Cross-Flow Fan Air Passage Twists to Reduce Wind Noise
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Solution Overview
Problem
Existing air conditioners with cross flow fans suffer from wind noise due to vortex airflow interference, which is not optimally addressed by prior solutions that compromise air-blowing performance.
Innovation Solution
The air conditioner features twisted portions on the rear guider and stabilizer that deviate from the axial direction in the circumferential direction, maintaining uniform shape across cross sections and aligning with vane wheel deviations to continuously generate wind noise, thereby suppressing it without deteriorating air-blowing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a rib protruding toward the fan is provided at the leading end portion of the front tongue portion with a corrugated edge, then wind noise is suppressed by temporal dispersion, but the shape becomes irregular across cross sections and air-blowing performance deteriorates
Solution Approach 1:
The invention replaces the corrugated (irregular) edge with a twisted portion that has a curved surface deviating from the axial direction. This twisted portion maintains a substantially uniform shape across cross sections orthogonal to the axial direction, allowing it to suppress wind noise while preserving air-blowing performance. The curvature is applied in a controlled manner along the axial direction rather than creating irregularities across cross sections.
Solution Approach 2:
The invention changes the geometric parameters of the tongue portion by introducing a twist angle that deviates from the axial direction. This parameter change allows the edge to gradually disperse vortex airflow in the circumferential direction, suppressing wind noise while maintaining a uniform cross-sectional shape that preserves air-blowing performance.
2Object-affected harmful factors
If the twisted portion deviates from the axial direction gradually in the circumferential direction, then wind noise is suppressed by continuous generation, but the shape uniformity must be maintained to avoid air-blowing performance deterioration
Solution Approach 1:
The invention resolves the contradiction by introducing a third dimension - the twist angle in the circumferential direction. The twisted portion deviates from the axial direction gradually in the circumferential direction, creating a three-dimensional curved surface. This allows the edge to interact with vortex airflow in multiple directions, suppressing wind noise while maintaining substantial uniformity when viewed from cross sections orthogonal to the axial direction.
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 solution effectively reduces wind noise while maintaining airflow efficiency by ensuring the twisted portions are uniformly shaped and aligned with vane wheel deviations, preventing simultaneous vane passage through vortex airflow regions.
Implementation Method 1
Between each tongue portion and the fan, a vortex airflow is generated. When a vane of the fan passes this vortex airflow, wind noise (NZ noise) is generated on account of the interference between the vortex airflow and the vane.
Data Source
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AI summary
Wind noise is suppressed while an air-blowing performance is maintained. An indoor unit 1 of an air conditioner includes a cross flow fan 10 and a rear guider 20 and a stabilizer 32 which are provided on the respective sides of the outer periphery of the cross flow fan 10 to form an air passage. Each of the rear guider 20 and the stabilizer 32 has, at least at a part in the axial direction which part is on the leading end side, twisted portions 23, 37. In the circumferential direction of the cross flow fan 10, each twisted portion 23, 37 is deviated from the axial direction of the cross flow fan 10 gradually from one end to the other end.