Defence in Mechanical Engineering M.Sc. (Tech) Alpo Laitinen
Title of thesis "Computational fluid dynamics simulations of thermal flows in various applications"
This thesis belongs to the field of computational physics using high performance computing Computational Fluid Dynamics (CFD) methods, with emphasis on Large-Eddy Simulation (LES). Fluid dynamical phenomena are essential in most applications related to energy technology. Understanding such physics is crucial in terms of the processes and improving efficiency. In this thesis, three societally relevant applications are numerically studied with relevance to fluid dynamics and heat transfer. The applications are a liquid cooling heat exchanger, kraft recovery boiler, and ventilation in a relatively large room with airborne pathogen transmission. The benefit of using high accuracy simulations is to be able to study the multiscale transport and mixing phenomena that would be difficult to study experimentally. Based on the results of the thesis, accurate modeling of turbulence is one of the most essential tasks in order to achieve realistic simulation results. In heat exchanger context, resolving the transitional flow features affected the local hot-spot temperatures significantly. In recovery boiler context, the usage of LES was shown to be particularly beneficial to capture the turbulent mixing and dispersion of droplets. In indoor air context, the pathogen transmission was observed to be highly affected by the transitional and buoyant flow features, modeling of which requires the use of high accuracy, scale-resolving simulation techniques, such as LES. Such simulations could be used as a part of the design process for various applications.
This thesis belongs to the field of computational physics using high performance computing Computational Fluid Dynamics (CFD) methods, with emphasis on Large-Eddy Simulation (LES). Fluid dynamical phenomena are essential in most applications related to energy technology. Understanding such physics is crucial in terms of the processes and improving efficiency. In this thesis, three societally relevant applications are numerically studied with relevance to fluid dynamics and heat transfer. The applications are a liquid cooling heat exchanger, kraft recovery boiler, and ventilation in a relatively large room with airborne pathogen transmission. The benefit of using high accuracy simulations is to be able to study the multiscale transport and mixing phenomena that would be difficult to study experimentally. Based on the results of the thesis, accurate modeling of turbulence is one of the most essential tasks in order to achieve realistic simulation results. In heat exchanger context, resolving the transitional flow features affected the local hot-spot temperatures significantly. In recovery boiler context, the usage of LES was shown to be particularly beneficial to capture the turbulent mixing and dispersion of droplets. In indoor air context, the pathogen transmission was observed to be highly affected by the transitional and buoyant flow features, modeling of which requires the use of high accuracy, scale-resolving simulation techniques, such as LES. Such simulations could be used as a part of the design process for various applications.
When
–
Where
K1, Lecture hall 216
PL 14100 Otakaari 4
floor 2. hall 216
Event language(s)
english
Opponent Professor Harvey Thompson, University of Leeds, UK
Custos Professor Ville Vuorinen, Aalto University, School of Engineering, Department of Mechanical Engineering
Contact information alpo.laitinen@aalto.fi tel +358 50 353 7789
Electronic dissertation link https://aaltodoc.aalto.fi/handle/123456789/49
The dissertation is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University; https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/