbine  32  as well as of a rotor  33  of a low-pressure turbine  34 , wherein, according to  FIG. 2 , a flow channel  35  extends between high-pressure turbine  32  and low-pressure turbine  34  through which channel the flow that leaves high-pressure turbine  32  will be guided and introduced into low-pressure turbine  34 . At least one support rib  36  that diverts the flow that flows through flow channel  35  is positioned in flow channel  35 , wherein for this purpose support rib  36  comprises a front edge  37 , which is also called a flow inlet edge, a rear edge  38 , which is also called a flow outlet edge, a suction side  39  as well as a pressure side  40 . A flow around suction side  39  of support rib  36  is visualized by arrow  41  in  FIG. 2 . 
     The present invention now relates here to details of support rib  36  or of each support rib  36  that is positioned in flow channel  35 , and in fact, to those details by means of which flow losses in the region of flow channel  35  can be reduced. In  FIG. 2 , for clarification of the invention, in addition to support rib  36  designed according to the invention, the support rib  25 , which is known from the prior art and shown in  FIG. 1 , is depicted by the dashed lines. 
     As can be particularly derived from section B-B of  FIG. 2  as well as  FIG. 4 , suction side  39  of support rib  36  can be contoured such that, viewed in the radial direction Ra, a thickness of support rib  36  is enlarged or increases in the direction onto a radially inner boundary wall  42  as well as in the direction onto a radially outer boundary wall  43  of flow channel  35 . 
     Thus, it can be derived from sectional view B-B through support rib  36  of  FIG. 2  that support rib  36  is concavely curved in the region of suction side  39 , wherein, proceeding from a middle section viewed in the radial direction Ra, the thickness of the rib continually increases in the direction onto the radially inner boundary wall  42  as well as in the direction onto the radially outer boundary wall  43 . 
     In  FIG. 4 , in addition to radial direction Ra, the axial direction Ax and the circumferential direction Um are also shown. In addition,  FIG. 4  shows that support rib  36  is designed as a hollow rib, in the inner space of which there extends in the radial direction Ra a preferably cylindrical guide element  44 , by means of which, e.g., supply lines can be guided from radially inside to radially outside, as well as vice versa from radially outside to radially inside, by bridging flow channel  35 . 
     The contouring of suction side  29  of support rib  25 , which is known from the prior art, is shown by the dashed lines in  FIG. 4 , whereby it follows from  FIG. 4  that by broadening the thickness of suction side  39 , the inner space of support rib  36  that is available for uptake of guide element  44  is enlarged in principle. 
     In the region of pressure side  40  of support rib  36 , as can be derived from  FIG. 5 , the rib can be contoured such that, viewed in the radial direction Ra, the thickness of support rib  36  is enlarged or increases at least directly in the region of the radially inner boundary wall  42  as well as directly in the region of the radially outer boundary wall  43 , whereby the inner space of support rib  36  that is available for the uptake of guide element  44  is also enlarged in the region of pressure side  40 , so that it is then possible to incline rear edge  38  or the flow outlet edge of support rib  36  in the circumferential direction Um. 
     Accordingly, the thickness of the support rib is increased in the region of pressure side  40  in the direct vicinity of the radially inner boundary wall  42  of flow channel  35  as well as in the direct vicinity of the radially outer boundary wall  43  of flow channel  35 . 
     In this way, it is then possible to displace radially outer sections as well as radially inner sections through support rib  36  in the circumferential direction, whereby the rear edge  38  as well as the front edge  37  of support rib  36  will then be inclined in the circumferential direction. 
     In  FIG. 5 , in addition to the radial direction Ra, the axial direction Ax and the circumferential direction Um, there is also found a flow direction St as well as a normal direction No for flow direction St, whereby an angle between the radially inner or hub-side boundary wall  42  of flow channel  35  and suction side  39  of support rib  36 , viewed about the flow direction St, is characterized as ε SS  in the region of rear edge  38  in  FIG. 5 . This angle is also called the suction-side corner angle, whereby, by thickening the pressure side  40  of support rib  36  and by displacement of the radially outer and radially inner sections of the rib in the circumferential direction, this suction-side corner angle ε SS  can be enlarged.  FIG. 5  shows the simplest case of a flow channel with cylindrical side walls. 
       FIG. 6  shows the case of a flow channel or annular space with rising side walls. Here, front edge  37  as well as rear edge  38  of support rib  36 , as can be derived from  FIG. 6 , are inclined in the meridian direction Me. Thus, the meridian direction Me is additionally depicted in  FIG. 6 , whereby the inclination of rear edge  38  of support rib  36  in the meridian direction Me is visualized by the offset ΔMe in  FIG. 6 . The conventional type of structure is shown in  FIG. 7  by the dashed lines for the front edge and the rear edge. Due to the inclination of front edge  37  and rear edge  38  in the meridian direction Me, the suction-side corner angle ε SS  can be enlarged once more, whereby the flow ratios can again be optimized. The suction-side corner angle ε SS  amounts to more than 80°, in particular more than 90°, in the region of rear edge  38  of support rib  36 . 
