Geared Turbine Airfoil Tangential Stacking Offset

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Solution Overview

Problem

Gas turbine engine compressor sections with geared architectures face challenges in aerodynamic design due to significantly different compressor speeds, leading to inefficiencies and turbulence, particularly with counter-rotating fan and compressor blades.

Innovation Solution

The use of airfoils with a tangential stacking offset that varies along the span, optimizing the center of gravity to enhance aerodynamic efficiency and thermal performance by leaning towards the suction or pressure side, addressing the unique speed requirements of geared architecture engines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional airfoil geometries are used in geared architecture engines, then the design is simpler, but aerodynamic efficiency deteriorates due to significantly different compressor speeds

Engineering Contradiction:

Improveairfoil design simplicityVSAvoidaerodynamic efficiency

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The airfoil geometry is customized with specific tangential stacking offsets at different span positions (root, mid-span, tip) to optimize aerodynamic performance for each local region under high-speed rotation conditions

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The tangential stacking offset parameter is varied along the span of the airfoil, creating a non-uniform distribution that adapts to the different flow conditions at various radial positions in the high-speed compressor

Inventive Principle:

Principle #35Parameter changes

2Power

If counter-rotating fan and compressor blades are used, then power transfer efficiency is improved, but downstream turbulence and losses increase

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoiddownstream turbulence

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The airfoil design incorporates dynamic optimization for high rotational speeds, with geometry parameters specifically tailored to maintain stable flow attachment and reduce turbulence generation during rapid rotation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The design converts the potentially harmful high-speed rotation effects into beneficial aerodynamic performance by optimizing the airfoil shape to harness the high kinetic energy while minimizing turbulence and flow separation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If compressor speed is increased to improve efficiency, then power output increases, but aerodynamic stability deteriorates

Engineering Contradiction:

Improvecompressor efficiencyVSAvoidaerodynamic stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The airfoil geometry is pre-optimized with specific tangential stacking offsets designed beforehand to maintain stable flow patterns even at the elevated rotational speeds required for high efficiency operation

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3108117B2Gas turbine engine airfoil

Publication Date: 2023.10.11 RTX CORP

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AI summary

A compressor airfoil of a turbine engine having a geared architecture includes pressure and suction sides that extend in a radial direction from a 0% span position to a 100% span position. The airfoil has a relationship between a tangential stacking offset and span position that defines a curve that is non-linear.