Rotor Assembly Rolling Element Damping for Blade Vibration
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Solution Overview
Problem
Existing rotor assemblies face challenges in reducing vibration of rotor blades at natural frequencies corresponding to rotational speeds, limiting their flexibility and reliability.
Innovation Solution
Incorporating rolling elements that roll on curved surfaces within the rotor disc, where centrifugal force acts to dampen vibrations by setting the rolling frequency proportional to rotational speed, thereby reducing vibrations at specific harmonic orders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an adjustment member is interposed between the platform and damper member to adjust the contact angle, then the reaction force from the platform to the damper member can be increased or decreased, but it becomes difficult to reduce the vibration of the rotor blade at the natural frequency corresponding to the rotational speed
Solution Approach 1:
The patent replaces the static adjustment member with a dynamic rolling element that automatically adapts its rolling frequency to the rotational speed. The rolling element's frequency is proportional to the rotational speed (fn=C×Ω), enabling continuous adaptation to different operating conditions without manual adjustment, thus resolving the contradiction between reliability and adaptability in vibration control.
Solution Approach 2:
The invention changes the fundamental parameter from contact angle adjustment to rolling frequency control. By setting the rolling frequency fn=C×Ω where C is an integer-multiple order of excitation harmonic, the system can effectively target and dampen specific vibration modes at different rotational speeds, providing both reliability and flexibility.
2Reliability
If the rolling frequency fn is set proportional to rotational speed Ω with fn=C×Ω, then the vibration of the rotor blade can be damped on the excitation harmonic, but the device complexity increases due to the curved surface and rolling element mechanism
Solution Approach 1:
The patent employs a curved surface with constant curvature radius R on the rotor blade,配合the rolling element with radius r. This curved geometry enables the rolling element to naturally generate the required rolling frequency fn=C×Ω through centrifugal force during rotation, achieving complex vibration damping functionality through relatively simple geometric features rather than complex mechanical mechanisms.
Solution Approach 2:
The rolling element mechanism is self-regulating: as the rotor assembly rotates at different speeds, the centrifugal force automatically adjusts the rolling element's contact and rolling motion, maintaining the proportional relationship fn=C×Ω without external control systems. The system serves itself by utilizing the rotational motion to generate the required damping effect.
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
Effectively reduces rotor blade vibrations at natural frequencies corresponding to rotational speeds, enhancing the flexibility and reliability of the rotor assembly.
Implementation Method 1
as the rotor assembly rotates, the centrifugal force acts on the rolling element. Due to the action of the centrifugal force, the rolling element is pressed against the curved surface facing inward in the radial direction of the rotor disc
Implementation Method 2
the rolling element rolls on the curved surface. Since the rolling frequency fn of the rolling element is proportional to the rotational speed Ω of the rotor assembly
Implementation Method 3
when the constant C is set to an integer-multiple order of excitation harmonic, the vibration of the rotor blade is damped on the excitation harmonic
Data Source
AI summary
A rotor assembly includes: a rotor disc; a plurality of rotor blades fixed to the rotor disc and extending radially outward in a radial direction of the rotor disc; and at least one rolling element configured to roll on a curved surface facing inward in the radial direction of the rotor disc.