Unducted Engine Stator Chord Variation for Obstacle-Driven Airflow
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Solution Overview
Problem
Unfaired turbomachines are more sensitive to external airflow disturbances caused by aerodynamic obstacles, leading to performance issues and increased risk of local stator overload.
Innovation Solution
Adapting stator blades with varying chords, including elongated blades facing aerodynamic obstacles to manage airflow disturbances and load distribution, and using conventional and shortened blades to optimize geometry and prevent overloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all stator blades have the same conventional chord length, then the stator structure is simple and easy to manufacture, but the stator cannot effectively handle heterogeneous airflow caused by aerodynamic obstacles, leading to performance degradation and potential local overload
Solution Approach 1:
The patent applies local quality by differentiating stator blade chords based on their angular position relative to aerodynamic obstacles. Blades facing obstacles (within angular interference range) have elongated chords to handle disturbed airflow, while other blades maintain conventional chords. This localized adaptation optimizes each blade's performance for its specific operating conditions without complicating the entire stator structure.
2Productivity
If elongated blades are positioned within the angular interference range, then airflow straightening is improved and thrust is enhanced, but the stator blade geometry becomes more complex
Solution Approach 1:
The invention implements local quality by applying elongated blade geometry only to specific blades within the angular interference range, while other blades retain conventional geometry. This selective approach enhances thrust where needed without unnecessarily complicating the entire stator assembly, balancing performance improvement with manufacturing feasibility.
3Loss of energy
If the stator uses blades with varying chords to adapt to aerodynamic obstacles, then aerodynamic efficiency is improved, but the manufacturing process becomes more difficult
Solution Approach 1:
The patent reduces aerodynamic losses by applying varying blade chords locally where needed - specifically, elongated chords for blades facing aerodynamic obstacles and conventional chords elsewhere. This targeted approach minimizes energy losses in critical areas while keeping manufacturing complexity manageable by not requiring all blades to be custom-shaped.
Solution Approach 2:
The stator is segmented into different blade types based on angular position: blades within the angular interference range have elongated chords, while blades outside this range have conventional chords. This segmentation allows the stator to optimize aerodynamic performance for different flow conditions while simplifying manufacturing by using repeated patterns of different blade types rather than completely unique blades.
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
Enhances turbomachine efficiency and thrust while reducing fuel consumption by minimizing aerodynamic separation and maintaining optimal airflow straightening.
Implementation Method 1
A primary function of a stator is to deflect the direction of the airflow in order to modify the kinetic energy so that it can be used to generate thrust in the turbomachine
Implementation Method 2
The fan, also referred to as the 'rotor,' is mounted to rotate around its longitudinal axis and accelerates the airflow from upstream to downstream
Data Source
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AI summary
The invention relates to an aircraft comprising at least one unducted turbine engine for the propulsion of the aircraft, the turbine engine comprising: a rotor and a stator comprising a plurality of stator blades extending radially with respect to the longitudinal axis, each stator blade being defined, in a plane (PT) transverse to the longitudinal axis, by an angular position (0); and at least one aerodynamic obstruction (OA) positioned close to the turbine engine. The stator of the turbine engine comprises stator blades having a first chord, referred to as conventional blades (51), and at least one stator blade having a second chord larger than the first chord, referred to as the elongate blade (52), said at least one elongate blade (52) being positioned in an interference angular range (PAI) defined opposite the aerodynamic obstacle (OA), so as to increase the straightening of the airflow from the rotor in the interference angular range (PAI).