modelAccumulator
Extends from Boundaries.PhaseSeparator (Base model for receiver and accumulator models).
Information
Model of an accumulator for application in vapor-cycle systems.
It inherits the basic balance equations from the volume model.
The purpose of this model is to separate the phases and provide gaseous phase to the compressor. The gas is extracted through a pipe. The low and high end of the pipe can be set by the respective parameters. Depending on the liquid level of the accumulator, the outlet enthalpy is set:
If the liquid level is higher than the upper end of the pipe, liquid is extracted.
If the liquid level is lower then the lower end of the pipe, the actual enthalpy of the medium in the accumulator is extracted.
If the liquid level is between the lower and the upper end of the pipe, the outlet enthalpy is weighted on the liquid level in the pipe.
Known problems: full phaseSeparator is very stiff, therefore simulation might get slow then, especially at the moment when the separator fills up. Consider changing the timeconstant and check if the mass-flow dynamic is fast enough.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| String | instanceName (from DropOfCommonsPlus) | getInstanceName() | Instance name |
| Boolean | useHeatport (from PartialVolume) | false | =true, if heatport is enabled |
| Boolean | useInlet (from PartialVolume) | true | = true, if inlet is enabled |
| Boolean | useOutlet (from PartialVolume) | true | = true, if outlet is enabled |
| SI.Area | A (from PartialVolume) | 1 | Heat transfer area |
| SI.CoefficientOfHeatTransfer | U (from PartialVolume) | 200 | Thermal transmittance |
| SI.Volume | V_par (from PhaseSeparator) | 0.01 | Volume |
| Real | pipe_low (from PhaseSeparator) | Low end of pipe | |
| Real | pipe_high (from PhaseSeparator) | High end of pipe | |
| Layout | |||
| Boolean | displayInstanceName (from DropOfCommonsPlus) | dropOfCommons.displayInstanceNames | = true, if instance name is displayed |
| Boolean | displayParameters (from DropOfCommonsPlus) | dropOfCommons.displayParameters | = true, if displaying parameters is enabled |
| Initialization › Pressure | |||
| Boolean | initialize_pressure (from PartialVolume) | true | =true, if pressure is initialized |
| Medium.AbsolutePressure | p_start (from PartialVolume) | Medium.p_default | Initial pressure set value |
| Initialization › Temperature | |||
| Boolean | initialize_energy (from PartialVolume) | true | = true, if internal energy is initialized |
| Medium.Temperature | T_start (from PartialVolume) | Medium.T_default | Initial Temperature set value |
| Initialization › Mass fractions | |||
| Boolean | initialize_Xi (from PartialVolume) | true | =true, if mass fractions are iinitialized |
| Medium.MassFraction[Medium.nXi] | Xi_0 (from PartialVolume) | Medium.X_default[1:Medium.nXi] | Initial mass fractions set values |
| Initialization › Specific enthalpy | |||
| Boolean | use_hstart (from PartialVolume) | false | =true, if internal energy is initialized with specific enthalpy |
| Medium.SpecificEnthalpy | h_start (from PartialVolume) | Medium.h_default | Initial specific enthalpy set value |
| Advanced | |||
| Boolean | enableFreeInlet (from PartialVolume) | false | true, if inlet is free (volume creates no pressure boundary condition) |
| Boolean | considerInertance (from PartialVolume) | dropOfCommons.considerInertance | =true, if transient momentum (inertance) term is considered; disable only for advanced use |
| Utilities.Units.Inertance | L (from PartialVolume) | dropOfCommons.L | Inertance of inlet/outlet |
| SI.MassFlowRate | m_flow_assert (from PartialVolume) | -dropOfCommons.m_flow_reg | Assertion threshold for negative massflow |
| Boolean | usePreferredMediumStates (from PartialVolume) | false | =true, if preferred medium states are used |
| Advanced › Damping | |||
| Real | k_volume_damping (from PartialVolume) | dropOfCommons.k_volume_damping | Damping factor multiplicator |
| Boolean | density_derp_h_from_media (from PhaseSeparator) | false | = true, if the derivative of density by pressure at const specific enthalpy is calculated from media model (only available for some media models) |
| Medium.DerDensityByPressure | density_derp_h_set (from PhaseSeparator) | 1e-6 | Derivative of density by pressure at const specific enthalpy set value (e.g approx. 1e-5 for air, 1e-7 for water) |
| Initialization | |||
| Init | init_method (from PhaseSeparator) | ThermofluidStream.Boundaries.Internal.InitializationMethodsPhaseSeperator.l | Initialization method |
| Medium.SpecificEnthalpy | h_0 (from PhaseSeparator) | Medium.h_default | Initial specific enthalpy |
| SI.Mass | M_0 (from PhaseSeparator) | 1 | Initial mass |
| Real | l_0 (from PhaseSeparator) | 0.5 | Initial liquid level |
| Real | x_0 (from PhaseSeparator) | 0.5 | Initial vapor quality |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPort (from PartialVolume) | ||
| Interfaces.Inlet | inlet (from PartialVolume) | ||
| Interfaces.Outlet | outlet (from PartialVolume) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.BaseProperties | medium (from PartialVolume) | ||
| SI.Volume | V (from PartialVolume) | Volume | |
| SI.Mass | M (from PartialVolume) | V*medium.d | Mass |
| SI.Mass[Medium.nXi] | MXi (from PartialVolume) | M*medium.Xi | Masses of species |
| SI.Energy | U_med (from PartialVolume) | M*medium.u | Internal energy |
| SI.HeatFlowRate | Q_flow (from PartialVolume) | Heat flow rate | |
| SI.Power | W_v (from PartialVolume) | Work due to change of volume | |
| Real | liquid_level (from PhaseSeparator) | Level of liquid line | |
| Real | liquid_level_pipe (from PhaseSeparator) | Level of liquid line in pipe | |
| Real | vapor_quality (from PhaseSeparator) | max(0, min(1, x)) |