Pipe, Bend

Figure: Bend
\begin{figure}\epsfig{file=Bend.eps,width=8cm}\end{figure}

A bend (Figure [*]) is characterized by head losses \Delta_1^2 F of the form:

\Delta_1^2 F = \zeta \frac{\dot{m}^2}{2 g \rho^2 A^2 }, (158)

where \zeta is a head loss coefficient depending on the bend angle \alpha and the ratio of the bend radius to the pipe diameter R/D, \dot{m} is the mass flow, g is the gravity acceleration and \rho is the liquid density. A is the cross section of the pipe. Values for \zeta can be found in file “liquidpipe.f”.

The following constants have to be specified on the line beneath the *FLUID SECTION, TYPE=PIPE BEND card:

\xi denotes the roughness of the pipe: \xi=0 applies to an extremely smooth pipe surface, \xi=1 to a very rough surface. The gravity acceleration must be specified by a gravity type *DLOAD card defined for the elements at stake. The material characteristic \rho can be defined by a *DENSITY card.


Example files: centheat1, pipe.