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Pipe, Gate Valve

Figure 72: Gatevalve
\begin{figure}\epsfig{file=Gatevalve.eps,width=8cm}\end{figure}

A gate valve (Figure 72) is characterized by head losses $ \Delta_1^2 F$ of the form:

$\displaystyle \Delta_1^2 F = \zeta \frac{\dot{m}^2}{2 g \rho^2 A^2 },$ (31)

where $ \zeta$ is a head loss coefficient depending on the ratio $ \alpha=x/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, $ x$ is a size for the remaining opening (Figure 72) and $ D$ is the diameter 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 GATE VALVE card:

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.



guido dhondt 2007-08-09