OpenTank

Simple tank with inlet/outlet ports

Diagram

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

Model of a tank that is open to the ambient at the fixed pressure p_ambient.

The vector of connectors ports represents fluid ports at configurable heights, relative to the bottom of tank. Fluid can flow either out of or in to each port.

The following assumptions are made:

The tank is filled with a single or multiple-substance medium having a density higher than the density of the ambient medium.
The fluid has uniform density, temperature and mass fractions
No liquid is leaving the tank through the open top; the simulation breaks with an assertion if the liquid level growths over the height.

The port pressures represent the pressures just after the outlet (or just before the inlet) in the attached pipe. The hydraulic resistances portsData.zeta_in and portsData.zeta_out determine the dissipative pressure drop between tank and port depending on the direction of mass flow. See VesselPortsData and [Idelchik, Handbook of Hydraulic Resistance, 2004].

With the setting use_portsData=false, the port pressure represents the static head at the height of the respective port. The relationship between pressure drop and mass flow rate at the port must then be provided by connected components; Heights of ports as well as kinetic and potential energy of fluid entering or leaving are not taken into account anymore.

Parameters (22)

energyDynamics	Value: system.energyDynamics Type: Dynamics Description: Formulation of energy balance
massDynamics	Value: system.massDynamics 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_ambient 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
nPorts	Value: 0 Type: Integer Description: Number of ports
use_portsData	Value: true Type: Boolean Description: = false to neglect pressure loss and kinetic energy
portsData	Value: Type: VesselPortsData[if use_portsData then nPorts else 0] Description: Data of inlet/outlet ports
m_flow_nominal	Value: if system.use_eps_Re then system.m_flow_nominal else 1e2 * system.m_flow_small Type: MassFlowRate (kg/s) Description: Nominal value for mass flow rates in ports
m_flow_small	Value: if system.use_eps_Re then system.eps_m_flow * m_flow_nominal else system.m_flow_small Type: MassFlowRate (kg/s) Description: Regularization range at zero mass flow rate
use_Re	Value: system.use_eps_Re Type: Boolean Description: = true, if turbulent region is defined by Re, otherwise by m_flow_small
use_HeatTransfer	Value: false Type: Boolean Description: = true to use the HeatTransfer model
height	Value: Type: Height (m) Description: Height of tank
crossArea	Value: Type: Area (m²) Description: Area of tank
p_ambient	Value: system.p_ambient Type: AbsolutePressure (Pa) Description: Tank surface pressure
T_ambient	Value: system.T_ambient Type: Temperature (K) Description: Tank surface Temperature
level_start	Value: 0.5 * height Type: Height (m) Description: Start value of tank level

Inputs (2)

fluidVolume	Default Value: V Type: Volume (m³) Description: Volume
fluidLevel	Default Value: level Type: Height (m) Description: Level of fluid in the vessel for treating heights of ports

fluidVolume

Default Value: V

Type: Volume (m³)

Description: Volume

fluidLevel

Default Value: level

Type: Height (m)

Description: Level of fluid in the vessel for treating heights of ports

Connectors (2)

	ports	Type: VesselFluidPorts_b[nPorts] Description: Fluid inlets and outlets
	heatPort	Type: HeatPort_a

ports

Type: VesselFluidPorts_b[nPorts]

Description: Fluid inlets and outlets

heatPort

Type: HeatPort_a

Components (4)

	system	Type: System Description: System properties
	medium	Type: BaseProperties
	portsData	Type: VesselPortsData[if use_portsData then nPorts else 0] Description: Data of inlet/outlet ports
	heatTransfer	Type: HeatTransfer

Used in Examples (7)

	PumpingSystem Modelica.Fluid.Examples Model of a pumping system for drinking water
	HeatingSystem Modelica.Fluid.Examples Simple model of a heating system
	ThreeTanks Modelica.Fluid.Examples.Tanks Demonstrating the usage of SimpleTank
	TanksWithOverflow Modelica.Fluid.Examples.Tanks Two tanks connected with pipes at different heights
	EmptyTanks Modelica.Fluid.Examples.Tanks Show the treatment of empty tanks
	ControlledTanks Modelica.Fluid.Examples.ControlledTankSystem Demonstrating the controller of a tank filling/emptying system
	MeasuringTemperature Modelica.Fluid.Examples.Explanatory Differences between using one port with and without explicit junction model and two port sensors for fluid temperature measuring