Turbine Endwall Fences for Horseshoe Vortex Control

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Solution Overview

Problem

Horseshoe vortices formed at the junctions of turbine rotor blades and stator vanes lead to pressure losses and reduced efficiency in gas turbine engines due to the interaction of pressure and suction side vortices, causing turbulence and increased heating of endwall components.

Innovation Solution

Incorporating leading edge endwall fences with nonzero camber and constant thickness, positioned near the leading edges of turbine airfoils, to disrupt the movement of horseshoe vortices and minimize pressure losses by blocking the pressure-side vortex leg from moving towards the adjacent suction-side.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional turbine airfoils are used without fences, then the structure is simple and manufacturing is easier, but pressure losses occur due to horseshoe vortex formation at the junctions of airfoils and endwalls

Engineering Contradiction:

Improvepressure lossesVSAvoidstructure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

Fences are introduced as intermediary structures extending from the endwall into the flow passage between adjacent airfoils. These fences act as mediators that disrupt the formation and movement of horseshoe vortices, reducing pressure losses while maintaining a relatively simple overall turbine structure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The flow passage is segmented by introducing fences that divide the region between airfoils into separate zones. This segmentation prevents the continuous movement of horseshoe vortices along the endwall, reducing their harmful effects on pressure distribution and turbine efficiency

Inventive Principle:

Principle #1Segmentation

2Productivity

If fences are added to disrupt horseshoe vortices, then pressure losses are reduced and turbine efficiency is improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improveturbine efficiencyVSAvoidmanufacturing ease

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

Rather than modifying the entire airfoil structure, fences are added only in specific locations where horseshoe vortices form at the airfoil-endwall junctions. This localized approach improves turbine efficiency by targeting the specific problem area while minimizing the overall increase in manufacturing complexity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Fences are positioned upstream near the leading edges of airfoils to preemptively disrupt the formation of horseshoe vortices before they can develop and travel downstream. This preliminary action prevents pressure losses from occurring in the first place, improving efficiency without requiring complex downstream modifications

Inventive Principle:

Principle #10Preliminary action

3Loss of energy

If fences are positioned near the leading edges of airfoils, then horseshoe vortex movement is disrupted and pressure losses are reduced, but the risk of increased heating of endwall components may occur

Engineering Contradiction:

Improvepressure lossesVSAvoidendwall heating

Core Design Contradiction:

Loss of energyVSTemperature

Solution Approach 1:

The fences are designed with specific dimensions (chord and span) that are less than the corresponding dimensions of the airfoils, creating a partial barrier that is sufficient to disrupt horseshoe vortices but not so extensive as to create excessive flow blockage that would lead to increased heating of endwall components

Inventive Principle:

Principle #16Partial or excessive action

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 fences effectively reduce pressure losses and flow turning deviations associated with horseshoe vortices, enhancing turbine performance and reducing undesirable heating of endwall components.

Implementation Method 1

horseshoe vortices generated as the combustion gases are split in their travel near the junction of an endwall and the leading edge of the blade

Methodology Applied

Scientific EffectVortex: Vortex Ring

Implementation Method 2

corresponding boundary layers are formed along the pressure and suction sides of each airfoil, as well as along each radially outer and inner endwall

Methodology Applied

Scientific EffectBoundary layer: Boundary Layer

Implementation Method 3

a pressure gradient normal to the endwall is generated in the boundary layer at the junction of the blade leading edge and the endwalls

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS11125089B2Turbine incorporating endwall fences

Publication Date: 2021.09.21 GENERAL ELECTRIC CO

AI summary

A turbomachinery apparatus includes: a turbine, including: a turbine component defining an arcuate flowpath surface; an array of axial-flow turbine airfoils extending from the flowpath surface, the turbine airfoils defining spaces therebetween; and a plurality of fences extending from the flowpath surface, in the spaces between the turbine airfoils, each fence having opposed concave and convex sides extending between a leading edge and a trailing edge, wherein the fences have a nonzero camber and a constant thickness, are axially located near the leading edges of adjacent turbine airfoils, and wherein at least one of a chord dimension of the fences and a span dimension of the fences is less than the corresponding dimension of the turbine airfoils.