modelStaticPipe
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
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Volume | V (from PartialStraightPipe) | crossArea*length*nParallel | Volume size |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialTwoPort) | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Geometry | |||
| Real | nParallel (from PartialStraightPipe) | 1 | Number of identical parallel pipes |
| SI.Diameter | diameter (from PartialStraightPipe) | Diameter of circular pipe | |
| Modelica.Fluid.Types.Roughness | roughness (from PartialStraightPipe) | 2.5e-5 | Average height of surface asperities (default: smooth steel pipe) |
| General › Geometry | |||
| SI.Length | length (from PartialStraightPipe) | Length | |
| Boolean | isCircular (from PartialStraightPipe) | true | = true, if cross sectional area is circular |
| SI.Area | crossArea (from PartialStraightPipe) | Modelica.Constants.pi*diameter*diameter/4 | Inner cross section area |
| SI.Length | perimeter (from PartialStraightPipe) | Modelica.Constants.pi*diameter | Inner perimeter |
| Static head | |||
| SI.Length | height_ab (from PartialStraightPipe) | 0 | Height(port_b) - Height(port_a) |
| Initialization | |||
| Medium.AbsolutePressure | p_a_start | system.p_start | Start value of pressure at port a |
| Medium.AbsolutePressure | p_b_start | p_a_start | Start value of pressure at port b |
| Medium.MassFlowRate | m_flow_start | system.m_flow_start | Start value for mass flow rate |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a (from PartialTwoPort) | Fluid connector a (positive design flow direction is from port_a to port_b) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b (from PartialTwoPort) | Fluid connector b (positive design flow direction is from port_a to port_b) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.System | system (from PartialTwoPort) | System wide properties | |
| FlowModel | flowModel | Flow model |