Flow-Straightening Stator Blade Loading for Lower Tip Noise
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Solution Overview
Problem
Conventional turbomachines with unfaired thrust generation assemblies face issues of decreased aerodynamic performance, increased noise, and mechanical stress at the blade tips due to loading the propeller and stator at the blade tip, which affects the airflow deflection and thrust generation.
Innovation Solution
A rectifier with blades having a specific deviation profile between 20° and 45° at the radially internal limit and between 10° and 40° at the vertex, with a decreasing and increasing deviation along the blade height, to improve airflow deflection and reduce mechanical stress and noise at the blade tips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the propeller and stator are loaded at the blade tip to maximize work and flow deflection, then thrust is increased, but mechanical stress and noise at the blade tip increase
Solution Approach 1:
The patent applies different loading characteristics to different radial zones of the blade. The stator blade has a first loading characteristic in the first radial zone (closer to hub) and a second loading characteristic in the second radial zone (closer to tip), with the second zone having lower loading. This local differentiation allows maintaining thrust while reducing tip stress and noise.
Solution Approach 2:
The blade is divided into multiple radial zones with distinct loading characteristics. By segmenting the blade into at least two radial zones with different loading profiles, the patent optimizes thrust generation in inner zones while reducing mechanical stress and noise in outer zones.
2Object-affected harmful factors
If guide vanes are added to deflect vortices radially outward, then noise at blade tips is reduced, but aerodynamic performance decreases
Solution Approach 1:
Instead of uniformly deflecting all vortices radially outward, the patent applies localized loading characteristics to different radial zones. The reduced loading in the second radial zone (near tip) specifically addresses noise reduction in that region while preserving aerodynamic performance in the first radial zone (inner region).
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 proposed rectifier enhances aerodynamic performance by maximizing airflow deflection at the stator's stronger area, reducing noise, and minimizing mechanical stress, thereby improving the overall efficiency and acoustic performance of the turbomachine.
Implementation Method 1
a deviation (δ) of the profile, corresponding to an absolute value of a difference between a tangent to the skeleton at the leading edge and a tangent to the skeleton at the trailing edge of the blade, between 20° and 45° at the level of the radially internal limit of the blade and between 10° and 40° at the level of the vertex of the blade
Data Source
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AI summary
The present invention relates to a flow-straightening stator (5) of an unducted thrust-generating assembly (3) comprising a plurality of blades (7) each having: - a tip (11) and a radially inner boundary (10) corresponding to an intersection between the blade (7) and a casing (8) of the turbine engine (1); - a skeleton (16); and - a deviation (δ) of the profile, corresponding to an absolute value of a difference between a tangent to the skeleton (16) at the leading edge (14) and a tangent to the skeleton (16) at the trailing edge (15) of the blade (7), of between 20° and 45° at the radially inner boundary (10) of the blade (7) and between 10° and 40° at the tip (11) of the blade (7).