modelPartial3WayValve
Partial for 3-way valves
Extends from IDEAS.Fluid.Interfaces.LumpedVolumeDeclarations (Declarations for lumped volumes).
Information
Description
3-way valve with temperature set point for mixing a cold and hot fluid to obtain outlet fluid at the desired temperature. If the desired temperature is higher than the hot fluid, no mixing will occur and the outlet will have the temperature of the hot fluid.
Inside the valve, the cold water flowrate is fixed with a pump component. The fluid content in the valve is equally split between the mixing volume and this pump. Without fluid content in the pump, this model does not work in all operating conditions.
Assumptions and limitations
- Correct connections of hot and cold fluid to the corresponding flowPorts is NOT CHECKED.
- The fluid content m of the valve has to be larger than zero
- There is an internal parameter mFlowMin which sets a minimum mass flow rate for mixing to start.
Model use
- Set medium and the internal fluid content of the valve (too small values of m could increase simulation times)
- Set mFlowMin, the minimum mass flow rate for mixing to start.
- Supply a set temperature at the outlet
Validation
None
Example (optional)
Examples of this model can be found in IDEAS.Thermal.Components.Examples.TempMixingTester and IDEAS.Thermal.Components.Examples.RadiatorWithMixingValve
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | l | 0.001 | Valve leakage, minimum fraction of flow rate passing through ports a |
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | Nominal mass flow rate | |
| Boolean | allowFlowReversal | true | = true to allow flow reversal |
| Modelica.Units.SI.Mass | m | m_flow_nominal*tau | Fluid content of the mixing valve |
| Dynamics › Conservation equations | |||
| Modelica.Fluid.Types.Dynamics | energyDynamics (from LumpedVolumeDeclarations) | Modelica.Fluid.Types.Dynamics.DynamicFreeInitial | Type of energy balance: dynamic (3 initialization options) or steady state |
| Modelica.Fluid.Types.Dynamics | substanceDynamics (from LumpedVolumeDeclarations) | energyDynamics | Type of independent mass fraction balance: dynamic (3 initialization options) or steady state |
| Modelica.Fluid.Types.Dynamics | traceDynamics (from LumpedVolumeDeclarations) | energyDynamics | Type of trace substance balance: dynamic (3 initialization options) or steady state |
| Advanced › Dynamics | |||
| Modelica.Fluid.Types.Dynamics | massDynamics (from LumpedVolumeDeclarations) | energyDynamics | Type of mass balance: dynamic (3 initialization options) or steady state, must be steady state if energyDynamics is steady state |
| Initialization | |||
| Medium.AbsolutePressure | p_start (from LumpedVolumeDeclarations) | Medium.p_default | Start value of pressure |
| Medium.Temperature | T_start (from LumpedVolumeDeclarations) | Medium.T_default | Start value of temperature |
| Medium.MassFraction[Medium.nX] | X_start (from LumpedVolumeDeclarations) | Medium.X_default | Start value of mass fractions m_i/m |
| Medium.ExtraProperty[Medium.nC] | C_start (from LumpedVolumeDeclarations) | fill(0, Medium.nC) | Start value of trace substances |
| Medium.ExtraProperty[Medium.nC] | C_nominal (from LumpedVolumeDeclarations) | fill(1E-2, Medium.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Dynamics | |||
| Real | mSenFac (from LumpedVolumeDeclarations) | 1 | Factor for scaling the sensible thermal mass of the volume |
| Dynamics › Filter | |||
| Real | tau | 1 | Thermal time constant |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_a1 | First fluid inlet | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_a2 | Second fluid inlet | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_b | Fluid outlet |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| IDEAS.Fluid.MixingVolumes.MixingVolume | vol | ||
| IDEAS.Fluid.Interfaces.IdealSource | idealSource |
Revisions
-
October 2, 2019 by Filip Jorissen:
Avoiding division by zero for zero flow rates whenSteadyState. See #1063. -
May 3, 2019 by Filip Jorissen:
PropagatedmSenFac. See #1018. -
April 23, 2019 by Filip Jorissen:
Using separate port for each connection to avoid algebraic loops. See #1019. -
March 26, 2018 by Filip Jorissen:
Implemented valve leakage, see #782. -
March 2014 by Filip Jorissen:
Initial implementation