modelStaticPipe

Basic pipe flow model without storage of mass or energy

Extends from Modelica.Fluid.Pipes.BaseClasses.PartialStraightPipe (Base class for straight pipe models).

Information

Model of a straight pipe with constant cross section and with steady-state mass, momentum and energy balances, i.e., the model does not store mass or energy. There exist two thermodynamic states, one at each fluid port. The momentum balance is formulated for the two states, taking into account momentum flows, friction and gravity. The same result can be obtained by using DynamicPipe with steady-state dynamic settings. The intended use is to provide simple connections of vessels or other devices with storage, as it is done in:

Numerical Issues

With the stream connectors the thermodynamic states on the ports are generally defined by models with storage or by sources placed upstream and downstream of the static pipe. Other non storage components in the flow path may yield to state transformation. Note that this generally leads to nonlinear equation systems if multiple static pipes, or other flow models without storage, are directly connected.

Parameters

TypeNameDefaultDescription
SI.VolumeV (from PartialStraightPipe)crossArea*length*nParallelVolume size
Assumptions
BooleanallowFlowReversal (from PartialTwoPort)system.allowFlowReversal= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Geometry
RealnParallel (from PartialStraightPipe)1Number of identical parallel pipes
SI.Diameterdiameter (from PartialStraightPipe)Diameter of circular pipe
Modelica.Fluid.Types.Roughnessroughness (from PartialStraightPipe)2.5e-5Average height of surface asperities (default: smooth steel pipe)
General › Geometry
SI.Lengthlength (from PartialStraightPipe)Length
BooleanisCircular (from PartialStraightPipe)true= true, if cross sectional area is circular
SI.AreacrossArea (from PartialStraightPipe)Modelica.Constants.pi*diameter*diameter/4Inner cross section area
SI.Lengthperimeter (from PartialStraightPipe)Modelica.Constants.pi*diameterInner perimeter
Static head
SI.Lengthheight_ab (from PartialStraightPipe)0Height(port_b) - Height(port_a)
Initialization
Medium.AbsolutePressurep_a_startsystem.p_startStart value of pressure at port a
Medium.AbsolutePressurep_b_startp_a_startStart value of pressure at port b
Medium.MassFlowRatem_flow_startsystem.m_flow_startStart value for mass flow rate

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_aport_a (from PartialTwoPort)Fluid connector a (positive design flow direction is from port_a to port_b)
Modelica.Fluid.Interfaces.FluidPort_bport_b (from PartialTwoPort)Fluid connector b (positive design flow direction is from port_a to port_b)

Components

TypeNameDefaultDescription
Modelica.Fluid.Systemsystem (from PartialTwoPort)System wide properties
FlowModelflowModelFlow model