modelSISOFlowAdvanced
Advanced model for SISOFlow
Extends from ThermofluidStream.Utilities.DropOfCommonsPlus (Extend this to use 'dropOfCommons', 'instanceName', 'displayInstanceName' and 'displayParameters').
Information
- For
setFlow=false, this model is equivalent to ThermofluidStream.Interfaces.SISOFlow, i.e it uses the approach:
der(inlet.m_flow)*L = inlet.r - outlet.r;
p_out = p_in + dp;
where the pressure difference dp + dr is given and the mass flow rate m_flow is adapted based on the (negative) inertial pressure
difference -dr = inlet.r - outlet.r.
The inertance L is its 'time constant' (strictly speaking by dimensional analysis (Buckingham pi theorem) one can derive that the time constant TC ~ L*dp_stationary/m_flow_stationary).
The inertance L can be derived from instationary Bernoulli equation.
- For
setFlow=true, this model is an extension of ThermofluidStream.Boundaries.TerminalSource, i.e it uses the approach:
TC * der(dp) = outlet.r - inlet.r;
p_out = p_in + dp;
where the mass flow rate m_flow is given and the pressure difference dp is adapted based on the
(positive) inertial pressure difference dr = outlet.r - inlet.r.
Currently the time constant TC is used as a numerical tool. It might have a physical explanation considering the pressure change der(dp)
of a volume for a given inflow/outflow.
Use dp(start=0) or dp(final start=0) if setFlow=true.
Parameters
| Type | Name | Default | Description |
|---|
| String | instanceName (from DropOfCommonsPlus) | getInstanceName() | Instance name |
| Boolean | setFlow | false | = true, if mass flow rate is set (=false, for standard approach) |
| Layout |
| Boolean | displayInstanceName (from DropOfCommonsPlus) | dropOfCommons.displayInstanceNames | = true, if instance name is displayed |
| Boolean | displayParameters (from DropOfCommonsPlus) | dropOfCommons.displayParameters | = true, if displaying parameters is enabled |
| Advanced › Pressure dynamics |
| SI.Time | TC | 1e-3 | Time constant for pressure adaption if mass flow rate is set |
| Advanced |
| ThermofluidStream.Utilities.Units.Inertance | L | dropOfCommons.L | Inertance |
| StateSelect | m_flowStateSelect | StateSelect.default | State selection for mass flow rate |
| Boolean | clip_p_out | | = false, if dr_corr=0 (correction of inertial pressure difference) |
| Medium.AbsolutePressure | p_min | dropOfCommons.p_min | Minimum steady-state output pressure |
| Initialization › Mass flow rate |
| InitializationMethods | initM_flow | ThermofluidStream.Utilities.Types.InitializationMethods.none | Initialization method for mass flow rate |
| SI.MassFlowRate | m_flow_0 | 0 | Initial value for mass flow rate |
| ThermofluidStream.Utilities.Units.MassFlowAcceleration | m_acceleration_0 | 0 | Initial value for derivative of mass flow rate |
Contents
| Name | Description |
|---|
 Medium | Medium model |
Revisions
-
May 2025, by Raphael Gebhart (raphael.gebhart@dlr.de):
Initial version.
