Fan Ring Part and Bell Mouth Design to Reduce Backflow Air Volume
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Solution Overview
Problem
Conventional fans experience reduced airflow efficiency due to backflow air reversing and merging with intake air, leading to a short-circuit and decreased airflow volume, with existing solutions focusing on noise reduction rather than backflow volume minimization.
Innovation Solution
The fan incorporates a third extending part that provides resistance to backflow air, detouring it away from the merging point with intake air, thereby increasing flow path resistance and reducing backflow volume, utilizing a bell mouth and ring part configuration to achieve this without increasing fan size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a clearance is formed between the ring part and the flow rectifying member to allow rotation, then the ring part can rotate with the vanes, but backflow air reverses through the clearance and merges with intake air causing short-circuit and reduced airflow volume
Solution Approach 1:
A third part is introduced as an intermediary structure between the ring part and the flow rectifying member. This third part extends in the rotation axis direction and provides resistance to backflow air, acting as a mediator that blocks the reverse flow path while allowing the ring part to rotate freely. The third part effectively separates the rotational function from the backflow prevention function.
Solution Approach 2:
The flow rectifying member is divided into multiple functional parts: a first part that rectifies the primary air flow, a second part that rectifies the secondary air flow, and a third part that specifically addresses backflow prevention. This segmentation allows each part to perform its specific function optimally without interfering with other functions.
2Productivity
If the backflow volume is reduced by increasing flow path resistance, then the airflow volume improves, but the fan structure becomes more complex
Solution Approach 1:
The third part that provides backflow resistance is merged with the existing ring part structure. The third part extends from the ring part in the rotation axis direction, combining the rotational support function of the ring part with the backflow resistance function of the third part into a single integrated structure, thereby avoiding additional complexity.
Solution Approach 2:
The third part serves multiple functions simultaneously: it provides resistance to backflow air, maintains the clearance for ring part rotation, and works in conjunction with the first and second parts to rectify air flows. This multi-functionality reduces the need for separate components and simplifies the overall fan structure.
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 configuration significantly reduces backflow volume, enhancing fan efficiency and maintaining performance while preventing noise increase, resulting in improved airflow and heat exchange efficiency in refrigeration apparatuses.
Implementation Method 1
the third part provides resistance on the backflow air (the air that reversely flows through the clearance between the ring part and the flow rectifying member)
Implementation Method 2
a flow rectifying member which is cylindrical and extends along the rotation axis direction
Data Source
Figure 1
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Figure 3
AI summary
A fan with improved efficiency is provided. A first extending part (61) includes a first extending part end (611) overlapping with a bell mouth upstream side end (66) as seen in a radial direction (dr2), and extends along a rotation axis direction (dr1) on an inner side in a radial direction (dr2) relative to a bell mouth (65). The second extending part (62) includes a second extending part end (621) overlapping with the bell mouth (65) as seen in the rotation axis direction (dr1). The second extending part (62) is connected to the first extending part end (611) and extends along the radial direction (dr2) to reach a second extending part end (621). The second extending part end (621) overlaps with a virtual point (P1) which is reached by the bell mouth upstream side end (66) being linearly extended toward the upstream side along the rotation axis direction (dr1). The third extending part (63) is connected to the second extending part end (621) and extending along the radial direction (dr2) on the radially outer side (dr2) than the bell mouth upstream side end (66). A dimension (L1) (the length in the radial direction (dr2) of the third extending part (63)) is at least 0.5 times as great as a distance (D1) (the straight-line distance between the bell mouth upstream side end (66) and the virtual point (P1)).