TURBINE MODULE FOR A TURBOMACHINE

Abstract

A turbine module (2) for a turbomachine (1). The turbine module (2) includes a main channel (26) to guide a main flow (36) through the turbine module (2), a rotor blade (21) and a stator vane (22), the stator vane (22) including a stator airfoil (22) and a platform (23), with the stator airfoil (22) arranged downstream of the rotor blade (21) in the main channel (26), and a cavity (30) including an inlet (31) for injecting a part (36.2) of the main flow (36) into the cavity (30), an outlet (32) for a reinjection of the part (36.2) of the main flow (36) from the cavity (30) into the main channel (26), wherein the cavity (30) is arranged at an axial position of the stator vane (20) and is radially offset from the stator airfoil (22).

Claims

1. A turbine module for a turbomachine, the turbine module comprising: a main channel to guide a main flow through the turbine module; a rotor blade; a stator vane, the stator vane including a stator airfoil and a platform, the stator airfoil being arranged downstream of the rotor blade in the main channel; and a cavity including an inlet for injecting a part of the main flow into the cavity and an outlet for a reinjection of the part of the main flow from the cavity into the main channel, the cavity being arranged at an axial position of the stator vane and radially offset from the stator airfoil.

2. The turbine module as recited in claim 1 wherein the part of the main flow guided into the cavity is a leakage flow of the rotor blade.

3. The turbine module as recited in claim 1 wherein an opening of the inlet is arranged upstream of the stator airfoil at a wall surface radially delimiting the main channel.

4. The turbine module as recited in claim 3 wherein the wall surface is of the platform of the stator vane.

5. The turbine module as recited in claim 1 wherein the cavity is radially delimited by the platform.

6. The turbine blade as recited in claim 5 wherein the cavity is radially delimited by a wall surface of the platform radially opposite to another wall surface delimiting the main channel.

7. The turbine module as recited in claim 1 wherein an opening of the outlet is arranged at a minimum 20% of an axial chord length of the stator airfoil, the axial chord length being defined at a wall surface of the platform.

8. The turbine module as recited in claim 1 wherein an opening of the outlet is arranged at a maximum 99% of an axial chord length of the stator airfoil, the axial chord length being defined at a wall surface of the platform.

9. The turbine module as recited in claim 1 wherein the outlet includes inclined holes or slots for guiding the part of the main flow reinjected from the cavity into the main channel.

10. The turbine module as recited in claim 9 wherein a middle axis of at least one of the inclined holes or slots forms an angle of maximum 60° with a wall surface radially delimiting the main channel.

11. The turbine module as recited in claim 1 wherein an opening of the outlet is arranged in the stator airfoil.

12. The turbine module as recited in claim 1 further comprising a heat shield element arranged bordering the cavity, the heat shield element radially delimiting the cavity.

13. The turbine module as recited in claim 1 further comprising ribs for guiding the flow in the cavity and arranged in the cavity.

14. The turbine module as recited in claim 1 wherein the cavity includes an additional inlet for guiding an additional flow into the cavity, the additional flow being sourced externally outside the main flow.

15. A turbomachine comprising the turbine module as recited in claim 14.

16. A method for operating the turbomachine as recited in claim 15 wherein the part of the main flow is guided into the cavity and reinjected from the cavity into the main channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention is explained in more detail below using an exemplary embodiment, with the individual features also being relevant to the invention in other combinations, and furthermore relating to all claim categories.

[0026] In Detail

[0027] FIG. 1 shows a jet engine in an axial section;

[0028] FIG. 2 shows a schematic representation of the turbine module according to the invention;

[0029] FIG. 3 shows a schematic representation of the stator passage of the turbine module in a meridional section;

DETAILED DESCRIPTION

[0030] FIG. 1 shows a turbomachine 1, specifically a turbofan engine, in an axial section. The turbomachine 1 is functionally divided into compressor 1a, combustion chamber 1b, turbine 1c and fan 1d. Both the compressor 1a and the turbine 1c are each made up of several stages, each stage comprising a stator vane ring and a rotor blade ring. During operation, the rotor blade rings rotate around the longitudinal axis 3 of the turbomachine 1, and air sucked in is compressed in the compressor 1a and then burned with kerosene in the combustion chamber 1b. The resulting hot gas is expanded in the turbine 1c and drives the rotor blade rings.

