Turbomachine Rotor Intermediate Support for Tie Rod Resonance
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Solution Overview
Problem
Existing turbomachine rotors with stacked impellers face limitations in achieving higher rotational speeds due to resonance issues with the tie rod, which restricts the number of impellers and compression ratios that can be achieved.
Innovation Solution
The introduction of an intermediate support member between the tie rod and the rotor segments, comprising an inner annular component and an outer annular component formed by resiliently coupled annular segments, increases the first resonance frequency of the tie rod, allowing for higher operational speeds and longer tie rods without resonance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the tie rod length is increased to accommodate more impellers, then the number of impellers increases, but the first resonance frequency decreases limiting operational speed
Solution Approach 1:
The intermediate support member acts as a mediator between the tie rod and the rotor segments. It provides additional support at an intermediate position along the tie rod, effectively dividing the tie rod into multiple supported sections. This increases the first resonance frequency of the tie rod system, allowing longer tie rods to be used without being limited by resonance at high rotational speeds, thereby enabling more impellers to be mounted while maintaining high operational speeds.
2Productivity
If the tie rod length is increased to achieve higher compression ratios, then the compression ratio increases, but the resonance frequency decreases
Solution Approach 1:
The intermediate support member serves as an intermediary structural element that enhances the reliability of the tie rod by increasing its resonance frequency. This allows the tie rod to be made longer to accommodate higher compression ratios through additional impellers, while the intermediate support prevents resonance issues that would otherwise limit the tie rod length and compromise system reliability.
3Speed
If shorter tie rods are used to increase resonance frequency, then the operational speed increases, but the number of mountable impellers decreases
Solution Approach 1:
The intermediate support member segments the tie rod structure by providing support at an intermediate position. This segmentation allows the tie rod to be effectively divided into multiple shorter supported sections, each contributing to the overall resonance characteristics. The result is that the system can achieve high resonance frequencies suitable for high-speed operation while still accommodating multiple impellers along the extended tie rod structure.
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 enables turbomachines to operate at higher rotational speeds with a larger number of impellers, enhancing compression ratios and efficiency, particularly beneficial for processing low-molecular weight gases like hydrogen.
Implementation Method 1
The annular segments are configured such that during rotation of the rotor around the rotation axis, the annular segments expand under the effect of the centrifugal force and press against the inner surface of the through bore of the impeller housing the intermediate support member
Implementation Method 2
Each annular segment is resiliently coupled to the inner annular component by at least one resilient member arranged between the inner annular component and the respective annular segment
Data Source
AI summary
The rotor comprises a plurality of rotor segments arranged axially adjacent to one another. A tie rod extends through the rotor segments. Opposed first and second locking members arranged at the axial ends of the tie rod lock the rotor segments to one another and to the tie rod. At least one intermediate support member is arranged in an intermediate position between the two axial ends of the tie rod and between the tie rod and one of the rotor segments.