modelPrescribedPump
Centrifugal pump with ideally controlled speed
Extends from Modelica.Fluid.Machines.BaseClasses.PartialPump (Base model for centrifugal pumps).
Information
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
| Type | Name | Default | Description |
|---|---|---|---|
| SI.VolumeFlowRate | V_flow_single_init (from PartialPump) | m_flow_start/rho_nominal/nParallel | Used for simplified initialization model |
| SI.Position | delta_head_init (from PartialPump) | flowCharacteristic(V_flow_single_init*1.1) - flowCharacteristic(V_flow_single_init) | Delta head for a 10% increase of flow at the initialization point |
| SI.Acceleration | g (from PartialPump) | system.g | Constant gravity acceleration |
| Medium.MassFlowRate | unit_m_flow (from PartialPump) | 1 | |
| Boolean | use_N_in | false | Get the rotational speed from the input connector |
| Modelica.Units.NonSI.AngularVelocity_rpm | N_const | N_nominal | Constant rotational speed |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialTwoPort) | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Boolean | checkValve (from PartialPump) | false | = true to prevent reverse flow |
| SI.Volume | V (from PartialPump) | 0 | Volume inside the pump |
| Initialization | |||
| Medium.AbsolutePressure | p_a_start (from PartialPump) | system.p_start | Guess value for inlet pressure |
| Medium.AbsolutePressure | p_b_start (from PartialPump) | p_a_start | Guess value for outlet pressure |
| Medium.MassFlowRate | m_flow_start (from PartialPump) | system.m_flow_start | Guess value of m_flow = port_a.m_flow |
| Types.CheckValveHomotopyType | checkValveHomotopy (from PartialPump) | Types.CheckValveHomotopyType.NoHomotopy | = whether the valve is Closed, Open, or unknown at initialization |
| Medium.AbsolutePressure | p_start (from PartialLumpedVolume) | system.p_start | Start value of pressure |
| Boolean | use_T_start (from PartialLumpedVolume) | true | = true, use T_start, otherwise h_start |
| Medium.Temperature | T_start (from PartialLumpedVolume) | if use_T_start then system.T_start else Medium.temperature_phX(p_start, h_start, X_start) | Start value of temperature |
| Medium.SpecificEnthalpy | h_start (from PartialLumpedVolume) | if use_T_start then Medium.specificEnthalpy_pTX(p_start, T_start, X_start) else Medium.h_default | Start value of specific enthalpy |
| Medium.MassFraction[Medium.nX] | X_start (from PartialLumpedVolume) | Medium.X_default | Start value of mass fractions m_i/m |
| Medium.ExtraProperty[Medium.nC] | C_start (from PartialLumpedVolume) | Medium.C_default | Start value of trace substances |
| Characteristics | |||
| Integer | nParallel (from PartialPump) | 1 | Number of pumps in parallel |
| NonSI.AngularVelocity_rpm | N_nominal (from PartialPump) | Nominal rotational speed for flow characteristic | |
| Medium.Density | rho_nominal (from PartialPump) | Medium.density_pTX(Medium.p_default, Medium.T_default, Medium.X_default) | Nominal fluid density for characteristic |
| Boolean | use_powerCharacteristic (from PartialPump) | false | Use powerCharacteristic (vs. efficiencyCharacteristic) |
| Assumptions › Dynamics | |||
| Types.Dynamics | energyDynamics (from PartialLumpedVolume) | system.energyDynamics | Formulation of energy balance |
| Types.Dynamics | massDynamics (from PartialLumpedVolume) | system.massDynamics | Formulation of mass balance |
| Types.Dynamics | substanceDynamics (from PartialLumpedVolume) | massDynamics | Formulation of substance balance |
| Types.Dynamics | traceDynamics (from PartialLumpedVolume) | massDynamics | Formulation of trace substance balance |
| Assumptions › Heat transfer | |||
| Boolean | use_HeatTransfer (from PartialPump) | false | = true to use a HeatTransfer model, e.g., for a housing |
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) | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPort (from PartialPump) | ||
| Modelica.Blocks.Interfaces.RealInput | N_in | Prescribed rotational speed |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.System | system (from PartialTwoPort) | System wide properties | |
| SI.Volume | fluidVolume (from PartialLumpedVolume) | Volume | |
| Medium.BaseProperties | medium (from PartialLumpedVolume) | ||
| SI.Energy | U (from PartialLumpedVolume) | Internal energy of fluid | |
| SI.Mass | m (from PartialLumpedVolume) | Mass of fluid | |
| SI.Mass | mXi (from PartialLumpedVolume) | Masses of independent components in the fluid | |
| SI.Mass | mC (from PartialLumpedVolume) | Masses of trace substances in the fluid | |
| Medium.ExtraProperty[Medium.nC] | C (from PartialLumpedVolume) | Trace substance mixture content | |
| SI.MassFlowRate | mb_flow (from PartialLumpedVolume) | Mass flows across boundaries | |
| SI.MassFlowRate | mbXi_flow (from PartialLumpedVolume) | Substance mass flows across boundaries | |
| Medium.ExtraPropertyFlowRate | mbC_flow (from PartialLumpedVolume) | Trace substance mass flows across boundaries | |
| SI.EnthalpyFlowRate | Hb_flow (from PartialLumpedVolume) | Enthalpy flow across boundaries or energy source/sink | |
| SI.HeatFlowRate | Qb_flow (from PartialLumpedVolume) | Heat flow across boundaries or energy source/sink | |
| SI.Power | Wb_flow (from PartialLumpedVolume) | Work flow across boundaries or source term | |
| HeatTransfer | heatTransfer (from PartialPump) | ||
| Medium.Density | rho (from PartialPump) | medium.d | |
| SI.Pressure | dp_pump (from PartialPump) | port_b.p - port_a.p | Pressure change |
| SI.Position | head (from PartialPump) | dp_pump/(rho*g) | Pump head |
| SI.MassFlowRate | m_flow (from PartialPump) | port_a.m_flow | Mass flow rate (total) |
| SI.MassFlowRate | m_flow_single (from PartialPump) | m_flow/nParallel | Mass flow rate (single pump) |
| SI.VolumeFlowRate | V_flow (from PartialPump) | Volume flow rate (total) | |
| SI.VolumeFlowRate | V_flow_single (from PartialPump) | Volume flow rate (single pump) | |
| NonSI.AngularVelocity_rpm | N (from PartialPump) | Shaft rotational speed | |
| SI.Power | W_single (from PartialPump) | Power Consumption (single pump) | |
| SI.Power | W_total (from PartialPump) | W_single*nParallel | Power Consumption (total) |
| Real | eta (from PartialPump) | Global Efficiency | |
| Real | s (from PartialPump) | Curvilinear abscissa for the flow curve in parametric form (either mass flow rate or head) | |
| Monitoring | monitoring (from PartialPump) | Monitoring model |
Revisions
- 31 Oct 2005
by Francesco Casella:
Model added to the Fluid library