modelValveLinear
Valve for water/steam flows with linear pressure drop
Extends from TRANSFORM.Fluid.Valves.BaseClasses.PartialTwoPortTransport (Partial element transporting fluid between two ports without storage of mass or energy).
Information
This very simple model provides a pressure drop which is proportional to the flowrate and to the opening input, without computing any fluid property. It can be used for testing purposes, when
a simple model of a variable pressure loss is needed.
A medium model must be nevertheless be specified, so that the fluid ports can be connected to other components using the same medium model.
The model is adiabatic (no heat losses to the ambient) and neglects changes in kinetic energy from the inlet to the outlet.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.MassFlowRate | m_flow_nominal | Nominal mass flowrate at full opening | |
| Modelica.Fluid.Types.HydraulicConductance | k | m_flow_nominal/dp_nominal | Hydraulic conductance at full opening |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialTwoPort) | true | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Visualization | |||
| Boolean | showDesignFlowDirection (from PartialTwoPort) | true | = false to hide the flow direction arrow |
| Boolean | showName (from PartialTwoPort) | true | = false to hide component name |
| Advanced | |||
| Medium.AbsolutePressure | dp_start (from PartialTwoPortTransport) | 1e-5 | Guess value of dp = port_a.p - port_b.p |
| Medium.MassFlowRate | m_flow_start (from PartialTwoPortTransport) | 0 | Guess value of m_flow = port_a.m_flow |
| Medium.MassFlowRate | m_flow_small (from PartialTwoPortTransport) | 1e-2 | Small mass flow rate for regularization of zero flow |
| Advanced › Diagnostics | |||
| Boolean | show_T (from PartialTwoPortTransport) | true | = true, if temperatures at port_a and port_b are computed |
| Boolean | show_V_flow (from PartialTwoPortTransport) | true | = true, if volume flow rate at inflowing port is computed |
| Nominal operating point | |||
| SI.AbsolutePressure | dp_nominal | Nominal pressure drop at full opening | |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| TRANSFORM.Fluid.Interfaces.FluidPort_Flow | port_a (from PartialTwoPort) | Fluid connector a (positive design flow direction is from port_a to port_b) | |
| TRANSFORM.Fluid.Interfaces.FluidPort_Flow | port_b (from PartialTwoPort) | Fluid connector b (positive design flow direction is from port_a to port_b) | |
| Modelica.Blocks.Interfaces.RealInput | opening | =1: completely open, =0: completely closed |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.MassFlowRate | m_flow (from PartialTwoPortTransport) | Mass flow rate in design flow direction | |
| Modelica.SIunits.Pressure | dp (from PartialTwoPortTransport) | Pressure difference between port_a and port_b (= port_a.p - port_b.p) | |
| Modelica.SIunits.VolumeFlowRate | V_flow (from PartialTwoPortTransport) | m_flow/Modelica.Fluid.Utilities.regStep(m_flow, Medium.density(state_a), Medium.density(state_b), m_flow_small) | Volume flow rate at inflowing port (positive when flow from port_a to port_b) |
| Medium.Temperature | port_a_T (from PartialTwoPortTransport) | Modelica.Fluid.Utilities.regStep(port_a.m_flow, Medium.temperature(state_a), Medium.temperature(Medium.setState_phX(port_a.p, port_a.h_outflow, port_a.Xi_outflow)), m_flow_small) | Temperature close to port_a, if show_T = true |
| Medium.Temperature | port_b_T (from PartialTwoPortTransport) | Modelica.Fluid.Utilities.regStep(port_b.m_flow, Medium.temperature(state_b), Medium.temperature(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow)), m_flow_small) | Temperature close to port_b, if show_T = true |
Revisions
- 2 Nov 2005
by Francesco Casella:
Adapted from the ThermoPower library.