Gas Turbine Cooled Vane Trailing Edge Lip Design
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Solution Overview
Problem
Existing gas turbine blades suffer from significant aerodynamic losses and uneven cooling air distribution due to thick trailing edges and high cooling air consumption, leading to local overheating ('hot spots') from inefficient cooling arrangements.
Innovation Solution
A cooled blade design with a pressure-side lip that directs cooling air to exit before the trailing edge, featuring parallel ribs forming cooling channels with turbulators and flow barriers, along with pins in a lattice arrangement, to minimize cooling air usage and aerodynamic losses while ensuring uniform cooling air distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick trailing edges are used to ensure effective cooling, then cooling effectiveness is improved, but aerodynamic losses increase
Solution Approach 1:
The cooling arrangement is segmented into multiple independent components: ribs forming cooling channels, pins arranged in lattice patterns, turbulators on wall surfaces, and flow barriers. This segmentation allows each element to contribute to cooling effectiveness while maintaining a thin overall trailing edge structure, resolving the contradiction between cooling effectiveness and aerodynamic losses.
2Reliability
If cooling air mass flow is increased to improve cooling, then cooling effectiveness is improved, but cooling air consumption increases
Solution Approach 1:
The invention changes the parameters of the cooling air flow through multiple mechanisms: ribs create high pressure drops to control flow distribution, turbulators increase heat transfer coefficients to improve cooling efficiency, and flow barriers with specific linear densities regulate the cooling air mass flow. These parameter changes enable effective cooling with reduced cooling air consumption.
3Quantity of substance
If throttling is applied at the trailing edge to reduce cooling air flow, then cooling air consumption is reduced, but uneven distribution of cooling air film occurs
Solution Approach 1:
The invention applies local quality by distributing flow barriers with specific linear densities throughout the cooling channels rather than using a single throttling point. This distributed arrangement ensures that cooling air is evenly distributed across the trailing edge while maintaining reduced overall consumption, preventing local overheating spots that would result from concentrated throttling.
4Quantity of substance
If a large blocking effect is created to reduce cooling air flow, then cooling air consumption is reduced, but lateral non-uniform distribution of cooling air film increases
Solution Approach 1:
Instead of using a single large blocking element that would create lateral non-uniformity, the invention segments the flow control into multiple flow barriers with controlled linear densities distributed across the cooling channels. This segmentation achieves the desired reduction in cooling air consumption while maintaining uniform cooling air film distribution across the trailing edge.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a thin, aerodynamically efficient trailing edge with reduced cooling air consumption and minimized 'hot spots' through enhanced heat transfer and flow management, resulting in improved efficiency and power output.
Implementation Method 1
The cooling air exits from the interior space on the pressure side... increase the surface area for heat transfer between the walls and the cooling air flow
Implementation Method 2
which cause a high pressure drop... produce an equalization of the cooling air flow in the associated effective area with a minimized blocking effect
Implementation Method 3
additional turbulators are arranged to increase the cooling effect... rib-shaped turbulators are provided in the cooling channels, which increase the heat transfer coefficient
Data Source
Figure 1~2
AI summary
A cooled vane (10) for a gas turbine comprises an airfoil (24) which extends between a leading edge and a trailing edge (13) in the direction of flow (25) and is respectively delimited by a wall (11 and 12) on the suction side (15) and the pressure side (16). Said walls (11, 12) enclose an interior (14), inside which cooling air flows to the trailing edge (13) in the direction of flow (25) and is discharged in the region of the trailing edge. In order to reduce aerodynamic losses on the trailing edge and the amount of cooling air used in such a vane, the wall (12) on the pressure side ends at a distance from the trailing edge (13) in the direction of flow (25) so as to form a lip (21) on the pressure side such that the cooling air is discharged from the interior (14) on the pressure side (16). Furthermore, at a distance from the trailing edge (13), the interior (14) is subdivided into a multitude of parallel cooling ducts (23) causing a great drop in pressure by means of a multitude of ribs (17) that are oriented parallel to the direction of flow (25), turbulators (18) are arranged inside the cooling ducts (23) to increase the cooling effect, and a plurality of flow barriers (20) is distributed transversely to the direction of flow within the flow path of the cooling air at a short distance upstream of the point where the cooling air is discharged from the interior (14).