modelTestWaterFlow1DFV_B
Extends from Modelica.Icons.Example (Icon for runnable examples).
Information
The model is designed to test the component Water.Flow1DFV (fluid side of a heat exchanger, finite volumes).
This model represent the fluid side of a heat exchanger with convective exchange with an external source of uniform given temperature. The operating fluid is liquid water. The number of transfer units in the selected operating point is NTU = 0.73. Assuming incompressible fluid and constant cp, when the external temperature is raised at time t = 20 s, the outlet temperature should follow a ramp change, with a duration equal to the residence time of the fluid in the tubes, and an amplitude equal to a fraction exp(-NTU) of the external temperature change.
Simulation Interval = [0...200] sec
Integration Algorithm = DASSL
Algorithm Tolerance = 1e-6
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | Nnodes | 10 | Number of nodes |
| Integer | Nt | 5 | Number of tubes |
| Modelica.SIunits.Length | Lhex | 2 | Total length |
| Modelica.SIunits.Diameter | Dihex | 0.02 | Internal diameter |
| Modelica.SIunits.Radius | rhex | Dihex/2 | Internal radius |
| Modelica.SIunits.Length | omegahex | Modelica.Constants.pi*Dihex | Internal perimeter |
| Modelica.SIunits.Area | Ahex | Modelica.Constants.pi*rhex^2 | Internal cross section |
| Real | Cfhex | 0.005 | Friction coefficient |
| Modelica.SIunits.MassFlowRate | whex | 0.31 | Nominal mass flow rate |
| Modelica.SIunits.Pressure | phex | 3e5 | Initial pressure |
| Modelica.SIunits.SpecificEnthalpy | hs | 1e5 | Initial inlet specific enthalpy |
| Modelica.SIunits.CoefficientOfHeatTransfer | gamma | 1500 | Fixed heat transfer coefficient |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real | cp | Medium.specificHeatCapacityCp(hex.fluidState[1]) | |
| Real | NTU | (Nt*Lhex*Dihex*3.1415*gamma)/(whex*Medium.specificHeatCapacityCp(hex.fluidState[1])) | Number of heat transfer units |
| Real | alpha | 1 - exp(-NTU) | Steady state gain of outlet temperature vs. external temperature |
| Water.ValveLin | valve | ||
| Water.SourceMassFlow | fluidSource | ||
| Water.SinkPressure | fluidSink | ||
| Modelica.Blocks.Sources.Step | Temperature | ||
| Modelica.Blocks.Sources.Constant | Constant1 | ||
| Water.SensT | T_in | ||
| Water.SensT | T_out | ||
| System | system | ||
| Thermal.TempSource1DFV | tempSource | ||
| Water.Flow1DFV | hex |
Contents
| Name | Description |
|---|---|
 Medium |
Revisions
- 18 Sep 2013 by Francesco Casella:
Updated to new FV structure. Updated parameters. - 1 Oct 2003 by Francesco Schiavo:
First release.