modelConductionElementHEX_twoPhase
ConductionElement for two-phase fluids
Extends from PartialConductionElementHEX (Parent for CEs for discretizedHEX).
Information
Implementation of the Conduction Element for the DiscritizedHex.
Concerning the heat transfer coefficient it is assumed, that the main term influencing the coefficient of heat transfer is the mass flow rate. Therefore a nominal value for the heat transfer coefficient at a nominal mass flow rate can be set. The reynolds exponents for normalization of the heat transfer coefficient for evaporation and condensation are taken from Yan, Yi-Yie, & Lin, T.-F. (1999). Condensation heat transfer and pressure drop of refrigerant R-134a in a small pipe. International Journal of Heat and Mass Transfer, 42(4) and Yan, Y.-Y., & Lin, T.-F. (1999). Evaporation Heat Transfer and Pressure Drop of Refrigerant R-134a in a Plate Heat Exchanger. Journal of Heat Transfer, 121(1). Furthermore a minimum value U_min for the coefficient of heat transfer is set to ensure heat transfer at zero mass flow.
For further documentation see the documentation of the motherclass.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| String | instanceName (from DropOfCommonsPlus) | getInstanceName() | Instance name |
| SI.Volume | V (from PartialConductionElement) | 0.001 | Volume |
| SI.Area | A (from PartialConductionElementHEX) | 1 | Heat transfer area |
| Integer | nCellsParallel (from PartialConductionElementHEX) | 1 | Number of parallel discretization elements |
| SI.CoefficientOfHeatTransfer | U_min (from PartialConductionElementHEX) | 1 | Minimum thermal transmittance (for temperature adaption at zero massflow) |
| SI.CoefficientOfHeatTransfer | U_liq_nom | 700 | Nominal coefficient of heat transfer for liquid flow |
| SI.CoefficientOfHeatTransfer | U_vap_nom | 500 | Nominal coefficient of heat transfer for vapour flow |
| SI.CoefficientOfHeatTransfer | U_tp_nom | 1000 | Nominal coefficient of heat transfer for condensation/evaporation |
| SI.MassFlowRate | m_flow_nom | 0.3 | Nominal mass flow rate for heat transfer calculation |
| Medium.MassFraction | delta_x | 0.05 | Value for interpolation width |
| Real | Re_exp_cond | 0.4 | Reynolds-Exponent for heat transfer calculation at condensation (Yan&Lin, 1999) |
| Real | Re_exp_evap | 0.5 | Reynolds-Exponent for heat transfer calculation at evaporation (Yan&Lin, 1999) |
| 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 |
| Advanced | |||
| Boolean | considerInertance (from SISOFlow) | dropOfCommons.considerInertance | =true, if transient momentum (inertance) term is considered; disable only for advanced use |
| Utilities.Units.Inertance | L (from SISOFlow) | dropOfCommons.L | Inertance |
| StateSelect | m_flowStateSelect (from SISOFlow) | StateSelect.default | State selection for mass flow rate |
| Boolean | clip_p_out (from SISOFlow) | = false, if dr_corr=0 (correction of inertial pressure difference) | |
| Medium.AbsolutePressure | p_min (from SISOFlow) | dropOfCommons.p_min | Minimum steady-state output pressure |
| Medium.Density | rho_min (from PartialConductionElement) | dropOfCommons.rho_min | Minimal density |
| Boolean | neglectPressureChanges (from PartialConductionElement) | true | =true, if pressure changes are neglected |
| SI.MassFlowRate | m_flow_assert (from PartialConductionElement) | -dropOfCommons.m_flow_reg | Assertion threshold for negative massflows |
| Initialization › Mass flow rate | |||
| InitializationMethods | initM_flow (from SISOFlow) | ThermofluidStream.Utilities.Types.InitializationMethods.none | Initialization method for mass flow rate |
| SI.MassFlowRate | m_flow_0 (from SISOFlow) | 0 | Initial value for mass flow rate |
| Utilities.Units.MassFlowAcceleration | m_acceleration_0 (from SISOFlow) | 0 | Initial value for derivative of mass flow rate |
| Initialization › Specific enthalpy | |||
| Internal.InitializationMethodsCondElement | init (from PartialConductionElement) | ThermofluidStream.Processes.Internal.InitializationMethodsCondElement.inlet | Initialization for specific enthalpy |
| Medium.Temperature | T_0 (from PartialConductionElement) | Medium.T_default | Initial Temperature |
| Medium.SpecificEnthalpy | h_0 (from PartialConductionElement) | Medium.h_default | Initial specific enthalpy |
| Advanced › Global energy conservation | |||
| Boolean | enforce_global_energy_conservation (from PartialConductionElement) | false | = true, if global conservation of energy is enforced |
| Advanced › global energy conservation | |||
| SI.Time | T_e (from PartialConductionElement) | 100 | Time constant for global conservation of energy |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Inlet | inlet (from SISOFlow) | ||
| Outlet | outlet (from SISOFlow) | ||
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPort (from PartialConductionElement) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| SI.MassFlowRate | m_flow (from SISOFlow) | inlet.m_flow | Mass flow rate |
| SI.Pressure | dr_corr (from SISOFlow) | Correction of inertial pressure difference | |
| SI.Pressure | dp (from SISOFlow) | Pressure difference | |
| Medium.AbsolutePressure | p_in (from SISOFlow) | Medium.pressure(inlet.state) | Inlet pressure |
| Medium.SpecificEnthalpy | h_in (from SISOFlow) | Medium.specificEnthalpy(inlet.state) | Inlet specific enthalpy |
| Medium.MassFraction[Medium.nXi] | Xi_in (from SISOFlow) | Medium.massFraction(inlet.state) | Inlet mass fractions |
| Medium.AbsolutePressure | p_out (from SISOFlow) | Outlet pressure | |
| Medium.SpecificEnthalpy | h_out (from SISOFlow) | Outlet specific enthalpy | |
| Medium.MassFraction[Medium.nXi] | Xi_out (from SISOFlow) | Outlet mass fractions | |
| Medium.SpecificEnthalpy | h (from PartialConductionElement) | Volume? specific enthalpy | |
| Medium.ThermodynamicState | state (from PartialConductionElement) | Medium.setState_phX(p_in, h, Xi_in) | Volume thermodynamic state |
| Medium.Temperature | T (from PartialConductionElement) | Medium.temperature(state) | Volume temperature |
| SI.ThermalConductance | k (from PartialConductionElement) | Thermal conductance | |
| SI.Energy | deltaE_system (from PartialConductionElement) | Energy difference between m_flow*(h_in-h_out) and Q_flow | |
| SI.Mass | M (from PartialConductionElement) | Mass (of the volume) | |
| SI.CoefficientOfHeatTransfer | U (from PartialConductionElementHEX) | Thermal transmittance | |
| Real | x | Vapor quality calculated from specific enthalpies |