Centrifugal Fan Impeller with Unequal Air Outlet Intervals
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Solution Overview
Problem
Conventional centrifugal fans in electronic systems suffer from structural limitations and noise issues due to non-uniform wake interactions with the fan impeller and tongue, leading to increased noise levels, especially when the gap between the impeller and tongue is narrow.
Innovation Solution
The centrifugal fan impeller structure features a hub with an extension section and multiple blade bodies that extend outward, with air outlets and inlets arranged at unequal intervals, reducing the single tone of blade passing frequency and sound pressure weighting to minimize noise, while allowing for flexible design based on boundary conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the gap between the fan impeller and the tongue is narrowed to reduce size, then the centrifugal fan can be miniaturized for electronic systems, but the noise increases due to non-uniform wake interactions with the tongue
Solution Approach 1:
The patent applies asymmetry by arranging air outlets at unequal intervals between adjacent blade bodies. This asymmetric configuration disrupts the periodic interaction between the non-uniform wake and the tongue, thereby reducing the single tone noise at blade passing frequency while maintaining a compact fan size
Solution Approach 2:
The patent changes the spatial parameter of air outlet positioning from uniform to unequal intervals. This parameter modification alters the wake-tongue interaction characteristics, reducing noise generation while preserving the miniaturized fan structure
2Device complexity
If conventional uniform air outlet arrangement is used, then the blade structure is simple, but the noise from non-uniform wake interaction with the tongue increases
Solution Approach 1:
The patent introduces asymmetry in the air outlet arrangement between adjacent blade bodies. This asymmetric design breaks the periodicity of wake-tongue interaction, effectively reducing single tone noise while maintaining relatively simple blade structure
Solution Approach 2:
The patent applies local quality by making each blade body have a distinct air outlet position rather than uniform positioning. This local variation in outlet arrangement disrupts the coherent noise generation mechanism while keeping the overall blade structure simple
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 design significantly reduces noise levels and enhances the flexibility of the blade structure, effectively addressing the noise challenges faced by conventional centrifugal fans.
Implementation Method 1
the blade bodies rotate to drive the ambient air to flow. The axial airflow going into the frame body from the air inlet is turned to radial airflow
Data Source
AI summary
A centrifugal fan impeller structure includes a hub and a blade body set. The hub has an extension section. The blade body set has multiple blade bodies. The blade bodies outward extend from the extension section of the hub. Each two adjacent blade bodies define therebetween a flow way, an air outlet and an air inlet. The air outlet and the air inlet are respectively positioned at two ends of the flow way in communication with the flow way. The air outlets are arranged at unequal intervals so as to greatly reduce noise in operation.