Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction

No pipe wall friction, no static head

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 PartialWallFriction (Partial wall friction characteristic (base package of all wall friction characteristics)).

Package Content

NameDescription
Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.massFlowRate_dp massFlowRate_dp Return mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction
Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.pressureLoss_m_flow 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
Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.massFlowRate_dp_staticHead 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
Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.pressureLoss_m_flow_staticHead 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 Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.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 (Return mass flow rate m_flow as function of pressure loss dp, i.e., m_flow = f(dp), due to wall friction).

Inputs

TypeNameDefaultDescription
Pressuredp Pressure loss (dp = port_a.p - port_b.p) [Pa]
Densityrho_a Density at port_a [kg/m3]
Densityrho_b Density at port_b [kg/m3]
DynamicViscositymu_a Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
DynamicViscositymu_b Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
Lengthlength Length of pipe [m]
Diameterdiameter Inner (hydraulic) diameter of pipe [m]
Lengthroughness2.5e-5Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
AbsolutePressuredp_small1Turbulent flow if |dp| >= dp_small (dummy if use_dp_small = false) [Pa]

Outputs

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

Inputs

TypeNameDefaultDescription
MassFlowRatem_flow Mass flow rate from port_a to port_b [kg/s]
Densityrho_a Density at port_a [kg/m3]
Densityrho_b Density at port_b [kg/m3]
DynamicViscositymu_a Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
DynamicViscositymu_b Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
Lengthlength Length of pipe [m]
Diameterdiameter Inner (hydraulic) diameter of pipe [m]
Lengthroughness2.5e-5Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
MassFlowRatem_flow_small0.01Turbulent flow if |m_flow| >= m_flow_small (dummy if use_m_flow_small = false) [kg/s]

Outputs

TypeNameDescription
PressuredpPressure 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 Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.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 (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

TypeNameDefaultDescription
Pressuredp Pressure loss (dp = port_a.p - port_b.p) [Pa]
Densityrho_a Density at port_a [kg/m3]
Densityrho_b Density at port_b [kg/m3]
DynamicViscositymu_a Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
DynamicViscositymu_b Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
Lengthlength Length of pipe [m]
Diameterdiameter Inner (hydraulic) diameter of pipe [m]
Realg_times_height_ab Gravity times (Height(port_b) - Height(port_a))
Lengthroughness2.5e-5Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
AbsolutePressuredp_small1Turbulent flow if |dp| >= dp_small (dummy if use_dp_small = false) [Pa]

Outputs

TypeNameDescription
MassFlowRatem_flowMass 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 Modelica.Fluid.Pipes.BaseClasses.WallFriction.NoFriction.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 (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

TypeNameDefaultDescription
MassFlowRatem_flow Mass flow rate from port_a to port_b [kg/s]
Densityrho_a Density at port_a [kg/m3]
Densityrho_b Density at port_b [kg/m3]
DynamicViscositymu_a Dynamic viscosity at port_a (dummy if use_mu = false) [Pa.s]
DynamicViscositymu_b Dynamic viscosity at port_b (dummy if use_mu = false) [Pa.s]
Lengthlength Length of pipe [m]
Diameterdiameter Inner (hydraulic) diameter of pipe [m]
Realg_times_height_ab Gravity times (Height(port_b) - Height(port_a))
Lengthroughness2.5e-5Absolute roughness of pipe, with a default for a smooth steel pipe (dummy if use_roughness = false) [m]
MassFlowRatem_flow_small0.01Turbulent flow if |m_flow| >= m_flow_small (dummy if use_m_flow_small = false) [kg/s]

Outputs

TypeNameDescription
PressuredpPressure 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;

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