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Deflection of a Crack Between Shaped Film Cooling Holes

IP.com Disclosure Number: IPCOM000202371D
Original Publication Date: 2010-Dec-14
Included in the Prior Art Database: 2010-Dec-14
Document File: 2 page(s) / 84K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

In the field of blades and vanes of a gas turbine, film cooling holes are required to create a film of comparatively cold air between the hot gas flow and the component material. The cooling film reduces the metal temperature considerably. The application of the film cooling holes allows the increase of the turbine inlet temperature, whereby the engine efficiency is enhanced. However the film cooling holes have negative effects regarding the stress distribution in the component. Due to the film cooling holes, a notch effect is created and the cooling holes are considered as crack initiators. The cracks mostly propagate from one hole to another (figure 1).

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Deflection of a Crack Between Shaped Film Cooling Holes

Idea: Fathi Ahmad, DE-Mühlheim (Ruhr); Christian Menke, DE-Mühlheim (Ruhr)

In the field of blades and vanes of a gas turbine, film cooling holes are required to create a film of comparatively cold air between the hot gas flow and the component material. The cooling film reduces the metal temperature considerably. The application of the film cooling holes allows the increase of the turbine inlet temperature, whereby the engine efficiency is enhanced. However the film cooling holes have negative effects regarding the stress distribution in the component. Due to the film cooling holes, a notch effect is created and the cooling holes are considered as crack initiators. The cracks mostly propagate from one hole to another (figure 1).

It is proposed to apply crack deflectors between the shaped holes in an inclined form (figure 2). The deflectors could be part of the cast procedure or can be brought in via EDM (Electrical Discharge Machining) or laser. As a crack propagate from one film cooling hole to another, the deflector changes its direction. Due to the use of crack deflectors it is possible to change the crack direction from horizontal to inclined, which is less critical. In this way, cracks can be moved to regions with low stress levels. The crack deflectors will also be coated in the normal...