QuadraticTurbulent

Pressure loss components that are mainly defined by a quadratic turbulent regime with constant loss factor data

Package Contents

LossFactorData

Data structure defining constant loss factor data for dp = zeta*rho*v*|v|/2 and functions providing the data for some loss types

massFlowRate_dp

Return mass flow rate from constant loss factor data and pressure drop (m_flow = f(dp))

massFlowRate_dp_and_Re

Return mass flow rate from constant loss factor data, pressure drop and Re (m_flow = f(dp))

pressureLoss_m_flow

Return pressure drop from constant loss factor and mass flow rate (dp = f(m_flow))

pressureLoss_m_flow_and_Re

Return pressure drop from constant loss factor, mass flow rate and Re (dp = f(m_flow))

BaseModel

Generic pressure drop component with constant turbulent loss factor data and without an icon

BaseModelNonconstantCrossSectionArea

Generic pressure drop component with constant turbulent loss factor data and without an icon, for non-constant cross section area

pressureLoss_m_flow_totalPressure

Return pressure drop from constant loss factor and mass flow rate (dp = f(m_flow))

Information

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

This library provides pressure loss factors of a pipe segment (orifice, bending etc.) with a minimum amount of data. If available, data can be provided for both flow directions, i.e., flow from port_a to port_b and from port_b to port_a, as well as for the laminar and the turbulent region. It is also an option to provide the loss factor only for the turbulent region for a flow from port_a to port_b. Basically, the pressure drop is defined by the following equation:

Δp = 0.5*ζ*ρ*v*|v|
   = 0.5*ζ/A^2 * (1/ρ) * m_flow*|m_flow|
   = 8*ζ/(π^2*D^4*ρ) * m_flow*|m_flow|

where

  • Δp is the pressure drop: Δp = port_a.p - port_b.p
  • v is the mean velocity.
  • ρ is the density.
  • ζ is the loss factor that depends on the geometry of the pipe. In the turbulent flow regime, it is assumed that ζ is constant and is given by "zeta1" and "zeta2" depending on the flow direction.
  • D is the diameter of the pipe segment. If this is not a circular cross section, D = 4*A/P, where A is the cross section area and P is the wetted perimeter.