Turbine Compressor Blade Protuberance for Flow Control

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Solution Overview

Problem

Existing axial turbomachines, such as aircraft turbojets and turboprops, face challenges in optimizing compression rate and reducing corner separations at the extrados level, while also requiring a solution that is simple, resistant, lightweight, economical, reliable, and easy to produce and maintain.

Innovation Solution

The compressor features a protuberance with two main bumps or convexities between consecutive blades, where the first bump is more developed radially and extends from the intrados surface, and the second bump is smaller and attached to the extrados surface, with specific dimensions and orientations to enhance compression and reduce swirls and separations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a three-dimensional relief with two humps separated by a sinusoidal channel is used on the inter-blade surface, then aerodynamic efficiency is improved, but corner separation on the upper surface of the blades increases

Engineering Contradiction:
Improveaerodynamic efficiencyVSAvoidcorner separation
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies different geometric features at different locations on the inter-blade surface. Specifically, it uses a first convexity (boss) extending from the intrados surface and a second convexity extending from the extrados surface, each with different characteristics. This local differentiation allows the first convexity to control flow attachment and reduce corner separation while the second convexity maintains aerodynamic efficiency, thus resolving the contradiction between improved efficiency and reduced corner separation.

Inventive Principle:
Principle #3Local quality

2Productivity

If the compression rate is increased, then the performance of the compressor improves, but the complexity of the blade geometry increases

Engineering Contradiction:
Improvecompression rateVSAvoidblade geometry complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the inter-blade surface into distinct geometric features: a first convexity (boss) and a second convexity, each serving specific functions. The first convexity extends over a significant portion of the bonding surface to enhance compression, while the second convexity is more localized. This segmentation allows independent optimization of each feature's contribution to compression rate, achieving high performance without excessive overall complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes specific geometric parameters of the convexities to achieve high compression rates. The first convexity has a controlled extension length (30-50% of blade length) and radial development, while the second convexity has specific dimensional relationships (surface area at most 5% of the protuberance surface). These parameter optimizations enable enhanced compression performance with manageable geometric complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3477049B1Turbine engine compressor with ring comprising elevations
Publication Date: 2023.11.22 SAFRAN AERO BOOSTERS SA
  • EP3477049B1 patent drawingFigure 1
  • EP3477049B1 patent drawingFigure 2
  • EP3477049B1 patent drawingFigure 3

AI summary

The invention relates to a low-pressure compressor for an axial turbomachine, such as a turbojet engine. The compressor comprises an annular row of blades (26) and an inter-blade passage (42) with a connecting surface (44) linking the lower surface (38) of a first blade (26) to the upper surface (40) of a second blade (26) in the row. The connecting surface (44) has a main protrusion (52) comprising a first hump (54) and a second hump (58) spaced apart from each other.