modelFluid_Volume
Extends from TransiEnt.Basics.Icons.Fluid_Volume.
Information
1. Purpose of model
Simple control volume for vle fluids. The volume has a heat port and variable number of fluid ports.
2. Level of detail, physical effects considered, and physical insight
L2: Model ist based on law of conservation of mass or volume. Fluid in the volume is assumed to be idaelly stirred, so the fluid in the volume has one temperature and one pressure. Kinetic energy and potential energy are neglected.
3. Limits of validity
Model is only valid for single phase fluids and nor pressure losses are included.
4. Interfaces
heatPort: model gives temperature and may get heat flow
ports[nPorts]: a variable number of fluid ports
5. Nomenclature
nPorts: number of fluid connections to the volume
V_const: Volume of Fluid
6. Governing Equations
The governing equations are law of conservation of mass or volume and the conservation of energy. The balance of mass is described in tne formula below. You can choose to use a steady state mass balance. In this case the sum of entering and leaving mass flow is to be zero.
The conservation of energy is shown in the following formula. The kinetic and potential energy are neglected. The amount of energy in the volume can be changed due to heat transfer or mass transfer (konvektive energy). There is no possibilty to add direct electrical or mechanical energy.
Image at src="Sketchbook/tr/Thermal/Images/equations/energy_balance.png" missing
7. Remarks for Usage
The simulation should be performed with steady mass balance. The inflowing an outflowing mass has always the same amount. On the other hand the simulation could also be performed with assuming constant fluid volume. The mass increases or decreases due to temperature
8. Validation
(no validation)
9. References
(no remarks)
10. Version History
Model created by Tobias Ramm (tobias.ramm@tuhh.de) on Fri Mar 20 2015
Revised and edited by Lisa Andresen (andresen@tuhh.de), Jun 2015
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Volume | V_start | V_const | Start Volume |
| Integer | nPorts | 2 | Number of fluid ports |
| SI.Volume | V_const | 2 | Volume |
| SI.Mass | m_const | V_start*d_start | Total system mass |
| Fundamental Definitions | |||
| TILMedia.VLEFluidTypes.BaseVLEFluid | medium | simCenter.fluid1 | Medium in the component |
| Boolean | Use_steady_state_mass_balance | true | Steady state mass balance |
| Initialisation | |||
| Boolean | useHomotopy | simCenter.useHomotopy | True, if homotopy method is used during initialisation |
| SI.SpecificEnthalpy | h_start | 1e5 | Start value of sytsem specific enthalpy |
| SI.Pressure | p_start | 1e5 | Start value of sytsem pressure |
| Nominal Values | |||
| SI.Pressure | p_nom | 1e5 | Nominal pressure |
| SI.SpecificEnthalpy | h_nom | 1e5 | Nominal specific enthalpy |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| TransiEnt.Basics.Interfaces.Thermal.FluidPortIn | ports | Fluid port | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPort |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| TransiEnt.SimCenter | simCenter | ||
| SI.Volume | V | Volume | |
| SI.Mass | m | Total system mass | |
| SI.SpecificEnthalpy | h | ||
| SI.Pressure | p | System pressure | |
| SI.Temperature | T | System temperature | |
| SI.Temperature[nPorts] | T_ports | Inlet Temperature | |
| SI.Density | d | bulk.d | |
| Real | drhodt | ||
| SI.HeatFlowRate | Q_flow | Heat Flow Rate | |
| SI.EnthalpyFlowRate[nPorts] | H_flow | Enthalpy flow rate passing from inlet to volume | |
| TILMedia.Internals.VLEFluidConfigurations.FullyMixtureCompatible.VLEFluid_ph | fluidPorts |