Trailing Edge Pressure Regulator for Gas Turbine Cooling
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Solution Overview
Problem
In gas turbine engines, the radial variation in gaspath pressure at the trailing edge of airfoil components leads to excess cooling flow due to constant supply pressure across all trailing edge slots, resulting in inefficient cooling flow distribution and potential overcooling in certain regions.
Innovation Solution
The use of axial ribs and pressure regulating features, such as crossover holes or pedestals, to separate the internal area adjacent to the trailing edge into individual cavities, allowing for tailored downstream supply pressure to mimic the exit pressure along the radial span, thereby minimizing cooling flow and maintaining minimum backflow margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If constant supply pressure is used for all trailing edge slots, then manufacturing is simplified, but cooling flow distribution becomes inefficient with excess cooling in certain regions
Solution Approach 1:
The internal area adjacent to the trailing edge is divided into multiple individual cavities by axial ribs, with each cavity serving a specific radial span. This segmentation allows independent pressure regulation for different trailing edge slots, enabling efficient cooling flow distribution while maintaining manufacturing simplicity through modular cavity design.
Solution Approach 2:
Pressure regulating features are selectively positioned at the entrance to specific cavities based on local cooling requirements. Each cavity receives tailored downstream supply pressure that mimics the exit pressure along its radial span, optimizing cooling flow efficiency for each local region rather than applying uniform pressure across all slots.
2Reliability
If supply pressure is set to meet minimum backflow margin requirements, then reliability is improved, but some slots experience higher backflow margins resulting in excess cooling flow
Solution Approach 1:
The downstream supply pressure is dynamically adjusted for each cavity based on the local exit pressure and cooling requirements. By changing the pressure parameter selectively in different radial regions, the system maintains minimum backflow margin requirements for reliability while preventing excess cooling flow that would waste energy.
Solution Approach 2:
The pressure regulating features are designed to respond to local exit pressure conditions, with downstream supply pressure tailored to mimic the exit pressure along each radial span. This feedback mechanism ensures that backflow margins meet minimum requirements without creating excessive pressure differences that would cause energy-wasting excess cooling flow.
3Manufacturing precision
If trailing edge slot sizes are determined by manufacturing requirements, then manufacturing precision is maintained, but flow distribution becomes uneven with some slots having higher cooling flows
Solution Approach 1:
By segmenting the internal area into individual cavities, the system decouples the relationship between uniform slot dimensions and uniform cooling flow. Each cavity can be independently pressurized to compensate for variations in slot sizes, maintaining manufacturing precision while achieving balanced flow distribution across all trailing edge slots.
Solution Approach 2:
Pressure regulating features are selectively applied to specific cavities based on their local cooling requirements. This allows the system to maintain precise manufacturing dimensions for all slots while providing localized pressure adjustments that optimize cooling flow distribution, preventing both excess and insufficient cooling in different radial regions.
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 solution ensures efficient cooling flow distribution by regulating the pressure ratio across each exit, reducing excess cooling flow and meeting temperature and flow requirements while maintaining the desired backflow margin, thus enhancing the overall efficiency of the gas turbine engine.
Implementation Method 1
At least one pressure regulating feature is located at an entrance to at least one individual cavity to control the downstream supply pressure to the trailing edge
Implementation Method 2
At least one axial rib separates an internal area adjacent to the trailing edge into a plurality of individual cavities
Data Source
AI summary
A gas turbine engine component comprises a body having a leading edge, a trailing edge, and a radial span. One internal channel in the body provides an upstream supply pressure. Another internal channel in body receives the upstream supply pressure and provides a downstream supply pressure. At least one axial rib separates an internal area adjacent to the trailing edge into a plurality of individual cavities. At least one pressure regulating feature is located at an entrance to at least one individual cavity entrance to control downstream supply pressure to the trailing edge. Exits formed in the trailing edge communicate with an exit pressure. The rib and pressure regulating features cooperate such that the downstream supply pressure mimics the exit pressure along the radial span.