This thesis describes work relating to the thermal management of hydrocarbon fluids issuing
from (typically sub-sea) wells and passing through flow lines to a processing facility (typically
an offshore platform). The hydrocarbon fluids must be kept at a temperature above that at
which solids (typically waxes or hydrates) are formed. One way of achieving this “Thermal
Management” is to place the flow lines inside a carrier pipe through which is also passed (in a
separate pipe) a heating fluid (typically hot water). The design of such “bundle” systems is a
significant challenge because of the complex combined natural convection and radiation heat
transfer processes involved. In related work, Computational Fluid Dynamics (CFD) methods
are being used to predict these complex processes and the principal objective of the work
described in this thesis was to carry out new experiments to validate these predictions.
Experiments were carried out on an industrial scale 5-Pipe Bundle covering the full range of
bundle orientations from horizontal to vertical so as to be able to simulate horizontal and
inclined flow lines and risers. The bundle chosen was 3 m long with a 30 inch (762 mm)
internal diameter carrier pipe with 4 pipes mounted inside it. The four internal pipes were
respectively a 14 inch (355.6 mm) outside diameter pipe, a 8 inch (219.1 mm) outside
diameter pipe and two 4 inch (114.3 mm) outside diameter pipes. These 4 pipes represented
the hydrocarbon product pipe, the test pipe and the heating flow and return pipes in a typical
industrial bundle. A support mechanism on which the bundle can be rotated from 0 to 360°
was designed and constructed. In the experiments, the surface temperatures of each pipe
surface were kept constant but differences were imposed between the respective surfaces.
Heat flow rates from or to each pipe surface in the bundle were measured using a calorimetric
method and the results were compared with those predicted using the ANSYS CFD code.
Good agreement was obtained between the heat flows measured and those calculated from the
code. This thesis also describes an analytical and numerical work on natural convection heat
transfer inside a vertical pipe taking into account the effect of solids formation by freezing of
the fluid at the wall.