modelEquilibriumDrumBoiler
Simple Evaporator with two states, see Åström, Bell: Drum-boiler dynamics, Automatica 36, 2000, pp.363-378
Extends from Modelica.Fluid.Interfaces.PartialTwoPort (Partial component with two ports).
Information
Model of a simple evaporator with two states. The model assumes two-phase equilibrium inside the component; saturated steam goes out of the steam outlet.
References: Åström, Bell: Drum-boiler dynamics, Automatica 36, 2000, pp.363-378
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Mass | m_D | Mass of surrounding drum metal | |
| Medium.SpecificHeatCapacity | cp_D | Specific heat capacity of drum metal | |
| SI.Volume | V_t | Total volume inside drum | |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialTwoPort) | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Initialization | |||
| Medium.AbsolutePressure | p_start | system.p_start | Start value of pressure |
| SI.Volume | V_l_start | V_t/2 | Start value of liquid volumeStart value of volume |
| Assumptions › Dynamics | |||
| Types.Dynamics | energyDynamics | system.energyDynamics | Formulation of energy balance |
| Types.Dynamics | massDynamics | system.massDynamics | Formulation of mass balance |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a (from PartialTwoPort) | Fluid connector a (positive design flow direction is from port_a to port_b) | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b (from PartialTwoPort) | Fluid connector b (positive design flow direction is from port_a to port_b) | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPort | ||
| Modelica.Blocks.Interfaces.RealOutput | V | Liquid volume |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.System | system (from PartialTwoPort) | System wide properties | |
| Medium.SaturationProperties | sat | State vector to compute saturation properties | |
| Medium.AbsolutePressure | p | Pressure inside drum boiler | |
| Medium.Temperature | T | Temperature inside drum boiler | |
| SI.Volume | V_v | Volume of vapour phase | |
| SI.Volume | V_l | Volumes of liquid phase | |
| Medium.SpecificEnthalpy | h_v | Medium.dewEnthalpy(sat) | Specific enthalpy of vapour |
| Medium.SpecificEnthalpy | h_l | Medium.bubbleEnthalpy(sat) | Specific enthalpy of liquid |
| Medium.Density | rho_v | Medium.dewDensity(sat) | Density in vapour phase |
| Medium.Density | rho_l | Medium.bubbleDensity(sat) | Density in liquid phase |
| SI.Mass | m | Total mass of drum boiler | |
| SI.Energy | U | Internal energy | |
| Medium.Temperature | T_D | heatPort.T | Temperature of drum |
| SI.HeatFlowRate | q_F | heatPort.Q_flow | Heat flow rate from furnace |
| Medium.SpecificEnthalpy | h_W | inStream(port_a.h_outflow) | Feed water enthalpy (specific enthalpy close to feedwater port when mass flows in to the boiler) |
| Medium.SpecificEnthalpy | h_S | inStream(port_b.h_outflow) | Steam enthalpy (specific enthalpy close to steam port when mass flows in to the boiler) |
| SI.MassFlowRate | qm_W | port_a.m_flow | Feed water mass flow rate |
| SI.MassFlowRate | qm_S | port_b.m_flow | Steam mass flow rate |
Revisions
- Dec 2008
by Rüdiger Franke:
Adapt initialization to new Types.Dynamics - 2 Nov 2005
by Francesco Casella:
Initialization options fixed - 6 Sep 2005
Model by Rüdiger Franke
See Franke, Rode, Krüger: On-line Optimization of Drum Boiler Startup, 3rd International Modelica Conference, Linköping, 2003.
Modified after the 45th Design Meeting