Axial-Flow Fan Housing With Non-Uniform Stationary Blade Angles
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Solution Overview
Problem
Conventional fan housings with evenly spaced stationary blades generate pure-tone noise due to identical angles between adjacent blades, leading to structural imbalance and increased manufacturing costs when trying to reduce noise, and existing solutions for impellers with varying blade angles complicate rotation balance adjustments.
Innovation Solution
A housing for an axial-flow fan with stationary blades arranged such that the included angles between any two adjacent blades have more than two values, allowing for non-uniform spacing to reduce pure-tone noise without altering the impeller's blade angles, simplifying balance adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stationary blades are spaced evenly with identical angles, then the structure is simple and easy to manufacture, but pure-tone noise is generated
Solution Approach 1:
The patent applies asymmetry by arranging stationary blades with different included angles between adjacent blades. Specifically, at least one stationary blade has a different included angle from the others, creating an asymmetric configuration that disrupts the uniform airflow patterns responsible for pure-tone noise while maintaining structural simplicity for easy manufacturing.
2Object-generated harmful factors
If impeller blade angles are varied to reduce pure-tone noise, then noise intensity decreases, but rotation balance adjustment becomes difficult and costs increase
Solution Approach 1:
The patent extracts the noise-reduction function from the impeller blades and transfers it to the stationary blades. By varying the included angles of stationary blades instead of impeller blades, the solution achieves pure-tone noise reduction while keeping the impeller structure simple and easy to balance, thus avoiding the complexity and cost increases associated with varying impeller blade angles.
3Object-generated harmful factors
If airflow-guiding elements are added to stationary blades, then turbulence is restrained and noise is reduced, but manufacturing difficulty and cost increase
Solution Approach 1:
The patent changes the geometric parameters of stationary blades by varying their included angles, rather than adding complex airflow-guiding elements. This parameter change approach achieves noise reduction by optimizing airflow guidance through simple angular variations, maintaining ease of manufacture while effectively reducing turbulence-induced noise.
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
Effectively suppresses pure-tone noise by varying the included angles between stationary blades, reducing noise intensity and simplifying impeller balance adjustments, thereby lowering manufacturing costs and improving fan housing quality.
Implementation Method 1
the stationary blades 941 are able to guide airflow generated from rotation of the impeller 93 to enhance air pressure
Implementation Method 2
the airflow-guiding elements can guide the airflow to restrain turbulence on the stationary blades from arising noise
Data Source
AI summary
A housing for an axial-flow fan includes a frame, a seat and a plurality of stationary blades. The frame has an air inlet and an air outlet. The seat is received in the frame and at a position where the air outlet is formed. Two ends of each stationary blade are respectively fixed to an outer periphery of the seat and an inner periphery of the frame. Furthermore, extending directions of any two adjacent stationary blades jointly define an included angle, and all of the included angles formed by all of the stationary blades are of more than two values in degrees, so that the stationary blades are not spaced with equal intervals. Consequently, while sucked air passes by the stationary blades, noises with the same tone can be suppressed effectively.