WOLFRAM SYSTEM MODELER
PrescribedPumpCentrifugal pump with ideally controlled speed |
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Diagram
Wolfram Language
In[1]:=
SystemModel["Modelica.Fluid.Machines.PrescribedPump"]
Out[1]:=
Information
This information is part of the Modelica Standard Library maintained by the Modelica Association.
This model describes a centrifugal pump (or a group of nParallel pumps) with prescribed speed, either fixed or provided by an external signal.
The model extends PartialPump
If the N_in input connector is wired, it provides rotational speed of the pumps (rpm); otherwise, a constant rotational speed equal to n_const (which can be different from N_nominal) is assumed.
Parameters (27)
| allowFlowReversal |
Value: system.allowFlowReversal Type: Boolean Description: = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
|---|---|
| energyDynamics |
Value: Types.Dynamics.SteadyState Type: Dynamics Description: Formulation of energy balance |
| massDynamics |
Value: Types.Dynamics.SteadyState Type: Dynamics Description: Formulation of mass balance |
| substanceDynamics |
Value: massDynamics Type: Dynamics Description: Formulation of substance balance |
| traceDynamics |
Value: massDynamics Type: Dynamics Description: Formulation of trace substance balance |
| p_start |
Value: p_b_start Type: AbsolutePressure (Pa) Description: Start value of pressure |
| use_T_start |
Value: true Type: Boolean Description: = true, use T_start, otherwise h_start |
| T_start |
Value: if use_T_start then system.T_start else Medium.temperature_phX(p_start, h_start, X_start) Type: Temperature (K) Description: Start value of temperature |
| h_start |
Value: if use_T_start then Medium.specificEnthalpy_pTX(p_start, T_start, X_start) else Medium.h_default Type: SpecificEnthalpy (J/kg) Description: Start value of specific enthalpy |
| X_start |
Value: Medium.X_default Type: MassFraction[Medium.nX] (kg/kg) Description: Start value of mass fractions m_i/m |
| C_start |
Value: Medium.C_default Type: ExtraProperty[Medium.nC] Description: Start value of trace substances |
| p_a_start |
Value: system.p_start Type: AbsolutePressure (Pa) Description: Guess value for inlet pressure |
| p_b_start |
Value: p_a_start Type: AbsolutePressure (Pa) Description: Guess value for outlet pressure |
| m_flow_start |
Value: system.m_flow_start Type: MassFlowRate (kg/s) Description: Guess value of m_flow = port_a.m_flow |
| checkValveHomotopy |
Value: Types.CheckValveHomotopyType.NoHomotopy Type: CheckValveHomotopyType Description: = whether the valve is Closed, Open, or unknown at initialization |
| V_flow_single_init |
Value: m_flow_start / rho_nominal / nParallel Type: VolumeFlowRate (m³/s) Description: Used for simplified initialization model |
| delta_head_init |
Value: flowCharacteristic(V_flow_single_init * 1.1) - flowCharacteristic(V_flow_single_init) Type: Position (m) Description: Delta head for a 10% increase of flow at the initialization point |
| nParallel |
Value: 1 Type: Integer Description: Number of pumps in parallel |
| N_nominal |
Value: Type: AngularVelocity_rpm (rev/min) Description: Nominal rotational speed for flow characteristic |
| rho_nominal |
Value: Medium.density_pTX(Medium.p_default, Medium.T_default, Medium.X_default) Type: Density (kg/m³) Description: Nominal fluid density for characteristic |
| use_powerCharacteristic |
Value: false Type: Boolean Description: Use powerCharacteristic (vs. efficiencyCharacteristic) |
| checkValve |
Value: false Type: Boolean Description: = true to prevent reverse flow |
| V |
Value: 0 Type: Volume (m³) Description: Volume inside the pump |
| use_HeatTransfer |
Value: false Type: Boolean Description: = true to use a HeatTransfer model, e.g., for a housing |
| g |
Value: system.g Type: Acceleration (m/s²) Description: Constant gravity acceleration |
| use_N_in |
Value: false Type: Boolean Description: Get the rotational speed from the input connector |
| N_const |
Value: N_nominal Type: AngularVelocity_rpm (rev/min) Description: Constant rotational speed |
Inputs (1)
| fluidVolume |
Default Value: V Type: Volume (m³) Description: Volume |
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Connectors (5)
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port_a |
Type: FluidPort_a Description: Fluid connector a (positive design flow direction is from port_a to port_b) |
|---|---|---|
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port_b |
Type: FluidPort_b Description: Fluid connector b (positive design flow direction is from port_a to port_b) |
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heatPort |
Type: HeatPort_a Description: Thermal port for 1-dim. heat transfer (filled rectangular icon) |
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N_in |
Type: RealInput Description: Prescribed rotational speed |
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N_in_internal |
Type: RealInput Description: Needed to connect to conditional connector |
Components (4)
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system |
Type: System Description: System properties |
|---|---|---|
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medium |
Type: BaseProperties Description: Base properties (p, d, T, h, u, R_s, MM and, if applicable, X and Xi) of a medium |
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heatTransfer |
Type: HeatTransfer Description: Wall heat transfer |
| monitoring |
Type: Monitoring Description: Monitoring model |
Used in Examples (1)
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Modelica.Fluid.Examples.AST_BatchPlant Model of an experimental batch plant |
Revisions
- 31 Oct 2005
by Francesco Casella:
Model added to the Fluid library