Restrictor, Enlargement

Properties: adiabatic, not isentropic, directional, inlet based restrictor

Figure 97: Geometry of an enlargement

The geometry of an enlargement is shown in Figure 97. It is described by the following constants (to be specified in that order on the line beneath the *FLUID SECTION, TYPE=RESTRICTOR ENLARGEMENT card):

• reduced cross section $A_1$.
• full cross section $A_2$.
• hydraulic diameter $D_h$ of the reduced cross section defined by $D_h=4 A/P$ where $P$ is the perimeter of the cross section.
• 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)

The loss coefficient for an enlargement is taken from [33].

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.

Example files: piperestrictor, restrictor, restrictor-oil.