modelPartialStaggeredFlowModel
Extends from TRANSFORM.Fluid.Pipes_Obsolete.PartialDistributedFlowOLD.
Information
This partial model defines a common interface for nFM flow models between nFM+1 device segments.
The flow models provide a steady-state or dynamic momentum balance using an upwind discretization scheme per default.
Extending models must add pressure loss terms for friction and gravity.
The fluid is specified in the interface with the thermodynamic states[nFM+1] for a given Medium model.
The geometry is specified with the pathLengths[nFM] between the device segments as well as
with the crossAreas[nFM+1] and the roughnesses[nFM+1] of the device segments.
Moreover the fluid flow is characterized for different types of devices by the characteristic dimensions[nFM+1]
and the average velocities vs[nFM+1] of fluid flow in the device segments.
See Pipes.BaseClasses.CharacteristicNumbers.ReynoldsNumber
for example definitions.
The parameter Res_turbulent can be specified for the least mass flow rate of the turbulent regime.
It defaults to 4000, which is appropriate for pipe flow.
The m_flows_turbulent[nFM] resulting from Res_turbulent can optionally be calculated together with the Reynolds numbers
Res[nFM+1] of the device segments (show_Res=true).
Using the thermodynamic states[nFM+1] of the device segments, the densities rhos[nFM+1] and the dynamic viscosities mus[nFM+1] of the segments as well as the actual densities rhos_act[nFM] and the actual viscosities mus_act[nFM] of the flows are predefined in this base model. Note that no events are raised on flow reversal. This needs to be treated by an extending model, e.g., with numerical smoothing or by raising events as appropriate.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | nParallel | number of identical parallel flow devices | |
| SI.Acceleration | g | system.g | Constant gravity acceleration |
| SI.ReynoldsNumber | Res_turbulent | 4000*ones(nFM) | Start of turbulent regime, depending on type of flow device |
| Internal Interface › Assumptions | |||
| Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction (states[1] -> states[nFM+1+1]) |
| Modelica.Fluid.Types.Dynamics | momentumDynamics | system.momentumDynamics | Formulation of momentum balance |
| Advanced | |||
| Boolean | useUpstreamScheme | true | = false to average upstream and downstream properties across flow segments |
| Boolean | use_Ib_flows | momentumDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState | = true to consider differences in flow of momentum through boundaries |
| Diagnostics | |||
| Boolean | show_Res | false | = true, if Reynolds numbers are included for plotting |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.ThermodynamicState | states | Thermodynamic states along design flow | |
| SI.Velocity | vs | Mean velocities of fluid flow | |
| SI.Temperature | Ts_w | Mean wall temperatures of heat transfer surface | |
| SI.Length | lengths | Lengths of flow elements | |
| SI.Area | crossAreas | Cross flow areas at segment boundaries | |
| SI.Length | dimensions | Characteristic dimensions for fluid flow (diameters for pipe flow) | |
| SI.Height | roughnesses | Average height of surface asperities | |
| SI.Length | dheights | Height(states[2:nFM+1]) - Height(states[1:nFM]) | |
| Medium.Density | rhos | if use_rho_nominal then fill(rho_nominal, nFM + 1) else Medium.density(states) | |
| Medium.Density | rhos_act | Actual density per segment | |
| Medium.DynamicViscosity | mus | if use_mu_nominal then fill(mu_nominal, nFM + 1) else Medium.dynamicViscosity(states) | |
| Medium.DynamicViscosity | mus_act | Actual viscosity per segment | |
| SI.Pressure | dps_fg | pressure drop between states | |
| SI.ReynoldsNumber | Res | Utilities.CharacteristicNumbers.ReynoldsNumber(vs, rhos, mus, dimensions) | Reynolds numbers |
| Medium.MassFlowRate | m_flows_turbulent | {nParallel*(crossAreas[i] + crossAreas[i + 1])/(dimensions[i] + dimensions[i + 1])*mus_act[i]*Res_turbulent[i] for i in 1:nFM} | Start of turbulent flow |