Turbine Nozzle Trailing-Edge Cooling for Thermal Stress Reduction
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Solution Overview
Problem
Turbine nozzles in gas turbine engines experience stresses due to thermal gradients and nonuniform mechanical loads, leading to reduced durability and performance, with existing solutions increasing costs, weight, and space without effectively addressing these issues.
Innovation Solution
Incorporating cooling features such as trailing edge slots and a baffle insert within the vane airfoil to manage thermal gradients and reduce local stresses, using combinations of cooling geometries that improve durability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling features are added to the nozzle, then thermal stresses are reduced and durability is improved, but device complexity increases
Solution Approach 1:
The nozzle is divided into multiple cooling zones with different cooling feature configurations. The first cooling zone has a first configuration of cooling features while the second cooling zone has a second configuration, allowing targeted cooling where thermal stresses are highest without unnecessarily complicating the entire nozzle structure.
Solution Approach 2:
Different regions of the nozzle are given different cooling feature configurations based on their specific thermal and mechanical stress conditions. The leading edge receives different cooling treatment compared to the trailing edge, optimizing each local area's cooling needs while maintaining overall structural simplicity.
2Reliability
If cooling features are added to the nozzle, then thermal stresses are reduced and durability is improved, but manufacturing complexity increases
Solution Approach 1:
The cooling features are segmented into distinct zones with different configurations, allowing each zone to be manufactured or assembled separately. This segmentation can simplify the manufacturing process by enabling modular production and easier quality control compared to a uniformly complex cooling system.
3Reliability
If the nozzle is designed to handle high thermal stresses, then durability is improved, but weight increases
Solution Approach 1:
The nozzle design utilizes parameter changes in the cooling feature configurations across different zones. By varying parameters such as cooling hole size, spacing, and distribution in different thermal zones, the nozzle achieves optimal stress distribution and durability without requiring excessive material weight throughout the entire structure.
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 proposed design reduces thermal stresses and improves durability of turbine nozzles, enhancing engine performance and longevity without increasing costs or weight.
Implementation Method 1
The airfoil further includes slots extending along the trailing edge in a generally radial direction, the slots defining a total slot flow area (SFA) between 0.0000160 m2 and 1.509 m2. The baffle insert includes cooling holes formed in a first surface, the cooling holes defining a total cooling hole area (CHA) between 0.000106 m2 and 0.0001940 m2
Data Source
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AI summary
A turbine engine (10) includes an engine core (16) extending along an engine centerline and includes a compressor section (24), a combustor (26), and a turbine section (28) in serial flow arrangement. A turbine nozzle (102) is arranged in the turbine section (28). Vanes (150) of the turbine nozzle (102) include a vane airfoil (160) having cooling features (190) formed in a trailing edge (172) of the vane airfoil (160). Vanes (150) of the turbine nozzle (102) further include a baffle insert (220) in a cavity (184) of the vane airfoil (160). The baffle insert (220) includes cooling holes (190).