WOLFRAM SYSTEM MODELER
VolumeFlowRateFlow model for generic resistance parameterized with the volume flow rate |
 |
Wolfram Language
In[1]:=
SystemModel["Modelica.Fluid.Fittings.GenericResistances.VolumeFlowRate"]
Out[1]:=
Information
This information is part of the Modelica Standard Library maintained by the Modelica Association.
This component models a generic resistance parameterized with the volume flow rate:
dp = a*V_flow^2 + b*V_flow m_flow = rho*V_flow
with
| a | as quadratic coefficient [Pa*s^2/m^6], |
| b | as linear coefficient [Pa*s/m3], |
| dp | as pressure loss [Pa], |
| m_flow | as mass flow rate [kg/s], |
| rho | as density of fluid [kg/m3], |
| V_flow | as volume flow rate [m3/s]. |
The geometry parameters of energy devices necessary for the pressure loss calculations are often not exactly known. Therefore the modelling of the detailed pressure loss calculation has to be simplified. This components use a linear and a quadratic dependence of the pressure loss on the volume flow rate. It is assumed that neither mass nor energy is stored in this component. In the model basically a function is called to compute the mass flow rate as a function of pressure loss. Also the inverse of this function is defined, and a tool might use this inverse function instead, in order to avoid the solution of a nonlinear equation.
The details of the model are described in the documentation of the underlying function.
Parameters (8)
| allowFlowReversal |
Value: system.allowFlowReversal Type: Boolean Description: = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
|---|---|
| dp_start |
Value: 0.01 * system.p_start Type: AbsolutePressure (Pa) Description: Guess value of dp = port_a.p - port_b.p |
| m_flow_start |
Value: system.m_flow_start Type: MassFlowRate (kg/s) Description: Guess value of m_flow = port_a.m_flow |
| m_flow_small |
Value: if system.use_eps_Re then system.eps_m_flow * system.m_flow_nominal else system.m_flow_small Type: MassFlowRate (kg/s) Description: Small mass flow rate for regularization of zero flow |
| show_T |
Value: true Type: Boolean Description: = true, if temperatures at port_a and port_b are computed |
| show_V_flow |
Value: true Type: Boolean Description: = true, if volume flow rate at inflowing port is computed |
| a |
Value: Type: Real ((Pa⋅s²)/m⁶) Description: Coefficient for quadratic term |
| b |
Value: Type: Real ((Pa⋅s)/m³) Description: Coefficient for linear term |
Connectors (2)
 |
port_a |
Type: FluidPort_a Description: Fluid connector a (positive design flow direction is from port_a to port_b) |
|---|---|---|
 |
port_b |
Type: FluidPort_b Description: Fluid connector b (positive design flow direction is from port_a to port_b) |
Components (4)
 |
system |
Type: System Description: System wide properties |
|---|---|---|
 |
state_a |
Type: ThermodynamicState Description: State for medium inflowing through port_a |
|
state_b |
Type: ThermodynamicState Description: State for medium inflowing through port_b |
|
state_dp_small |
Type: ThermodynamicState Description: Medium state to compute dp_small |