Scalloped Airfoil Platform Reduces Secondary Flow Vortices

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Solution Overview

Problem

Gas turbine engines face inefficiencies due to the formation of secondary flow vortices in the flow passages, which disrupt airflow and reduce the work done by airfoils, leading to decreased engine efficiency and increased fuel consumption.

Innovation Solution

The implementation of a scalloped flow surface design in turbine engine stages, featuring bulges and troughs on the airfoil platforms, which direct airflow along the suction side and reduce mixing losses, thereby enhancing the work done by airfoils and increasing engine efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional flat flow surface is used on airfoil platforms, then the structure is simple and easy to manufacture, but secondary flow vortices form in the flow passages which disrupt airflow and reduce engine efficiency

Engineering Contradiction:

Improveengine efficiencyVSAvoidflow surface structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The flow surface is modified with localized scalloped features (bulges and troughs) at specific positions rather than changing the entire surface. The bulge is positioned adjacent to the pressure side with its local maximum aft of the fore edge, and the trough is positioned adjacent to the suction side, creating local flow control zones that reduce secondary vortices while maintaining overall structural simplicity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The flat flow surface is replaced with a scalloped surface featuring curved bulges and troughs. The bulge has a rounded profile extending forward of the fore edge with its maximum located aft, and the trough has a corresponding curved profile, using curvature to guide airflow smoothly and reduce vortex formation

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Productivity

If the bulge local maximum is positioned close to the pressure side, then the bulge flow channel is narrow and provides strong flow direction, but the risk of flow separation and increased mixing losses increases

Engineering Contradiction:

Improvework done by airfoilsVSAvoidmixing losses

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The position of the bulge local maximum is optimized to be aft of the fore edge at a specific distance that balances flow direction strength with flow separation prevention. This parameter optimization ensures the bulge flow channel provides sufficient flow direction to increase work done by airfoils while maintaining smooth flow attachment to minimize mixing losses

Inventive Principle:

Principle #35Parameter changes

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 scalloped flow surface design reduces secondary flow vortices, increases the work done by airfoils, and improves engine efficiency by directing airflow effectively and minimizing mixing losses, resulting in enhanced performance and reduced fuel consumption.

Implementation Method 1

scalloped flow surface including a bulge adjacent the pressure side and a trough adjacent the suction side... define a bulge flow channel between the bulge and the pressure side

Methodology Applied

Scientific EffectFlow redirection:

Implementation Method 2

The scalloped flow surface design reduces secondary flow vortices, increases the work done by airfoils, and improves engine efficiency

Methodology Applied

Scientific EffectVortex reduction:

Data Source

PatentUS10577955B2Airfoil assembly with a scalloped flow surface

Publication Date: 2020.03.03 GENERAL ELECTRIC CO

AI summary

A stage for a compressor or a turbine in a turbine engine can include an annular row of airfoils radially extending from corresponding platforms, where each platform can include a fore edge and aft edge and each airfoil can include a leading edge and trailing edge. At least one of the platforms can have a scalloped flow surface including a bulge and a trough.