Counter-rotating fan with guide vanes for noise reduction
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Solution Overview
Problem
Counter-rotating axial flow fans exhibit high noise and low air pressure, particularly when miniaturized, which existing technologies have not effectively addressed.
Innovation Solution
The design incorporates supporting guide vanes that bend towards the air outlet side, reducing noise and pressure loss by guiding air towards the inlet of the blades, and a flow guide cover that extends from the axis to direct airflow towards the impeller, optimizing the wind field and air pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a counter-rotating axial flow fan is miniaturized, then the device size is reduced, but noise increases and air pressure decreases
Solution Approach 1:
The supporting guide vanes are positioned upstream of the first impeller to pre-condition the airflow before it enters the impeller. This preliminary action guides the air in a direction toward the inlet of the first blades, reducing inlet air noise and pressure loss, thereby allowing the fan to maintain lower noise levels even when miniaturized.
Solution Approach 2:
The supporting guide vanes act as an intermediary element between the air inlet and the first impeller. These vanes modify the airflow characteristics before it reaches the impeller, serving as a mediator that reduces the harmful noise generation at the impeller inlet while maintaining compact dimensions.
2Volume of moving object
If a counter-rotating axial flow fan is miniaturized, then the device size is reduced, but air pressure decreases
Solution Approach 1:
The supporting guide vanes perform preliminary airflow conditioning by guiding air toward the inlet of the first blades in a direction that optimizes flow entry. This reduces pressure loss at the inlet and allows the compact fan to maintain higher air pressure output despite its miniaturized size.
Solution Approach 2:
The invention changes the airflow parameters (direction, velocity distribution) through the supporting guide vanes before the air enters the impeller. By optimizing the inlet flow parameters, the fan achieves better pressure characteristics in a miniaturized configuration.
3Object-generated harmful factors
If supporting guide vanes are added to guide airflow, then noise is reduced and pressure loss decreases, but device complexity increases
Solution Approach 1:
The supporting guide vanes are integrated with the air inlet structure, merging the flow guidance function into the existing inlet design. This combination approach reduces noise and pressure loss while minimizing the increase in overall device complexity by consolidating functions into a unified structure.
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 configuration significantly reduces noise and increases air pressure while maintaining airflow efficiency, even at reduced rotation speeds, making it suitable for applications like electric fans and air-conditioning systems.
Implementation Method 1
the support guide vanes guide air in a direction toward an inlet of each of the first blades by providing the supporting guide vanes which bend in the direction toward the air outlet side
Implementation Method 2
a flow guide cover that extends from the axis to direct airflow towards the impeller, optimizing the wind field and air pressure
Data Source
Figure 1
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Figure 4~5
AI summary
A counter-rotating fan (100), comprising an impeller assembly (20) and an air guide structure (10). The impeller assembly (20) comprises a first stage impeller (21) and a second stage impeller (22), of which the rotation directions are opposite. The pressure surfaces of first blades (212) of the first stage impeller (21) are configured to be opposite the suction surfaces of second blades (222) of the second stage impeller (22), and from the blade root to the blade tip, each of the first blades (212) and the second blades (222) bends toward its own rotation direction. The air guide structure (10) comprises a flow guide cover (13). The flow guide cover (13) is provided at the center position of the air intake side of the first stage impeller (21), and the air intake side surface of the flow guide cover (13) at least partially forms a flow guide surface, the flow guide surface extending along the axis of the first stage impeller (21) in the direction away from the counter-rotating fan (100). The present counter-rotating fan can reduce noise and increase air pressure.