Cooling Fan Winglets Reduce Tip Recirculation
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Solution Overview
Problem
Existing cooling fan modules suffer from reduced efficiency and increased noise due to recirculating airflow between the fan blades and the shroud, which is exacerbated by the presence of a fan ring or band, and lack thereof, leading to inefficiencies in air flow and noise generation.
Innovation Solution
The cooling fan module incorporates winglets at the distal end of each blade, which extend in both axial and radial directions, forming specific leading and trailing edges to minimize recirculation leakage and eliminate the need for a fan ring, thereby reducing material usage, weight, and increasing natural frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fan ring or band is used to reduce blade tip recirculation, then air flow efficiency is improved, but device complexity and material usage increase
Solution Approach 1:
The fan ring is divided into multiple individual winglets that are attached to each blade. This segmentation allows the functionality of the fan ring to be distributed across multiple smaller components, reducing overall complexity while maintaining the air flow efficiency benefits.
Solution Approach 2:
The winglet functionality is merged with the blade structure itself, where each blade includes an integrated winglet at its distal end. This merging eliminates the need for a separate fan ring component, reducing device complexity and material usage while maintaining air flow control.
2Productivity
If a fan ring or band is used to reduce blade tip recirculation, then air flow efficiency is improved, but weight increases
Solution Approach 1:
The heavy fan ring is segmented into multiple smaller winglets attached to individual blades. This segmentation distributes the weight across multiple lighter components rather than one large heavy ring, reducing overall weight while maintaining air flow efficiency.
Solution Approach 2:
The winglet functionality is merged with the blade structure, eliminating the need for a separate fan ring. This integration reduces material usage and weight while maintaining the air flow control benefits.
3Object-generated harmful factors
If a fan ring or band is used to reduce blade tip recirculation, then noise is reduced, but manufacturing complexity increases
Solution Approach 1:
The fan ring manufacturing process is segmented into attaching individual winglets to each blade. This can be done through simpler processes such as adhesive bonding or mechanical attachment rather than complex forming operations required for a complete fan ring.
Solution Approach 2:
The winglet is merged with the blade as a single component or easily attachable part, simplifying the manufacturing process. This integration eliminates the need for complex fan ring formation and assembly operations.
4Reliability
If winglets are added to blade distal ends, then natural frequency increases, but device complexity increases
Solution Approach 1:
The winglet is merged with the blade structure, where each blade includes an integrated winglet at its distal end. This merging increases the natural frequency while avoiding the complexity of a separate fan ring assembly.
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 enhances the operating efficiency of the cooling fan by at least 3% and reduces noise, with winglets increasing the natural frequency by at least 20 Hz, resulting in a lighter and more efficient fan assembly compared to banded fans.
Implementation Method 1
Air drawn to the downstream side of the frame recirculates to the upstream side through gap between fan blade tip and frame opening, thus leading to in efficiencies
Data Source
AI summary
The cooling fan module may include a fan assembly and a fan shroud. The fan shroud of the cooling fan module may include a first sidewall that may extend in a radial direction and define an opening. The fan assembly may include a hub disposed within the opening, a blade extending from the hub to a distal end that may include a first side and a second side converging to form a first leading edge with respect to the rotational direction. The fan assembly may include a winglet that may include a first fin, extending in the axial direction from the distal end of the blade and a second fin extending in the radial direction.