Extending mechanistic thermal-hydraulic modelling and dynamic simulation for new industrial applications

Jari T.J. Lappalainen

    Research output: ThesisDissertationCollection of Articles


    The process and energy industries have a remarkable position in developing sustainable future. They play an important role in mitigating climate change. Whilst aiming at energy efficient, material recycling, and emission-free processes, the industrial systems are becoming more complex. Process automation is fundamental in confirming that also complex systems can be managed and operated in an easy and safe way. Dynamic system-wide process simulation is practically the only way to verify the interoperability of the process and control solutions before building up the system. For the systems in operation, it enables virtual realistic studies without disturbances or risks for the actual process or people. The qualitative research approach in this work is case study. The modelling and dynamic simulation software Apros is used in five distinct cases, which extend the modelling from traditional nuclear and conventional power plant applications to a board machine, a carbon dioxide capturing power plant, ship energy systems, a seawater desalination plant, and a molten salt based energy storage system. The methodology relies on mechanistic thermal-hydraulic modelling and dynamic simulation. Method development was performed to model and simulate the application specific unit operations and working fluids. The functionality of the basic methodology and the extensions are demonstrated in the cases. The results of the work can be used in research and commercial simulation projects. New unit operation models and improvements for the fluid property calculation provide a variety of new potential applications. The model validation results help to estimate prediction capability in similar applications. The simulation applications guide modellers to use the methodology in both the presented and new areas. Regarding the case-specific results, the board machine simulator helped to understand complex interactions related to grade changes, to tune the related automation, and thus to shorten the grade change times. The simulation of the ship energy systems revealed design deficiencies and assisted in troubleshooting related problems during the commissioning. The study on the thermal energy storage facility uncovered systematic anomalous behaviour in the molten salt flow path. Based on the cross-case analysis, it can be stated that the methodology can be successfully applied beyond its traditional application domain and that it provides meaningful and valuable benefits. Furthermore, the methodology supports versatile use of the simulation model during the life cycle of an industrial plant: in R&D, design, testing, operator training and further development of the operating plant. The challenges that the process and energy industries meet today, require consideration of the interactions and dynamics of the process and automation systems together. The methodology used and further extended provides a valuable tool for tackling these challenges.
    Original languageEnglish
    QualificationDoctor Degree
    Awarding Institution
    • Aalto University
    • Alopaeus, Ville, Supervisor, External person
    • Alopaeus, Ville, Advisor, External person
    • Korvola, Timo, Advisor
    • Karhela, Tommi, Advisor, External person
    Award date8 Nov 2019
    Place of PublicationHelsinki
    Print ISBNs978-952-60-8758-0
    Electronic ISBNs978-952-60-8759-7
    Publication statusPublished - 8 Nov 2019
    MoE publication typeG5 Doctoral dissertation (article)


    • Industrial process
    • computational modelling
    • process modelling
    • mechanistic model
    • thermal-hydraulic
    • dynamic simulation
    • process control
    • simulation-aided engineering


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