Cross-Flow Fan Guide Twist to Suppress Air Conditioner Wind Noise
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Solution Overview
Problem
Air conditioners with cross flow fans experience wind noise due to vortex airflow interference, and existing solutions like rib protrusions on the stabilizer and rear guider compromise air-blowing performance by having irregular shapes across cross sections, leading to deteriorated efficiency and airflow amount.
Innovation Solution
Incorporating twisted portions on the stabilizer and rear guider that gradually deviate from the axial direction in the circumferential direction, maintaining a uniform shape across cross sections, and aligning deviation angles between twisted portions and vane wheels to prevent simultaneous vane passage and reduce wind noise.
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 temporally spreading the generation of wind noise, but the shape becomes irregular across cross sections orthogonal to the axial direction, deteriorating air-blowing performance
Solution Approach 1:
The invention replaces the corrugated rib structure with a twisted portion that has a curved, twisted shape extending from the leading end of the tongue portion. This twisted structure gradually deviates from the axial direction in the circumferential direction, creating a smooth curved surface that maintains regular cross-sectional shapes while still achieving the wind noise suppression effect by preventing simultaneous passage of vanes through the vortex airflow region.
2Object-affected harmful factors
If the edge of the rib is corrugated to have apexes deviated from one another in the rotation direction, then wind noise generation is temporally spread, but the irregular shape deteriorates air-blowing efficiency and air amount
Solution Approach 1:
The twisted portion employs a smooth curved surface that twists gradually in the circumferential direction while maintaining rotational symmetry. This curved geometry ensures that the cross-sectional shape remains regular and uniform, avoiding the irregularities caused by corrugated ribs, while the twisted configuration still achieves temporal spreading of wind noise generation by stagging the interaction between vanes and vortex airflow.
Solution Approach 2:
The invention changes the geometric parameters of the tongue portion by introducing a twist angle that gradually increases from the leading end toward the rear. This parameter change creates a twisted surface that maintains regular cross-sections while altering the spatial arrangement of the surface relative to the rotating fan, thereby suppressing wind noise without compromising air-blowing efficiency.
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
The solution effectively suppresses wind noise while maintaining air-blowing performance by ensuring continuous airflow and uniform airflow generation, avoiding the inefficiencies associated with irregular shapes and simultaneous vane interference.
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
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.