Hot Gas Path Component Impingement Pedestal Cooling
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Solution Overview
Problem
Existing gas turbine engines face challenges in efficiently cooling hot gas path components like turbine bucket platforms, leading to excessive cooling medium losses and reduced component lifetime due to high thermally induced stresses and mechanical loading.
Innovation Solution
A hot gas path component design incorporating combined impingement cooling and pedestal cooling, featuring internal and external wall pedestals and impingement holes to distribute cooling medium effectively, reducing thermal stresses and enhancing heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If impingement cooling is used with small impingement holes, then cooling effectiveness is improved, but pressure drop increases and more cooling flow is required
Solution Approach 1:
The cooling system is segmented into multiple zones: an impingement cooling zone with impingement holes in the impingement wall, and two pedestal cooling zones (internal and external) with pedestals positioned between the impingement wall and the platform. This segmentation allows different cooling mechanisms to work in different regions, optimizing overall cooling effectiveness while managing pressure drop.
Solution Approach 2:
Different cooling approaches are applied to different regions of the platform. The impingement cooling zone uses direct impingement jets for high heat flux areas, while the pedestal cooling zones provide distributed cooling through the pedestal structures. This local differentiation optimizes cooling efficiency for each specific thermal condition.
2Temperature
If more cooling medium flow is used, then cooling effectiveness is improved, but gas turbine efficiency decreases due to excessive cooling medium losses
Solution Approach 1:
The patent merges impingement cooling and pedestal cooling into a hybrid system. The impingement wall with impingement holes provides direct cooling, while the internal and external pedestals distribute cooling medium through their respective cooling zones. This combination achieves effective platform cooling with reduced total cooling medium requirements compared to using either method alone.
3Stress or pressure
If platform cooling is implemented, then thermally induced stresses are reduced, but device complexity increases
Solution Approach 1:
The impingement wall serves multiple functions: it forms part of the platform structure, provides the impingement cooling surface, and supports the pedestal cooling zones. The pedestals similarly serve both structural and cooling distribution functions. This multi-functionality reduces overall system complexity while achieving effective cooling and stress reduction.
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 combined cooling method reduces cooling medium requirements, improves gas turbine efficiency, and extends component lifetime by managing pressure drop and redistributing thermal stresses across the component.
Implementation Method 1
flowing a cooling medium through an internal wall pedestal cooling zone having a number of internal wall pedestals, flowing the cooling medium though an impingement cooling zone having a number of impingement holes, and flowing the cooling medium through an external wall pedestal cooling zone
Implementation Method 2
combined pedestal cooling and impingement cooling... redistributing thermal stresses across the component
Implementation Method 3
impingement cooling is well-known in, for example, stage one nozzle cooling schemes... flowing the cooling medium though an impingement cooling zone having a number of impingement holes
Data Source
AI summary
The present application provides a hot gas path component for use in a hot gas path of a gas turbine engine. The hot gas path component may include an internal wall, an external wall facing the hot gas path, an impingement wall, a number of internal wall pedestals positioned between the internal wall and the impingement wall, and a number of external wall pedestals positioned between the external wall and the impingement wall.