Slotted Rotor Secondary Flow for Gas Turbine Cooling
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Solution Overview
Problem
Gas turbine rotor systems face challenges with thermo-mechanical fatigue due to high pressure and temperature differentials, leading to heavier-than-optimal components and inefficient secondary cooling flow systems that reduce engine performance.
Innovation Solution
The use of a hybrid dual alloy integrally bladed rotor design with differential materials and heat treatments for blades and rotor disks, along with a spoked configuration that reduces thermo-mechanical fatigue and incorporates optimized airflow paths for enhanced cooling, allows for weight reduction and improved engine efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If traditional rotor design with solid structure is used, then structural strength is maintained, but weight increases and cooling efficiency decreases
Solution Approach 1:
The rotor design incorporates slots that divide the rotor disk into segmented regions, allowing secondary cooling airflow to pass through. This segmentation reduces the amount of material required while maintaining structural integrity through the blade root attachments and spoke configurations, thereby reducing weight without compromising strength.
Solution Approach 2:
The rotor employs a porous-like structure with multiple slots and passages integrated into the rotor disk and blades. These openings allow cooling airflow to penetrate and circulate through the rotor structure, providing efficient cooling while reducing material usage and overall weight compared to a solid rotor design.
2Temperature
If secondary cooling flow system is added, then thermal protection is improved, but engine efficiency decreases due to airflow losses
Solution Approach 1:
The cooling flow passages are integrated directly into the rotor structure, merging the cooling function with the rotor's structural components. The slots and passages are formed as part of the rotor disk and blade geometry, eliminating separate cooling system components and reducing airflow restrictions that would cause energy losses.
Solution Approach 2:
The cooling airflow is directed through three-dimensional passages and slots within the rotor structure, utilizing the radial and axial dimensions of the rotor. This dimensional integration allows cooling air to reach thermal hot spots directly through internal pathways, improving thermal protection while minimizing the volume of cooling air required compared to external cooling systems.
3Reliability
If hybrid dual alloy design is used, then resistance to thermo-mechanical fatigue is improved, but manufacturing complexity increases
Solution Approach 1:
The rotor employs different alloy materials in specific regions where thermal and mechanical stresses differ. The rotor disk and blades utilize dual alloy construction with heat-treated regions in areas subject to high thermo-mechanical fatigue, while other regions use standard materials. This localized application of enhanced materials improves reliability without requiring the entire rotor to be manufactured with complex high-performance alloys.
Data Source
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AI summary
A rotor (60) for a gas turbine engine includes a plurality of blades (64) which extend from a rotor disk (66) and at least one spacer (62CA) adjacent to the plurality of blades (64). A flow passage is defined between the rotor disk (66) and the blades (62) and spacer (62CA). A plurality of inlets (88) are formed within the spacer (62CA) to pump air into the flow passage.