Turbomachine arrangement with a platform cooling device for a blade of a turbomachine
A turbomachine arrangement having a platform cooling device for a blade positioned at a platform of the blade. The cooling device's peripheral edge is in contact with the platform; a first surface portion forms a first cavity between the cooling device and platform and has impingement holes to impinge onto the platform; a second surface portion forms a second cavity between the cooling device and platform; a barrier in contact with the platform forms a connection between two sections of the edge and fluidically separates the first and second cavity. The cooling device is connected at the edge to the blade so the first and second cavity are formed between the cooling device and blade. The blade has a supply passage, connecting a hollow core and the second cavity for supplying cooling fluid to the second cavity and the first cavity is supplied with cooling fluid via the impingement holes.
1. A turbomachine arrangement, comprising:
a blade of a turbomachine; and
a platform cooling device for the blade configured to be positioned at a platform of the blade, the platform cooling device comprising:
a peripheral edge configured to be in contact with the platform; and
a first surface portion configured to form a first cavity between the platform cooling device and the platform, the first surface portion comprising a plurality of impingement holes configured to impinge onto the platform during operation of the turbomachine; and
a second surface portion configured to form a second cavity between the platform cooling device and the platform; and
a barrier configured to be in contact with the platform, the barrier forming a connection between two sections of the edge and separating the first cavity from the second cavity fluidically;
wherein the platform cooling device and the blade are separately manufactured components, and
wherein the platform cooling device is connected at the edge to the blade, such that the first cavity and the second cavity are formed between the platform cooling device and the blade, and
wherein the blade comprises a cooling fluid supply passage, connecting a hollow blade core and the second cavity, for supplying of cooling fluid to the second cavity during operation, and
wherein the first cavity is supplied, during operation, with cooling fluid via the impingement holes of the first surface portion.
2. The turbomachine arrangement according to claim 1 ,
wherein the second surface portion (a) is free of impingement holes, or (b) comprises a plurality of further impingement holes with a different pattern and/or different hole diameters than the impingement holes of the first surface portion.
3. The turbomachine arrangement according to claim 1 ,
wherein a first segment of the edge is configured to connect with a root or neck section of the blade and a second segment of the edge is configured to connect with a rear surface of the platform.
4. The turbomachine arrangement according to claim 3 ,
wherein the barrier is a straight wall and substantially perpendicular to the first segment and/or the second segment of the edge.
5. The turbomachine arrangement according to claim 1 ,
wherein the platform cooling device is connected to the blade either
(i) fixedly via brazing, welding, laser welding, or boding, or
(ii) loosely by fitting the platform cooling device to a corresponding recess of the blade in which the platform cooling device is held in place by centrifugal force during operation.
6. The turbomachine arrangement according to claim 1 ,
wherein the platform comprises at least one first passage through the platform for releasing cooling fluid from the first cavity and/or,
wherein the platform comprises at least one second passage through the platform for releasing cooling fluid from the second cavity.
7. The turbomachine arrangement according to claim 6 ,
wherein the at least one first passage and/or the at least one second passage are configured as film cooling holes to film cool the platform during operation.
8. The turbomachine arrangement according to claim 1 ,
wherein the blade comprises
an aerofoil;
an aerofoil cooling system within the aerofoil;
at least one aerofoil supply passage through the blade for supplying the aerofoil cooling system with cooling fluid; and
a cooling fluid release passage for releasing of cooling fluid from the first cavity into the aerofoil supply passage.
9. The turbomachine arrangement according to claim 1 ,
wherein the platform cooling device is connected to the blade at a pressure side of the blade.
10. The turbomachine arrangement according to claim 1 ,
wherein the platform cooling device is built from a different material than the blade.
11. The turbomachine arrangement according to claim 1 ,
wherein the first cavity is positioned, in respect of a fluid flow of a working medium during operation, adjacent to a central section and/or trailing edge section of the platform, and
wherein the second cavity is positioned adjacent to a leading edge section.
12. A turbomachine sub section comprising:
a rotary disc with a plurality of blades connected to the disc, each of the blades connected with the platform cooling device according to claim 1 ;
an annular stator section upstream of the rotary disc and upstream of the blades in respect of a fluid flow of a working medium during operation;
a disc cavity defined between the rotary disc and the stator section, underneath leading edges of a plurality of the platforms of the blades;
wherein during operation, cooling fluid is supplied from the disc cavity, via the impingement holes of the first surface portion, to the first cavity.
13. The turbomachine sub section of claim 12 ,
wherein the annular stator section comprises a plurality of vanes.