Pressure Control
Physical Model
The pressure control component enforces a specific pressure at the controlled_junction
.
This is achieved by adding a required pressure lift or pressure drop between the
from_junction
and to_junction
, so that controlled_p_bar
will be reached
at the controlled junction. The controlled junction can be identical to
the to_junction
to control the pressure directly at the outlet.
Internally, the behaviour is achieved by fixing the pressure variable at
controlled_junction
in the system matrix and keeping the pressure drop of the
pressure control unit variable, so that is calculated during the Newton-Raphson-calculation.
Note
The temperature at the inlet and outlet junction will not be adapted by the pressure control unit. Therefore, these components usually operate isothermal (inlet temperature = outlet temperature). It is assumed that temperature changes due to compression or expansion (Joule-Thomson-effect) are balanced internally by adding or removing heat.
Warning
A sufficient hydraulic connection between from_junction
, to_junction
and
controlled_junction
is crucial for proper operation of this component.
Hydraulically impossible configurations (e.g., if the controlled junction is on a different
stub) or contradicting other pressure control units will lead to non-convergence of the pipeflow.
Create Function
For creating a single pressure control unit:
For creating multiple pressure control units at once:
Component Table Data
net.press_control
Parameter |
Datatype |
Value Range |
Explanation |
net |
pandapipesNet |
The pandapipes net object in whose |
|
from_junction |
integer |
\(>\) 0 |
Index of junction at which the pressure control unit starts |
to_junction |
integer |
\(>\) 0 |
Index of junction at which the pressure control unit ends |
controlled_junction |
integer |
> 0 |
ID of the junction at which the pressure is controlled |
controlled_p_bar |
float |
> 0 |
Pressure set point [barg] |
control_active |
boolean |
If false, the unit behaves like an open valve |
|
loss_coefficient |
float |
> ß |
Pressure loss coefficient (only effective if control is not active) |
name |
string |
Name of the pressure control unit |
|
index |
integer |
> 0 |
Force specific index the |
in_service |
boolean |
True / False |
If false, the unit behaves like a closed valve. |
type |
string |
Type variable to classify different kinds of pressure control units (not considered by pandapipes’ calculations) |
Result Table Data
net.res_press_control
Parameter |
Datatype |
Explanation |
p_from_bar |
float |
Pressure at “from”-junction [bar] |
p_to_bar |
float |
Pressure at “to”-junction [bar] |
t_from_k |
float |
Temperature at “from”-junction [K] |
t_to_k |
float |
Temperature at “to”-junction [K] |
mdot_to_kg_per_s |
float |
Mass flow out of pressure control unit [kg/s] |
mdot_from_kg_per_s |
float |
Mass flow into pressure control unit [kg/s] |
vdot_norm_m3_per_s |
float |
Norm volume flow [m^3/s] |
deltap_bar |
float |
Pressure difference between to- and from junction created by the pressure controller [bar] |