Gas-Turbine Rotor Disk Vibration Damper Mass Flexibility
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Solution Overview
Problem
Existing vibration dampers for gas turbine blades face challenges in achieving optimal mass and flexibility, particularly in slow turbines, leading to inefficient vibration damping due to the incompatibility between compliance with vibratory context and frictional quality, especially in reduced inter-platform spaces.
Innovation Solution
The solution involves separating the functions of mass and flexibility by independently producing a flexible plate and a mass part, coupling them reversibly, and inserting the dampers into dedicated housings, where the flexible plate adapts to contact zones and the mass part concentrates friction forces, allowing for adjustable mass and improved deformation under centrifugal forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of the sheet is increased to achieve optimal mass for damping slow turbines, then the damping mass is improved, but the flexibility and frictional quality of the damper deteriorate
Solution Approach 1:
The damper is divided into two separate parts: a flexible plate component and a mass component (counterweight). The flexible plate is made from thin sheet material (0.2-0.7mm) that can deform and adapt to the platform surface, while the counterweight provides the necessary mass for damping slow turbine vibrations. This segmentation allows each component to optimize its specific function without compromising the other.
Solution Approach 2:
The damper combines two different materials with distinct properties: a flexible metallic plate material that provides adaptability and frictional contact, and a dense counterweight material (such as lead or steel) that provides the required mass. This composite approach enables the damper to simultaneously achieve flexibility and optimal mass, resolving the technical contradiction between these two opposing requirements.
2Weight of moving object
If the thickness of the sheet is increased to provide sufficient mass, then the mass requirement is met, but the ability to deform under centrifugal forces and adapt to contact zones is reduced
Solution Approach 1:
The functional separation divides the sheet into a thin flexible plate portion that deforms under centrifugal forces to adapt to contact zones, and a separate counterweight portion that provides the necessary mass. The thin plate (0.2-0.7mm) maintains high deformation capability while the counterweight supplies adequate mass for damping effectiveness.
Solution Approach 2:
The flexible plate is designed as a thin film structure that can easily deform under centrifugal forces during turbine operation. This thin film approach maximizes adaptability to the platform contact zones while the separate counterweight compensates for the reduced mass of the thin plate itself.
3Weight of moving object
If the mass of the damper is increased to control vibrations in slow turbines, then the damping effectiveness is improved, but the distribution of contact zones and friction forces becomes uneven
Solution Approach 1:
By separating the mass function (counterweight) from the contact function (flexible plate), the system allows the flexible plate to naturally conform to the platform surface and distribute contact zones evenly, while the counterweight provides the necessary mass without interfering with contact distribution. This resolves the issue of uneven friction force distribution that occurs with thick rigid sheets.
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 effective damping of resonances in slow turbines by ensuring optimal mass distribution and flexibility, enhancing the adaptation to bearing surfaces and reducing wear points, thereby improving vibration absorption efficiency.
Implementation Method 1
In their movements, the sheets are pressed against the platforms by centrifugal forces
Implementation Method 2
the energy generated by the movement of the blades and the vibrating platforms is dissipated by friction of these sheets against the platforms
Implementation Method 3
The flexible plate is sufficiently flexible to adapt to the level of contact required
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The invention relates to providing a turbine wheel with optimal-mass dampers capable of damping a predetermined resonance in the context of the vibration of a turbine, particularly a low-speed turbine, while assisting in the flexibility of adapting to the bearing surfaces of the recesses of the dampers. To this end, the invention involves separating the mass and flexibility functions by means of a flexible portion for clamping against the platform, and a mass portion for controlling frictional forces. A damper (2) according to the invention specifically comprises a plate (10) and a counterweight (12). The plate (10) is punched from a metal sheet that is substantially thinner than that of the counterweight (12). The plate (10) has a wall (101) capable of flexibly contacting a platform of the blade of the wheel while at least partially surrounding a surface (121) of the counterweight (12). The invention can be used in particular for the wheel of the turbine of a turbine engine, of a blower, or of a BP compressor having mounted blades.