Turbomachinery Blade Phase Angle for Flutter Suppression

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Solution Overview

Problem

Existing turbomachinery designs face issues with blade cascade flutter due to improper blade combinations, leading to reduced efficiency and shortened product lifetime, as seen in techniques like JP 5883610 B2, which destabilize airflow and reduce aerodynamic performance.

Innovation Solution

The turbomachinery design involves setting the number of first and second blades such that the interblade phase angle of the second blade row is ±180°, suppressing self-excited vibrations while maintaining aerodynamic performance by arranging blades at constant pitches in the circumferential direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of rotary blades is changed for each sector to suppress excitation, then blade cascade flutter is suppressed, but air flow stabilization deteriorates and aerodynamic performance reduces

Engineering Contradiction:

Improveblade cascade flutter suppressionVSAvoidaerodynamic performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent changes the parameter of blade count from a spatially variable distribution (different counts in different sectors) to a uniform distribution (constant count throughout), while simultaneously adjusting the interblade phase angle parameter to ±180° to achieve both flutter suppression and airflow stabilization

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces asymmetry in the phase relationship between blade rows by setting the interblade phase angle to ±180°, creating an antisymmetric vibration pattern that suppresses flutter while maintaining symmetric uniform blade distribution for stable airflow

Inventive Principle:

Principle #4Asymmetry

2Device complexity

If improper blade combinations are used, then device complexity is reduced, but blade cascade flutter occurs and product lifetime shortens

Engineering Contradiction:

Improveblade configuration simplicityVSAvoidproduct lifetime

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent identifies and applies a specific parameter relationship (interblade phase angle = ±180°) that provides a simple design rule for selecting blade combinations, ensuring both structural simplicity and reliability through extended product lifetime

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If blades are arranged at constant pitches in the circumferential direction, then manufacturing precision is improved, but self-excited vibrations occur due to improper blade combinations

Engineering Contradiction:

Improveblade pitch uniformityVSAvoidvibration suppression

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent maintains the simple constant pitch arrangement for manufacturing ease while changing the operational parameter of interblade phase angle to ±180°, thereby achieving vibration suppression without compromising manufacturing precision

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11753989B2Turbomachinery and method for designing turbomachinery

Publication Date: 2023.09.12 HONDA MOTOR CO LTD

AI summary

A turbomachinery includes a casing, a rotor shaft rotatably attached to the casing, a first blade row fixed to either one of the rotor shaft or the casing, and a second blade row fixed to either one of the rotor shaft or the casing and arranged adjacent to the upstream side or downstream side of the first blade row, wherein the turbomachinery sets the number of first blades and the number of second blades in a manner that the interblade phase angle difference of the second blade row is ±180°.