modelAccumulator
Water-Gas Accumulator
Extends from ThermoPower.Icons.Water.Accumulator.
Information
This model describes a water-gas accumulator (the gas is modeled as ideal bi-atomic).
Water flows in and out through the interfaces at the component bottom (flow reversal supported).
The gas is supposed to flow in at constant temperature (parameter Tgin) and with variable flow-rate (GasInfl signal port), and to flow out by a valve operating in choked condition; the valve coefficient is determined by the working point at full opening (wg_out0,Tg0, Pg0) while the valve opening (in the range 0-1) is an input signal (OutletValveOpening signal port).
Dimensional parameters
- V: accumulator total volume;
- Vl0: volume occupied by water at the nominal level (reference value);
- zl0: height of water nominal level above the water connectors;
- A: cross-sectional area at actual water level;
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Volume | V | Total volume | |
| SI.Volume | Vl0 | Water nominal volume (at reference level) | |
| SI.Area | A | Cross Sectional Area | |
| SI.Height | zl0 | Height of water reference level over inlet/outlet connectors | |
| SI.CoefficientOfHeatTransfer | gamma_ex | 50 | Water-Gas heat transfer coefficient |
| SI.Temperature | Tgin | 300 | Inlet gas temperature |
| SI.MolarMass | MM | 29e-3 | Gas molar mass |
| SI.MassFlowRate | wg_out0 | Nominal gas outlet flowrate | |
| Units.AbsoluteTemperature | Tg0 | 300 | Nominal gas temperature |
| Units.AbsolutePressure | pg0 | Nominal gas pressure | |
| Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction |
| Initialisation | |||
| SI.Height | zl_start | Water start level (relative to reference) | |
| Medium.SpecificEnthalpy | hl_start | Water start specific enthalpy | |
| SI.Pressure | pg_start | Gas start pressure | |
| Units.AbsoluteTemperature | Tg_start | 300 | Gas start temperature |
| Choices.Init.Options | initOpt | system.initOpt | Initialisation option |
| Boolean | noInitialPressure | false | Remove initial equation on pressure |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | GasInfl | ||
| FlangeA | WaterInfl | ||
| FlangeB | WaterOutfl | ||
| Modelica.Blocks.Interfaces.RealInput | OutletValveOpening |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.ThermodynamicState | liquidState | Thermodynamic state of the liquid | |
| ThermoPower.System | system | System wide properties | |
| Medium.MassFlowRate | wl_in | Water inflow mass flow rate | |
| Medium.MassFlowRate | wl_out | Water outflow mass flow rate | |
| SI.Height | zl | Water level (relative to reference) | |
| Medium.SpecificEnthalpy | hl_in | Water inlet specific enthalpy | |
| Medium.SpecificEnthalpy | hl_out | Water outlet specific enthalpy | |
| Medium.SpecificEnthalpy | hl | Water internal specific enthalpy | |
| SI.Volume | Vl | Volume occupied by water | |
| SI.Mass | Mg | Mass of gas | |
| Medium.AbsolutePressure | pf | Water Pressure at the inlet/outlet flanges | |
| SI.EnergyFlowRate | Qp | Water-Gas heat flow | |
| SI.MassFlowRate | wg_in | Gas inflow mass flow rate | |
| SI.MassFlowRate | wg_out | Gas outflow mass flow rate | |
| Units.GasDensity | rhog | Gas density | |
| Medium.Temperature | Tg | Gas temperature | |
| SI.Volume | Vg | Volume occupied by gas | |
| Medium.AbsolutePressure | pg | Gas pressure | |
| Units.LiquidDensity | rho | Density of the water |
Contents
| Name | Description |
|---|---|
 Medium |
Revisions
- 30 May 2005
by Francesco Casella:
Initialisation support added. - 16 Dec 2004
by Francesco Casella:
Standard medium definition added. - 18 Jun 2004
by Francesco Casella:
Adapted to Modelica.Media. - 5 Feb 2004
by Francesco Schiavo:
First release.