Booster Stator Vane Exit Swirl Angle Distribution

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Solution Overview

Problem

Conventional gas turbine engine booster and compressor designs face a trade-off between efficiency and stall margin, where increasing efficiency reduces stall margin and vice versa, particularly in high-performance jet engines, and the booster's unique geometry and operation lead to radial incidence swings that compromise operability.

Innovation Solution

The design incorporates stator vanes with tailored exit swirl angle distributions and rotor blades with specific leading edge sweep profiles and dihedral angles to reduce incidence angle swings in the hub region, enhancing stall margin and efficiency without sacrificing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If airfoil efficiency is optimized by minimizing wetted surface area and reducing solidity, then efficiency improves, but stall margin decreases

Engineering Contradiction:

Improveairfoil dragVSAvoidstall margin

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent applies different geometric characteristics to different regions of the airfoil. The leading edge features forward sweep and positive dihedral angle to control flow attachment and reduce incidence angle swings in the hub region, while the trailing edge has specific sweep and dihedral angle configurations to optimize wake characteristics. This localized optimization allows efficiency improvement without sacrificing stall margin.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The airfoil design incorporates dynamic flow control through geometric features that adapt to varying operating conditions. The forward swept leading edge and positive dihedral angles create flow patterns that maintain attachment across a wider range of incidence angles, allowing the airfoil to dynamically respond to changing flow conditions without stalling.

Inventive Principle:

Principle #15Dynamics

2Reliability

If rotor speed is increased to achieve adequate stall margin, then stall margin improves, but efficiency decreases due to increased airfoil Mach numbers and drag

Engineering Contradiction:

Improvestall marginVSAvoidairfoil drag

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes key geometric parameters of the airfoil including leading edge sweep angle, leading edge dihedral angle, trailing edge sweep angle, and trailing edge dihedral angle. These parameter changes optimize the flow characteristics and incidence angle distribution, allowing adequate stall margin to be achieved without increasing rotor speed and thus avoiding the associated drag penalties.

Inventive Principle:

Principle #35Parameter changes

3Power

If booster geometry is optimized for high power extraction, then power output improves, but radial incidence swings in hub region increase reducing operability

Engineering Contradiction:

Improvepower extractionVSAvoidoperability

Core Design Contradiction:

PowerVSEase of operation

Solution Approach 1:

The airfoil design introduces asymmetry in the leading edge configuration with forward sweep and positive dihedral angles specifically in the hub region. This asymmetric geometry counteracts the radial incidence swings caused by booster geometry, creating more uniform flow distribution and improving operability while maintaining high power extraction capability.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS8087884B2Advanced booster stator vane

Publication Date: 2012.01.03 GENERAL ELECTRIC CO

AI summary

A stator vane includes leading and trailing edges extending longitudinally between a root and a tip, the trailing edge having an exit swirl angle distribution such that the exit swirl angle has a maximum value at an intermediate radius location.