Squeeze Film Damper for Multiphase Pump Rotor Vibration Control
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Solution Overview
Problem
Multiphase pumps face challenges in rotor vibration damping, particularly at high gas volume fraction (GVF) values, where the Lomakin effect provides minimal damping due to large clearances and reduced pressure drop, leading to efficiency losses and increased vibrations.
Innovation Solution
The implementation of a squeeze film damper around radial bearings, using lubricant as damping fluid, which is independent of process fluid GVF and does not require recirculation of pressurized fluid, thereby enhancing rotor damping and hydraulic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiphase pump operates at high GVF values, then gas handling capability is improved, but rotor vibration damping deteriorates due to large clearances and reduced pressure drop
Solution Approach 1:
The pump clearance is segmented into two distinct regions: a large radial clearance for gas handling and a separate axial clearance for vibration damping. This allows each region to be optimized for its specific function without compromising the other.
Solution Approach 2:
A damping plate is introduced as an intermediary component between the impeller and pump housing. This plate creates a dedicated damping clearance that mediates the vibration control function, separating it from the main radial clearance used for gas handling.
2Reliability
If conventional hydrodynamic stabilization is used, then rotor damping is improved, but device complexity increases due to fluid recirculation requirements
Solution Approach 1:
The vibration damping function is extracted from the process fluid recirculation system. Instead of relying on recirculated process fluid, the damping function is achieved through a separate damping clearance that uses ambient or lubricating fluid, eliminating the need for complex recirculation piping and control systems.
Solution Approach 2:
The damping clearance automatically generates the necessary damping effect through the relative motion between the damping plate and pump housing, without requiring external control or recirculation systems. The system self-regulates based on the operational conditions.
3Adaptability or versatility
If large clearances are used for gas handling, then gas volume fraction capability is improved, but Lomakin effect damping is reduced
Solution Approach 1:
The clearance system is segmented into radial and axial components. The radial clearance maintains large dimensions for gas handling, while the axial damping clearance maintains small dimensions to preserve the Lomakin effect for vibration damping.
Solution Approach 2:
The vibration damping function is shifted from the radial dimension to the axial dimension through the damping plate arrangement. This dimensional transition allows the radial clearance to be optimized for gas handling while the axial clearance provides the necessary damping.
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 squeeze film damper effectively reduces rotor vibrations across all GVF values, maintaining pump efficiency and performance without the need for additional fluid recirculation, thus addressing the limitations of existing hydrodynamic stabilization methods.
Implementation Method 1
a squeeze film damper is provided to reduce vibrations of the rotor
Implementation Method 2
The physical phenomenon, on which this damping is based, is the Lomakin effect. The Lomakin effect is a force created at small gaps e.g. at wear rings, throttling bushes or balancing devices in centrifugal pumps.
Data Source
AI summary
A multiphase pump for conveying a multiphase process fluid includes a pump housing, a rotor and a radial bearing. The rotor is arranged in the pump housing and is configured to rotate about an axial direction. The radial bearing has a support carrier and a support structure to support the rotor with respect to a radial direction. The rotor includes a pump shaft and an impeller fixedly mounted on the pump shaft to convey the process fluid from a pump inlet to a pump outlet. A squeeze film damper is provided to reduce vibrations of the rotor, the squeeze film damper arranged around the support structure of the radial bearing, and having an radially outer surface. A damping gap is arranged between the support structure of the radial bearing and the radially outer surface of the squeeze film damper. The damping gap is configured to receive a damping fluid.