Variable Contact Damping for Turbomachine Bucket Vibration
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Solution Overview
Problem
Existing turbomachines experience vibration issues at low rotational speeds, which are not effectively damped by conventional structures that separate at low speeds, leading to inefficiencies and potential damage.
Innovation Solution
A variable contact-type vibration damping structure is implemented on bucket blades, featuring first and second damping members with specific geometric configurations that adjust contact areas and gaps based on rotational speed, ensuring consistent damping across varying turbine speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If connections are separated at low speed, then device complexity is reduced, but vibration damping capability deteriorates
Solution Approach 1:
The connection structure transitions from static separation to dynamic variable contact based on rotational speed. The first and second connections are designed to contact each other within a specific rotational speed range, providing vibration damping when needed while remaining separated at low speeds to maintain simplicity.
Solution Approach 2:
The contact state between connections changes based on rotational speed parameter. At low speeds, connections remain separated; within the specific speed range, they contact to damp vibrations; at high speeds, they separate again. This parameter-based state change resolves the contradiction between structural simplicity and vibration damping effectiveness.
2Reliability
If connections contact at high speed, then vibration damping capability is improved, but device complexity increases
Solution Approach 1:
The connection structure is designed to dynamically contact only within specific operational conditions (medium rotational speeds), rather than maintaining constant contact. This dynamic behavior provides vibration damping when needed while avoiding the complexity of always-contact structures.
Solution Approach 2:
The contact state is controlled by rotational speed parameters. The connections are positioned and dimensioned to contact each other only within a specific speed range, automatically providing vibration damping without requiring complex control mechanisms or permanent contact structures.
3Reliability
If variable contact structure is implemented, then vibration damping capability is improved across all speeds, but device complexity increases
Solution Approach 1:
The damping structure is segmented into multiple connections (first connection, second connection, third connection, fourth connection) with specific geometric features (protrusions and recesses). These segmented elements work together to provide variable contact damping across different speed ranges without requiring a single complex mechanism.
Solution Approach 2:
The connections feature asymmetric geometric configurations with specific protrusions and recesses positioned at predetermined locations. This asymmetric design enables selective contact between specific connection pairs at different rotational speeds, achieving comprehensive vibration damping through simple geometric arrangements rather than complex mechanisms.
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 damps vibrations at both low and high speeds by optimizing contact areas and gaps between damping members, enhancing power generation efficiency and preventing damage.
Implementation Method 1
the first and second connections may contact each other within a predetermined rotational speed range... effectively damps vibrations at both low and high speeds by optimizing contact areas and gaps between damping members
Data Source
AI summary
Disclosed herein are a bucket vibration damping structure and a bucket and turbomachine having the same. The bucket vibration damping structure comprises a plurality of blades disposed on a plurality of buckets mounted on an outer peripheral surface of a rotor disk and a variable contact-type vibration damping means disposed on the plurality of blades and performing variable contact according to rotational speed of a rotor for damping vibration. The variable contact-type vibration damping means may comprise a first damping member disposed on one of the blades, and a second damping member disposed at a position corresponding to the first damping member on the other blade. According to the disclosure, it is possible to effectively damp vibration while performing variable contact according to the rotational speed of a turbine.