Impeller with Varying Blade Lengths for Noise Suppression
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Solution Overview
Problem
Existing fans used in electronic devices for heat dissipation generate high noise due to uniform air flow distribution and limited number of blades, which cannot effectively meet the increasing heat dissipation requirements of lightweight and slender products.
Innovation Solution
The design of an impeller with a fan hub and blades of varying lengths, where every two adjacent blades have different lengths and outlets of varying widths, breaking the uniformity of air flow distribution and reducing noise frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of blades is increased to improve heat dissipation, then cooling capacity is improved, but manufacturing difficulty increases due to process limitations
Solution Approach 1:
The patent applies local quality by making each blade have a different length from its adjacent blades, creating local variations in the blade structure. This allows the impeller to have effectively more blade segments for improved heat dissipation while maintaining manufacturability through a systematic design approach rather than requiring excessively thin individual blades
Solution Approach 2:
The patent segments the blade structure by dividing the impeller into multiple blades of varying lengths. This segmentation increases the effective number of blade elements for better air flow and heat dissipation, while each segment remains manufacturable within existing process capabilities
2Ease of manufacture
If all blades are of equal length with uniform openings, then manufacturing is simplified, but noise increases due to overlapping noise from each opening
Solution Approach 1:
The patent applies asymmetry by designing blades with different lengths, which creates asymmetric outlet openings. This breaks the uniformity that causes noise waves from different openings to overlap and reinforce each other, thereby reducing overall noise while still being manufacturable
Solution Approach 2:
The patent introduces local quality variations by making each blade have a different length, creating locally distinct outlet characteristics. This prevents the uniform noise distribution that occurs with identical blades, reducing noise through local differentiation while maintaining manufacturing feasibility
3Ease of manufacture
If blade thickness is increased to facilitate manufacturing, then ease of manufacture is improved, but the number of blades that can be fitted is limited
Solution Approach 1:
The patent applies local quality by varying blade lengths rather than uniformly increasing blade thickness. This allows for more blade elements to be accommodated on the impeller while maintaining sufficient structural integrity through localized thickness optimization rather than uniform thickening
Solution Approach 2:
The patent segments the impeller into multiple blades of varying lengths, which allows more blade elements to be fitted compared to a design with fewer, uniformly thick blades. This segmentation strategy increases the number of blades while maintaining 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
This solution effectively reduces noise frequency by distributing air velocity in a 'weak-strong-weak-strong' mode, increases the number of blades, and enhances heat dissipation capabilities, while maintaining a reduced noise frequency compared to conventional impellers.
Implementation Method 1
Due to the different lengths of every two adjacent blades, the uniform air-out in the radial direction is broken. In other words, the uniform air-out in the radial direction is weakened.
Implementation Method 2
the air velocity from the first outlet is relatively low, while the air velocity from the second outlet is relatively high. Thus, it can be seen that the air velocity around the impeller is distributed in a 'weak-strong-weak-strong...' mode, breaking the uniformity of the air-out and resulting in differences in air velocity. After testing, it is found that this effectively reduces the frequency of noise generated during the impeller operation and suppresses noise.
Data Source
AI summary
An impeller with different blades with different lengths for suppressing noise is disclosed. The impeller includes a fan hub and a plurality of blades. The blades are positioned at intervals around the fan hub and arranged in a circular array. The blades extend radially from the fan hub, and two opposite ends of each of the blades are a root portion and a head portion respectively. All root portions of the blades are connected to a peripheral side of the fan hub, and all head portions of the blades are located on a same circle. Every two adjacent blades are different in length in a longitudinal direction from the root portion thereof to the head portion thereof.