Package Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​Laminar
Pipe wall friction for laminar flow in circular tubes (linear correlation)

Information

This component defines only the laminar region of wall friction: dp = k*m_flow, where "k" depends on density and dynamic viscosity. The roughness of the wall does not have an influence on the laminar flow and therefore argument roughness is ignored. Since this is a linear relationship, the occurring systems of equations are usually much simpler (e.g., either linear instead of non-linear). By using nominal values for density and dynamic viscosity, the systems of equations can still further be reduced.

In UsersGuide the complete friction regime is illustrated. This component describes only the Hagen-Poiseuille equation.


Extends from Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​PartialWallFriction (Partial wall friction characteristic (base package of all wall friction characteristics)).

Package Contents

NameDescription
massFlowRate_dpReturn mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction
massFlowRate_dp_staticHeadReturn mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction and static head
pressureLoss_m_flowReturn pressure loss dp as function of mass flow rate m_flow, i.e., dp = f(m_flow), due to wall friction
pressureLoss_m_flow_staticHeadReturn pressure loss dp as function of mass flow rate m_flow, i.e., dp = f(m_flow), due to wall friction and static head

Package Constants

TypeNameValueDescription
Booleandp_is_zerofalse= true, if no wall friction is present, i.e., dp = 0 (function massFlowRate_dp() cannot be used)
final Booleanuse_dp_smallfalse= true, if dp_small is used in function, otherwise value is not used
final Booleanuse_m_flow_smallfalse= true, if m_flow_small is used in function, otherwise value is not used
final Booleanuse_mutrue= true, if mu_a/mu_b are used in function, otherwise value is not used
final Booleanuse_Re_turbulentfalse= true, if Re_turbulent input is used in function, otherwise value is not used
final Booleanuse_roughnessfalse= true, if roughness is used in function, otherwise value is not used

Function Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​Laminar.​massFlowRate_dp
Return mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction

Information

Extends from Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​PartialWallFriction.​massFlowRate_dp (Return mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction).

Inputs

TypeNameDescription
PressuredpPressure loss (dp = port_a.p - port_b.p)
Densityrho_aDensity at port_a
Densityrho_bDensity at port_b
DynamicViscositymu_aDynamic viscosity at port_a (dummy if use_mu = false)
DynamicViscositymu_bDynamic viscosity at port_b (dummy if use_mu = false)
LengthlengthLength of pipe
DiameterdiameterInner (hydraulic) diameter of pipe
AreacrossAreaInner cross section area
LengthroughnessAbsolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false)
AbsolutePressuredp_smallRegularization of zero flow if |dp| < dp_small (dummy if use_dp_small = false)
ReynoldsNumberRe_turbulentTurbulent flow if Re >= Re_turbulent (dummy if use_Re_turbulent = false)

Outputs

TypeNameDescription
MassFlowRatem_flowMass flow rate from port_a to port_b

Function Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​Laminar.​massFlowRate_dp_staticHead
Return mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction and static head

Information

Extends from Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​PartialWallFriction.​massFlowRate_dp_staticHead (Return mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction and static head).

Inputs

TypeNameDescription
PressuredpPressure loss (dp = port_a.p - port_b.p)
Densityrho_aDensity at port_a
Densityrho_bDensity at port_b
DynamicViscositymu_aDynamic viscosity at port_a (dummy if use_mu = false)
DynamicViscositymu_bDynamic viscosity at port_b (dummy if use_mu = false)
LengthlengthLength of pipe
DiameterdiameterInner (hydraulic) diameter of pipe
Realg_times_height_abGravity times (Height(port_b) - Height(port_a))
AreacrossAreaInner cross section area
LengthroughnessAbsolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false)
AbsolutePressuredp_smallRegularization of zero flow if |dp| < dp_small (dummy if use_dp_small = false)
ReynoldsNumberRe_turbulentTurbulent flow if Re >= Re_turbulent (dummy if use_Re_turbulent = false)

Outputs

TypeNameDescription
MassFlowRatem_flowMass flow rate from port_a to port_b

Function Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​Laminar.​pressureLoss_m_flow
Return pressure loss dp as function of mass flow rate m_flow, i.e., dp = f(m_flow), due to wall friction

Information

Extends from Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​PartialWallFriction.​pressureLoss_m_flow (Return pressure loss dp as function of mass flow rate m_flow, i.e., dp = f(m_flow), due to wall friction).

Inputs

TypeNameDescription
MassFlowRatem_flowMass flow rate from port_a to port_b
Densityrho_aDensity at port_a
Densityrho_bDensity at port_b
DynamicViscositymu_aDynamic viscosity at port_a (dummy if use_mu = false)
DynamicViscositymu_bDynamic viscosity at port_b (dummy if use_mu = false)
LengthlengthLength of pipe
DiameterdiameterInner (hydraulic) diameter of pipe
AreacrossAreaInner cross section area
LengthroughnessAbsolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false)
MassFlowRatem_flow_smallRegularization of zero flow if |m_flow| < m_flow_small (dummy if use_m_flow_small = false)
ReynoldsNumberRe_turbulentTurbulent flow if Re >= Re_turbulent (dummy if use_Re_turbulent = false)

Outputs

TypeNameDescription
PressuredpPressure loss (dp = port_a.p - port_b.p)

Function Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​Laminar.​pressureLoss_m_flow_staticHead
Return pressure loss dp as function of mass flow rate m_flow, i.e., dp = f(m_flow), due to wall friction and static head

Information

Extends from Modelica.​Fluid.​Pipes.​BaseClasses.​WallFriction.​PartialWallFriction.​pressureLoss_m_flow_staticHead (Return pressure loss dp as function of mass flow rate m_flow, i.e., dp = f(m_flow), due to wall friction and static head).

Inputs

TypeNameDescription
MassFlowRatem_flowMass flow rate from port_a to port_b
Densityrho_aDensity at port_a
Densityrho_bDensity at port_b
DynamicViscositymu_aDynamic viscosity at port_a (dummy if use_mu = false)
DynamicViscositymu_bDynamic viscosity at port_b (dummy if use_mu = false)
LengthlengthLength of pipe
DiameterdiameterInner (hydraulic) diameter of pipe
Realg_times_height_abGravity times (Height(port_b) - Height(port_a))
AreacrossAreaInner cross section area
LengthroughnessAbsolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false)
MassFlowRatem_flow_smallRegularization of zero flow if |m_flow| < m_flow_small (dummy if use_m_flow_small = false)
ReynoldsNumberRe_turbulentTurbulent flow if Re >= Re_turbulent (dummy if use_Re_turbulent = false)

Outputs

TypeNameDescription
PressuredpPressure loss (dp = port_a.p - port_b.p)

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