Counter-Rotating Fan With Spacer Ring For Blade Rigidity

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Solution Overview

Problem

Existing counter-rotating fans face issues with blade deformation, reduced airflow strength, and increased noise due to complex structures and limited rotation speed adjustment, which affect aerodynamic performance and motor heat dissipation.

Innovation Solution

The counter-rotating fan design incorporates multiple annular arrays of blades with a spacer ring to enhance rigidity, improve airflow uniformity, and stabilize rotation, while positioning the motor centrally to boost cooling efficiency and facilitate motor maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the length of a single blade of the fan is relatively long, then the air blowing area is increased, but the blade deformation becomes serious and aerodynamic performance is degraded

Engineering Contradiction:
Improveair blowing areaVSAvoidblade deformation resistance
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The fan blade is divided into multiple segments along its length, with each segment being independently supported. This segmentation allows the long blade to maintain structural integrity while covering a large area, preventing deformation without sacrificing air blowing capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the blade structure are given different properties - the root area has enhanced support and rigidity to prevent deformation, while the tip area maintains flexibility for optimal aerodynamic performance. This local differentiation allows the blade to simultaneously achieve strength and airflow efficiency

Inventive Principle:
Principle #3Local quality

2Length of stationary object

If the distance between the two stages of fans is relatively small, then the overall fan thickness is reduced, but the leakage vortex from the first stage easily enters the second stage blades causing increased noise

Engineering Contradiction:
Improvefan thicknessVSAvoidnoise from vortex interference
Core Design Contradiction:
Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

A flow control structure is introduced as an intermediary element between the two fan stages. This intermediary component guides and smooths the airflow, preventing the leakage vortex from the first stage from directly entering the second stage blades, thereby reducing noise while maintaining compact dimensions

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The flow control structure extends in the radial dimension to manage the axial flow between stages. By utilizing the radial space effectively, the design achieves vortex control without significantly increasing the axial thickness of the fan

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Stability of the object's composition

If a rectifier device is arranged between the two stages of fans, then the swirl is de-rotated to generate straight wind, but the structure becomes complicated and noise increases

Engineering Contradiction:
Improveairflow straightnessVSAvoidstructure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The rectifier function is merged with the fan blade design itself. The blades are configured to inherently perform both propulsion and flow rectification functions, eliminating the need for a separate rectifier device and simplifying the overall structure while maintaining airflow straightness

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fan blades are designed with multi-functionality, serving both to generate thrust and to rectify the airflow. This universal design allows a single component to fulfill multiple roles, reducing structural complexity and noise while achieving the desired straight wind output

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 results in a stable, high-rigidity fan with enhanced airflow strength and uniformity, reducing noise and extending motor service life by improving airflow de-rotation and heat dissipation.

Implementation Method 1

the swirl at the outlet of the first stage fan can be de-rotated by the blades of the second stage fan, to generate a straight wind to accelerate the air circulation

Methodology Applied
Scientific EffectVortex de-rotation: Vortex Ring

Implementation Method 2

an impeller with multiple annular arrays of blades, so that the air outlet capacity in the middle of the counter-rotating fan can be enhanced, speed distribution of the outlet wind field of the counter-rotating fan close to the center position of the fan can be improved

Methodology Applied
Scientific EffectAerodynamic flow distribution: Aerofoil

Implementation Method 3

The counter-rotating fan is provided with impellers each with a spacer ring and multiple annular arrays of blades, so that the air transmission between the previous stage impeller and the latter stage impeller can be significantly strengthened

Methodology Applied
Scientific EffectAxial flow transmission: Impeller

Implementation Method 4

the blades close to the motor rotate and produce work, which can increase the speed of the wind field close to the motor, improve the cooling effect of the motor

Methodology Applied
Scientific EffectForced convection cooling: Forced Convection

Data Source

PatentEP3839261B1Counter-rotating fan
Publication Date: 2023.08.23 GUANGDONG MIDEA WHITE HOME APPLIANCE TECH INNOVATION CENT CO LTD
  • EP3839261B1 patent drawingFigure 1~2
  • EP3839261B1 patent drawingFigure 3~5
  • EP3839261B1 patent drawingFigure 6~7

AI summary

A counter-rotating fan (100), comprising two impellers and a motor (10). The motor (10) is used for driving the two impellers to rotate. The two impellers are axially spaced apart from each other, and are divided into a first-stage impeller (30) and a second-stage impeller (40). When the counter-rotating fan (100) operates, airflow is blown to the direction of the second-stage impeller (40) by means of the first-stage impeller (30). At least one impeller has a plurality of turns of blades arranged in the radial direction of the impeller. A plurality of blades of each turn are spaced apart from each other around a hub (60) of the impeller, and a spacer ring (50) is connected between two adjacent turns of blades. The counter-rotating fan is stable in rotation and good in cooling effect, it is not easy to deform, and the wind is strong in the center.