Centrifugal Fan Blade Draft Angle Optimization
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Solution Overview
Problem
Centrifugal fans with uniformly formed draft angles above and below the main plate experience uneven wind speeds due to varying air suction amounts, leading to reduced air flow rates.
Innovation Solution
A centrifugal fan design with blades having inclinations in the same direction above and below the main plate, where the inclination of the lower blade portion is larger than the upper blade portion, ensuring uniform wind speed in the axial direction and optimizing air flow rates by adjusting the blade cross-sectional lengths and draft angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform draft angles are formed above and below the main plate, then the blade structure is simple and easy to manufacture, but uneven wind speed occurs and air flow rate cannot be increased
Solution Approach 1:
The patent applies local quality by differentiating the draft angles above and below the main plate. Specifically, the draft angle above the main plate is set to 5-15 degrees while the draft angle below the main plate is set to 0-5 degrees, creating locally optimized blade surfaces that address the uneven wind speed issue in different regions
Solution Approach 2:
The patent implements asymmetry by using different draft angles for the upper and lower blade portions. This asymmetric configuration compensates for the uneven air suction distribution, with the larger draft angle above the main plate helping to increase wind speed in regions where air suction is weaker
2Productivity
If the draft angle is increased to increase wind speed, then air flow rate can be improved, but unevenness in wind speed across the blade increases
Solution Approach 1:
The patent applies local quality by differentiating the draft angles above and below the main plate. Specifically, the draft angle above the main plate is set to 5-15 degrees while the draft angle below the main plate is set to 0-5 degrees, creating locally optimized blade surfaces that address the uneven wind speed issue in different regions
Solution Approach 2:
The patent changes the draft angle parameter differently for upper and lower blade portions. By setting the draft angle above the main plate to 5-15 degrees and below the main plate to 0-5 degrees, the patent optimizes wind speed distribution while maintaining overall uniformity across the blade
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 achieves a substantial increase in air flow rate by maintaining uniform wind speeds across the blade axis, enhancing airflow efficiency without relying on uniform draft angles.
Implementation Method 1
a centrifugal fan includes: a casing that has a base portion at a lower side, to which a motor unit is installed; and an impeller that is provided in the casing and attached to a rotation shaft of the motor to be rotatable with respect to the casing
Data Source
AI summary
A centrifugal fan includes: a casing; and an impeller that is attached to a rotation shaft of a motor, wherein the casing has an upper suction port and a lower suction port, wherein the impeller has a rotor hub, a plurality of blades arranged around the rotor hub in a circumferential direction, and a main plate coupled to the rotor hub and connects the blades in the circumferential direction, and wherein an inclination of an outer edge of the blades at an upper blade portion that is located above the main plate with respect to a plane parallel to the rotation shaft and an inclination of the outer edge of the blades at a lower blade portion that is located below the main plate with respect to the plane parallel to the rotation shaft are set to be in the same direction.