Undulated Nosecone Geometry for Fan Root Wake Control
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Solution Overview
Problem
Fan stages in ducted fan gas turbine engines experience complex aerodynamic interactions and undesirable aeromechanical coupling due to wake effects from fan blade roots, affecting local efficiency and potentially leading to component failure.
Innovation Solution
A nosecone with an outer surface featuring undulations that taper from an apex to a base, with peaks and troughs extending between specific axial locations, creating turbulence to manage vortical flows and reduce secondary loss cores at the fan blade roots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a streamlined nosecone profile is used to direct incoming air to the fan stage, then air flow guidance is improved, but complex aerodynamic interactions and wake effects from fan blade roots cause undesirable aeromechanical coupling in the compression system
Solution Approach 1:
The nosecone surface is modified with undulations only in specific regions (between 30-70% of the nosecone length from the apex), while other regions maintain a smooth streamlined profile. This local modification creates turbulence in the root passage wake area to reduce aeromechanical coupling, while preserving the overall streamlined shape for proper air flow guidance to the fan stage.
2Loss of energy
If the outer surface of the nosecone is modified with undulations to reduce wake effects, then aerodynamic efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The undulations are defined by specific geometric parameters including amplitude (5-20% of nosecone radius), wavelength (10-30% of nosecone length), and axial position (30-70% from apex). These parameterized definitions allow the complex surface geometry to be manufactured using modern CNC machining or additive manufacturing processes, balancing improved aerodynamic efficiency with manufacturing feasibility.
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 undulations enhance aerodynamic efficiency by faster decay of vortical flows and reduce induced vibrations, improving the performance and reliability of the fan assembly.
Implementation Method 1
creating turbulence to manage vortical flows and reduce secondary loss cores at the fan blade roots
Data Source
AI summary
A nosecone for a ducted fan gas turbine engine is shown. The nosecone includes a body with an outer surface that tapers in axial extent from an apex to a base of the body, the apex defining a position of 0 percent axial extent and the base defining a position of 100 percent axial extent, and in which the outer surface includes a plurality of undulations extending between a first location on the outer surface and a second location on the outer surface, wherein the first location is positioned at from 0 to 50 percent of axial extent and the second location is positioned at from 85 to 100 percent of axial extent.