Tuned Rotor Disk for Gas Turbine Clearance Control
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Solution Overview
Problem
In gas turbine engines, the design paradigm primarily focused on temperature and strength requirements limits the tightness of clearances between rotor blades and their cases, leading to inefficiencies due to mismatched centrifugal and thermal growth, which affects engine performance and efficiency.
Innovation Solution
The rotor disks are designed with materials and mass that enhance centrifugal and thermal growth responsiveness, using single crystal alloys like nickel-based superalloys to achieve a tuned clearance response, allowing for tighter clearances and improved engine performance by matching the expansion and contraction rates of rotor disks and their cases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotor disks are designed with traditional materials focusing on temperature and strength requirements, then structural integrity is maintained, but clearance tightness between rotor blades and cases deteriorates due to mismatched centrifugal and thermal growth
Solution Approach 1:
The patent changes the physical parameters of the rotor disk by using selective laser melting to create a cellular internal structure. This transforms the disk from a solid structure to one with controlled porosity, enabling independent tuning of centrifugal and thermal growth characteristics to achieve better clearance matching while maintaining structural integrity
Solution Approach 2:
The patent employs composite material structure combining solid outer shell with cellular internal structure. This composite approach allows the rotor disk to exhibit tailored mechanical properties, specifically controlling the differential expansion between centrifugal and thermal growth to optimize blade clearance
2Strength
If rotor disk mass is increased to maintain structural strength, then temperature and strength requirements are met, but centrifugal growth responsiveness increases causing clearance mismatch
Solution Approach 1:
The patent segments the rotor disk internal structure into a cellular configuration with interconnected struts and cavities. This segmentation reduces overall mass while maintaining structural strength through the distributed load-bearing network, thereby decreasing centrifugal growth responsiveness and improving clearance matching
Solution Approach 2:
The patent applies local quality by creating non-uniform cellular structures with varying cell sizes, shapes, and densities in different regions of the rotor disk. This allows localized optimization of mass distribution and stiffness characteristics to control differential expansion patterns and achieve optimal clearance response
3Ease of manufacture
If traditional solid rotor disk structure is used, then manufacturing is straightforward, but clearance control between rotor blades and cases is poor due to mismatched growth characteristics
Solution Approach 1:
The patent replaces traditional mechanical manufacturing methods with additive manufacturing (selective laser melting). This substitution enables direct fabrication of complex cellular internal structures that would be impossible to create with conventional machining, achieving both manufacturing feasibility and superior clearance control
Solution Approach 2:
The patent introduces dynamic adaptability by creating a rotor disk structure that responds differently to centrifugal and thermal loads. The cellular structure allows the disk to dynamically adjust its dimensional characteristics under operating conditions, enabling active clearance management through passive structural design
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 approach enables tighter clearances and enhanced engine efficiency by controlling the radial location of rotor blades, reducing gas escape and increasing performance parameters like T3 and OPR, while maintaining design life objectives.
Implementation Method 1
mismatched centrifugal and thermal growth
Implementation Method 2
thermal growth responsiveness
Data Source
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AI summary
A gas turbine engine (20) includes a rotor (62) that has a rotor disk (66; 166; 266; 366) and a plurality of circumferentially-spaced blades (68; 168). The rotor disk (66; 166; 266; 366) and the blades are co-rotatable about an axis (A). A case (64) circumscribes the rotor. The rotor disk (66; 166; 266; 366) is tuned, with regard to centrifugal and thermal growth responsiveness, to the case for a given operational scenario of the gas turbine engine (20) such that the rotor disk (66; 166; 266; 366) and case (64) together provide a tuned clearance response. The operational scenario involves a series of engine events that include at least two of engine acceleration, engine deceleration, engine steady-state operation.