functionbasicFlowFunction_dp_der

1st derivative of function that computes mass flow rate for given pressure drop

Extends from Modelica.Icons.Function (Icon for functions).

Information

Function that implements the first order derivative of Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp, assuming a constant flow coefficient.

When called with dp_der=der(dp), this function returns the time derivative of m_flow. When called with dp_der=1, this function returns the derivative of m_flow with respect to dp.

Inputs

TypeNameDefaultDescription
Modelica.Units.SI.PressureDifferencedpPressure difference between port_a and port_b (= port_a.p - port_b.p)
RealkFlow coefficient, k=m_flow/sqrt(dp), with unit=(kg.m)^(1/2)
Modelica.Units.SI.MassFlowRatem_flow_turbulentMass flow rate where transition to turbulent flow occurs
Realdp_derDerivative of pressure difference between port_a and port_b (= port_a.p - port_b.p)

Outputs

TypeNameDefaultDescription
Realm_flow_derDerivative of mass flow rate in design flow direction

Revisions

  • January 4, 2019, by Michael Wetter:
    Set `Inline=false`.
    See #1070.
  • May 1, 2017, by Filip Jorissen:
    Revised implementation such that Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp is C2 continuous. See #725.
  • April 14, 2017, by Filip Jorissen:
    Changed implementation such that it cannot lead to square roots of negative numbers and reduced the number of required operations. This is for #723.
  • January 22, 2016, by Michael Wetter:
    Corrected type declaration of pressure difference. This is for #404.
  • July 29, 2015, by Michael Wetter:
    First implementation to avoid in Dymola 2016 the warning "Differentiating ... under the assumption that it is continuous at switching".