modelTestGasFlow1DFV_A
Test case for Gas.Flow1DFV
Extends from Modelica.Icons.Example (Icon for runnable examples).
Information
The model is designed to test the component Gas.Flow1DFV (fluid side of a heat exchanger, finite volumes). A uniform prescribed heat flux is applied to the lateral boundary. The working fluid is pure nitrogen.
The model starts at steady state.
- At t = 10 s, step variation of the temperature of the fluid entering the heat exchanger. The temperature change is propagated at the outlet with a delay approximately equal to the residence time
- At t = 20 s, a thermal power flow W is applied to the heat exchanger lateral surface. The outlet temperature undergoes a ramp change, whose duration is approximately equal to the residence time, and whose amplitude is equal to W/(whex*cp)
- At t = 50 s, step reduction of the outlet valve opening
Simulation Interval = [0...80] sec
Integration Algorithm = DASSL
Algorithm Tolerance = 1e-6
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | Nnodes | 10 | number of Nodes |
| SI.Length | Lhex | 200 | total length |
| SI.Diameter | Dihex | 0.02 | internal diameter |
| SI.Radius | rhex | Dihex/2 | internal radius |
| SI.Length | omegahex | Modelica.Constants.pi*Dihex | internal perimeter |
| SI.Area | Ahex | Modelica.Constants.pi*rhex^2 | internal cross section |
| Real | Cfhex | 0.005 | friction coefficient |
| SI.MassFlowRate | whex | 0.05 | nominal (and initial) mass flow rate |
| SI.Pressure | phex | 3e5 | initial pressure |
| SI.Temperature | Tinhex | 300 | initial inlet temperature |
| SI.Temperature | Touthex | 300 | initial outlet temperature |
| SI.EnergyFlowRate | W | 500 | height of power step |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real | gamma | Medium.specificHeatCapacityCp(hex.gas[1].state)/Medium.specificHeatCapacityCv(hex.gas[1].state) | cp/cv |
| Real | dMtot_dp | hex.Mtot/(hex.p*gamma) | compressibility |
| Real | dw_dp | valve.Kv | sensitivity of valve flow to pressure |
| SI.Time | tau | dMtot_dp/dw_dp | time constant of pressure transient |
| SI.Mass | Mhex | Mass in the heat exchanger | |
| SI.Mass | Mbal | Mass resulting from the mass balance | |
| SI.Mass | Merr | Mass balance error | |
| Gas.SourceMassFlow | Source | ||
| Gas.SinkPressure | Sink | ||
| Gas.SensT | SensT1 | ||
| Gas.SensT | SensT2 | ||
| Gas.Flow1DFV | hex | ||
| Gas.ValveLin | valve | ||
| Thermal.HeatSource1DFV | heatSource | ||
| Modelica.Blocks.Sources.Step | Step1 | ||
| Modelica.Blocks.Sources.Step | Step4 | ||
| Modelica.Blocks.Sources.Step | Step2 | ||
| System | system |
Contents
| Name | Description |
|---|---|
 Medium |