Flexible Pipe Carcass Protrusions for Vibration Control
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Solution Overview
Problem
Rough bore flexible pipes experience vortex-induced vibrations and 'singing' due to the irregular inner surface of the carcass layer, leading to fluid flow disruptions and potential equipment damage, especially at higher fluid export velocities.
Innovation Solution
Incorporating protrusions on the inner surface of the carcass layer, formed as integral aerodynamic features, to break up the boundary layer and reduce turbulence, thereby minimizing vorticity and shear layer oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a carcass layer with interlocked construction is used to prevent pipe collapse, then collapse resistance is improved, but the irregular inner surface causes vortex-induced vibrations and fluid flow disruptions
Solution Approach 1:
The invention applies a smooth inner surface treatment specifically to the carcass layer's internal surface, while maintaining the interlocked construction's collapse resistance properties. This localized modification of surface quality allows the structure to simultaneously achieve both collapse resistance and reduced vortex-induced vibrations.
Solution Approach 2:
Instead of modifying the interlocked construction itself to reduce irregularities, the invention inverts the approach by adding a smooth surface layer over the existing interlocked structure. This reverses the problem-solving strategy from modifying the structural elements to covering the surface, thereby preserving collapse resistance while eliminating flow disruptions.
2Productivity
If fluid export velocity is increased to improve productivity, then production rates increase, but vortex-induced vibrations and singing become more severe
Solution Approach 1:
The smooth inner surface treatment is applied specifically to the flow-contact regions of the pipe, allowing high fluid velocities to be maintained without generating excessive vortex-induced vibrations and acoustic pulsations.
3Object-generated harmful factors
If the inner surface of the carcass layer is made smoother to reduce turbulence, then fluid flow is improved, but the interlocked construction's collapse resistance may be compromised
Solution Approach 1:
The invention creates a composite structure where a smooth surface layer is applied over the interlocked carcass construction. This composite approach combines the flow-smoothing properties of the outer layer with the structural strength and collapse resistance of the underlying interlocked construction, achieving both objectives simultaneously.
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 significantly reduces fluid turbulence, pressure oscillations, and acoustic pulsations, enhancing fluid flow and preventing equipment damage, allowing for increased production rates and extended pipe lifetime by minimizing vortex-induced vibrations.
Implementation Method 1
break up the boundary layer and reduce turbulence
Implementation Method 2
reduce turbulence, thereby minimizing vorticity and shear layer oscillations
Implementation Method 3
reduce shear layer oscillations and vorticity of fluid flowing through the pipe body
Data Source
Figure 1
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AI summary
A flexible pipe body (100) and method of producing a flexible pipe body are disclosed. The flexible pipe body includes a collapse resistant layer (701) comprising a radially inner surface (711) and a radially outer surface, the radially inner surface comprising, in cross section, a substantially flat portion (705) and at least one cavity (703) extending from the flat portion radially outwards, and the radially inner surface further comprising, in cross section, at least one aerodynamic feature (715) extending from the flat portion for breaking up a boundary layer (509) of fluid flowing along the flexible pipe body in use.