Browse Prior Art Database

DS Blade With SX LE

IP.com Disclosure Number: IPCOM000029862D
Original Publication Date: 2004-Aug-25
Included in the Prior Art Database: 2004-Aug-25
Document File: 1 page(s) / 28K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

In the design of gas turbines DS (Directional Solidificated) materials will be increasingly applied, contrasting to SX (Single Crystal) materials. Unfortunately, in components with film cooling holes the grain boundary in these DS materials could be hit during the drilling process, and micro-cracks could be effected in the boundary. This is problematic especially at the leading edge (LE) of a turbine blade or vane, where usually several rows of closely distributed, small holes exist for the purpose of film cooling. Therefore, in this region the material properties (fracture mechanics and fatigue) of DS elements will be lower than those of SX. An idea to solve the problem is to furnish film cooled DS components with only one grain (i.e. Single Crystal) in the area where the cooling holes have to be drilled, and especially the leading edge of blades and vanes should be produced with only one grain (cf. Fig. 1).

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© SIEMENS AG 2004 file: 2004J09758.doc page: 1

DS Blade With SX LE

Idea: Dr. Ying Pan, DE-Muelheim; Fathi Ahmad, DE-Muelheim

In the design of gas turbines DS (Directional Solidificated) materials will be increasingly applied, contrasting to SX (Single Crystal) materials. Unfortunately, in components with film cooling holes the grain boundary in these DS materials could be hit during the drilling process, and micro-cracks could be effected in the boundary. This is problematic especially at the leading edge (LE) of a turbine blade or vane, where usually several rows of closely distributed, small holes exist for the purpose of film cooling. Therefore, in this region the material properties (fracture mechanics and fatigue) of DS elements will be lower than those of SX.

An idea to solve the problem is to furnish film cooled DS components with only one grain (i.e. Single Crystal) in the area where the cooling holes have to be drilled, and especially the leading edge of blades and vanes should be produced with only one grain (cf. Fig. 1).

The lifetime calculation for such DS parts with a SX leading edge can be carried out using SX material properties, and it is expected that DS parts could reach the lifetime of common SX parts. Difficulties and concerns in laser-drilling of DS parts could be strongly reduced or eliminated.

Fig. 1: Embodiment of a laser-drilled DS turbine blade with a SX leading edge

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