Controlled Pressure Difference Source (TL)
Source of differential pressure.
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Description
The Pressure Difference Source (TL) unit is an ideal source of mechanical energy in a thermal liquid network. The source can maintain a constant or variable pressure differential across the ports regardless of the mass flow rate through it. There is no hydraulic resistance and no heat exchange with the environment.
Ports A and B correspond to the inlet and outlet of the source. If the Controlled source parameters are enabled, the differential pressure is controlled by the input signal at the P port. If Controlled source is off, the pressure drop is controlled by the Pressure differential parameters. If the differential is positive, the pressure at port B is greater than the pressure at port A.
The amount of energy in the source depends on the energy flow through ports A and B and the work done on the fluid. The equation describing the conservation of energy in the source:
,
where
-
- is the energy flow through port A;
-
- is the energy flux through port B;
-
- isoentropic work done on the liquid.
The isoentropic work done on a thermal liquid can be defined as
,
where
-
- is the mass flow rate of liquid from port A to port B;
-
- pressure at port A;
-
- pressure at port B;
-
- average density of liquid, determined by the formula:
.
Ports
Input
P - differential pressure setpoint signal, Pa
scalar
Input scalar signal setting the pressure drop of thermal liquid in the source.
Dependencies
Used when the Controlled source parameters are enabled.
Non-directional
A - source input
thermal liquid
The thermal liquid port, corresponds to the source inlet. Positive pressure drop causes the pressure at port B to be greater than the pressure at port A.
B is the source outlet
`thermal liquid'.
The thermal liquid port, corresponds to the source outlet. Positive pressure drop causes the pressure at port B to be greater than the pressure at port A.
Parameters
Controlled source - whether the differential pressure is set by the input signal
On (by default) | Off
Defines how the differential pressure will be set:
-
On- the differential pressure is set by the P input signal. -
Disabled - constant differential pressure is set by the Pressure differential parameters.
Pressure differential - constant pressure drop
0.0 (By default) | scalar
Constant pressure differential at the source ports.
Dependencies
Used when the Controlled source parameters are set to `Disabled'.
Isentropic power added - whether the source is performing isentropic work
On (By default) | Off
Sets whether the source does isentropic work with thermal liquid flow:
-
On- the source does isoentropic work with the thermal liquid flow to maintain the specified pressure drop. Use this parameter to represent an ideal pump or compressor and to properly account for energy input and output, especially in closed loop systems. -
Off- the source does not perform any work on the flow, either adding or removing power, regardless of the pressure drop generated by the source. Use this option to set the desired flow condition upstream of the system without affecting the flow temperature.
Cross-sectional area at ports A and B - cross-sectional area normal to the flow path at ports A and B
`0.01 m² (by default).
Cross-sectional area normal to the flow path at ports A and B.