modelIdealSource

Base class for pressure and mass flow source with optional power input
Diagram of IdealSourceOpen the diagram
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Extends from Buildings.Fluid.Interfaces.PartialTwoPortTransport (Partial element transporting fluid between two ports without storage of mass or energy).

Information

Model of a fictitious pipe that is used as a base class for a pressure source or to prescribe a mass flow rate.

Note that for fans and pumps with dynamic balance, both the heat and the flow work are added to the volume of air or water. This simplifies the equations compared to adding heat to the volume, and flow work to this model.

Typically either control_m_flow or control_dp should be true to avoid a singular system. If control_m_flow = true, then the mass flow rate is set to the value of the input connector m_flow_in. Otherwise, this model does not specify the mass flow rate. Similarly, if control_dp = true, the head is equal to the value of the input connector dp_in. Otherwise, this model does not specify the head.

Parameters

TypeNameDefaultDescription
Booleancontrol_m_flowif true, then the mass flow rate is equal to the value of m_flow_in
Booleancontrol_dpnot control_m_flowif true, then the head is equal to the value of dp_in
Assumptions
BooleanallowFlowReversal (from PartialTwoPort)true= false to simplify equations, assuming, but not enforcing, no flow reversal
Advanced
Modelica.Units.SI.PressureDifferencedp_start (from PartialTwoPortTransport)0Guess value of dp = port_a.p - port_b.p
Medium.MassFlowRatem_flow_start (from PartialTwoPortTransport)0Guess value of m_flow = port_a.m_flow
Medium.MassFlowRatem_flow_small (from PartialTwoPortTransport)Small mass flow rate for regularization of zero flow
Advanced › Diagnostics
Booleanshow_T (from PartialTwoPortTransport)true= true, if temperatures at port_a and port_b are computed
Booleanshow_V_flow (from PartialTwoPortTransport)true= true, if volume flow rate at inflowing port is computed

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_aport_a (from PartialTwoPort)Fluid connector a (positive design flow direction is from port_a to port_b)
Modelica.Fluid.Interfaces.FluidPort_bport_b (from PartialTwoPort)Fluid connector b (positive design flow direction is from port_a to port_b)
Modelica.Blocks.Interfaces.RealInputm_flow_inPrescribed mass flow rate
Modelica.Blocks.Interfaces.RealInputdp_inPrescribed pressure difference port_a.p-port_b.p

Components

TypeNameDefaultDescription
Medium.MassFlowRatem_flow (from PartialTwoPortTransport)Mass flow rate in design flow direction
Modelica.Units.SI.PressureDifferencedp (from PartialTwoPortTransport)Pressure difference between port_a and port_b (= port_a.p - port_b.p)
Modelica.Units.SI.VolumeFlowRateV_flow (from PartialTwoPortTransport)m_flow/Modelica.Fluid.Utilities.regStep(m_flow, Medium.density(Medium.setState_phX(p = port_a.p, h = inStream(port_a.h_outflow), X = inStream(port_a.Xi_outflow))), Medium.density(Medium.setState_phX(p = port_b.p, h = inStream(port_b.h_outflow), X = inStream(port_b.Xi_outflow))), m_flow_small)Volume flow rate at inflowing port (positive when flow from port_a to port_b)
Medium.Temperatureport_a_T (from PartialTwoPortTransport)Modelica.Fluid.Utilities.regStep(port_a.m_flow, Medium.temperature(Medium.setState_phX(p = port_a.p, h = inStream(port_a.h_outflow), X = inStream(port_a.Xi_outflow))), Medium.temperature(Medium.setState_phX(port_a.p, port_a.h_outflow, port_a.Xi_outflow)), m_flow_small)Temperature close to port_a, if show_T = true
Medium.Temperatureport_b_T (from PartialTwoPortTransport)Modelica.Fluid.Utilities.regStep(port_b.m_flow, Medium.temperature(Medium.setState_phX(p = port_b.p, h = inStream(port_b.h_outflow), X = inStream(port_b.Xi_outflow))), Medium.temperature(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow)), m_flow_small)Temperature close to port_b, if show_T = true

Revisions

  • May 4, 2017, by Filip Jorissen:
    Implemented option to set control_dp independently from control_m_flow. This is for #770.
  • March 2, 2017, by Filip Jorissen:
    Implemented simplification when allowFlowReversal=false. This is for #673.
  • March 20, 2016, by Michael Wetter:
    Corrected documentation for dp_in.
  • January 22, 2016, by Michael Wetter:
    Added units to the signal connectors. This is for #404.
  • October 8, 2013, by Michael Wetter:
    Removed parameter show_V_flow.
  • May 25, 2011 by Michael Wetter:
    Removed the option to add power to the medium, as this is dealt with in the volume that is used in the mover model.
  • July 27, 2010 by Michael Wetter:
    Redesigned model to fix bug in medium balance.
  • April 13, 2010 by Michael Wetter:
    Made heat connector optional.
  • March 23, 2010 by Michael Wetter:
    First implementation.