     Despite the circumferential inclination described in connection with  FIG. 5  and the meridian inclination described in connection with  FIG. 6 , now as before, support element  44  can be guided in radial direction Ra in the inside space of support rib  36 . 
     According to an advantageous enhancement of the present invention here, the radially inner boundary wall  42  of flow channel  35  is bent radially inwardly, and the radially outer boundary wall  43  of flow channel  35  is bent radially outwardly, in such a way that a widening of flow channel  35  that is brought about by this contouring of boundary walls  42 ,  43  equilibrates an obstruction of flow channel  35  brought about by increasing the thickness of support rib  36  in the region of the suction side. In particular, this contouring of boundary walls  42 ,  43  additionally compensates for the obstruction of flow channel  35  caused by increasing the thickness of support rib  36  in the region of pressure side  40 . 
     This contouring of the radially inner boundary wall  42  of flow channel  35  which is bent radially inwardly and the contouring of the radially outer boundary wall  43  of flow channel  35  which is bent radially outwardly can be derived from  FIGS. 2 and 3 . 
     According to an advantageous enhancement of the present invention here, support rib  36  is contoured at front edge  37  or the flow inlet edge in such a way that in the direction onto the radially inner boundary wall  42  of flow channel  35  as well as in the direction onto the radially outer boundary wall  43  of flow channel  35 , front edge  37  has a back sweep, i.e., front edge  37  is displaced downstream in the flow direction, viewed in this direction. The offset of front edge  37  in the region of the radially outer boundary wall  43  is characterized by the dimension ΔAx 1  in  FIG. 3 . The offset of front edge  37  in the region of the radially inner boundary wall  42  is characterized by ΔAx 3  in  FIG. 3 . These two offsets may be of equal magnitude or may also be of different magnitude. 
     Likewise, according to  FIG. 3 , support rib  36  is contoured in the region of rear edge  38  with a back sweep, and in fact both in the direction onto the radially inner boundary wall  42  as well as in the direction onto the radially outer boundary wall  43 , rear edge  38  has a back sweep and accordingly, it is displaced downstream viewed in the flow direction. The offset of rear edge  38  in the region of the radially outer boundary wall  43  is characterized by the dimension ΔAx 2  in  FIG. 3 ; the dimension ΔAx 4  characterizes the offset of rear edge  38  in the region of the radially inner boundary wall  42 . These two offsets may be of equal magnitude or may also be of different magnitude. 
     Further preferred details of the turbo engine according to the invention, i.e., details for the configuration of support rib  36 , can be taken from  FIGS. 9 to 12 . Thus the relative height of flow channel  35  is plotted on the vertically running axis in  FIGS. 9 to 12 . The radially inner boundary wall  42  of the flow channel lies accordingly at the relative height 0 of the flow channel, while the radially outer boundary wall  43  lies at the relative height 1 thereof. 
     In  FIG. 9 , a relative thickness of support rib  36  in the region of suction side  39  or in the region of pressure side  40  is plotted on the horizontally running axis, and in fact, in such a way that the relative thickness amounts to 1 in the region of a center cut through support rib  36 . 
     Proceeding from this center cut, which lies at a relative height of the flow channel of approximately 0.5, the relative thickness of support rib  36  increases in the region of suction side  39  and in the region of pressure side  40 . In this way,  FIG. 9  shows that support rib  36  has the greatest relative thickness increase of approximately 40% in the region of the radially outer side wall as well as in the region of suction side  39 . In the region of the radially inner boundary wall, the relative thickness increase on suction side  39  amounts to approximately 25% according to  FIG. 9 . In the region of the radially outer boundary wall of flow channel  35 , the relative thickness increase of pressure side  40  amounts to approximately 10% according to  FIG. 9 ; in the region of the radially inner boundary wall, this relative thickness increase of pressure side  40  amounts to approximately 5%. 
     In  FIG. 10 , the suction-side corner angle in the region of rear edge  38  of support rib  36  is plotted on the horizontally running axis, whereby, as can be taken from  FIG. 10 , the suction-side corner angle of rear edge  38  in the region of the radially inner boundary wall  42  of flow channel  35  amounts to approximately 90° and in the region of the radially outer boundary wall  43  of flow channel  35 , it amounts to approximately 110°. Viewed over the entire rear edge  38 , the suction-side corner angle is always greater than 80°. 
     In  FIGS. 11 and 12 , a downstream offset of front edge  37  or rear edge  38  referred to the axial dimension of support rib  36  is plotted on the horizontally running axis, whereby, as can be taken from  FIGS. 11 and 12 , both in the region of front edge  37  as well as in the region of rear edge  38 , the downstream offset referred to the axial dimension of support rib  36  both in the region of the radially inner boundary wall  42  as well as also in the region of the radially outer boundary wall  43  amounts to more than 1%, preferably approximately 2%. 
     Due to the special design of support rib  36 , which is positioned in flow channel  35  between two turbines, flow losses can be considerably reduced. 
     Both the flow around support ribs  36  and the flow of a row of vanes in turbine  34  positioned downstream of support ribs  36 , viewed in the flow direction, are improved in this way.