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

This function returns the pressure loss dp as function of mass flow rate m_flow for a thick edged orifice. The details of the function are described here.

The orifice characteristic is valid for constant density and constant dynamic viscosity. It can be approximately also used for compressible media. This is performed by providing the upstream density and upstream dynamic viscosity. In order to be able to regularize density and dynamic viscosity around zero mass flow rate, the two quantities have to be given if fluid flows from port_a to port_b (d_a, eta_a) and if fluid flows from port_b to port_a (d_b, eta_b).

dp = pressureLoss(m_flow, geometry, d_a, d_b, eta_a, eta_b, dp_small, m_flow_small)

m_flow	Type: MassFlowRate (kg/s) Description: Mass flow rate (= port_a.m_flow)
geometry	Type: Geometry Description: Geometry of bend
d_a	Type: Density (kg/m³) Description: Density at port_a when fluid is flowing from port_a to port_b
d_b	Type: Density (kg/m³) Description: Density at port_b when fluid is flowing from port_b to port_a
eta_a	Type: DynamicViscosity (Pa⋅s) Description: Dynamic viscosity at port_a when fluid is flowing from port_a to port_b
eta_b	Type: DynamicViscosity (Pa⋅s) Description: Dynamic viscosity at port_b when fluid is flowing from port_b to port_a
dp_small	Type: AbsolutePressure (Pa) Description: Small pressure drop used for regularization if m_flow=f(...,dp_small,..,dp)
m_flow_small	Type: MassFlowRate (kg/s) Description: Small mass flow rate used for regularization if dp=f_inv(...,m_flow_small,m_flow)

dp	Type: Pressure (Pa) Description: Pressure loss