modelCFDFluidInterface
Extends from Buildings.BaseClasses.BaseIcon (Base icon).
Information
This model is used to connect the fluid port with the block that communicates with the CFD program.
This model also implements the pressure balance of the medium, as the
FFD implementation uses a constant pressure that is independent of the
pressure of the Modelica model.
If the parameter massDynamics == Modelica.Fluid.Types.Dynamics.SteadyState,
then there is a steady-state mass balance and the pressure of the room
is an algebraic variable.
Otherwise, the time derivative of the pressure is
dp⁄dt = p_start ∑ ṁi ⁄ mstart,
where p_start is the initial pressure, ∑ ṁi is the sum of the mass flow rates over all ports, and mstart is the initial mass of the room.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Density | rho_start | Density, used to compute fluid mass | |
| Modelica.Units.SI.Volume | V | Volume | |
| Modelica.Units.SI.Mass | m_start | rho_start*V | Initial mass of air inside the room. |
| Dynamics › Conservation equations | |||
| Modelica.Fluid.Types.Dynamics | massDynamics | Modelica.Fluid.Types.Dynamics.DynamicFreeInitial | Formulation of mass balance |
| Initialization | |||
| Medium.AbsolutePressure | p_start | Medium.p_default | Start value of pressure |
| General › Ports | |||
| Integer | nPorts | 0 | Number of ports |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput[nPorts] | T_outflow | Temperature if m_flow < 0 | |
| Modelica.Blocks.Interfaces.RealInput[nPorts*Medium.nXi] | Xi_outflow | Species concentration if m_flow < 0 | |
| Modelica.Blocks.Interfaces.RealInput[nPorts*Medium.nC] | C_outflow | Trace substances if m_flow < 0 | |
| Modelica.Blocks.Interfaces.RealOutput | p | Room-averaged total pressure | |
| Modelica.Blocks.Interfaces.RealOutput[nPorts] | m_flow | Mass flow rates | |
| Modelica.Blocks.Interfaces.RealOutput[nPorts] | T_inflow | Temperature if m_flow >= 0 | |
| Modelica.Blocks.Interfaces.RealOutput[nPorts*Medium.nXi] | Xi_inflow | Species concentration if m_flow >= 0 | |
| Modelica.Blocks.Interfaces.RealOutput[nPorts*Medium.nC] | C_inflow | Trace substances if m_flow >= 0 | |
| Modelica.Fluid.Vessels.BaseClasses.VesselFluidPorts_b[nPorts] | ports | Fluid inlets and outlets |
Contents
| Name | Description |
|---|---|
 Medium | Medium in the component |
Revisions
-
July 24, 2014, by Wangda Zuo and Michael Wetter:
Removed the parameterinitialize_p. This parameter is used in.Mediaas equations are obtained fromBaseProperties. This implementation does not useMedium.BasePropertiesand hence this parameter is not needed. -
July 24, 2014, by Wangda Zuo and Michael Wetter:
Changed minimum attribute fornPortsfrom 2 to 0 as the FFD code uses atmospheric pressure and hence does not use the pressure of the fluid connector. -
January 25, 2014, by Wangda Zuo:
Added unit for mass flow rate. -
July 20, 2013, by Michael Wetter:
First implementation.