Turbomachine Fan Blade Arrangement for Noise Reduction

Solution Overview

Problem

Conventional methods for manufacturing turbomachine fan blades fail to effectively reduce noise levels at multiple rotation frequencies due to geometric disparities and changes in blade behavior when hot and under aerodynamic load, leading to increased noise annoyance during aircraft take-off and landing.

Innovation Solution

A method that accounts for the hot behavior of blades by estimating structural parameters in operation and determining an optimal scheduling for blade arrangement around the disc, using cold measurements and predictive response surfaces to minimize noise levels at multiple frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional cold measurement methods are used to determine blade arrangement, then manufacturing simplicity is maintained, but noise level at FMR frequencies increases due to geometric disparities and hot behavior changes

Engineering Contradiction:

Improveblade arrangement determinationVSAvoidnoise level at FMR frequencies

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The method performs preliminary characterization of blade geometric parameters and hot behavior changes before final blade arrangement determination. By measuring geometric parameters cold and predicting hot behavior in advance, the system prepares compensation data that will be applied when arranging blades around the disk, thus preventing noise issues before they occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the parameters used for blade arrangement determination from simple cold geometric measurements to a combination of cold geometric parameters and predicted hot behavior parameters. This parameter transformation allows the system to account for thermal and aerodynamic effects that occur during operation, thereby reducing noise at FMR frequencies

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If blade arrangement is optimized for cold geometric parameters, then manufacturing precision is maintained, but noise attenuation deteriorates due to blade behavior changes under aerodynamic load and heat

Engineering Contradiction:

Improveblade geometric parametersVSAvoidnoise level at FMR frequencies

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention introduces a predictive model as an intermediary between cold geometric measurements and actual hot blade behavior. This model acts as a mediator that translates cold measurements into predictions of hot behavior, allowing the blade arrangement optimization to account for operational conditions without requiring direct measurement of hot blades

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The method performs preliminary characterization of blade geometric parameters and hot behavior changes before final blade arrangement determination. By measuring geometric parameters cold and predicting hot behavior in advance, the system prepares compensation data that will be applied when arranging blades around the disk, thus preventing noise issues before they occur

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If blades are arranged to minimize geometric disparities, then manufacturing complexity is reduced, but noise level at FMR frequencies increases due to nonlinear shock propagation sensitivity

Engineering Contradiction:

Improveblade arrangement determinationVSAvoidnoise level at FMR frequencies

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the parameters used for blade arrangement determination from simple cold geometric measurements to a combination of cold geometric parameters and predicted hot behavior parameters. This parameter transformation allows the system to account for thermal and aerodynamic effects that occur during operation, thereby reducing noise at FMR frequencies

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3303850B1Method for manufacturing a turbomachine fan having a reduced noise level at multiple rotational frequencies of said turbomachine

Publication Date: 2021.08.04 SAFRAN AIRCRAFT ENGINES SAS

Figure 1a~1b
Figure 2a~2b
Figure 3

AI summary

The invention relates to a method (100) for manufacturing a turbomachine fan comprising a plurality of blades mounted on a disc extending along a longitudinal axis, said method comprising the following steps of: - measuring (102) at least one structural parameter of each of the blades in the cold state, and, for each of the blades, estimating (103) at least one structural parameter in operation relating to a blade from the structural parameter(s) measured on said blade in the cold state, - determining (104) an optimal sequence of the blades around the disc from the structural parameters estimated in operation for each of the blades, and - mounting (105) the blades on the disc in the optimal sequence thus determined.