Axial Flow Fan Blade Layout for Separation Flow Suppression
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Solution Overview
Problem
Existing axial flow fans experience performance degradation due to separation flow generation, leading to stalling, reduced heat dissipation, and noise disturbances.
Innovation Solution
The axial flow fan design incorporates a hub with multiple fan sets, each comprising blades with specific distance and surface configurations to minimize separation flow, including varying curvatures and orientations to guide airflow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cross sections of the blades are designed to be airfoil-shaped, then the axial flow fan can generate lift and drive air, but separation flow may be generated causing the fan to stall and idle
Solution Approach 1:
The blade is divided into multiple sections along its span, with each section having a different cross-sectional shape. The root section has a different airfoil configuration than the tip section, allowing each part to optimize for its specific flow conditions and reduce overall separation flow tendency
Solution Approach 2:
Different portions of the blade cross-section are given different geometric properties. Specifically, the leading edge radius, thickness distribution, and camber are varied locally along the blade span to control flow attachment and prevent separation in critical regions
2Productivity
If the axial flow fan operates with airfoil-shaped blades, then it can maintain airflow, but disturbing noise is caused due to separation flow generation
Solution Approach 1:
The blade is divided into multiple sections along its span, with each section having a different cross-sectional shape. The root section has a different airfoil configuration than the tip section, allowing each part to optimize for its specific flow conditions and reduce overall separation flow tendency
Solution Approach 2:
Different portions of the blade cross-section are given different geometric properties. Specifically, the leading edge radius, thickness distribution, and camber are varied locally along the blade span to control flow attachment and prevent separation in critical regions
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
Reduces the likelihood of separation flow generation, preventing stalling and lowering noise levels while maintaining efficient airflow.
Implementation Method 1
When the axial flow fan generates a separation flow, the separation flow may cause the axial flow fan to stall
Data Source
Figure 1A~1B
Figure 1C
Figure 2A
AI summary
An axial flow fan includes a hub and a plurality of fan sets disposed around the hub. The hub rotates around a center axis and has a positive pressure side and a negative pressure side opposite to each other. Each of the fan sets includes at least two blades, and each blade has a wind inlet end, a wind outlet end opposite to the wind inlet end, a negative pressure surface, and a positive pressure surface opposite to the negative pressure surface. The wind outlet end of one of the adjacent two blades corresponds to the wind inlet end of the other one of the adjacent two blades. A gap is provided between the negative pressure surface of one of the adj acent two blades and the positive pressure surface of the other one of the adjacent two blades.