Two-Stage Axial Fan Blade Design for Noise Reduction
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Solution Overview
Problem
Axial-flow fans generate excessive noise due to airflow concentration at the blade tip, with the central part of the blade contributing minimally to airflow, resulting in reduced air quantity.
Innovation Solution
A fan assembly with blades configured in two stages and additional orifices on the boundary of the blades, where the first part extends radially from the hub, features a bent part and a second part further extended radially, altering airflow direction and reducing noise by distributing airflow more evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional axial-flow fan blade design is used, then the blade tip generates maximum airflow, but noise increases due to flow concentration and the central part of the blade does not contribute significantly to airflow formation
Solution Approach 1:
The blade is divided into multiple sections along its length, with each section having a different radial extension length. This segmentation allows the inner part of the blade to generate airflow independently rather than relying solely on the tip, distributing the airflow generation across multiple zones and reducing concentration at the tip
Solution Approach 2:
Different parts of the blade are given different local characteristics by varying the radial extension length at different positions. The inner part of the blade has a shorter radial extension while the outer part maintains a longer extension, allowing each local region to contribute optimally to airflow generation according to its position
2Object-generated harmful factors
If the blade configuration is modified to improve airflow distribution, then noise decreases and air quantity increases, but the blade structure becomes more complex with additional bent parts and orifices
Solution Approach 1:
The blade is divided into multiple sections along its length, with each section having a different radial extension length. This segmentation allows the inner part of the blade to generate airflow independently rather than relying solely on the tip, distributing the airflow generation across multiple zones and reducing concentration at the tip
Solution Approach 2:
Different parts of the blade are given different local characteristics by varying the radial extension length at different positions. The inner part of the blade has a shorter radial extension while the outer part maintains a longer extension, allowing each local region to contribute optimally to airflow generation according to its position
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 decreases noise and increases air quantity by redirecting airflow through additional orifices, ensuring the central part of the blade contributes to airflow formation and preventing concentration at the blade tip.
Implementation Method 1
a flow formed by an inner part of the blade is bent out by a centrifugal force and a flow direction is changed by the additional orifice
Data Source
AI summary
A fan assembly according to an exemplary embodiment of the present invention includes: a hub; and a plurality of blades including a leading edge corresponding to a side hit by air and a trailing edge corresponding to an opposite side of the leading ledge, the plurality of blades configured to be extended radially from an outer peripheral surface of the hub, wherein each of the plurality of blades includes a first part extended radially from the outer peripheral surface of the hub, a bent part stepped on the end of the first part, and a second part further extended radially on the end of the bent part.