Cooling Fan Bypass Passage for Reverse Air Flow Noise
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Solution Overview
Problem
Conventional cooling fans experience noise and motor overload due to backward air flow and reduced blowing efficiency at high power or when air flow resistance is generated, particularly in seat cooling devices.
Innovation Solution
A cooling fan design with a bypass passage at the air inlet edge to discharge reverse air flow externally, improving blowing efficiency and minimizing noise by removing the bell mouth shape and forming the bypass passage at regular intervals in the circumferential direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cooling fan operates at high power to increase air discharge, then the blowing efficiency is improved, but noise is generated and motor overload occurs due to backward air flow
Solution Approach 1:
The air inlet is segmented into two functional zones: a main air inlet for normal air intake and a bypass passage specifically for discharging backward air flow. This segmentation allows the system to handle high power operation by directing reverse flow through the bypass passage, preventing noise and motor overload while maintaining high air discharge capability through the main inlet.
Solution Approach 2:
The bypass passage acts as an intermediary channel that intercepts and redirects backward air flow before it can collide with discharged air and generate noise. This intermediate structure prevents the harmful interaction between reverse and forward air flows, eliminating the source of noise and preventing motor overload conditions.
2Productivity
If a bell mouth is formed in the air inlet to improve air intake, then the blowing efficiency is improved, but the device complexity increases
Solution Approach 1:
Instead of modifying the air inlet shape (bell mouth) to improve performance, the invention inverts the approach by adding a bypass passage that handles the problematic backward air flow. This alternative solution achieves improved blowing efficiency without the complexity of shaped air inlets, as the bypass is a simple additional passage rather than a complex geometric modification.
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 cooling fan effectively prevents noise generation and motor overload while maintaining blowing performance by bypassing reverse air flow, enhancing efficiency and reducing noise levels.
Implementation Method 1
an impeller mounted inside the fan housing to introduce air in an axial direction thereof and discharge air in a radial direction thereof
Implementation Method 2
a bypass passage is formed at an edge of the air inlet so that air flowing in a direction opposite to the air outlet can be discharged to the outside
Data Source
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AI summary
Provided is a cooling fan including: a fan housing having an air inlet formed on a front surface thereof and through which air flows and an air outlet formed at a side surface of the fan housing and through which air is discharged; and an impeller mounted inside the fan housing to introduce air in an axial direction thereof and discharge air in a radial direction thereof, wherein a bypass passage is formed at an edge of the air inlet so that air flowing in a direction opposite to the air outlet can be discharged to the outside. At high power of a cooling fan, backward-flow air is discharged to the outside to minimize noise and improve blowing efficiency.