Detailed

Pipe wall friction for laminar and turbulent flow (detailed characteristic)

Package Contents

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

Internal

Functions to calculate mass flow rate from friction pressure drop and vice versa

Package Constants (6)

use_mu

Value: true

Type: Boolean

Description: = true, if mu_a/mu_b are used in function, otherwise value is not used

use_roughness

Value: true

Type: Boolean

Description: = true, if roughness is used in function, otherwise value is not used

use_dp_small

Value: true

Type: Boolean

Description: = true, if dp_small is used in function, otherwise value is not used

use_m_flow_small

Value: true

Type: Boolean

Description: = true, if m_flow_small is used in function, otherwise value is not used

dp_is_zero

Value: false

Type: Boolean

Description: = true, if no wall friction is present, i.e., dp = 0 (function massFlowRate_dp() cannot be used)

use_Re_turbulent

Value: true

Type: Boolean

Description: = true, if Re_turbulent input is used in function, otherwise value is not used

Information

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

This component defines the complete regime of wall friction. The details are described in the UsersGuide. The functional relationship of the friction loss factor λ is displayed in the next figure. Function massFlowRate_dp() defines the "red curve" ("Swamee and Jain"), where as function pressureLoss_m_flow() defines the "blue curve" ("Colebrook-White"). The two functions are inverses from each other and give slightly different results in the transition region between Re = 1500 .. 4000, in order to get explicit equations without solving a non-linear equation.

PipeFriction1.png

Additionally to wall friction, this component properly implements static head. With respect to the latter, two cases can be distinguished. In the case shown next, the change of elevation with the path from a to b has the opposite sign of the change of density.

PipeFrictionStaticHead_case-a.png

In the case illustrated second, the change of elevation with the path from a to b has the same sign of the change of density.

PipeFrictionStaticHead_case-b.png

Extended by (1)

WallFriction

Modelica.Fluid.Pipes.BaseClasses.FlowModels.PartialGenericPipeFlow

Wall friction model