The cryogenic dynamic process simulation consists in reproducing the evolution of temperatures, pressures and massflows in a cryogenic system over the time.
To perform this kind of simuation, the process is modelled using an object-oriented approach where each component is first modelled indivividually in a generic way.
Then, a set of components can be inter-connected between them to build a particualr cryogenic system.
Objectives of simulations
Dynamic simulation is a great tool to:
- Train operators: Safe training with no risk on the process, simulate failure scenarios (e.g turbine or compressor trips),
simulate occasional events (e.g. cooldown phases).
- Improve control strategies:No disturbance on the real process, fair comparison between strategies, time saving.
- Validate future cryogenic design during transients:Fast comparison between several designs, evaluate all process data during transients,
anticipate future required control strategies.
How do we simulate cryogenic processes at CERN ?
CERN is using a commercial modelling and simulation software called EcosimPro
Then, a commercial library dedicated to cryogenics called CRYOLIB
(originally developed during my phD at CERN) provides the basic cryogenic equipment models with the fluid properties. Note that this library can be then easily
modified and enlarged by users for specific models if needed.
The components of the CRYOLIB library in ecosimPro
To simulate the cryogenic system, actuators need to be manipulated by a equivalent control system. Two solutions can be used, depending on the simulation objectives:
(1) Stand alone simulation in EcosimPro with simplified control embedded inside the model.
(2) Couple the model to a copy of the real control system (PLC and supervision).
Examples of cryogenic process simulation performed at CERN:
- LHC Helium main refrigerators (18 kW @ 4.5 K )
- LHC 1.8 K refrigeration units (2.4 kW @ 1.8 K )
- LHC cryogenic distribution line
- LHC Beam Screens
- LHC Distribution Feed Boxes
- Future HL-LHC cryogenic distribution system
- Future String 3 cryogenic system after a quench
Contact : benjamin dot bradu at cern dot ch
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Last update: December 2021