Controlled Mass Flow Rate Source (TL)
A source of mass or volumetric flow.
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Description
The Flow Rate Source (TL) unit is an ideal source of mechanical energy in a thermal liquid network. The source maintains a given mass or volume flow rate regardless of the pressure drop across 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 mass or volume flow rate is controlled by the input signal at ports M or V respectively. If Controlled source is off, the mass or volumetric flow rate is controlled by the Mass flow rate or Volumetric flow rate parameters, respectively. If the flow rate is positive, fluid flows from port A to port B.
The block icon changes depending on the values of the Controlled source and Flow type parameters.
Volume flow rate and mass flow rate are related by the expression:
,
where:
-
- is the mass flow rate of liquid from port A to port B,
-
and - values of liquid density at ports A and B respectively,
-
- volumetric flow rate.
Energy conservation in the source depends on the value of energy flow through ports A and B and on the work done on the fluid:
,
where
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- is the energy flow through port A,
-
- 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 pressure at port A,
-
- port pressure B,
-
- average density of the liquid, determined by the formula:
.
Ports
Inlet
M - mass flow control signal, kg/sec
scalar
The signal input port that determines the mass flow rate through the source.
Dependencies
Used when the Controlled source parameter is set to On and the Flow type parameter is set to `Mass'.
V - volumetric flow control signal, m³/c
scalar
Signal input port that determines the volumetric flow rate through the source.
Dependencies
Used when the Controlled source parameter is set to On and the Flow type parameter is set to `Volumetric'.
Non-directional
A - source input
thermal liquid
Thermal liquid port, corresponds to the source inlet. When the flow rate is positive, the fluid flows from port A to port B.
B is the source outlet
thermal liquid.
Thermal liquid port, corresponds to the source outlet. When the flow rate is positive, the fluid flows from port A to port B.
Parameters
Controlled source - possibility to change the flow rate during simulation
Off (by default) | On
Select whether the flow rate generated by the source can be changed during simulation:
-
Off- the flow rate generated by the source remains constant during the simulation. The M or V ports are hidden. Selecting this value enables the Mass or Volumetric parameters, depending on the value of the Flow type parameter. -
On- the flow rate is variable and is controlled by the input signal. Selecting this option allows access to the M or V input ports, depending on the value of the Flow type parameters.
Flow type - mass or volumetric flow rate is set
Mass (By default) | Volumetric.
Specifies which flow type is set:
-
Mass- mass flow rate is set. -
Volumetric' - sets the volumetric flow rate.
Mass flow rate - constant mass flow rate through the source
0.0 (By default).
Constant mass flow rate through the source.
Dependencies
Used when the Controlled source parameter is set to `Disabled' and the Flow type parameter is set to `Mass'.
Volumetric flow rate - constant volumetric flow rate through the source
0.0 (By default).
Constant volumetric flow rate through the source.
Dependencies
Used when Controlled source is set to `Disabled' and Flow type parameters are set to `Volumetric'.
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 performs isoentropic work on the thermal liquid flow to maintain the specified mass or volume flow rate. 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 mass or volumetric flow rate 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.