Gas Turbine Rotor Disk Damper Pivot Support
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Solution Overview
Problem
The existing damper systems in gas turbine engines, particularly those using Ceramic Matrix Composite (CMC) blades, face increased bending stresses due to the mass of traditional dampers, which can compromise the structural integrity and efficiency of the blades, as thicker platforms are required to support the damper and platform mass, negating the advantages of CMC materials.
Innovation Solution
A rotor disk assembly with a damper pivot support extending from the rim of the disk, featuring independently pivotable dampers with angled contact surfaces that contact the blades below their platforms, reducing stress on the platform and utilizing counterweights to manage centrifugal forces for effective damping without increasing platform thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional dampers are mounted to the platform of CMC turbine blades, then vibration damping is achieved, but bending stress on the blade increases due to damper mass
Solution Approach 1:
The damper assembly is extracted from the blade platform and relocated to the rotor disk. The damper pivot support extends from the rotor disk rim, positioning the damper mass away from the blade platform, thereby eliminating the additional bending stress on the CMC blade while maintaining vibration damping functionality through frictional contact with the blade platform.
2Strength
If the platform is made thicker to support damper mass, then structural capability is improved, but the advantages of CMC materials are negated
Solution Approach 1:
The damper mass is extracted from the blade platform location and relocated to the rotor disk. This extraction eliminates the need to increase platform thickness, allowing the platform to maintain its original thin design that enables CMC material advantages such as reduced weight, improved heat transfer, and higher temperature operation.
3Ease of manufacture
If dampers are mounted using posts and shelf features on blade platforms, then damper support is achieved, but additional platform thickness is required
Solution Approach 1:
The damper mounting system is extracted from the blade platform and relocated to the rotor disk. The damper pivot support extends from the rotor disk rim with the damper assembly pivotably attached, eliminating the need for posts and shelf features on the blade platform and avoiding any increase in platform thickness.
4Reliability
If multiple dampers are mounted on each side of the platform, then vibration damping coverage is improved, but bending stress and platform mass increase
Solution Approach 1:
Multiple dampers are extracted from the blade platform location and relocated to the rotor disk. The first and second dampers are pivotably attached to the damper pivot support on the rotor disk, allowing them to contact the respective blades during rotation. This provides comprehensive vibration damping coverage for multiple blades without adding mass or stress to any single blade platform.
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 effectively dissipates vibration while minimizing bending stresses on the CMC blades, maintaining the structural benefits of CMC materials by distributing damping forces efficiently and reducing the risk of platform damage from excessive stress.
Implementation Method 1
a damper mounted to the seal and the platforms between adjacent turbine blades dissipates vibration through frictional contact between the damper and an underplatform surface of the two adjacent turbine blade platforms
Implementation Method 2
utilizing counterweights to manage centrifugal forces for effective damping without increasing platform thickness
Data Source
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AI summary
A rotor disk assembly (60) for a gas turbine engine (20) includes a rotor disk (86) that defines an axis; and a damper pivot support (112) that extends from a rim (106) of the rotor disk (86), the damper pivot support (112) comprising an aperture (114) that defines a pivot axis (T) parallel to the axis. A method to dampen a rotor blade (84) of a gas turbine engine (20), includes pivotably mounting a damper assembly (126) to a damper pivot support (112) that extends from a rim (106) of a lug (110) in a rotor disk (86), the lug (110) between a first blade slot (94) and a second blade slot (94), the damper pivot support (112) defines a pivot axis (T) parallel to the axis; and independently pivoting a first damper (120) and a second damper (122) of the damper assembly (126) about the pivot axis (T) to respectively contact a first blade (84A) and a second blade (84B) in response to centrifugal force, a first contact surface (130) of the first damper (120) and a second contact surface (132) of the second damper (122) contacting the respective blades (84A, 84B) below a platform (90A, 90B) of the respective first blade (84A) and second blade (84B).