V-Shaped Axial Fan Blade Noise Reduction
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Solution Overview
Problem
Large diameter axial fans face challenges in achieving low noise and high efficiency due to structural complexities and high power consumption, with existing solutions resulting in significant energy losses and increased costs, particularly when requiring adjustable pitch and aerodynamic efficiency.
Innovation Solution
A V-shaped blade design is introduced, comprising a first inner blade part and a second outer blade part forming an obtuse angle, which can be fixed at zero pitch-angle, allowing for efficient noise reduction and maintaining high aerodynamic efficiency while reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If large diameter axial fans use conventional blade designs, then structural strength is sufficient, but noise levels are high and aerodynamic efficiency is poor
Solution Approach 1:
The blade is divided into multiple span sections (root section, intermediate section, tip section) with different chord length characteristics. Each section has optimized aerodynamic properties, allowing the blade to achieve low noise at the tip while maintaining structural strength at the root, resolving the contradiction between noise reduction and aerodynamic efficiency
Solution Approach 2:
Different portions of the blade have different chord length ratios relative to their span position. The root section has higher chord length for strength, while the tip section has lower chord length for noise reduction. This local variation in geometry allows simultaneous optimization of structural integrity and aerodynamic performance across different blade regions
2Adaptability or versatility
If large diameter axial fans require adjustable pitch, then operational adaptability is improved, but the gap between blade tip and fan ring increases causing efficiency loss
Solution Approach 1:
The blade incorporates a variable pitch mechanism that changes the attack angle parameter along the span. The leading edge is positioned at different angles relative to the rotational plane at different span locations, allowing optimization of airflow attachment across the blade surface while maintaining minimal tip clearance for energy efficiency
3Object-generated harmful factors
If complex blade shapes are used to reduce noise in small fans, then noise is reduced, but structural design becomes too complicated for large fans
Solution Approach 1:
The blade employs a dynamic geometry where the chord length varies continuously along the span according to a power law relationship. This dynamic variation in dimensions, rather than fixed complex shapes, achieves noise reduction through optimized aerodynamic loading distribution while keeping the structural design manageable through mathematical scaling relationships
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 V-shaped blade design effectively reduces noise levels and maintains or improves efficiency compared to prior art, achieving noise reductions comparable to super low noise fans while minimizing energy losses and costs, making it suitable for large diameter industrial axial fans.
Implementation Method 1
The V-shaped blade design effectively reduces noise levels and maintains or improves efficiency compared to prior art
Data Source
AI summary
Today the low noise blades and especially the super low noise blades for large diameter axial fans which are employed in the big cooling machines and cooling plants are so costly and are requiring so many extra costs on the other related equipment, that the noise pollution abatement can increase the whole cooling apparatus cost by up to a 35%. This invention, provides a new technology to make low noise fans able to transform any common blade into a low noise or very low noise at very low cost, preserving the same high efficiency and tip speed, as opposite to all the other low noise blades at actual status of art. As the fans for the big cooling apparatus are generally their main noise source, this invention will offer the opportunity to dramatically reduce the noise pollution produced by big cooling machines and cooling plants.