Modelica.Fluid.Pipes.BaseClasses.WallFriction.Laminar

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.

Package Content

Name	Description
massFlowRate_dp	Return mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction
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
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
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
Inherited
use_mu=true	= true, if mu_a/mu_b are used in function, otherwise value is not used
use_roughness=true	= true, if roughness is used in function, otherwise value is not used
use_dp_small=true	= true, if dp_small is used in function, otherwise value is not used
use_m_flow_small=true	= true, if m_flow_small is used in function, otherwise value is not used
dp_is_zero=false	= true, if no wall friction is present, i.e., dp = 0 (function massFlowRate_dp() cannot be used)
use_Re_turbulent=true	= true, if Re_turbulent input is used in function, otherwise value is not used

Modelica.Fluid.Pipes.BaseClasses.WallFriction.Laminar.massFlowRate_dp

Information

Inputs

Name	Description
dp	Pressure loss (dp = port_a.p - port_b.p) [Pa]
rho_a	Density at port_a [kg/m3]
rho_b	Density at port_b [kg/m3]
mu_a	Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
mu_b	Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
length	Length of pipe [m]
diameter	Inner (hydraulic) diameter of pipe [m]
roughness	Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
dp_small	Regularization of zero flow if |dp| < dp_small (dummy if use_dp_small = false) [Pa]
Re_turbulent	Turbulent flow if Re >= Re_turbulent (dummy if use_Re_turbulent = false) [1]

Outputs

Name	Description
m_flow	Mass flow rate from port_a to port_b [kg/s]

Modelica.Fluid.Pipes.BaseClasses.WallFriction.Laminar.pressureLoss_m_flow

Information

Inputs

Name	Description
m_flow	Mass flow rate from port_a to port_b [kg/s]
rho_a	Density at port_a [kg/m3]
rho_b	Density at port_b [kg/m3]
mu_a	Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
mu_b	Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
length	Length of pipe [m]
diameter	Inner (hydraulic) diameter of pipe [m]
roughness	Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
m_flow_small	Regularization of zero flow if |m_flow| < m_flow_small (dummy if use_m_flow_small = false) [kg/s]
Re_turbulent	Turbulent flow if Re >= Re_turbulent (dummy if use_Re_turbulent = false) [1]

Outputs

Name	Description
dp	Pressure loss (dp = port_a.p - port_b.p) [Pa]

Modelica.Fluid.Pipes.BaseClasses.WallFriction.Laminar.massFlowRate_dp_staticHead

Information

Inputs

Name	Description
dp	Pressure loss (dp = port_a.p - port_b.p) [Pa]
rho_a	Density at port_a [kg/m3]
rho_b	Density at port_b [kg/m3]
mu_a	Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
mu_b	Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
length	Length of pipe [m]
diameter	Inner (hydraulic) diameter of pipe [m]
g_times_height_ab	Gravity times (Height(port_b) - Height(port_a))
roughness	Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
dp_small	Regularization of zero flow if |dp| < dp_small (dummy if use_dp_small = false) [Pa]
Re_turbulent	Turbulent flow if Re >= Re_turbulent (dummy if use_Re_turbulent = false) [1]

Outputs

Name	Description
m_flow	Mass flow rate from port_a to port_b [kg/s]

Modelica.Fluid.Pipes.BaseClasses.WallFriction.Laminar.pressureLoss_m_flow_staticHead

Information

Inputs

Name	Description
m_flow	Mass flow rate from port_a to port_b [kg/s]
rho_a	Density at port_a [kg/m3]
rho_b	Density at port_b [kg/m3]
mu_a	Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
mu_b	Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
length	Length of pipe [m]
diameter	Inner (hydraulic) diameter of pipe [m]
g_times_height_ab	Gravity times (Height(port_b) - Height(port_a))
roughness	Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
m_flow_small	Regularization of zero flow if |m_flow| < m_flow_small (dummy if use_m_flow_small = false) [kg/s]
Re_turbulent	Turbulent flow if Re >= Re_turbulent (dummy if use_Re_turbulent = false) [1]

Outputs

Name	Description
dp	Pressure loss (dp = port_a.p - port_b.p) [Pa]