Axial Fan Blade Connector Geometry for Tip Leakage and Noise
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Solution Overview
Problem
Conventional axial fans in outdoor air conditioner units suffer from reduced air volume and noise issues due to weakened rigidity at the coupling portion of separate inner and outer blade groups, as well as tip leakage flow caused by gaps with the orifice, which affects flow performance and generates noise.
Innovation Solution
Designing the axial fan blades with a curved connector in the radial direction to connect the blade inner and outer portions, allowing for different shapes and a larger area of the blade outer portion, with a maximum camber position closer to the rear end and a phase difference in the circumferential direction to enhance air volume and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate inner blade group and outer blade group are manufactured and coupled to a middle ring, then manufacturing flexibility is improved, but rigidity at coupling portion is weakened
Solution Approach 1:
The patent merges the inner blade group and outer blade group into a single integrated blade structure without requiring a middle ring for coupling. This eliminates the coupling portion entirely, resolving the contradiction by achieving both manufacturing flexibility (through integrated design) and structural rigidity (by removing the weak coupling interface).
Solution Approach 2:
The patent extracts and removes the middle ring component from the blade assembly. By taking out the coupling mechanism, the design eliminates the rigidity problem at the coupling portion while maintaining manufacturing flexibility through the simplified single-piece blade structure.
2Ease of manufacture
If gap exists between blade tip and orifice of outdoor unit, then ease of assembly is improved, but tip leakage flow occurs reducing air volume
Solution Approach 1:
The patent changes the geometric parameters of the blade, specifically extending the blade length to reduce the gap between the blade tip and the orifice. This parameter adjustment reduces tip leakage flow and improves air volume while maintaining adequate assembly clearance.
Solution Approach 2:
The patent applies curvature to the blade tip portion, creating a rounded or curved tip geometry rather than a straight edge. This curved design optimizes airflow patterns at the tip, reduces leakage through the gap, and maintains ease of assembly by accommodating manufacturing tolerances.
3Device complexity
If conventional blade design is used, then manufacturing simplicity is maintained, but noise is generated at coupling portion
Solution Approach 1:
The patent removes the middle ring and coupling portion from the blade assembly, eliminating the source of noise generation at the coupling interface. This extraction maintains manufacturing simplicity by using a single integrated blade structure without additional coupling components.
Solution Approach 2:
The patent combines the inner and outer blade groups into a single unified structure, eliminating the coupling portion that generates noise. This merging maintains manufacturing simplicity through integrated production while eliminating the harmful noise effect.
4Productivity
If blade outer portion area is increased, then air volume is improved, but structural complexity increases
Solution Approach 1:
The patent uses curved surfaces and smooth transitions in the blade outer portion design to increase the effective area for air movement. The curved geometry achieves increased air volume capability while maintaining manufacturing simplicity through conventional forming techniques for curved surfaces.
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 solution improves air volume performance and reduces noise by creating a pressure difference between blade surfaces and preventing tip leakage flow, while maintaining structural integrity and enhancing blowing ability.
Implementation Method 1
connecting a blade inner portion and a blade outer portion in a curved surface through a blade connector in a radial direction
Implementation Method 2
a pressure difference is generated at front/rear surfaces of the plurality of blades and a suction force for blowing air is generated due to the pressure difference
Implementation Method 3
a pressure difference is generated at front/rear surfaces of the plurality of blades and a suction force for blowing air is generated due to the pressure difference
Implementation Method 4
bending a blade outer portion toward a blade inner portion at a front end of the blade in a suction surface direction and bending the blade outer portion toward the blade inner portion at a rear end of the blade in a pressure surface direction
Data Source
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AI summary
An axial fan for an outdoor unit of an air conditioner is provided. The axial fan may include at least one blade connected to a hub. The at least one blade may include a blade inner portion, a blade outer portion provided outside of the blade inner portion in a radial direction, and a blade connector that connects the blade inner portion and the blade outer portion as a curved surface, thereby improving noise and increasing an air volume.