Fan Array Vibration Control via Phase Reversal
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Solution Overview
Problem
Fan arrays in air-handling systems generate undesirable vibrations due to residual imbalance, which are additive and can be maximized when fans are in-phase, leading to structural damage and noise.
Innovation Solution
A control system that includes a control unit connected to multiple fans, equipped with phase sensors and vibration sensors to detect and adjust the phase relationship among fans, maintaining them in an out-of-phase configuration to minimize vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fans are operated in-phase to maximize airflow output, then productivity is improved, but vibrations increase additively causing structural damage and noise
Solution Approach 1:
The control system implements periodic reversal of fan rotation directions. Fans alternate between clockwise and counter-clockwise rotation in a periodic manner, which prevents sustained in-phase operation and reduces cumulative vibrational effects while maintaining overall airflow productivity
Solution Approach 2:
The system changes the operational parameters of the fans by reversing their rotation direction. This parameter change allows the fans to operate in opposing phases rather than in-phase, transforming the vibrational characteristics while preserving the airflow generation capability
2Ease of manufacture
If fans are oriented with mass centers at the same radial positions (in-phase), then manufacturing and installation are simplified, but vibration energy becomes additive and transmits maximum force to the structure
Solution Approach 1:
Rather than permanently orienting fans in opposite positions, the system uses periodic reversal to achieve the beneficial out-of-phase operation. This maintains the simple in-phase orientation for manufacturing while dynamically creating the force-cancelling out-of-phase condition during operation
Solution Approach 2:
The system transitions from a static fan orientation approach to a dynamic operation mode. Fans are oriented simply for manufacturing, but their rotation directions are dynamically reversed periodically to achieve the desired force reduction effect during operation
3Object-affected harmful factors
If a control system with phase sensors and vibration sensors is implemented to reduce vibrations, then harmful vibrations are minimized, but device complexity increases
Solution Approach 1:
The control system uses the fans' own operational characteristics and natural vibrations as feedback signals. The phase sensors detect the inherent phase relationships and the system automatically adjusts fan operation based on this self-generated information, reducing the need for external complex control mechanisms
Data Source
AI summary
A fan array vibration control system may include a fan array having a plurality of fans, and a control unit operatively connected to the fans. The control unit is configured to operate the plurality of fans and detect a phase relationship among the plurality of fans. The control unit is configured to reduce the phase relationship among the plurality of fans in order to reduce vibrations within the fan array.