Reverse-Bent Turbo Fan Wings for Stable Flow and Lower Noise
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Solution Overview
Problem
Turbo fans in ventilation devices, such as air conditioners, face inefficiencies and noise issues due to air separation at the contact portion between the side plate and the leading edge of the wings, as the bended portion of the wing is not effectively reattaching the air separation at the negative pressure surface.
Innovation Solution
The turbo fan design includes wings with a bended portion between the leading and trailing edges, bended in the reverse direction of the wing's rotation, featuring distinct curvature variations at contact points and a specific geometry that reattaches air separation at the negative pressure surface, enhancing ventilation efficiency and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the bended portion is located at the contact portion between the side plate and the leading edge of each wing, then the structure is simplified, but the air separation at the negative pressure surface cannot be reattached
Solution Approach 1:
The bended portion is positioned at a specific location on the wing (between the contact portion and the trailing edge) rather than at the contact portion itself. This local positioning allows the bended portion to effectively reattach air separation at the negative pressure surface while maintaining structural simplicity, resolving the contradiction between device complexity and reliability.
2Ease of manufacture
If the wing is not bended toward the downstream side from the contact portion, then the manufacturing is easier, but the air separation is not reattached
Solution Approach 1:
Instead of bending the wing toward the downstream side from the contact portion (conventional approach), the bended portion is positioned downstream from the contact portion and bent in the opposite direction. This inverted approach achieves better air flow reattachment and ventilation efficiency while maintaining ease of manufacture.
3Force
If air is greatly turned at the contact portion, then the suction force is increased, but the flow becomes highly unstable causing noise
Solution Approach 1:
The bended portion converts the harmful air separation and unstable flow into beneficial reattached flow. By positioning the bended portion downstream from the contact portion, it redirects the greatly turned air flow to reattach smoothly at the negative pressure surface, reducing noise while maintaining suction force.
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 improves ventilation efficiency and reduces noise by effectively reattaching air separation at the negative pressure surface, while maintaining mechanical strength and reducing stress concentration, thus enhancing the overall performance of the turbo fan.
Implementation Method 1
an air separation occurring at a negative pressure surface is easily generated at a contact portion between the side plate and a leading edge of each wing because air suctioned through the opening of the side plate is greatly turned at the contact portion to cause a highly unstable flow of the air
Data Source
AI summary
Disclosed herein are a turbo fan, which is capable of implementing high efficiency of ventilation and reducing noise by providing a bended portion being bended in a reverse direction against a rotational direction of a wing between a leading edge and a tailing edge thereof to reattach an air separation generated at a negative pressure surface of the wing, and an air conditioner having the same. The air conditioner includes the turbo fan, wherein the turbo fan includes a main plate having a disc shape and on which a rotational shaft is mounted, a side plate provided to be separated from the main plate along an axial direction of the rotational shaft and having a ring shape in which an opening is provided at a center portion of the side plate, and a wing fixed between the main plate and the side plate and provided in plural numbers along a circumferential direction of the main plate, and wherein a bended portion, which is bended in a reverse direction against a rotational direction of the wing, is provided at the wing between a portion of a leading edge of the wing coming in contact with the side plate and a tailing edge of the wing.