Impeller Tube Assembly Attenuation Bracket Design

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Solution Overview

Problem

Existing impeller tube assemblies in turbomachines face challenges in retaining the impeller and damper tubes at high and low rotational speeds, leading to noise and wear due to misassembly and vibration, as most designs require additional retention features.

Innovation Solution

An annular attenuation bracket with an annular attenuation arm and base, featuring cylindrical and frusto-conical through-holes, provides secure radial support and mechanical bonding through frictional shear bonds, eliminating the need for additional parts and minimizing stress concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional retention features are added to hold tubes in place during low speed operation, then tube retention reliability improves, but device complexity increases

Engineering Contradiction:

Improvetube retention reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The retention function is merged into the single-piece attenuation bracket structure itself, eliminating the need for separate retention features. The bracket's geometry directly provides retention through its configuration, combining support and retention functions in one integrated component.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The attenuation bracket is designed to retain the tubes through its own structural configuration without requiring additional retention features or external mechanisms. The single-piece structure self-retains the tubes through its geometric design.

Inventive Principle:

Principle #25Self-service

2Reliability

If traditional retention designs are used, then tube retention is achieved, but misassembly and tube clanking occur leading to noise and wear

Engineering Contradiction:

Improvetube retentionVSAvoidnoise and wear

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The attenuation bracket is designed with built-in vibration damping capabilities that counteract tube vibrations before they can cause clanking and wear. The structure proactively prevents the harmful effects of vibration through its geometric configuration.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The design converts the potential harmful effect of tube vibrations into a beneficial damping effect through the attenuation bracket's geometry. The structure utilizes the vibration energy to engage its damping features, transforming vibration from a harmful force into a mechanism that actively reduces noise and wear.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If multiple retention features are added to secure tubes at high and low speeds, then retention reliability improves, but manufacturing complexity and assembly difficulty increase

Engineering Contradiction:

Improveretention reliabilityVSAvoidmanufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple retention functions are merged into a single attenuation bracket component, eliminating the need for multiple separate retention features. This integration simplifies manufacturing to a single part production process and reduces assembly steps.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The attenuation bracket serves multiple functions simultaneously: it supports the tubes radially, retains them at both high and low speeds, and dampens vibrations. This multi-functionality in a single component reduces the total number of parts and simplifies both manufacturing and assembly.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The solution effectively secures the tubes in both rotational and non-rotational modes, reducing noise and wear by maintaining radial orientation and allowing differential thermal growth, while eliminating the need for extra retention features.

Implementation Method 1

mechanically bonded to the attenuation arm... frictional shear bonds

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

second frusto-conical through-holes... mechanical bonding through frictional shear bonds

Methodology Applied

Scientific EffectMechanical interference: Mechanical Force

Data Source

PatentUS8926290B2Impeller tube assembly

Publication Date: 2015.01.06 GE INFRASTRUCTURE TECH LLC

AI summary

An attenuation bracket is provided and includes an annular body having an annular attenuation arm defining first through-holes and an annular base defining second through-holes. A cross-section of the attenuation arm includes a flange, a connector opposite the flange and a curvilinear section extending between the flange and the connector. A cross-section of the base includes a first side corresponding with the flange and a second side opposite the first side and corresponding with the connector. The second side is connectable with the connector such that each of the first through-holes is defined in positional alignment with a corresponding one of the second through-holes.