Gas Turbine Vane Cooling Circuits for Uniform Coating
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Solution Overview
Problem
The existing cooling methods for gas turbine engine vane clusters face challenges in ensuring uniform thermal barrier coating application due to interference between airfoils, leading to local thinning and gaps, which can result in reduced coating thickness and increased thermal damage, especially in regions with high aerodynamic heating.
Innovation Solution
The reengineering of the vane cluster configuration includes the addition of in-wall circuits that direct airflow from the shroud to the platform, incorporating streamwise arrays of passageways and outlets to enhance supplemental wall cooling, allowing for more uniform coating application and improved thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If airfoils are arranged in a clustered configuration, then the engine part count is reduced and manufacturing is eased, but the coating application is interfered with causing local thinning and gaps
Solution Approach 1:
The airfoil cluster is divided into separate modular units (doublets) that can be manufactured and coated independently, then assembled together. This segmentation allows each airfoil to receive uniform coating application without interference from adjacent airfoils, while still achieving the overall cluster configuration benefits for reduced part count.
Solution Approach 2:
The airfoils are pre-coated with thermal barrier coating before being assembled into the final cluster configuration. This preliminary coating action prevents coating interference issues during final assembly, ensuring uniform coating thickness on each airfoil surface while maintaining the clustered design advantages.
2Temperature
If cooling holes are drilled in the airfoil surface, then direct cooling is achieved, but the structural integrity may be compromised
Solution Approach 1:
Cooling holes are strategically positioned and sized to provide effective cooling only in the specific regions where thermal loads are highest, rather than uniformly distributing holes throughout the airfoil. This localized approach maintains structural integrity in critical load-bearing areas while achieving adequate cooling performance where needed.
Solution Approach 2:
The airfoil employs a composite structure combining the base airfoil material with thermal barrier coating and integrated cooling channels. This composite design allows the structure to withstand high temperatures and thermal stresses without compromising the mechanical strength of the primary load-bearing material.
3Object-affected harmful factors
If thermal barrier coating is applied to coated airfoils, then thermal damage is reduced, but coating thickness becomes non-uniform due to airfoil interference
Solution Approach 1:
The airfoils are segmented into independent units that are coated separately before assembly, eliminating the interference problem that causes non-uniform coating thickness in clustered configurations. Each airfoil receives consistent coating application, ensuring uniform thermal protection throughout the cluster.
Solution Approach 2:
Thermal barrier coating is applied to each airfoil before the airfoils are positioned in their final clustered arrangement. This preliminary coating action prevents the geometric interference that would otherwise cause coating thinning and gaps, ensuring uniform coating thickness while maintaining the desired cluster configuration.
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
This approach ensures a more uniform coating thickness and reduces thermal damage by providing additional cooling pathways without compromising the aerodynamic performance or increasing intergap air discharge, thereby enhancing the overall thermal and mechanical integrity of the vane clusters.
Implementation Method 1
The reengineering of the vane cluster configuration includes the addition of in-wall circuits that direct airflow from the shroud to the platform, incorporating streamwise arrays of passageways and outlets to enhance supplemental wall cooling
Implementation Method 2
The casting may be coated with a thermal and/or erosion-resistant coating. Exemplary thermal barrier coatings include two-layer thermal barrier coating systems
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A vane cluster (60) has a coated metallic substrate. The cluster (60) includes a platform (68) and a shroud (72). At least first and second airfoils (62,64) extend between an outer face (74) of the platform (68) and an inner face (76) of the shroud (72). Each airfoil has a pressure side (144,154) and a suction side (146,156). The pressure side (144) of the first airfoil (62) faces the suction side (156) of the second airfoil (64). The cluster (60) includes a cooling passageway system including one or more first feed passageways in the first airfoil (62) and one or more second feed passageways in the second airfoil (64). At least a first side selected from the pressure side (144) of the first airfoil (62) and the suction side (156) of the second airfoil (64) includes a first region (164,172) with a local thinning or gap in the coating. Along the first side, the cooling passageway system includes means for locally cooling said first region.