Numerical analysis of convective cooling of pipe-type electric cables

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1977

OSTI ID:7211117

Chern, S Y

A numerical analysis is developed for predicting friction factors and heat transfer coefficients in pipes with irregular cross-sections such as those occurring in underground pipe-type electric cable systems. The method is to find three-dimensional temperature and velocity fields in laminar flow for three different cable configurations. The secondary flow generated by natural convection becomes very important for this system. Thus, the Nusselt number is strongly dependent on Rayleigh number and cable configuration, both of which affect the secondary flow. The analysis employs the finite element method which can be easily applied to irregular geometries and non-uniform meshes. The numerical solutions substantially agree with experimental results. They show that the Nusselt number increases with increasing the Rayleigh numbers, and that increasing the Rayleigh number decreases the thermal entrance length. The results also determine how the Nusselt number is affected by cable configurations. The friction factors are essentially independent of the natural circulation and depend only on the Reynolds number and the configuration. For each configuration f-Re is a different constant. The calculated constants are somewhat lower than the experimental data. This is due, primarily, to the presence of skid wires in the experiments, which are not taken into account explicitly in the analysis.

• OSTI ID: 7211117
• Country of Publication: United States
• Language: English

Related Subjects

200301* -- Power Transmission & Distribution-- AC Systems
EHV & UHV-- (-1989)
24 POWER TRANSMISSION AND DISTRIBUTION
CABLES
CONDUCTOR DEVICES
CONVECTION
COOLING
ELECTRIC CABLES
ELECTRICAL EQUIPMENT
ENERGY TRANSFER
EQUIPMENT
FINITE ELEMENT METHOD
FLUID FLOW
FORCED CONVECTION
FRICTION
HEAT TRANSFER
LAMINAR FLOW
NUMERICAL SOLUTION
NUSSELT NUMBER
POWER TRANSMISSION
REYNOLDS NUMBER
TEMPERATURE DISTRIBUTION
UNDERGROUND POWER TRANSMISSION