Turbomachine rotor blade, turbomachine rotor disc, turbomachine rotor, and gas turbine engine with different root and slot contact face angles

Patent metadata

Field	Value
Publication number	US-9903213-B2
Application number	US-201414763756-A
Country	US
Kind code	B2
Filing date	Feb 3, 2014
Priority date	Feb 4, 2013
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A turbomachine rotor blade has a firtree shaped root, to be secured in a rotor disc rotatable around a rotor axis. In a plane perpendicular to the rotor axis, the root has a first, second, and third root lobe with a first, second, and third root contact face. Each of the first, second, and third root contact face is angled relative to a radial root bottom axis with a first, second, and third root angle, respectively. The first root angle is smaller than the second and the second root angle is substantially equal to the third. A turbomachine rotor disc has a firtree shaped slot having a first, second, and third slot angle, the first slot angle being smaller than the second and the second slot angle being substantially equal to the third. A gas turbine engine has the turbomachine rotor herein.

First claim

The invention claimed is:

1. A turbomachine rotor blade comprising:
a firtree shaped root, arranged to be secured in a turbomachine rotor disc, the rotor disc being rotatable around a rotor axis,
wherein in a plane perpendicular to the rotor axis
the root comprises a root bottom and a root side;
the root side comprises a plurality of root lobes, each of the root lobes comprises a root contact face, arranged to be in physical contact with a slot contact face of the rotor disc;
the plurality of root lobes comprises a first root lobe with a first root contact face, a second root lobe with a second root contact face and a third root lobe with a third root contact face, the first root lobe being closer to the root bottom than the second root lobe and the second root lobe being closer to the root bottom than the third root lobe;
the first root contact face is angled relative to a radial root bottom axis with a first root angle, the radial root bottom axis being defined by a line through the rotor axis and the root bottom;
the second root contact face is angled relative to the radial root bottom axis with a second root angle; and
the third root contact face is angled relative to the radial root bottom axis with a third root angle;
wherein any one or more of the first root angle or the second root angle or the third root angle is in the range 1° to 15° of any of the other root angles; and
wherein the first root angle is greater than the second root angle and greater than the third root angle, effective to increase stress in the first root lobe relative to the second root lobe and third root lobe, so that in the event of a failure of the first root lobe, the second root lobe and third root lobe are capable of carrying a total loading.

2. The turbomachine rotor blade according to claim 1 ,
wherein any one or more of the first root angle or the second root angle or the third root angle is in the range 1° to 5° of any of the other root angles.

3. The turbomachine rotor blade according to claim 1 ,
wherein the second root angle is substantially equal to the third root angle.

4. The turbomachine rotor blade according to claim 1 ,
wherein the first root angle is 2° greater than the second root angle or third root angle.

5. The turbomachine rotor blade according to claim 1 ,
wherein the first root angle is 2° greater than the second root angle and the second root angle is equal to the third root angle.

6. The turbomachine rotor blade according to claim 1 ,
wherein the root comprises a further root side, the further root side comprising a plurality of further root lobes, and the root side and the further root side being circumferentially opposite to each other.

7. The turbomachine rotor blade according to claim 6 ,
wherein the plurality of root lobes comprises a first root shape and the plurality of further root lobes comprises a second root shape, the first root shape being a copy, flipped at the radial root bottom axis, of the second root shape.

8. The turbomachine rotor blade according to claim 1 ,
wherein each of the root lobes has a maximum root distance to the radial root bottom axis, the root distance being defined by the length of a root line segment between a surface section of a root lobe and an axis section of the radial root bottom axis, the root line segment being perpendicular to the radial root bottom axis; and
wherein the maximum root distance of the first root lobe is smaller than the maximum root distance of the second root lobe and/or the maximum root distance of the second root lobe is smaller than the maximum root distance of the third root lobe.

9. The turbomachine rotor blade according to claim 1 ,
wherein the turbomachine rotor blade is part of a gas turbine engine, part of a turbine section of the gas turbine engine and/or part of a compressor section of the gas turbine engine.

10. A turbomachine rotor comprising
the turbomachine rotor blade according to claim 1 , and
the turbomachine rotor disc comprising:
a firtree shaped slot, the rotor disc being rotatable around the rotor axis;
wherein in the plane perpendicular to the rotor axis
the slot comprises a slot bottom and a slot side;
the slot side comprises a plurality of slot lobes, each of the slot lobes comprises the slot contact face, arranged to be in physical contact with the root contact face of the turbomachine rotor blade;
the plurality of slot lobes comprises a first slot lobe with a first slot contact face, a second slot lobe with a second slot contact face and a third slot lobe with a third slot contact face, the first slot lobe being closer to the slot bottom than the second slot lobe and the second slot lobe being closer to the slot bottom than the third slot lobe;
the first slot contact face is angled relative to a radial slot bottom axis with a first slot angle, the radial slot bottom axis being defined by a line through the rotor axis and the slot bottom;
the second slot contact face is angled relative to the radial slot bottom axis with a second slot angle; and
the third slot contact face is angled relative to the radial slot bottom axis with a third slot angle; characterised in that
any one or more of the first slot angle or the second slot angle or the third slot angle is in the range 1° to 15° of any of the other slot angles.

11. The turbomachine rotor according to claim 10 ,
wherein the physical contact between the first root contact face and the first slot contact face and/or
between the second root contact face and the second slot contact face and/or between the third root contact face and the third slot contact face is established during operation of the turbomachine rotor.

12. A gas turbine engine, comprising a turbomachine rotor according to claim 10 .

13. A turbomachine rotor disc comprising:
a firtree shaped slot, the rotor disc being rotatable around a rotor axis;
wherein in a plane perpendicular to the rotor axis
the slot comprises a slot bottom and a slot side;
the slot side comprises a plurality of slot lobes, each of the slot lobes comprises a slot contact face, arranged to be in physical contact with a root contact face of a turbomachine rotor blade;
the plurality of slot lobes comprises a first slot lobe with a first slot contact face, a second slot lobe with a second slot contact face and a third slot lobe with a third slot contact face, the first slot lobe being closer to the slot bottom than the second slot lobe and the second slot lobe being closer to the slot bottom than the third slot lobe;
the first slot contact face is angled relative to a radial slot bottom axis with a first slot angle, the radial slot bottom axis being defined by a line through the rotor axis and the slot bottom;
the second slot contact face is angled relative to the radial slot bottom axis with a second slot angle; and
the third slot contact face is angled relative to the radial slot bottom axis with a third slot angle; characterised in that
any one or more of the first slot angle or the second slot angle or the third slot angle is in the range 1° to 15° of any of the other slot angles; and
wherein the first slot angle is greater than the second slot angle and greater than the third slot angle.

14. The turbomachine rotor disc according to claim 13 ,
wherein any one or more of the first slot angle or the second slot angle or the third slot angle is in the range 1° to 5° of any of the other slot angles.

15. The turbomachine rotor disc according to claim 13 ,
wherein the first slot angle is greater than the second slot angle and the second slot angle is substantially equal to the

Assignees

• Siemens Ag

Inventors

• Bluck Richard
• Butler David
• Overton David

Classifications

• F05D2250/314

  the axes being inclined in relation to each other · CPC title

• F01D5/30

  Fixing blades to rotors; Blade roots {; Blade spacers} · CPC title

• F01D5/3007 Primary

  of axial insertion type · CPC title

• F05D2200/33

  bigger or smaller · CPC title

• F05D2250/38

  angled, e.g. sweep angle · CPC title