Variable-Cell Flow Discourager for Rotor-Stator Leakage Control
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Solution Overview
Problem
Conventional honeycomb flow discouragers in gas turbine engines suffer from inefficiencies due to uniform cell geometry, leading to leakage and reduced engine performance, as they fail to effectively manage the interaction between rotor and stator interfaces.
Innovation Solution
A cellular structure with varying cell geometries and non-linear contours, featuring different maximum dimensions in specific regions, is introduced to optimize the interface between rotor and stator, utilizing additive manufacturing for precise thickness and contour control, allowing for enhanced radial stiffness and improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform honeycomb cell geometry is used in flow discouragers, then manufacturing is simplified, but leakage between rotor and stator increases and engine efficiency decreases
Solution Approach 1:
The patent applies local quality by varying the cell geometry parameters (cell size, wall thickness, contour shape) in different regions of the flow discourager. Specifically, the cell dimensions and wall thickness are adjusted based on the local flow conditions and rotor-stator interaction requirements at each interface location, creating non-uniform cellular structures that optimize leakage prevention in critical areas while maintaining manufacturability.
2Strength
If non-linear cell wall contours and variable thickness are implemented, then radial stiffness and leakage prevention improve, but manufacturing complexity increases
Solution Approach 1:
The patent implements parameter changes by systematically varying key geometric parameters of the cellular structure including cell size, wall thickness, and contour curvature. These parameter variations are designed to optimize radial stiffness in regions experiencing high centrifugal forces while controlling manufacturing complexity through defined parameter ranges and progression patterns across different radial zones of the flow discourager.
Data Source
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AI summary
A cellular structure (400), comprising: a thickness dimension defined by cell walls and a surface plane defined by the edges of interconnecting cells, wherein the rotor and stator define a rub path (402) on the surface plane where a rotor tip of the rotor moves past the surface plane; the surface plane comprising a first cellular region of the cells (406) having a first maximum dimension in the surface plane, wherein cells of the cellular structure defining the rub path include greater than 90% of the cells having the first maximum dimension; the surface plane comprising a second cellular region of the cells (404) having a second maximum dimension in the surface plane, wherein the second dimension is less than the first dimension, wherein cells of the cellular structure outside the rub path include greater than 90% of the cells having the second maximum dimension; and the cell walls of at least one of the first or second cellular regions having a non-linear contour or variable thickness.