Fan Inlet Rectifier Geometry for Inner-Circumference Airflow
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Solution Overview
Problem
Existing air-conditioning apparatuses suffer from insufficient rectifying effects due to the shape and size relationship between the conical rectifying member and the motor support base, leading to reduced fan efficiency as air currents do not effectively flow into the inner circumferential region of the fan, causing turbulence and reduced efficiency.
Innovation Solution
An air sending device with a rectifying member that protrudes from the motor support base, featuring a spherical upstream distal end surface and a tapered main surface, directing air currents towards the inner circumferential region of the fan, thereby reducing the likelihood of air currents striking the motor support base and enhancing fan efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conical rectifying member with the same outside diameter as the motor is used, then the motor is protected from direct air current impact, but the air current flows toward the outside of the fan and strikes against the motor support base, reducing rectifying effectiveness
Solution Approach 1:
The rectifying member's geometry is changed from a simple cone to a multi-surface structure with specific angle ranges (first angle 10-30 degrees, second angle 30-60 degrees). This parameter optimization redirects the air current flow angle to prevent it from striking the motor support base while still protecting the motor, thereby improving fan efficiency without sacrificing motor protection
Solution Approach 2:
The rectifying member employs asymmetric surface design where the first rectifying surface and second rectifying surface have different inclination angles relative to the fan's rotation axis. This asymmetric configuration creates optimal flow redirection that guides air current into the fan's inner circumferential region rather than allowing it to flow outward and strike the support base
2Ease of manufacture
If the rectifying member has a triangular shape as viewed side-on, then the structure is simple to manufacture, but the extended line from the rectifying surface does not intersect the fan, causing air current to flow away from the inner circumferential region
Solution Approach 1:
The angular parameters of the rectifying surfaces are precisely controlled within specific ranges (first angle 10-30 degrees, second angle 30-60 degrees). This parameter optimization ensures that the extended line from the rectifying surface properly intersects the fan's inner circumferential region, directing air flow where needed while maintaining manufacturability through straightforward geometric forms
3Device complexity
If the air current is not properly rectified, then the flow path is simple, but turbulence occurs and fan efficiency is reduced
Solution Approach 1:
The rectifying member applies different surface qualities in different regions: the first rectifying surface has a specific inclination angle (10-30 degrees) for initial flow direction control, while the second rectifying surface has a different inclination angle (30-60 degrees) for final flow optimization. This localized quality variation creates smooth flow transitions that eliminate turbulence without requiring complex overall structure
Solution Approach 2:
The rectifying surfaces are designed with curved transitions rather than sharp edges, creating smooth flow paths that guide air current gradually from the upstream direction into the fan's inner circumferential region. This curvature eliminates flow separation and turbulence that would occur with angular transitions, maintaining simple overall structure while achieving laminar flow
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 facilitates the flow of air currents into the inner circumferential region of the fan, improving fan efficiency by reducing turbulence and increasing the volume of air that can be efficiently processed, thus enhancing overall performance.
Implementation Method 1
a rectifying member provided on an upstream side that is located upstream of the motor support base in the flow direction of the air current, protruding in a direction from the motor support base toward the upstream side, and having a rectifying surface configured to change the flow direction of the air current in such a manner as to cause the air current to flow toward an inner circumferential region of the fan
Data Source
AI summary
An air sending device includes: a housing; a fan motor; a fan configured to generate an air current; a motor support base provided upstream of the fan and the fan motor in a flow direction of the air current, and supporting the fan motor; and a rectifying member provided upstream of the motor support base, protruding in a direction from the motor support base toward the upstream side, and having a rectifying surface configured to change the flow direction of the air current such that the air current flows toward an inner circumferential region of the fan. The rectifying surface of the rectifying member includes an upstream-side distal end surface formed spherically, and a main surface located between the upstream-side distal end surface and the motor support base, forming an outer peripheral surface of the rectifying member, and tapered in a direction away from the motor support base.