Turbomachine Rotor Drum Bleed Device Orifice Design

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Solution Overview

Problem

Aircraft turbomachine rotor drums face challenges in efficiently draining liquids such as oil, fuel, or water, which can accumulate and cause retention, leading to potential mechanical weaknesses and increased complexity in manufacturing due to existing drainage solutions.

Innovation Solution

A bleed device with three adjacent orifices, comprising a central orifice of larger diameter and two lateral orifices of smaller diameters, aligned along a line, is designed to efficiently discharge liquids while minimizing mechanical strength impact and manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single large orifice is used for liquid drainage, then the drainage efficiency is improved, but the mechanical strength of the drum wall is reduced

Engineering Contradiction:

Improveliquid drainage efficiencyVSAvoiddrum wall mechanical strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The single large orifice is segmented into three smaller adjacent orifices (central orifice of diameter D1 and two lateral orifices of diameter D2). This segmentation maintains the cumulative drainage area (D1² + 2×D2² ≈ D_single²) while distributing the stress concentration, thereby preserving mechanical strength while achieving effective liquid drainage.

Inventive Principle:

Principle #1Segmentation

2Productivity

If complex non-circular orifices (oblong or elliptical) are used, then the drainage performance is improved, but the manufacturing complexity and cost increase

Engineering Contradiction:

Improveliquid drainage performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The invention uses simple circular orifices with standardized dimensions (D1 and D2) instead of complex non-circular shapes. This homogeneous design allows for easier machining, simpler tool paths, and more straightforward quality control while achieving the required drainage performance through optimized orifice placement and size ratios.

Inventive Principle:

Principle #33Homogeneity

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 solution effectively manages liquid drainage, reducing mechanical stress and manufacturing costs by optimizing orifice diameters and locations, ensuring efficient liquid passage without compromising the drum's mechanical integrity.

Implementation Method 1

a bleed device configured to allow at least one liquid to pass through the wall

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS11286815B2Rotor drum for a turbomachine

Publication Date: 2022.03.29 SAFRAN AERO BOOSTERS SA

AI summary

A rotor drum for an aircraft turbomachine includes an annular wall extending around a longitudinal axis (A), the annular wall carrying rotor blades and having at least one bleed device configured to allow at least one liquid to pass through the annular wall. The bleed device includes a series of three adjacent circular orifices, the three orifices being aligned along a line and having a central orifice of larger diameter D1 and two lateral orifices of smaller diameter D2 diametrically opposed with respect to the central orifice.