Flexible risers such as flexible pipes and umbilical cables find increasing application in the marine environment and represent a crucial element of a floating production system. At the same time, it provides ease of installation, retrieval and usage elsewhere. Flexible pipes and umbilical cables both work as composite pipes that are compliant and highly deformable in bending, but strong and stiff in response to internal pressure, external pressure, tension and torque. Umbilical cables generally consist of electrical conductors for signal and power transmissions that are surrounded by a number of protective layers. The protective layer is designed to secure the conductors from adverse chemical and mechanical damage. The objective of this work is to predict the temperature distribution of partially submersed umbilical cables under different operating and environmental conditions. The commercial code Fluent® was used to simulate the heat transfer and the air fluid flow of part of a vertical umbilical cable near the air-water interface. A free-convective three-dimensional turbulent flow in open-ended vertical annuli was solved. The influence of parameters such as the heat dissipating rate, wind velocity, air temperature and solar radiation was analyzed. The influence of the presence of a radiation shield consisting of a partially submersed cylindrical steel tube was also considered. The air flow and the buoyancydriven convective heat transfer in the annular region between the steel tube and the umbilical cable were calculated using the standard k-ε turbulence model. The radiative heat transfer between the umbilical external surface and the radiation shield was calculated using the Discrete Ordinates model. The results indicate that the influence of a hot environment and intense solar radiation may affect the umbilical cable performance in its dry portion.
Prediction of the temperature distribution of partially submersed umbilical cables
Journal of the Brazilian Society of Mechanical Sciences and Engineering ; 34 , 2 ; 205-212
2012
8 Seiten, 10 Bilder, 3 Tabellen, 10 Quellen
Article (Journal)
English
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