modelValve
Valve with incompressible flow hypothesis for the calculation of the pressure drop
Extends from ThermoCycle.Icons.Water.Valve.
Information
The Valve model represents the expansion of a fluid through a valve.
The assumptions for this model are:
- No dynamics ( it is considered negligible when compared to the one characterizing the heat exchanger).
- No ambient heat losses (the expansion is assumed isenthalpic)
- Incompressible flow for computing the pressure drop
- Quadratic pressure drop (turbulent flow)
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | UseNom | false | Use Nominal conditions to compute pressure drop characteristics |
| Modelica.SIunits.Area | Afull | 10e-5 | Cross-sectional area of the fully open valve |
| Real | Xopen | 1 | Valve opening if no external command is connected (0=fully closed; 1=fully open) |
| Modelica.SIunits.Pressure | DELTAp_0 | 500 | Pressure drop below which a 3rd order interpolation is used for the computation of the flow rate in order to avoid infinite derivative at 0 |
| Nominal Conditions | |||
| Modelica.SIunits.MassFlowRate | Mdot_nom | 0.1 | Nominal mass flow rate |
| Modelica.SIunits.Pressure | p_nom | 1e5 | Nominal inlet pressure |
| Modelica.SIunits.Temperature | T_nom | 423.15 | Nominal inlet temperature |
| Modelica.SIunits.Density | rho_nom | Medium.density_pTX(p_nom, T_nom, fill(0, 0)) | Nominal density |
| Modelica.SIunits.Pressure | DELTAp_nom | 0 | Nominal pressure drop |
| Boolean | use_rho_nom | false | Use the nominal density for the computation of the pressure drop (i.e it depends only on the flow rate) |
| Initialization | |||
| Modelica.SIunits.Time | t_init | 10 | if constinit is true, time during which the pressure drop is set to the constant value DELTAp_nom |
| Boolean | constinit | false | if true, sets the pressure drop to a constant value at the beginning of the simulation in order to avoid oscillations |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput | cmd | ||
| Modelica.SIunits.Area | A | Valve throat area | |
| Modelica.SIunits.Pressure | DELTAp | ||
| Modelica.SIunits.Pressure | DELTAp_bis | ||
| Modelica.SIunits.MassFlowRate | Mdot | ||
| Medium.ThermodynamicState | fluidState | ||
| Medium.Density | rho | Inlet density | |
| Modelica.SIunits.Time | t_change | 5 | |
| ThermoCycle.Interfaces.Fluid.FlangeA | InFlow | ||
| ThermoCycle.Interfaces.Fluid.FlangeB | OutFlow |
Contents
| Name | Description |
|---|---|
| Medium |