Ring sector of turbomachine turbine
View Patent ↗A turbine ring sector comprising a wall presenting an inside face and an outside face, in which the inside face defines an axially oriented airflow passage through which gas flows; and a multiply-perforated metal sheet situated on the side of the wall that is opposite from the airflow passage is disclosed. The multiply-perforated metal sheet has a bottom, and the space between the outside face of the wall and the bottom of the multiply-perforated metal sheet defines a gap. The variation in the value of the gap over the entire axial extent thereof decreases from a first maximum value towards a minimum value and then increases from the minimum value to a second maximum value.
1. A turbine ring sector comprising:
a wall presenting an inside face and an outside face, the inside face defining an axially oriented airflow passage through which gas flows; and
a multiply-perforated metal sheet situated on a side of the wall that is opposite from the airflow passage, said multiply-perforated metal sheet having a bottom,
wherein, in an axial cross section, the outside face of the wall is planar and the bottom of the multiply-perforated metal sheet presents an arcuate convex shape extending toward an axis of the turbine ring sector,
wherein a minimum radial distance between the outside face of the wall and the bottom of the multiply-perforated metal sheet defines a gap, and
wherein a variation in a value of the gap over an entire axial or circumferential extent thereof gradually decreases from a first maximum value at a first end of the multiply-perforated metal sheet towards a minimum value, said minimum value defining a minimum of the gap, and gradually increases from the minimum value to a second maximum value at a second end of the multiply-perforated metal sheet.
2. The ring sector according to claim 1 , wherein the minimum of the gap is placed in register with a hot zone of the wall.
3. The ring sector according to claim 1 , wherein the minimum of the gap is placed, along the axial direction, in a middle of at least one of the bottom of the multiply-perforated metal sheet or the wall.
4. The ring sector according to claim 1 , wherein the first maximum value is substantially equal to the second maximum value.
5. The ring sector according to claim 1 , wherein the multiply-perforated metal sheet presents at least one perforation at the minimum of the gap.
6. The ring sector according to claim 1 , wherein a middle zone extends around the minimum of the gap, the multiply-perforated metal sheet presenting more perforations in the middle zone than in the zones located on either side of the middle zone.
7. The ring sector according to claim 1 , wherein the bottom of the multiply-perforated metal sheet is substantially symmetrical about a radial plane passing through the minimum of the gap.
8. The ring sector according to claim 1 , wherein the bottom of the multiply-perforated metal sheet is connected to fastener tabs which fasten the multiply-perforated metal sheet to rims of the wall.
9. A turbine ring including at least one ring sector according to claim 1 .
10. A turbine including a ring according to claim 9 .
11. A turbomachine including a turbine according to claim 10 .