modelBaseValve
Extends from OpenHPL.Interfaces.TwoContacts (Model of two connectors).
Information
This is a partial, simple model of hydraulic valve.
This model is based on the energy balance of a valve.
- Mass flow is equal at inflow and outflow
- The head loss and pressure difference is proportional to square of velocity
Specifically:
$$ \Delta p \cdot f(\mathrm{opening}) = \nu \cdot | \nu | $$
The function f(opening) is expressed as:
$$ f(\mathrm{opening}) = \left( C_\mathrm{v} \cdot \mathrm{max}(\epsilon, u^\alpha)\right)^2 $$
When \(\alpha\) is 1, this implies a linear relation between closing and head loss.
The valve capacity can either be specified
directly by the user by specifying C_v or it will be calculated from
the nominal head H_n and nominal flow rate Vdot_n.
The valve efficiency is in per-unit values from 0 to 1, where 1 means that there are no losses in the valve. The valve power is defined as the product of the valve power and valve efficiency.
Besides hydraulic input and output,
there is an input u for controlling the valve opening.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Nominal values | |||
| Boolean | ValveCapacity | 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 | 1 | Valve capacity |
| SI.Height | H_n | 100 | Nominal net head |
| SI.VolumeFlowRate | Vdot_n | 3 | Nominal volume flow rate |
| SI.PerUnit | u_n | 1 | Nominal opening |
| Advanced › Closing law | |||
| Real | alpha | 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) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Data | data (from TwoContacts) | ||
| SI.Pressure | dp | Pressure drop | |
| SI.MassFlowRate | mdot | Mass flow rate | |
| SI.VolumeFlowRate | Vdot | Volume flow rate |