modelLiquidNode
Information
The Modelica License 2
This model represents a pool containing a liquid water mass. The interface with its environment is treated through 3 ports.
One thermal port for only heat exchanges. The power could come from, for example :
- An internal heating or cooling power
- The condensation or evaporation at the water surface
- The convection at water surface or with the container
One fluidport for mass exchange with an air node. It has been added to transfer the steam from the boiling to the air node.
One input vector to allow an water inlet from an external input. The first component of the input vector is the mass flow rate and
the second is the water temperature. This input could represent for exemple :
- a flow a pumping system
- a flow from the wall condensation that flows to the pool
To model the pool, the followings hypotheses are made:
- Hypothesis 1: The fluid coming from the inlet vector is only liquid water
- Hypothesis 2: The solidification of the water is not treated
- Hypothesis 3: The specific heat capacity at constant pressure and at constant volume are the same for the liquid water
The basic constitutive equations for the pool is :
m = medium.d * V
der(m) = m_flow_boiling + Water_Input_internal[1]
m * LiquidWater.cp * der(T) - m_flow_boiling*LiquidWater.LHea = Heatport.Q_flow + Water_Input_internal[1] * LiquidWater.cp * (Water_Input_internal[2] - T )
The match with the saturation condition are made with the following condition :
if /*noEvent*/(T > Tsat) and /*noEvent*/(m_flow_boiling ≤ 0) then
der(T) = der(Tsat)
else
m_flow_boiling = 0
end if
Parameters
| Type | Name | Default | Description |
|---|
| Medium.MassFraction[Medium.nX] | X_start | Medium.X_default | |
| Integer | nPorts | 1 | Number of fluidport |
| Assumptions › Dynamics |
| Types.Dynamics | energyDynamics | Dynamics.FixedInitial | Formulation of energy balance |
| Types.Dynamics | massDynamics | Dynamics.FixedInitial | Formulation of mass balance |
| Types.Dynamics | substanceDynamics | massDynamics | Formulation of substance balance |
| Types.Dynamics | traceDynamics | massDynamics | Formulation of trace substance balance |
| Initialization |
| SI.Temperature | T_start | 293.15 | Initial temperature |
| Geometrical properties |
| SI.Volume | V_start | 0 | Initial volume |
Components
| Type | Name | Default | Description |
|---|
| Medium.BaseProperties | medium | | |
| SI.Enthalpy | H | | Medium enthalpy |
| SI.Mass | m | | Medium mass |
| SI.Mass[Medium.nXi] | mXi | | Masses of independent components in the fluid |
| SI.Mass | mC | | Masses of trace substances in the fluid |
| SI.Volume | V | | |
| Medium.ExtraProperty[Medium.nC] | C | | Trace substance mixture content |
| SI.MassFlowRate | mb_flow | | Mass flows across boundaries |
| SI.MassFlowRate | mbXi_flow | | Substance mass flows across boundaries |
| Medium.MassFlowRate[nPorts,Medium.nXi] | ports_mXi_flow | | |
| Medium.ExtraPropertyFlowRate | mbC_flow | | Trace substance mass flows across boundaries |
| SI.EnthalpyFlowRate | Hb_flow | | Enthalpy flow across boundaries or energy source/sink |
| SI.HeatFlowRate | Qb_flow | | Heat flow across boundaries or energy source/sink |
Contents
| Name | Description |
|---|
 Medium | |
 MediumGas | |
