WOLFRAM SYSTEMMODELER

TurbulentPipeFlow

TurbulentPipeFlow: Quadratic turbulent flow in circular tubes (using mu to regularize laminar region)

Wolfram Language

In[1]:=
SystemModel["Modelica.Fluid.Pipes.BaseClasses.FlowModels.TurbulentPipeFlow"]
Out[1]:=

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

This model defines only the quadratic turbulent regime of wall friction: dp = k*m_flow*|m_flow|, where "k" depends on density and the roughness of the pipe and is not a function of the Reynolds number. This relationship is only valid for large Reynolds numbers. The turbulent pressure loss correlation might be useful to optimize models that are only facing turbulent flow.

Parameters (18)

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)

use_Re

Value: system.use_eps_Re

Type: Boolean

Description: = true, if turbulent region is defined by Re, otherwise by m_flow_small

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: if use_Re then Re_turbulent * ones(n - 1) else zeros(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