Aircraft Engine Compressor Stator Depressions

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Solution Overview

Problem

Aircraft engine compressors experience performance impairments due to corner losses and secondary flows, particularly at high loading conditions, leading to flow deviation and potential corner separation.

Innovation Solution

Incorporating depressions in the stator walls of the compressor, located between the pressure and suction sides of the airfoils, which extend downstream and overlap the trailing edges, helping to divert flow and reduce local loading, thereby minimizing corner losses and improving flow alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional stator design is used, then manufacturing is simple, but corner losses and secondary flows impair performance

Engineering Contradiction:
Improvecompressor performanceVSAvoidstator structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by introducing depressions only in specific regions of the stator wall where corner losses and secondary flows occur, rather than modifying the entire stator structure. The depressions are strategically positioned to address local flow problems while maintaining the simplicity of the overall stator design.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces a new dimensional feature (depressions extending into the gaspath volume) to the traditionally two-dimensional stator wall surface. This third-dimensional modification allows control of flow characteristics without adding complex structural elements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Power

If stator vanes are designed to handle high loading conditions, then power output increases, but corner separation and flow deviation worsen

Engineering Contradiction:
Improvecompressor powerVSAvoidflow stability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The depressions are positioned upstream of the corner regions to preemptively counteract the development of corner losses and secondary flows. By creating favorable pressure gradients before the problematic regions, the design prevents corner separation from occurring even under high loading conditions.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful corner losses and secondary flows into beneficial effects by using the depressions to generate controlled vortices that energize the boundary layer and prevent flow separation, thereby improving overall flow stability under high power conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP4144959A1Fluid machine for an aircraft engine and aircraft engine
Publication Date: 2023.03.08 PRATT & WHITNEY CANADA CORP
  • EP4144959A1 patent drawingFigure 1
  • EP4144959A1 patent drawingFigure 2
  • EP4144959A1 patent drawingFigure 3

AI summary

A fluid machine has first (21A) and second walls (21B), a gaspath defined between the first wall (21A) and the second wall (21B); a rotor having blades rotatable about the central axis (11) and a stator (31) having a row of vanes (33) having airfoils (35) including leading edges (35A), trailing edges (35B), pressure sides (35C) and suction sides (35D) opposed the pressure sides (35C), and depressions (40) defined in the first wall (21A), the depressions (40) extending from a baseline surface (BS) of the first wall (21A) away from the second wall (21B), a depression (40) of the depressions (40) located circumferentially between a pressure side (35C) of the pressure sides (35C) and a suction side (35D) of the suction sides (35D), the depression (40) axially overlapping the airfoils (35) and extending in a downstream direction from an upstream end to a downstream end, the downstream end located closer to a trailing edge (35B) of the trailing edges (35B) than to a leading edge (35A) of the leading edges (35A).