Pipeline Natural Frequency Control for Flow-Induced Vibration
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Solution Overview
Problem
Subsea hydrocarbon production and processing facilities face significant challenges due to flow-induced vibrations (FIV) in piping systems, which can lead to damage and maintenance needs, as existing solutions either reduce hydrocarbon output or do not address resonance issues effectively.
Innovation Solution
A method and apparatus that measure FIV and automatically adjust the natural frequency of pipeline sections by applying forces to minimize vibrations, using sensors and mechanical means to alter tension or compression within the pipes, thereby moving the natural frequency away from resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pipe section incorporates bends to accommodate tolerances, then the ease of installation is improved, but the susceptibility to flow induced vibrations increases
Solution Approach 1:
The patent applies parameter changes by actively modifying the natural frequency of the pipe section through controlled forces applied by actuators. This dynamic adjustment of physical parameters (natural frequency) allows the system to adapt to varying flow conditions and avoid resonance, thereby reducing FIV while maintaining the bent pipe configuration for installation flexibility.
2Object-affected harmful factors
If flow rate is reduced to mitigate FIV, then the vibration amplitude is reduced, but the hydrocarbon output is reduced
Solution Approach 1:
Instead of changing the flow rate parameter, the invention changes the natural frequency parameter of the pipe section through active control forces. This allows the system to maintain high flow rates for maximum hydrocarbon output while dynamically adjusting the pipe's natural frequency to avoid resonance and reduce vibration amplitudes.
Solution Approach 2:
The system employs feedback control by continuously monitoring vibration levels and flow conditions, then automatically adjusting the natural frequency through actuators. This closed-loop feedback mechanism enables the system to maintain low vibration amplitudes without requiring flow rate reductions, thus preserving hydrocarbon productivity.
3Reliability
If the natural frequency is adjusted dynamically, then the reliability against FIV is improved, but the device complexity increases
Solution Approach 1:
The patent implements dynamic parameter changes by using actuators to apply controlled forces that adjust the natural frequency of the pipe section. This active control of physical parameters enhances reliability against FIV by continuously adapting to changing operating conditions, despite the added complexity of the control system.
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 approach reduces the amplitude of vibrations, enhancing the durability and reliability of subsea piping systems by continuously adjusting the natural frequency based on real-time vibration measurements, thus preventing damage and maintaining optimal operational output.
Implementation Method 1
Flow induced vibrations are particularly troublesome when the vibrations approach the natural frequency of any given pipe section. When forced vibrations such as FIV approach the natural frequency of a pipe section, the amplitude of vibration greatly increases due to resonance.
Implementation Method 2
The mechanical means is configured to apply a controllable force to the pipe section to adjust its natural frequency. The force can be applied in a direction substantially parallel to the axis of the pipe section, affecting the tension within the pipe itself.
Data Source
AI summary
An apparatus for controlling flow induced vibrations in a section of pipeline caused by a flow of liquid therethrough comprising: a sensor for measuring flow induced vibrations of the section of pipeline; a mechanical means for adjusting the natural frequency of the section of pipeline; wherein the mechanical means automatically adjusts the natural frequency of the section of pipeline based on the measured vibration in order to reduce the flow induced vibration.