Mid-Turbine Frame Baffle for Uniform Cooling Air Temperature
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Solution Overview
Problem
The existing cooling systems for gas turbine engines, particularly the mid-turbine frame, often fail to maintain desired temperature levels due to heating of cooling air, leading to non-uniform temperature distribution and increased thermal stresses within the turbine case.
Innovation Solution
A baffle system is introduced within the outer cavity of the mid-turbine frame, featuring a plurality of openings that direct cooling airflow transverse to the radially inner wall, preventing impingement and ensuring a uniform temperature distribution by circulating cooling air forward, aft, and circumferentially, thereby maintaining the cooling air within a desired temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is routed directly to the low pressure turbine case through the mid-turbine frame cavity, then cooling is provided to the turbine case, but the cooling air is heated above a temperature capable of sufficiently cooling the low pressure turbine case
Solution Approach 1:
The cooling air flow path is segmented into multiple directions using baffles with multiple openings. Instead of a single direct flow path, the cooling air is divided into multiple streams that travel forward, aft, and circumferentially, preventing direct impingement on the inner wall and maintaining lower temperatures throughout the cavity.
Solution Approach 2:
Baffles act as intermediary structures within the cavity to redirect and distribute cooling air flow. These baffles with multiple openings serve as mediators that transform the direct impinging flow into a distributed multi-directional flow pattern, preventing excessive heating while maintaining cooling effectiveness.
2Productivity
If cooling air flows directly impinging on the inner wall of the outer cavity, then cooling air is delivered to the turbine case, but non-uniform temperature distribution and increased thermal stresses occur
Solution Approach 1:
The cooling air flow is segmented into multiple directional streams using baffles with multiple openings arranged to direct flow forward, aft, and circumferentially. This segmentation ensures uniform temperature distribution across the cavity by preventing concentrated impingement on any single area of the inner wall.
Solution Approach 2:
Different regions of the cavity are provided with tailored cooling air flow patterns through strategically positioned baffles with multiple openings. Each local area receives cooling air in an optimized manner appropriate to its specific thermal requirements, achieving uniform overall temperature distribution.
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 baffle system effectively prevents direct impingement of cooling air on the inner wall, maintaining a uniform temperature and reducing thermal stresses, ensuring efficient cooling of the turbine case while maintaining the cooling air within a desired temperature threshold.
Implementation Method 1
A baffle is configured to receive cooling air through the radially outer wall and direct cooling airflow within the outer cavity to prevent impingement on the inner wall
Implementation Method 2
the baffle includes a plurality of openings for directing cooling air transverse to the radially inner wall of the outer cavity
Data Source
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AI summary
A turbine engine includes a frame assembly (58) including an outer cavity (62) and an inner cavity (64) with the outer cavity (62) including at least one opening configured and adapted to communicate cooling air to the turbine case. A baffle (68) within the outer cavity (62) includes a plurality of openings (86) for directing cooling airflow into the outer cavity (62) for preventing impingement on a radially inner wall (78) of the outer cavity (62) for maintaining a desired temperature of the cooling air within the outer cavity (62).