Compressor Rotor Blade Thickening for Resonance Control

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Solution Overview

Problem

Compressor rotor blades of the ninth phase face challenges in achieving high aerodynamic efficiency while minimizing resonance problems due to flexural vibrations, which reduce component life and affect mechanical load, necessitating a design that balances efficiency and reliability.

Innovation Solution

The rotor blade features a unique aerodynamic profile with a concave and convex surface combination, including a thickening portion that shifts resonance frequencies outside the operational range, preventing instability and vibrations, and an adaptive thickness trend to optimize performance and longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the rotor blade uses a conventional aerodynamic profile, then the aerodynamic efficiency is improved, but resonance problems due to flexural vibrations increase

Engineering Contradiction:
Improveaerodynamic efficiencyVSAvoidresonance stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent applies local quality by introducing a thickening portion at a specific location on the rotor blade (at least at one of the leading edge or trailing edge). This localized structural modification changes the resonance frequencies specifically at that region without altering the overall aerodynamic profile, thereby resolving the contradiction between maintaining aerodynamic efficiency and reducing resonance problems.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by modifying the thickness parameter of the rotor blade through the thickening portion. This parameter change shifts the resonance frequencies outside the functioning frequency range of the rotor, allowing the blade to maintain its aerodynamic efficiency while avoiding resonance instability in the operational range.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the rotor blade thickness is increased to reduce vibrations, then the resonance stability is improved, but the aerodynamic efficiency decreases

Engineering Contradiction:
Improveresonance stabilityVSAvoidaerodynamic efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Instead of uniformly increasing the blade thickness which would harm aerodynamic efficiency, the patent applies local quality by concentrating the thickening portion only at specific locations (leading edge or trailing edge). This localized approach modifies resonance characteristics without significantly impacting the overall aerodynamic performance of the blade.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the blade structure by introducing a discrete thickening portion rather than uniformly thickening the entire blade. This segmentation allows independent optimization of structural stability and aerodynamic efficiency, as the thickening is confined to specific regions that do not critically affect the aerodynamic flow.

Inventive Principle:
Principle #1Segmentation

3Power

If the rotor blade operates at high speed, then the power output is increased, but flexural vibrations and resonance problems worsen

Engineering Contradiction:
Improvepower outputVSAvoidvibration stability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent uses parameter changes by modifying the thickness parameter through the thickening portion to shift resonance frequencies. This allows the rotor to operate at high speeds for increased power output while the shifted resonance frequencies remain outside the functioning frequency range, preventing vibration-related reliability issues.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1826413B1Rotor blade for a ninth phase of a compressor
Publication Date: 2011.11.02 NUOVO PIGNONE SPA
  • EP1826413B1 patent drawingFigure 1~2
  • EP1826413B1 patent drawingFigure 3
  • EP1826413B1 patent drawing

AI summary

The invention relates to a blade (10) of a rotor of a ninth phase of a compressor, which can be defined by coordinates of a discreet combination of points, in a Cartesian reference system (X,Y,Z), wherein the axis (Z) is a radial axis intersecting the central axis of the compressor, said blade (10) having a profile which can be identified by means of a series of closed intersection curves between the profile itself and planes (X,Y) lying at distances (Z) from the central axis, said blade (10) also comprising a thickening (30), substantially parallel to a base portion (12) of the blade (10) itself, fixable to said rotor, said thickening (30) being substantially situated half-way up the blade (10) and being suitable for shifting the natural resonance frequencies of the blade (10) itself outside a functioning frequency range of said rotor.