Layer-Type Cooling-Air Supply Device for Gas Turbines
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Solution Overview
Problem
The existing cooling-air supply devices for gas turbines, particularly those with cast or forged parts, are complex and costly to manufacture, leading to high weight and stability issues due to the required wall thickness for cooling air bores.
Innovation Solution
A layer-type structure for the axial bounding wall with deformations in material layers, allowing for the formation of cooling-air outlet orifices through bending and stamping operations, which reduces material usage and weight while enabling variable design of cooling air channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cast or forged parts with cooling air bores are used, then cooling air can be supplied to turbine components, but the device becomes complex and costly to manufacture with increased weight
Solution Approach 1:
The bounding wall is divided into multiple layers (first layer, second layer, third layer) that can be manufactured separately and then assembled. This segmentation allows each layer to be produced using simple sheet metal forming processes rather than complex casting or forging, reducing manufacturing difficulty and weight while maintaining structural integrity for cooling air supply
Solution Approach 2:
The bounding wall is constructed as a composite structure using multiple layers of sheet material with different properties. The first layer provides the cooling air chamber boundary, the second layer forms the turbine housing, and the third layer provides additional structural support. This composite approach allows optimization of each layer for its specific function, reducing overall weight compared to a single heavy forged part
2Stability of the object's composition
If wall thickness is increased to maintain stability for cooling air bores, then structural stability is improved, but weight and material usage increase
Solution Approach 1:
The wall stability function is distributed across multiple thin layers rather than requiring a single thick wall. The first layer with cooling air bores, second layer forming the turbine housing, and third layer providing external support work together to maintain stability, allowing each layer to be thin and lightweight while the composite structure provides overall structural integrity
Solution Approach 2:
The layers are nested within each other, with the first layer containing cooling air bores embedded within it, the second layer nested around the first layer forming the turbine housing, and the third layer nested around the second layer for additional support. This nesting allows efficient use of material while maintaining stability through the layered composite structure
3Ease of manufacture
If cooling air bores are drilled through bounding walls, then cooling air can be delivered to turbine blades, but manufacturing complexity and cost increase
Solution Approach 1:
The cooling air bores are formed as integral features of the first layer during its fabrication process rather than being drilled through the assembled bounding wall. This allows the bores to be created with precise geometry and proper orientation using forming operations on the sheet material before assembly, avoiding the need for complex post-assembly drilling and tapping operations
Solution Approach 2:
The cooling air bores are pre-formed in the first layer during its manufacturing process, with the correct diameter, length, and angular orientation established before the layer is assembled into the bounding wall. This preliminary formation of the bores ensures manufacturing precision while simplifying the overall manufacturing process compared to drilling through assembled components
Data Source
AI summary
A cooling-air supply device for a gas turbine, in particular an aircraft gas turbine, including a cooling air chamber, that is disposed about a turbine shaft of the gas turbine, at least one cooling-air inlet opening, and at least one cooling-air outlet orifice; the cooling-air supply device having a first and a second axial bounding wall, and a peripheral wall that joins the two axial bounding walls, which, together, form the cooling air chamber; in at least one of the axial bounding walls, a plurality of cooling-air outlet orifices being provided, which are circumferentially distributed about the turbine shaft and are adapted to allow the cooling air to essentially be discharged from the individual cooling-air outlet orifices in the direction of rotation of the gas turbine. In the axial direction, the respective axial bounding wall having the cooling-air outlet orifices has a layer-type structure; the cooling-air outlet orifices being formed by deformation of at least one first cooling air chamber-side layer and by deformation of at least one second, turbine-side layer.