Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction

Information

This component sets the pressure loss due to wall friction to zero, i.e., it allows to switch off pipe wall friction.

Extends from Modelica.Icons.Package (Icon for standard packages), PartialWallFriction (Partial wall friction characteristic (base package of all wall friction characteristics)).

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)

Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.massFlowRate_dp

Information

Extends from (Return mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction).

Inputs

Type	Name	Default	Description
Pressure	dp		Pressure loss (dp = port_a.p - port_b.p) [Pa]
Density	rho_a		Density at port_a [kg/m3]
Density	rho_b		Density at port_b [kg/m3]
DynamicViscosity	mu_a		Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
DynamicViscosity	mu_b		Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
Length	length		Length of pipe [m]
Diameter	diameter		Inner (hydraulic) diameter of pipe [m]
Length	roughness	2.5e-5	Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
AbsolutePressure	dp_small	1	Turbulent flow if |dp| >= dp_small (dummy if use_dp_small = false) [Pa]

Outputs

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

Modelica definition

redeclare function extends massFlowRate_dp 
  "Return mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction"

algorithm 
  assert(false, "function massFlowRate_dp (option: from_dp=true)
cannot be used for WallFriction.NoFriction. Use instead
function pressureLoss_m_flow (option: from_dp=false)");
end massFlowRate_dp;

Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.pressureLoss_m_flow

Information

Extends from (Return pressure loss dp as function of mass flow rate m_flow, i.e., dp = f(m_flow), due to wall friction).

Inputs

Type	Name	Default	Description
MassFlowRate	m_flow		Mass flow rate from port_a to port_b [kg/s]
Density	rho_a		Density at port_a [kg/m3]
Density	rho_b		Density at port_b [kg/m3]
DynamicViscosity	mu_a		Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
DynamicViscosity	mu_b		Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
Length	length		Length of pipe [m]
Diameter	diameter		Inner (hydraulic) diameter of pipe [m]
Length	roughness	2.5e-5	Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
MassFlowRate	m_flow_small	0.01	Turbulent flow if |m_flow| >= m_flow_small (dummy if use_m_flow_small = false) [kg/s]

Outputs

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

Modelica definition

redeclare function extends 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"

algorithm 
  dp := 0;
end pressureLoss_m_flow;

Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.massFlowRate_dp_staticHead

Information

Extends from (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

Type	Name	Default	Description
Pressure	dp		Pressure loss (dp = port_a.p - port_b.p) [Pa]
Density	rho_a		Density at port_a [kg/m3]
Density	rho_b		Density at port_b [kg/m3]
DynamicViscosity	mu_a		Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
DynamicViscosity	mu_b		Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
Length	length		Length of pipe [m]
Diameter	diameter		Inner (hydraulic) diameter of pipe [m]
Real	g_times_height_ab		Gravity times (Height(port_b) - Height(port_a))
Length	roughness	2.5e-5	Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
AbsolutePressure	dp_small	1	Turbulent flow if |dp| >= dp_small (dummy if use_dp_small = false) [Pa]

Outputs

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

Modelica definition

redeclare function extends 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"

algorithm 
  assert(false, "function massFlowRate_dp (option: from_dp=true)
cannot be used for WallFriction.NoFriction. Use instead
function pressureLoss_m_flow (option: from_dp=false)");
end massFlowRate_dp_staticHead;

Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.pressureLoss_m_flow_staticHead

Information

Extends from (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

Type	Name	Default	Description
MassFlowRate	m_flow		Mass flow rate from port_a to port_b [kg/s]
Density	rho_a		Density at port_a [kg/m3]
Density	rho_b		Density at port_b [kg/m3]
DynamicViscosity	mu_a		Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
DynamicViscosity	mu_b		Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
Length	length		Length of pipe [m]
Diameter	diameter		Inner (hydraulic) diameter of pipe [m]
Real	g_times_height_ab		Gravity times (Height(port_b) - Height(port_a))
Length	roughness	2.5e-5	Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
MassFlowRate	m_flow_small	0.01	Turbulent flow if |m_flow| >= m_flow_small (dummy if use_m_flow_small = false) [kg/s]

Outputs

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

Modelica definition

redeclare function extends 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"

/* To include only static head:
protected
  Real dp_grav_a = g_times_height_ab*rho_a
    "Static head if mass flows in design direction (a to b)";
  Real dp_grav_b = g_times_height_ab*rho_b
    "Static head if mass flows against design direction (b to a)";
*/
algorithm 
//  dp := Utilities.regStep(m_flow, dp_grav_a, dp_grav_a, m_flow_small);
  dp := 0;
  assert(abs(g_times_height_ab) < Modelica.Constants.small,
   "WallFriction.NoFriction does not consider static head and cannot be used with height_ab<>0!");
end pressureLoss_m_flow_staticHead;