WOLFRAM SYSTEMMODELER

FlowModel

Wall friction, gravity, momentum flow

Wolfram Language

In[1]:=
SystemModel["Modelica.Fluid.Pipes.BaseClasses.PartialStraightPipe.FlowModel"]
Out[1]:=

Parameters (17)

m

Value: n - 1

Type: Integer

Description: Number of flow segments

n

Value: 2

Type: Integer

Description: Number of discrete flow volumes

nParallel

Value:

Type: Real

Description: number of identical parallel flow devices

g

Value: system.g

Type: Acceleration (m/s²)

Description: Constant gravity acceleration

allowFlowReversal

Value: system.allowFlowReversal

Type: Boolean

Description: = true to allow flow reversal, false restricts to design direction (states[1] -> states[n+1])

momentumDynamics

Value: system.momentumDynamics

Type: Dynamics

Description: Formulation of momentum balance

m_flow_start

Value: system.m_flow_start

Type: MassFlowRate (kg/s)

Description: Start value of mass flow rates

p_a_start

Value:

Type: AbsolutePressure (Pa)

Description: Start value for p[1] at design inflow

p_b_start

Value:

Type: AbsolutePressure (Pa)

Description: Start value for p[n+1] at design outflow

useUpstreamScheme

Value: true

Type: Boolean

Description: = false to average upstream and downstream properties across flow segments

use_Ib_flows

Value: momentumDynamics <> Types.Dynamics.SteadyState

Type: Boolean

Description: = true to consider differences in flow of momentum through boundaries

Re_turbulent

Value: 4000

Type: ReynoldsNumber

Description: Start of turbulent regime, depending on type of flow device

show_Res

Value: false

Type: Boolean

Description: = true, if Reynolds numbers are included for plotting

from_dp

Value: momentumDynamics >= Types.Dynamics.SteadyStateInitial

Type: Boolean

Description: = true, use m_flow = f(dp), otherwise dp = f(m_flow)

dp_nominal

Value:

Type: AbsolutePressure (Pa)

Description: Nominal pressure loss (only for nominal models)

m_flow_nominal

Value: if system.use_eps_Re then system.m_flow_nominal else 1e2 * m_flow_small

Type: MassFlowRate (kg/s)

Description: Nominal mass flow rate

m_flow_small

Value: if system.use_eps_Re then system.eps_m_flow * m_flow_nominal else system.m_flow_small

Type: MassFlowRate (kg/s)

Description: Within regularization if |m_flows| < m_flow_small (may be wider for large discontinuities in static head)

Inputs (9)

pathLengths

Type: Length[m] (m)

Description: Lengths along flow path

states

Type: ThermodynamicState[n]

Description: Thermodynamic states along design flow

vs

Type: Velocity[n] (m/s)

Description: Mean velocities of fluid flow

crossAreas

Type: Area[n] (m²)

Description: Cross flow areas at segment boundaries

dimensions

Type: Length[n] (m)

Description: Characteristic dimensions for fluid flow (diameters for pipe flow)

roughnesses

Type: Roughness[n] (m)

Description: Average height of surface asperities

dheights

Type: Length[n - 1] (m)

Description: Height(states[2:n]) - Height(states[1:n-1])

pathLengths_internal

Default Value: pathLengths

Type: Length[n - 1] (m)

Description: pathLengths used internally; to be defined by extending class

Res_turbulent_internal

Default Value: Re_turbulent * ones(n - 1)

Type: ReynoldsNumber[n - 1]

Description: Re_turbulent used internally; to be defined by extending class

Components (2)

system

Type: System

Description: System properties

states

Type: ThermodynamicState[n]

Description: Thermodynamic states along design flow

Used in Components (1)

StaticPipe

Modelica.Fluid.Pipes

Basic pipe flow model without storage of mass or energy