modelStaticCore
Extends from AixLib.Fluid.Interfaces.PartialTwoPort.
Information
Pipe with heat loss using the time delay based heat losses for the transport delay of the fluid.
Implementation
This model is based on FixedResistances.BaseClasses.PlugFlowCore but does not contain the spatialDistribution operator.
The spatialDistribution operator is used for the temperature wave propagation through the length of the pipe. This operator is contained in BaseClasses.PlugFlow.
This model does not include thermal inertia of the pipe wall. The wall inertia is implemented in StaticPipe.
The removal of the thermal inertia with a mixing volume can be desirable in the case where mixing volumes are added manually at the pipe junctions.
The model PlugFlowHeatLoss implements a heat loss in design direction, but leaves the enthalpy unchanged in opposite flow direction. Therefore it is used in front of and behind the time delay.
The pressure drop is implemented using AixLib.Fluid.FixedResistances.HydraulicDiameter.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Length | dh | Hydraulic diameter (assuming a round cross section area) | |
| Modelica.Units.SI.Length | length | Pipe length | |
| Real | R | Thermal resistance per unit length from fluid to boundary temperature | |
| Real | C | Thermal capacity per unit length of pipe | |
| Real | fac | 1 | Factor to take into account flow resistance of bends etc., fac=dp_nominal/dpStraightPipe_nominal |
| Modelica.Units.SI.Length | thickness | Pipe wall thickness | |
| Real | ReC | 4000 | Reynolds number where transition to turbulent starts |
| Nominal condition | |||
| Modelica.Units.SI.Velocity | v_nominal | Velocity at m_flow_nominal (used to compute default value for hydraulic diameter dh) | |
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | Nominal mass flow rate | |
| Advanced | |||
| Modelica.Units.SI.MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow |
| Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | homotopyInitialization | true | = true, use homotopy method |
| Boolean | linearized | false | = true, use linear relation between m_flow and dp for any flow rate |
| Geometry | |||
| Modelica.Units.SI.Height | roughness | 2.5e-5 | Average height of surface asperities (default: smooth steel pipe) |
| Initialization | |||
| Modelica.Units.SI.Temperature | T_start_in | Medium.T_default | Initialization temperature at pipe inlet |
| Modelica.Units.SI.Temperature | T_start_out | Medium.T_default | Initialization temperature at pipe outlet |
| Boolean | initDelay | false | Initialize delay for a constant mass flow rate if true, otherwise start from 0 |
| Modelica.Units.SI.MassFlowRate | m_flow_start | 0 | |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| AixLib.Fluid.FixedResistances.HydraulicDiameter | res | Pressure drop calculation for this pipe | |
| AixLib.Fluid.FixedResistances.BaseClasses.PlugFlowHeatLoss | heaLos_a | Heat loss for flow from port_b to port_a | |
| AixLib.Fluid.FixedResistances.BaseClasses.PlugFlowHeatLoss | heaLos_b | Heat loss for flow from port_a to port_b | |
| AixLib.Fluid.Sensors.MassFlowRate | senMasFlo | Mass flow sensor | |
| StaticTransportDelay | timDel | Time delay | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPort | Heat port to connect environment (positive heat flow for heat loss to surroundings) |
Revisions
- September 25, 2019, by Nils Neuland:
Revised variable names and documentation to follow guidelines. Corrected malformed hyperlinks.