Notched Turbine Airfoils for Weight Reduction and Flow Separation Control

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Solution Overview

Problem

Current gas turbine engine airfoils suffer from large closed pressure surface separation, exacerbating end-wall flow fields, and there is a desire to reduce weight in these engines.

Innovation Solution

The airfoils are designed with notches on the pressure side that extend into the external surface, minimizing weight while isolating radial outward separation of the pressure surface boundary layer to allow airflow, featuring varying notch heights and configurations to enhance airflow efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If notches are added to the airfoil pressure side, then weight is reduced, but airflow separation may increase

Engineering Contradiction:

Improveairfoil weightVSAvoidairflow separation losses

Core Design Contradiction:

Weight of moving objectVSLoss of energy

Solution Approach 1:

The airfoil pressure surface is segmented into multiple discrete notches rather than a continuous modification. This segmentation allows weight reduction through material removal while the discrete nature of individual notches limits the extent of airflow separation to localized regions, preventing large-scale separation losses

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The notches are strategically positioned and sized to create local modifications only where beneficial for weight reduction, while maintaining the integrity of the overall pressure surface geometry. The local nature of the notches ensures that airflow separation remains localized rather than propagating across the entire airfoil surface

Inventive Principle:

Principle #3Local quality

2Weight of moving object

If notches extend deeper into the airfoil, then more weight is removed, but boundary layer separation worsens

Engineering Contradiction:

Improveairfoil weightVSAvoidboundary layer separation

Core Design Contradiction:

Weight of moving objectVSObject-generated harmful factors

Solution Approach 1:

The notches extend partially into the airfoil depth rather than through the entire thickness, removing sufficient material for weight reduction while stopping before the depth that would trigger significant boundary layer separation. This partial action achieves the weight reduction goal without excessive modification that would harm airflow

Inventive Principle:

Principle #16Partial or excessive action

3Weight of moving object

If notches are spaced closer together, then weight reduction increases, but airflow disruption increases

Engineering Contradiction:

Improveairfoil weightVSAvoidairflow losses

Core Design Contradiction:

Weight of moving objectVSLoss of energy

Solution Approach 1:

The spacing and positioning of notches are predetermined through design optimization to achieve maximum weight reduction before airflow disruption becomes significant. The notches are placed at locations where they can be closely spaced for weight benefits while remaining in regions less sensitive to causing large-scale flow separation

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12435634B2Notched turbine airfoils for weight reduction in gas turbine engines

Publication Date: 2025.10.07 ROLLS ROYCE NORTH AMERICAN TECHNOLOGIES INC

AI summary

An airfoil adapted for use in a gas turbine engine includes a base and an airfoil body that extends radially outward from the base relative to an axis to a tip of the airfoil body. The airfoil body has a leading edge, a trailing edge, a suction side, and a pressure side. The airfoil body is formed to include notches that extend into the airfoil body to reduce a weight of the airfoil.