Restrictor, Exit

Properties: adiabatic, not isentropic,directional, $A$-inlet based restrictor

An exit element is used to model the exit from a gas pipe into a large chamber. For an exit the value of $\zeta$ is 1. It is described by the following constants (to be specified in that order on the line beneath the *FLUID SECTION, TYPE=RESTRICTOR EXIT card):

• cross section of the exit $A$.
• not used (internally: set to 100,000 $A$ as downstream section)
• hydraulic diameter $D_h$ defined by $D_h=4 A/P$ where $P$ is the perimeter of the cross section.
• number of the upstream element; this element must be of type GAS PIPE FANNO
• oil mass flow in the restrictor (only if the OIL parameter is used to define the kind of oil in the *FLUID SECTION card)
• not used (internally: oil material number)

By specifying the parameter LIQUID on the *FLUID SECTION card the loss is calculated for liquids. In the absence of this parameter, compressible losses are calculated.