modelDuctManifoldFixedResistance
Manifold for a heat exchanger air duct connection
Extends from PartialDuctManifold.
Information
Duct manifold with a fixed flow resistance.
This model is composed of a pressure drop calculation, and
a flow distributor. The flow distributor distributes the
mass flow rate equally to each instance of port_b,
without having to compute a pressure drop in each flow leg.
Note: It is important that there is an equal pressure drop in each flow leg between this model, and the model that collects the flows. Otherwise, no solution may exist, and therefore the simulation may stop with an error.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | use_dh | false | Set to true to specify hydraulic diameter |
| Modelica.Units.SI.Length | dh | 1 | Hydraulic diameter of duct |
| Real | ReC | 4000 | Reynolds number where transition to turbulence starts |
| Real | deltaM | 0.3 | Fraction of nominal mass flow rate where transition to turbulent occurs |
| Nominal Condition | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | Mass flow rate at port_a | |
| Modelica.Units.SI.PressureDifference | dp_nominal | Pressure drop | |
| Advanced | |||
| Boolean | linearized | false | = true, use linear relation between m_flow and dp for any flow rate |
| Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.FixedResistances.PressureDrop | fixRes | Fixed resistance for each duct |
Revisions
-
November 8, 2016, by Michael Wetter:
Removed wrong usage ofeachkeyword. -
January 22, 2016, by Michael Wetter:
Corrected type declaration of pressure difference. This is for #404. -
June 29, 2014, by Michael Wetter:
Added model that distributes the mass flow rate equally to each instance ofport_b. -
June 26, 2014, by Michael Wetter:
Conditionally removed the volume if the energy balance is steady state. This was done as the overhead for modeling a volume is not needed in this configuration. -
September 10, 2008, by Michael Wetter:
Added additional parameters. -
August 22, 2008, by Michael Wetter:
Added start value for resistance mass flow rate. -
August 21, 2008, by Michael Wetter:
Added mixing volume to break large nonlinear system of equations in model Buildings.Fluid.HeatExchangers.DryCoilDiscretized. -
April 14, 2008, by Michael Wetter:
First implementation.