Axial Impeller Blade Wrap Angle for Tip Vortex and Noise Reduction
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Solution Overview
Problem
Traditional blades in rotating machinery such as fans, pumps, and compressors experience significant flow separation leading to vortices, resulting in loud noise and uneven airflow distribution.
Innovation Solution
The blade design features a varying wrap angle, starting angle, winglet angle, and sweep forward angle, along with curved upper and lower surfaces, which reduce turbulent vortices and improve airflow uniformity, thereby mitigating noise and load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional monotonous smooth curves are used for blade edges, then the blade structure is simple and easy to manufacture, but flow separation occurs seriously inducing vortices and producing loud noise
Solution Approach 1:
The patent applies local quality by varying the wrap angle differentially across the blade height. The wrap angle is designed to decrease from the blade root to the middle blade height and then increase from the middle blade height to the blade tip. This non-uniform distribution optimizes the airflow characteristics at different locations along the blade, reducing flow separation and vortex formation while maintaining manufacturing feasibility through a systematic geometric progression.
2Device complexity
If the wrap angle is constant along the blade height, then the blade design is simple, but airflow velocity becomes uneven and velocity pulsations occur
Solution Approach 1:
The patent implements dynamics by making the wrap angle variable rather than constant, allowing it to change dynamically along the blade height according to a specific pattern (decreasing then increasing). This dynamic adjustment of the geometric parameter optimizes the airflow velocity distribution across different blade sections, eliminating velocity pulsations and achieving more uniform airflow while maintaining a systematic design approach.
3Ease of manufacture
If the blade edges have monotonic curves, then the manufacturing process is simple, but turbulent vortices are severe at the blade tip junctions
Solution Approach 1:
The patent applies parameter changes by systematically varying the wrap angle parameter along the blade height rather than maintaining a constant value. The wrap angle transitions from larger values at the blade root through a minimum at the middle blade height to larger values at the blade tip. This parameter variation optimizes the aerodynamic characteristics, reducing turbulent vortex formation at the blade tip junctions while keeping the manufacturing process relatively simple through a defined geometric progression.
Data Source
AI summary
The present application discloses a blade and an axial-flow impeller using the same. The present application provides a blade, comprising a blade tip, a blade root, a leading edge and a trailing edge, wherein the leading edge and the trailing edge extend from the blade tip to the blade root, respectively. The blade is capable of rotating about a rotation axis X which is perpendicular to a normal plane. In a projection of the blade on the normal plane, a circumferential included angle between the leading edge and the trailing edge forms a wrap angle, and the wrap angle decreases gradually from the blade root to a middle blade height of the blade and increases gradually from the middle blade height to the blade tip. Wherein, the middle blade height is an arc line formed by center points of the blade tip and the blade root along a radial direction. The blade of the present application allows for significantly reduced turbulent vortices and reduced intensity in the vicinity of the junction of the leading edge and the blade tip of the blade and in the vicinity of the junction of the trailing edge and the blade tip of the blade during the operation of the axial-flow impeller, leading to evenly lightened load of airflow on the blade, more uniform distributions of velocity and pressure, reduced velocity and pressure pulsations, and reduced noise.