Axial fan
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Solution Overview
Problem
The porous portions in existing axial fan blades reduce the strength of the blades while attempting to mitigate noise, and the noise reduction is not effectively targeted to specific areas where noise is predominantly generated.
Innovation Solution
The axial fan design includes blades with a porous part positioned at specific locations relative to the leading or trailing edge, such as 40% or more rearward from the leading edge for five or less blades, and 60% or more forward from the trailing edge for six or more blades, to reduce noise without significantly compromising blade strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a porous part is arranged in the blade to reduce noise, then noise is reduced, but the strength of the blade decreases
Solution Approach 1:
The porous part is positioned at specific locations on the blade (rearward from the leading edge by 40% or more of the blade chord length) rather than being distributed throughout the entire blade. This localized placement targets the noise generation area while preserving blade strength in other regions.
2Object-affected harmful factors
If the porous part is arranged over the entire blade to maximize noise reduction, then noise is reduced, but the blade strength significantly decreases
Solution Approach 1:
The porous part is extracted from the entire blade structure and placed only in the specific region where noise is generated (rearward from the leading edge by 40% or more of the blade chord length). This extraction approach achieves noise reduction while minimizing the impact on overall blade strength.
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
This positioning effectively reduces noise at the trailing or leading edge areas where noise is likely to occur, maintaining blade strength by minimizing the porous part's size and area, thus achieving noise reduction with minimal strength loss.
Implementation Method 1
The blades each include a leading edge located forward in a rotation direction of the rotary shaft, a trailing edge located rearward in the rotation direction of the rotary shaft, and a porous part
Data Source
AI summary
An axial fan includes a hub attachable to a rotary shaft, and five or less blades arranged on the hub. Each blade includes a leading edge located forward in a rotation direction of the rotary shaft, a trailing edge located rearward in the rotation direction of the rotary shaft, and a porous part. A dimension from the leading edge to the trailing edge is a blade chord length, and the porous part is arranged at a position located rearward from the leading edge by 40% or more of the blade chord length.