Compressor Blade Stacking Line Geometry for Leakage Control

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Solution Overview

Problem

Existing turbomachine compressor blade designs suffer from significant radial clearance between the blade and the casing, leading to leakage flows and potential damage from contact, which limits efficiency and operational reliability.

Innovation Solution

A compressor blade design featuring a stacking line that passes through specific points, including the root, tip, and radial extremum, allowing for a 'cylinder/plane' contact that enables elastic deformation and reduces radial clearance, thereby minimizing leakage flows and preventing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If radial clearance is reduced to improve compressor efficiency, then leakage flows are reduced, but the risk of blade-casing contact and blade damage increases

Engineering Contradiction:
Improveleakage flow lossVSAvoidblade damage risk
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the blade head by introducing a stacking line with specific characteristics (passing through three points including root, tip, and radial extremum). This geometric modification allows the blade to achieve both reduced radial clearance and controlled elastic deformation capability, resolving the contradiction between reducing leakage flow and preventing blade damage

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent makes the blade head dynamic by enabling elastic deformation through its specific geometry. The stacking line design allows the blade to deform elastically during operation, transforming from a static rigid structure to a dynamic one that can adapt to contact conditions, thus reducing damage risk while maintaining small clearance

Inventive Principle:
Principle #15Dynamics

2Productivity

If radial clearance is reduced to improve compressor efficiency, then leakage flows are reduced, but operational reliability decreases due to potential blade contact

Engineering Contradiction:
Improvecompressor efficiencyVSAvoidoperational reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By modifying the geometric parameters of the blade head through the stacking line design, the patent enables the system to achieve higher compressor efficiency via reduced clearance while simultaneously improving operational reliability through controlled elastic deformation capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The specific stacking line geometry acts as a pre-designed cushioning mechanism that anticipates potential contact conditions. The geometry is configured in advance to allow elastic deformation that absorbs contact energy, preventing damage before it occurs and ensuring continuous reliable operation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Loss of energy

If blade geometry is modified to reduce radial clearance, then leakage flows are reduced, but blade rigidity may be compromised

Engineering Contradiction:
Improveleakage flow lossVSAvoidblade rigidity
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

The patent applies local quality by modifying only the blade head region (where the stacking line is defined) while maintaining the rigidity of other blade portions. The stacking line geometry is specifically designed in the head area to enable controlled deformation, while the rest of the blade retains its structural strength and rigidity for normal operational loads

Inventive Principle:
Principle #3Local quality

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 design achieves reduced radial clearance, preventing leakage flows and allowing higher rotation speeds, enhancing compressor efficiency and operational reliability while maintaining air flow guidance without damaging the blade.

Implementation Method 1

the conventional 'tip/plane' contact of the blade head on the casing becomes a 'cylinder/plane' contact, which allows elastic deformation of the blade in case of contact and limits damage to the blade head

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the geometry of the blade tip creates 'obstacles' to the radial airflow. The formation of leakage vortices at the blade tip is prevented

Methodology Applied
Scientific EffectVortex formation prevention: Vortex Ring

Data Source

PatentEP4115090B1Blade for a turbine engine compressor
Publication Date: 2023.05.10 SAFRAN AERO BOOSTERS SA
  • EP4115090B1 patent drawingFigure 1~3
  • EP4115090B1 patent drawingFigure 4~5C
  • EP4115090B1 patent drawingFigure 6~9

AI summary

The invention relates to a rotar blade (24) for a compressor (4) extending substantially radially and comprising a vane (24.1), the geometry of which is due to the stacking of wing section-shaped profiles in a line (L) called a stacking line, characterised in that the stacking line (L) passes through at least three points including a point (A) forming the blade foot (24), a point (F) defining the blade head (24) and a point (E) forming the radial extremum of the stacking line (L).