modelValve
Extends from ElectroMech.BaseClasses.BaseValve (Simple hydraulic valve (base class)), Icons.Valve (Valve icon).
Information
Hydraulic Valve Model
Simple model of a hydraulic valve for controlling water flow in hydropower systems. Represents various control valve types (butterfly, spherical, needle valves) based on energy balance principles.
Flow Equation
The valve uses a valve-like flow expression relating flow rate to pressure drop:
$$ \dot{V} = C_v \cdot u \cdot \sqrt{\frac{2\Delta p}{\rho}} $$
where Cv is the valve capacity coefficient [m²], u is valve opening (0=closed, 1=fully open), Δp is pressure drop [Pa], and ρ is water density [kg/m³].
Valve Capacity
The valve capacity can be specified in two ways:
- Direct specification: User provides Cv from manufacturer data (set
ValveCapacity=true) - From nominal conditions: Cv computed from nominal head Hn and flow rate V̇n (set
ValveCapacity=false)
Efficiency Modeling
Energy losses can be modeled through efficiency parameter η (0 to 1):
- Constant efficiency: Single value
- Variable efficiency: Lookup table based on valve opening
Valve power loss: $$ \dot{W}_\mathrm{loss} = \dot{V} \cdot \Delta p \cdot (1 - \eta) $$
Control Interface
The opening input accepts control signals (0 = completely closed, 1 = fully open).
Applications
Useful for emergency shutdown scenarios, flow regulation, load rejection analysis, water hammer mitigation studies, and bypass systems.
More Information
This model extends BaseValve which contains the core valve equations.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Nominal values | |||
| Boolean | ValveCapacity (from BaseValve) | true | If checked, the valve capacity C_v should be specified, otherwise specify the nominal values (net head and flow rate at nominal opening) |
| Real | C_v (from BaseValve) | 1 | Valve capacity |
| SI.Height | H_n (from BaseValve) | 100 | Nominal net head |
| SI.VolumeFlowRate | Vdot_n (from BaseValve) | 3 | Nominal volume flow rate |
| SI.PerUnit | u_n (from BaseValve) | 1 | Nominal opening |
| Advanced › Closing law | |||
| Real | alpha (from BaseValve) | 1 | Exponent of closing curve (if different from 1, the closing law will be non-linear) |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Contact_i | i (from TwoContacts) | Inlet contact (positive design flow direction is from i to o) | |
| Contact_o | o (from TwoContacts) | Outlet contact (positive design flow direction is from i to o) | |
| Modelica.Blocks.Interfaces.RealInput | opening | =1: completely open, =0: completely closed |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Data | data (from TwoContacts) | ||
| SI.Pressure | dp (from BaseValve) | Pressure drop | |
| SI.MassFlowRate | mdot (from BaseValve) | Mass flow rate | |
| SI.VolumeFlowRate | Vdot (from BaseValve) | Volume flow rate |