modelPumpNPSH
Extends from Pump (Centrifugal pump with ideally controlled speed).
Information
Same as Pump. Additionally, the net positive suction head available is computed. Requires a two-phase medium model to compute the saturation properties.Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | Np0 (from PumpBase) | 1 | Nominal number of pumps in parallel |
| SI.Volume | V (from PumpBase) | 0 | Pump Internal Volume |
| Boolean | CheckValve (from PumpBase) | false | Reverse flow stopped |
| Boolean | allowFlowReversal (from PumpBase) | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction |
| SI.Acceleration | g (from PumpBase) | Modelica.Constants.g_n | |
| SI.VolumeFlowRate | q_single0 (from PumpBase) | w0/(Np0*rho0) | Nominal volume flow rate (single pump) |
| SI.Height | head0 (from PumpBase) | dp0/(rho0*g) | Nominal pump head |
| Real | d_head_dq_0 (from PumpBase) | (flowCharacteristic(q_single0*1.05) - flowCharacteristic(q_single0*0.95))/(q_single0*0.1) | Approximate derivative of flow characteristic w.r.t. volume flow |
| Real | d_head_dn_0 (from PumpBase) | 2/n0*head0 - q_single0/n0*d_head_dq_0 | Approximate derivative of the flow characteristic w.r.t. rotational speed |
| SI.Power | W_eps (from PumpBase) | 1e-8 | Small coefficient to avoid numerical singularities |
| NonSI.AngularVelocity_rpm | n_eps (from PumpBase) | 1e-6 | |
| NonSI.AngularVelocity_rpm | n_const (from Pump) | n0 | Constant rotational speed |
| Characteristics | |||
| Boolean | usePowerCharacteristic (from PumpBase) | false | Use powerCharacteristic (vs. efficiencyCharacteristic) |
| Units.LiquidDensity | rho0 (from PumpBase) | 1000 | Nominal Liquid Density |
| NonSI.AngularVelocity_rpm | n0 (from PumpBase) | Nominal rotational speed | |
| Medium.MassFlowRate | w0 (from PumpBase) | Nominal mass flow rate | |
| SI.Pressure | dp0 (from PumpBase) | Nominal pressure increase | |
| External inputs | |||
| Boolean | use_in_Np (from PumpBase) | false | Use connector input for the pressure |
| Boolean | use_in_n (from Pump) | false | Use connector input for the rotational speed |
| Initialisation | |||
| Medium.MassFlowRate | wstart (from PumpBase) | w0 | Mass Flow Rate Start Value |
| Medium.SpecificEnthalpy | hstart (from PumpBase) | 1e5 | Specific Enthalpy Start Value |
| Choices.Init.Options | initOpt (from PumpBase) | system.initOpt | Initialisation option |
| Boolean | noInitialPressure (from PumpBase) | false | Remove initial equation on pressure |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| FlangeA | infl (from PumpBase) | ||
| FlangeB | outfl (from PumpBase) | ||
| Modelica.Blocks.Interfaces.IntegerInput | in_Np (from PumpBase) | Number of parallel pumps | |
| Modelica.Blocks.Interfaces.RealInput | in_n (from Pump) | RPM |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.ThermodynamicState | inletFluidState (from PumpBase) | Thermodynamic state of the fluid at the inlet | |
| ThermoPower.System | system (from PumpBase) | System wide properties | |
| Medium.MassFlowRate | w_single (from PumpBase) | Mass flow rate (single pump) | |
| Medium.MassFlowRate | w (from PumpBase) | Np*w_single | Mass flow rate (total) |
| SI.VolumeFlowRate | q_single (from PumpBase) | Volume flow rate (single pump) | |
| SI.VolumeFlowRate | q (from PumpBase) | Np*q_single | Volume flow rate (total) |
| SI.PressureDifference | dp (from PumpBase) | Outlet pressure minus inlet pressure | |
| SI.Height | head (from PumpBase) | Pump head | |
| Medium.SpecificEnthalpy | h (from PumpBase) | Fluid specific enthalpy | |
| Medium.SpecificEnthalpy | hin (from PumpBase) | Enthalpy of entering fluid | |
| Medium.SpecificEnthalpy | hout (from PumpBase) | Enthalpy of outgoing fluid | |
| Units.LiquidDensity | rho (from PumpBase) | Liquid density | |
| Medium.Temperature | Tin (from PumpBase) | Liquid inlet temperature | |
| NonSI.AngularVelocity_rpm | n (from PumpBase) | Shaft r.p.m. | |
| Integer | Np (from PumpBase) | Number of pumps in parallel | |
| SI.Power | W_single (from PumpBase) | Power Consumption (single pump) | |
| SI.Power | W (from PumpBase) | Np*W_single | Power Consumption (total) |
| SI.Power | Qloss (from PumpBase) | 0 | Heat loss (single pump) |
| SI.PerUnit | eta (from PumpBase) | Pump efficiency | |
| SI.PerUnit | s (from PumpBase) | Auxiliary non-dimensional variable | |
| SI.Height | NPSHa | Net Positive Suction Head available | |
| Medium.AbsolutePressure | pv | Saturated liquid pressure |
Revisions
- 30 Jul 2007
by Francesco Casella:
Added (removed NPSH from Pump model).