Flexible Pipe Carcass Insert Profile Mitigating Flow-Induced Vibration
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Solution Overview
Problem
Flexible pipes used in offshore applications experience flow-induced vibrations and pulsations due to synchronized vortex shedding in their corrugated inner carcass, leading to excessive noise and vibration, which limits production capacity and is not effectively addressed by existing solutions like velocity control or silencers.
Innovation Solution
A flexible inner corrugated pipe carcass with an insert profile that covers the carcass gap between interlocking sections, reducing vortex shedding frequency resonance and enhancing hydraulic efficiency by smoothing the inner surface, thereby mitigating flow-induced vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gas flow velocity is increased to enhance production capacity, then productivity improves, but flow-induced vibrations and pulsations occur due to vortex shedding in the corrugated carcass
Solution Approach 1:
The patent applies local quality by modifying only the inner surface of the carcass where the flow-induced vibrations originate. An insert profile is positioned in the carcass gap to smooth the inner surface locally, while the rest of the carcass structure remains unchanged to maintain flexibility and strength.
Solution Approach 2:
The insert profile acts as an intermediary element between the flowing gas and the corrugated carcass structure. It mediates the interaction by providing a smooth surface that prevents vortex shedding, while allowing the carcass to maintain its interlocking section structure for flexibility.
2Object-affected harmful factors
If silencers are introduced to suppress vibrations, then flow-induced pulsations are reduced, but device complexity and cost increase
Solution Approach 1:
The patent extracts the vibration-suppression function from a separate silencer component and integrates it directly into the carcass structure through the insert profile. This eliminates the need for additional silencer devices while maintaining the vibration suppression capability.
Solution Approach 2:
The insert profile merges the vibration suppression function with the existing carcass structure. Instead of adding a separate silencer, the smooth inner surface is created as part of the carcass itself, combining structural integrity with flow stabilization.
3Object-affected harmful factors
If smooth bore pipes are used to eliminate vibrations, then flow-induced vibrations are suppressed, but manufacturing complexity increases and maximum diameter is limited
Solution Approach 1:
The patent segments the solution by using an insert profile that can be separately manufactured and then positioned within the existing carcass structure. This allows the smooth inner surface to be created without remanufacturing the entire pipe, maintaining the advantages of modular carcass construction.
Solution Approach 2:
The insert profile is nested within the existing carcass structure, fitting into the carcass gap between interlocking sections. This nested approach allows the smooth bore functionality to be incorporated without replacing the entire carcass, maintaining manufacturing efficiency.
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 effectively suppresses flow-induced vibrations and pulsations, allowing higher operational flow rates without significant noise or vibration, thus enhancing production capacity and reducing economic constraints.
Implementation Method 1
the second portion being in the form of a protrusion having an extension transverse to the carcass gap, wherein the second portion is resilient or elastic and wherein the pipe carcass is arranged so that in use the second portion is deformed by relative movement between adjacent interlocking sections
Implementation Method 2
These pulsations are generated by lock-in of synchronized vortex shedding in the groves on the inner corrugated layer (carcass) of the flexible pipe
Data Source
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AI summary
The invention relates to a flexible pipe carcass comprising a flexible tubular wall structure comprising a helically wound wall strip; wherein interlocking sections (57) of successive windings of said wall strip form the wall structure. The interlocking sections (57) of adjacent wall strips define a length and are movable with respect to each other between a first position and a second, extended position for changing said length, the interlocking sections (57) being formed such that in the extended position a carcass gap (53) is provided between adjacent interlocking sections (57) for accommodating relative movement there between upon flexure of the wall structure. An insert profile (50) is located in the carcass gap (53) of the tubular wall structure on an inside of the wall structure to at least partly cover the carcass gap (53).