Compressor Airfoil Compound Leading Edge Profile

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Solution Overview

Problem

Current compressor airfoil designs in gas turbine engines face challenges in achieving optimal aerodynamic performance due to limitations in leading edge shape, which affects the incident angle of air and can lead to stall, thereby reducing surge margin.

Innovation Solution

The compressor airfoil features a compound curvature profile on the suction side, including a leading edge with elliptical, flat/chamfered, and blended curve segments, reducing air over-acceleration and delaying stall onset by minimizing aerodynamic losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional leading edge shape is used, then the manufacturing is simple, but the aerodynamic performance is suboptimal due to flow separation and stall

Engineering Contradiction:
Improveaerodynamic performanceVSAvoidleading edge profile complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The leading edge profile is segmented into three distinct curvature regions: a first curvature region at the forward portion, a second curvature region at the aft portion, and a third curvature region at the trailing portion. Each region has a different radius of curvature, allowing optimized aerodynamic performance in each zone while maintaining manufacturing feasibility through defined transition points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the leading edge are assigned different curvature characteristics tailored to their specific aerodynamic functions. The forward portion has a larger radius of curvature to reduce flow separation, the middle portion transitions smoothly, and the aft portion has a smaller radius to control the incident angle of air on the airfoil, with each region optimized for its local flow conditions.

Inventive Principle:
Principle #3Local quality

2Reliability

If the leading edge shape is optimized for aerodynamic performance, then surge margin improves, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvesurge marginVSAvoidprofile precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent defines specific transition points where curvature changes occur, allowing the complex multi-curvature profile to be manufactured through a series of controlled, discrete shaping operations rather than requiring a single complex tooling operation. The transition points serve as predetermined targets for manufacturing processes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The leading edge employs a compound curvature profile with three distinct radius of curvature values, creating a smooth, continuous curved surface that eliminates sharp transitions. This approach maintains aerodynamic performance while being more manufacturable than truly complex non-uniform curves, as each curvature region can be addressed with appropriate forming tools.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of manufacture

If a simple leading edge profile is used, then the manufacturing is easier, but aerodynamic losses increase due to flow separation

Engineering Contradiction:
Improveleading edge fabricationVSAvoidaerodynamic losses
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The leading edge profile is designed with dynamic curvature variation along its length, transitioning from a larger radius of curvature at the forward portion to smaller radii toward the aft portion. This dynamic profile adapts to the changing flow conditions along the leading edge, reducing flow separation and aerodynamic losses while remaining manufacturable through controlled curvature transitions.

Inventive Principle:
Principle #15Dynamics

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

This design enhances aerodynamic performance by reducing unwanted flow separation and aerodynamic losses, improving the compressor's surge margin and overall efficiency.

Implementation Method 1

the leading edge shape of each airfoil affects the incident angle of the air on the stator vanes and/or rotor blades

Methodology Applied
Scientific EffectAerodynamic flow:

Implementation Method 2

This design enhances aerodynamic performance by reducing unwanted flow separation and aerodynamic losses

Methodology Applied
Scientific EffectFlow separation: Flow Separation

Data Source

PatentEP3098383B1Compressor airfoil with compound leading edge profile
Publication Date: 2021.12.22 PRATT & WHITNEY CANADA CORP
  • EP3098383B1 patent drawingFigure 1
  • EP3098383B1 patent drawingFigure 2
  • EP3098383B1 patent drawingFigure 3a~3b

AI summary

A compressor airfoil (30) of a gas turbine engine includes a pressure side (48) and a suction side (50) of the airfoil (30) extending downstream from a stagnation point (68), the suction side (50) including a suction side surface portion (59) within a leading edge region (52), and a main suction side airfoil surface downstream from the suction side surface portion and extending contiguously therewith. The suction side surface portion (59) has a compound curvature profile which includes at least a leading edge (36) having a first curvature profile and a chamfered surface (54) having a second curvature profile different from the first curvature profile. The chamfered surface (54) is contiguous with and extends immediately downstream from the leading edge (36). The first curvature profile is curved. The second curvature profile of the chamfered surface (54) is substantially flat and defining a substantially straight-line profile in a cross-section transverse to the span-wise axis of the airfoil. Corresponding compressor of a gas turbine engine comprising such an airfoil.