Fluid Section Types: Liquids

A network element is characterized by a type of fluid section. It has to be specified on the *FLUID SECTION card unless the analysis is a pure thermomechanical calculation.

Typical material properties needed for a liquid network are the density \rho (temperature dependent, cf. the *DENSITY card), the heat capacity c=c_p=c_v and the dynamic viscosity \mu (both temperature dependent and to be specified with the FLUID CONSTANTS card).

A special case is the purely thermal liquid network. This applies if:

• no TYPE is specified on any *FLUID SECTION card or
• the parameter THERMAL NETWORK is used on the *STEP card or
• all mass flow is given and either all pressures or given or none.

In that case only c_p is needed.

For liquids the orifice (only for C_d=1), restrictor, branch, and vortex fluid section types of gases can be used by specifying the parameter LIQUID on the *FLUID SECTION card. In addition, the following types are available as well (the coefficients for the head losses are taken from [10], unless specified otherwise):