TurbulentPipeFlowTurbulentPipeFlow: Quadratic turbulent flow in circular tubes (using mu to regularize laminar region) |
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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, if flow reversal is enabled, otherwise restrict flow 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)
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system |
Type: System Description: System properties |
|---|---|---|
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states |
Type: ThermodynamicState[n] Description: Thermodynamic states along design flow |