Fan Impeller Flow Element Axial Height for Noise Reduction
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Solution Overview
Problem
Existing fan impeller designs fail to effectively reduce noise during operation while maintaining optimal air flow, leading to noise pollution and inefficiencies.
Innovation Solution
The fan impeller features a flow element with maximum axial height at the front and rear edges of the fan blades, decreasing towards the center, which enhances noise reduction and air flow by minimizing leakage and optimizing the shape of the fan blades and flow elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the flow element has constant height along the radially outer edge, then the structure is simple, but noise reduction is insufficient and air flow is hindered
Solution Approach 1:
The flow element's axial height varies along the radially outer edge of the fan blade, being maximum at the front and rear edges and minimum at the center. This local variation optimizes noise reduction at critical locations while maintaining structural integrity, resolving the contradiction between structural simplicity and noise reduction effectiveness.
2Object-generated harmful factors
If the flow element height is increased to reduce noise, then noise reduction improves, but air flow from pressure side to suction side is hindered
Solution Approach 1:
The flow element achieves maximum axial height at the front and rear edges where noise generation is most critical, while maintaining minimum height at the center to preserve unobstructed air flow paths. This localized height distribution simultaneously optimizes noise reduction and maintains productivity.
Solution Approach 2:
The flow element's height varies in the axial dimension along the radial length, creating a three-dimensional profile that optimizes both noise reduction and air flow. The height transitions from maximum at edges to minimum at center, utilizing dimensional variation to resolve the noise-productivity contradiction.
3Ease of manufacture
If the flow element has maximum height at the center of the fan blade, then the structure is simple, but noise reduction is poor and air flow is obstructed
Solution Approach 1:
The flow element is designed with maximum height at the front and rear edges where noise generation occurs, rather than uniform or center-maximum height. This local optimization at critical noise-generating locations achieves superior noise reduction while maintaining overall structural simplicity.
Data Source
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AI summary
A fan impeller is rotatably mounted about a central axis and has a hub on which fan blades (7) are arranged. The fan blade (7) has at least similar profile sections (21 to 21.7) along its radial length, as seen in a cylindrical section through the fan blade (7). The outermost radial profile section (21), which lies within a cylindrical surface (22) of the impeller (4), is offset from the adjacent profile section (21.2) by a greater distance than this adjacent profile section (21.2) is offset from its adjacent profile section (21.3). The impeller (4) can also be provided with at least one projecting flow element at its radially outer edge, the axial height of which reaches a maximum in the region of the leading and trailing edges of the fan blade (7). With a simple design, the impellers (4) exhibit very low noise levels during fan operation.