Serial Axial Fan Unit Flow Control Vanes
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Solution Overview
Problem
Conventional serial axial fan units experience decreased air volume and static pressure due to energy loss when air flows from the upstream fan to the downstream fan, with the downstream fan failing to act sufficiently on the air due to a whirl component in the same direction as its rotation, limiting their ability to improve static pressure characteristics.
Innovation Solution
A serial axial fan unit is designed with a flow control device featuring flow control vanes that impart a whirl component opposite to the rotation direction of the second impeller, increasing its rotation speed relative to the air flow and enhancing static pressure energy, allowing the second impeller to provide sufficient energy to the air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If two axial fans are arranged in series to increase static pressure, then the maximum static pressure is expected to be twice as high, but in practice it is only about 1.5 times as high due to energy loss
Solution Approach 1:
A flow control device with flow control vanes is introduced as an intermediary component between the upstream and downstream fans. The flow control vanes actively manage the air flow, removing whirl components and optimizing the flow pattern to reduce energy loss and improve static pressure characteristics
Solution Approach 2:
The invention changes the flow parameters by using flow control vanes to modify the velocity distribution and remove whirl components from the air flow. This parameter change optimizes the flow conditions for the downstream fan, enabling it to operate more efficiently and achieve the expected static pressure multiplication
2Device complexity
If the upstream fan and downstream fan are arranged to rotate in the same direction, then the structure is simple, but the downstream fan fails to act sufficiently on the air due to whirl component in the same direction as rotation
Solution Approach 1:
The flow control device serves as an intermediary that conditions the air flow between the two fans rotating in the same direction. It removes the harmful whirl components while maintaining the simple same-direction rotation configuration, thus preserving structural simplicity while improving performance reliability
Solution Approach 2:
The flow control vanes extract and remove the harmful whirl component from the air flow. By taking out this adverse velocity component, the downstream fan can effectively act on the air without being counteracted by opposing whirl, thereby improving performance while maintaining simple structure
3Stress or pressure
If stationary vanes are provided between the upstream fan and downstream fan to improve static pressure, then the maximum static pressure increases to about 1.8 times, but still falls short of the expected 2 times
Solution Approach 1:
The invention transitions from static stationary vanes to dynamic flow control vanes that actively optimize the flow. The flow control vanes are designed to efficiently remove whirl components and optimize flow patterns, achieving superior static pressure multiplication (close to 2 times) with reduced device complexity compared to traditional stationary vane arrangements
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 results in improved static pressure characteristics and increased efficiency, enabling the serial axial fan unit to exhibit more than twice the static pressure of a single axial fan while maintaining the same air volume, thus overcoming the limitations of conventional designs.
Implementation Method 1
The plurality of flow control vanes are arranged to impart a whirl component in a direction opposite to a direction of rotation of the second impeller to a flow of air caused by the rotation of the first impeller
Implementation Method 2
a first impeller including a plurality of first blades arranged side-by-side in a circumferential direction to be centered about a central axis; a first motor portion arranged to rotate the first impeller
Data Source
AI summary
A serial axial fan unit includes a first axial fan arranged to rotate about a central axis, a flow control device connected to the first axial fan along the central axis, and a second axial fan connected to the flow control device along the central axis. The flow control device preferably includes a wind tunnel portion, a base portion, and a plurality of flow control vanes. A flow of air caused by rotation of first blades has a whirl velocity component in substantially the same direction as the rotation direction thereof. This whirl velocity component is converted to a velocity component in a direction parallel or substantially parallel to the central axis by interference of first stationary vanes. The above arrangement provides an improvement in air volume characteristics of a serial axial fan unit including two axial fans arranged in series.