modelTestWaterFlow1DFEM_K
Extends from Modelica.Icons.Example (Icon for runnable examples).
Information
The model is designed to test the coupling between the mass and energy balance equations in the component Flow1DFEM (fluid side of a heat exchanger, finite element method).
The pipe is connected to two pressure source at the same pressure, with initial conditions corresponding to superheated steam @ 30 bar, 700 K.
At time t = 0, a constant uniform heat flux is applied to the lateral boundary of the pipe. The steam heats up and expands uniformly; since the configuration is symmetric, there is a backflow in the left half of the pipe and a forward flow on the right half of the pipe. The parameter wout is an analytical estimate of the flow rate going out each end of the pipe, which is in a good agreement with the actual solution.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | Nnodes | 11 | |
| SI.Length | Lhex | 10 | |
| SI.Diameter | Dihex | 0.02 | |
| SI.Radius | rhex | Dihex/2 | |
| SI.Length | omegahex | Modelica.Constants.pi*Dihex | |
| SI.Area | Ahex | Modelica.Constants.pi*rhex^2 | |
| SI.PerUnit | Cfhex | 0.05 | |
| SI.MassFlowRate | whex | 0.3 | |
| SI.Pressure | phex | 30e5 | |
| SI.Temperature | Thex | 700 | |
| SI.SpecificEnthalpy | hhex | Medium.specificEnthalpy_pT(phex, Thex) | |
| SI.Density | rhohex | Medium.density_pT(phex, Thex) | |
| SI.SpecificHeatCapacity | cp | Medium.specificHeatCapacityCp(Medium.setState_pT(phex, Thex)) | |
| SI.EnergyFlowRate | W | 100 | |
| Real | drho_dT | rhohex/Thex | |
| SI.Mass | M | rhohex*Ahex*Lhex | |
| Real | dT_dt | W/(cp*M) | |
| SI.MassFlowRate | dM_dT | Ahex*Lhex*drho_dT*dT_dt | |
| SI.MassFlowRate | wout | 0.5*dM_dT |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| ThermoPower.Water.SinkPressure | sink1 | ||
| Water.Flow1DFEM | pipe1 | ||
| System | system | ||
| Water.SourcePressure | source1 | ||
| Thermal.HeatSource1DFEM | heatSource1D | ||
| Modelica.Blocks.Sources.Step | step |
Contents
| Name | Description |
|---|---|
 Medium |
Revisions
- 7 Jan 2015 by Francesco Casella:
Updated to new FEM model. - 23 Aug 2011 by Francesco Casella:
First release.