Gas Pump

From SysCAD Documentation
Jump to: navigation, search

Navigation: Main Page -> Models -> Pressure Changing Models

General Description

The gas pump model will add pressure boost to the stream or operates at a specified pressure.



The diagram shows the default drawing of the Gas Pump, with the required connecting streams. The unit will not operate unless all of the above streams are connected.

The physical location of the connections is not important, the user may connect the streams to any position on the drawing.

Inputs and Outputs

Label Required
Number of Connections Description
Min Max.






Input stream to pump.






Output stream from pump.

Model Theory

From the first law of thermodynamics, the energy balance is:


From the second law of thermodynamics:

[math]\mathbf{\mathit{Entropy_{in} = Entropy_{out}}}[/math]

Calculating Work:

Step 1) Enthalpy and Entropy in is calculated from the inlet stream Temperature and Pressure.

Step 2) Outlet Temperature and Enthalpy is calculated based on the Entropy and outlet pressure.

Step 3) Work is calculated from the difference in enthalpy.


  1. The process is in steady state and steady flow.
  2. The process is adiabatic.
  3. The change in Potential and Kinetics energy is ignored.
  4. Process is reversible and adiabatic

Data Sections

Summary of Data Sections

  1. GasPump1 tab - Contains general information relating to the unit.
  2. VLE - Optional tab, only visible if the VLEquilibrium is enabled in the Evaluation Block.
  3. Info tab - Contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
  4. Links tab, contains a summary table for all the input and output streams.
  5. Audit tab - Contains summary information required for Mass and Energy balance. See Model Examples for enthalpy calculation Examples.

Gas Pump Page

Unit Type: GasPump1 - The first tab page in the access window will have this name.

Symbol / Tag
Input / Calc
Description/Calculated Variables

Common Data on First Tab Page


PressMethod None No pressure change
Boost The user specifies a pressure increase. Therefore, Pout = Pin + Pboost
Fixed The user specifies a fixed outlet pressure from the unit.
PressBoostReqd / PBoostReqd Input The required pressure increase. Visible if the Boost method is selected.
PressureReqd / P_Reqd Input The required outlet pressure. Visible if the Fixed method is selected.
VLEquilibrium Off Vapour Liquid Equilibrium is off.
On Vapour Liquid Equilibrium (VLE) is enabled. The associated section, VLE becomes visible and may be configured.
Note: This option may automatically adjust the species make-up in Qo.


Work Calc The work done.
MassFlow / Qm Calc The mass flow rate.
TemperatureIn / Ti Calc The inlet temperature.
TemperatureOut / To Calc The outlet temperature.
PressureIn / Pi Calc The inlet pressure.
PressChange / dP Calc The pressure change.
PressureOut / Po Calc The outlet pressure.
DensityIn / Rhoi Calc The inlet Density.
DensityOut / Rhoo Calc The outlet Density, after pressure change.
VapourFracIn / Vfi Calc The inlet vapour fraction.
VapourFracOut / Vfo Calc The outlet vapour fraction.

Adding this Model to a Project

Insert into Configuration file

Sort either by DLL or Group.





Piping: GasPump - General



Mass Transfer


Piping: GasPump - General

See Project Configuration for more information on adding models to the configuration file.

Insert into Project


Insert Unit


GasPump - General

See Insert Unit for general information on inserting units.