Turbine engine with a rotating blade having a fin

1 . A turbine engine comprising:

an engine casing; and

a blade assembly configured to rotate about a rotational axis, the blade assembly comprising:

a blade having an outer wall extending between a root and a tip, and between a blade leading edge and a blade trailing edge;

a tip platform provided along the tip of the blade, the tip platform being radially spaced from the engine casing to define a space therebetween; and

a fin extending radially into and circumferentially within the space, the fin having:

a wall extending radially and terminating at a distal end within the space with respect to the tip platform; and

a plurality of circumferentially spaced fin projections, each fin projection extending axially outward from the wall and being formed as a hook.

2 . The turbine engine of claim 1 , wherein each fin projection has a first leg extending axially from the wall, and a second leg extending from the first leg and being non-parallel to the first leg.

3 . The turbine engine of claim 2 , wherein the second leg extends from the first leg at a 90 degree angle.

4 . The turbine engine of claim 2 , wherein each second leg of the plurality of fin projections extends from a respective first leg in a same circumferential direction between fin projections of the plurality of fin projections, with respect to the rotational axis.

5 . The turbine engine of claim 1 , wherein the fin is included in a plurality of fins axially spaced with respect to one another.

6 . The turbine engine of claim 5 , wherein a single fin of the plurality of fins includes the plurality of fin projections.

7 . The turbine engine of claim 6 , wherein the single fin is a farthest axially forward fin of the plurality of fins.

8 . The turbine engine of claim 1 , wherein the plurality of circumferentially spaced fin projections are arranged in a series and spaced along the wall.

9 . The turbine engine of claim 1 , wherein each fin projection extends from a forward surface of the wall.

10 . The turbine engine of claim 1 , wherein the blade is included in a plurality of circumferentially spaced blades, and the tip platform extends at least from the tip of a first blade of the plurality of circumferentially spaced blades and to the tip of a second blade of the plurality of circumferentially spaced blades, with the first blade being circumferentially adjacent to the second blade.

11 . The turbine engine of claim 1 , wherein the tip platform forms a continuous annulus about the rotational axis.

12 . The turbine engine of claim 1 , wherein:

the tip platform extends between a fore edge and an aft edge, and the tip platform comprises a first surface and a second surface radially spaced outwardly from the first surface with respect to the rotational axis; and

the first surface is spaced at a non-constant radial distance along a span of the first surface from the fore edge and to the aft edge, the non-constant radial distance being with respect to a horizontal plane, the horizontal plane intersecting a first point radially halfway between where the fore edge meets the first surface and the second surface, and a second point radially halfway between where the aft edge meets the first surface and the second surface.

13 . The turbine engine of claim 1 , wherein the tip platform further comprises a set of projections circumferentially spaced along an aft edge, the set of projections forming a series of alternating peaks and valleys interconnected by a set of legs to define a set of voids defined as a circumferential area between circumferentially adjacent legs of the set of legs.

14 . The turbine engine of claim 1 , wherein the tip platform is segmented to define multiple discrete platforms that collectively extend circumferentially about an entirety of the rotational axis.

15 . The turbine engine of claim 1 , wherein the tip platform further comprises a set of projections forming an axial wave along a portion of the tip platform.

16 . The turbine engine of claim 1 , wherein the fin extends radially outward from the tip platform.

17 . The turbine engine of claim 1 , further comprising a low pressure turbine, with the blade being provided within the low pressure turbine.

18 . A turbine engine comprising:

an engine casing; and

a blade assembly configured to rotate about a rotational axis, the blade assembly comprising:

a blade having an outer wall extending between a root and a tip, and between a blade leading edge and a blade trailing edge;

a tip platform provided along the tip of the blade, the tip platform being radially spaced from the engine casing to define a space therebetween; and

a fin extending radially into and circumferentially within the space, the fin having:

a wall extending radially and terminating at a distal end within the space with respect to the tip platform; and

a fin projection extending axially outward from the wall, wherein the tip platform further comprises a set of projections circumferentially spaced along an aft edge, the set of projections forming a series of alternating peaks and valleys interconnected by a set of legs to define a set of voids defined as a circumferential area between circumferentially adjacent legs of the set of legs.