[0031] FIG. 2 shows a turbine module 2 of the turbine 1c in schematic representation. A main flow 36 is guided through a main channel 26 of the turbine module 2. In the main channel 26, a stator airfoil 22 is arranged downstream of a rotor blade 21. An inner wall 25 of the engine casing can also be seen, radially delimiting the rotor passage of the main channel 26 to the outside. The stator airfoil 22 belongs to a stator vane 20, which additionally comprises an outer platform 23.

[0032] A cavity 30 is arranged at an axial position of the stator vane 20, and radially offset to the outside of the stator airfoil 22. It is radially delimited by a wall surface 23.2 of the outer platform 23. The cavity comprises an inlet 31 with an opening 31.1 arranged upstream of the stator airfoil 22 and an outlet 32 with an opening 32.1 arranged downstream from the inlet 31 at a position between 50% to 70% of the axial chord length of the stator airfoil 22. Furthermore, openings 32.2 of the outlet 32 are arranged in the stator airfoil 22, guiding a flow reinjected from the cavity 30 into the main channel 26. In alternative embodiments not shown here, either the openings 32.1 or 32.2 can be omitted, resulting in a reinjection solely occurring through the outer platform 23 or the stator airfoil 22.

[0033] The vane hooks 24, as well as a heat shield element 34 can be seen bordering the cavity 30. The heat shield element 34 radially delimits the cavity 30 outwards. Additionally, ribs 33 are arranged in the cavity 30 (one rib is indicated in a side view by the hatched lines). The ribs 33 guide the flow inside the cavity, see in detail above. The cavity 30 furthermore comprises an additional inlet 35 for guiding an additional flow 29 from the compressor section 1a, which is an optional feature.

[0034] The rotating rotor blade 21 creates a tip-leakage flow 36.1, which could disturb the flow, see in detail above. To prevent such secondary flows, at least a part 36.2 of the main flow 36 is guided through the inlet 31 into the cavity 30. In particular, the tip-leakage flow 36.1 is bled into the cavity 30. Subsequently, it is reinjected via the outlet 32 comprising inclined holes 37 into the main channel 26. The reinjected flow possesses a relatively large tangential component relative to the main flow 36.

[0035] FIG. 3 shows the stator passage of the turbine module in a meridional section. The inclined holes 37 are arranged in two rows axially, one behind the other. The flow in the cavity 30 is guided by the ribs 33 (shown as hatched lines in FIG. 2) and the inclined holes 37 in such a way, that the reinjected flow shows a circumferential velocity largely corresponding to that of the main flow 36, additionally, it is directed towards the pressure side of the stator airfoil 22. An air passage 38 extending through the stator airfoil 22 is shown by hatched lines, which channels a flow to the openings 32.2 in the stator airfoil 22.

REFERENCE LIST

[0036] Turbomachine 1 [0037] Compressor section 1a [0038] Combustion chamber 1b [0039] Turbine section 1c [0040] Fan section 1d [0041] Turbine module 2 [0042] Longitudinal axis 3 [0043] Stator vane 20 [0044] Rotor blade 21 [0045] Stator airfoil 22 [0046] Outer platform of the stator vane 23 [0047] Inner wall surface of outer platform 23.1 [0048] Outer wall surface of outer platform 23.2 [0049] Vane hooks 24 [0050] Inner wall surface of engine casing 25 [0051] Main channel 26 [0052] Additional flow into the cavity 29 [0053] Cavity 30 [0054] Inlet 31 [0055] Opening of the Inlet 31.1 [0056] Outlet 32 [0057] Opening of the Outlet 32.1, 32.2 [0058] Ribs in the cavity 33 [0059] Heat shield element 34 [0060] Additional inlet 35 [0061] Main flow 36 [0062] Tip-Leakage flow 36.1 [0063] A part of the main flow into the cavity 36.2 [0064] Inclined holes 37 [0065] Air passage through the stator airfoil 38