NominalLaminarFlowNominalLaminarFlow: Linear laminar flow for given nominal values |
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Information
This information is part of the Modelica Standard Library maintained by the Modelica Association.
This model defines a simple linear pressure loss assuming laminar flow for
specified dp_nominal and m_flow_nominal.
Select show_Res = true to analyze the actual flow and the lengths of a pipe that would fulfill the
specified nominal values for given geometry parameters crossAreas, dimensions and roughnesses.
Parameters (15)
| m |
Value: n - 1 Type: Integer Description: Number of flow segments |
|---|---|
| n |
Value: 2 Type: Integer Description: Number of discrete flow volumes |
| nParallel |
Value: Type: Real Description: Number of identical parallel flow devices |
| g |
Value: system.g Type: Acceleration (m/s²) Description: Constant gravity acceleration |
| allowFlowReversal |
Value: system.allowFlowReversal Type: Boolean Description: = true, if flow reversal is enabled, otherwise restrict flow to design direction (states[1] -> states[n+1]) |
| momentumDynamics |
Value: system.momentumDynamics Type: Dynamics Description: Formulation of momentum balance |
| m_flow_start |
Value: system.m_flow_start Type: MassFlowRate (kg/s) Description: Start value of mass flow rates |
| p_a_start |
Value: Type: AbsolutePressure (Pa) Description: Start value for p[1] at design inflow |
| p_b_start |
Value: Type: AbsolutePressure (Pa) Description: Start value for p[n+1] at design outflow |
| useUpstreamScheme |
Value: true Type: Boolean Description: = false to average upstream and downstream properties across flow segments |
| use_Ib_flows |
Value: momentumDynamics <> Types.Dynamics.SteadyState Type: Boolean Description: = true to consider differences in flow of momentum through boundaries |
| Re_turbulent |
Value: 4000 Type: ReynoldsNumber Description: Start of turbulent regime, depending on type of flow device |
| show_Res |
Value: false Type: Boolean Description: = true, if Reynolds numbers are included for plotting |
| dp_nominal |
Value: Type: AbsolutePressure (Pa) Description: Nominal pressure loss |
| m_flow_nominal |
Value: Type: MassFlowRate (kg/s) Description: Mass flow rate for dp_nominal |
Inputs (7)
| pathLengths |
Type: Length[m] (m) Description: Lengths along flow path |
|---|---|
| states |
Type: ThermodynamicState[n] Description: Thermodynamic states along design flow |
| vs |
Type: Velocity[n] (m/s) Description: Mean velocities of fluid flow |
| crossAreas |
Type: Area[n] (m²) Description: Cross flow areas at segment boundaries |
| dimensions |
Type: Length[n] (m) Description: Characteristic dimensions for fluid flow (diameters for pipe flow) |
| roughnesses |
Type: Roughness[n] (m) Description: Average height of surface asperities |
| dheights |
Type: Length[n - 1] (m) Description: Height(states[2:n]) - Height(states[1:n-1]) |
Components (2)
 |
system |
Type: System Description: System properties |
|---|---|---|
 |
states |
Type: ThermodynamicState[n] Description: Thermodynamic states along design flow |