Večnivojsko modeliranje kemijskih in biokemijskih procesov v mikrofluidnih napravah

doktorska disertacija

Filip Strniša (Author), Igor Plazl (Mentor), Andrej Pohar (Thesis defence commission member), Jurij Reščič (Thesis defence commission member), Bruno Zelić (Thesis defence commission member), Tomaž Urbič (Co-mentor)

Abstract

Za mikrofluidne naprave štejemo tiste pretočne naprave, ki se uporabljajo v kemiji oziroma kemijski proizvodnji, katerih vsaj ena dimenzija je manjša od enega milimetra. Zaradi te lastnosti je za njih značilno visoko razmerje med površino in volumnom, katerega posledica so boljša energijska učinkovitost, izboljšan nadzor procesa, izboljšan prenos toplote in snovi, ter zaradi njihovega majhnega volumna, manjša poraba topil. Modeliranje služi v kemijskem inženirstvu kot orodje za boljše razumevanje procesov, pomoč pri dimenzioniranju naprav in optimizaciji procesov ter kot pomoč pri vodenju procesov. Tradicionalni postopki modeliranja se v naši panogi praviloma poslužujejo makroskopskih metod, ki slonijo na predpostavki kontinuuma, torej zanemarjajo delčno sestavo snovi. Majhne karakteristične dimenzije mikrofluidnih naprav postavljajo upravičenost uporabe makroskopskih modelov pod vprašaj. Mezoskopska mrežna Boltzmannova metoda ima potencial za modeliranje mikrofluidnih naprav, saj z njenim statistično-mehanskim izvorom ne zanemarja delčne sestave snovi, hkrati pa je primerna za opis mehanike fluidov in transportnih pojavov tudi v kompleksnih geometrijah. Mrežno Boltzmannovo metodo je smiselno razširiti v večnivojski model, da na ta način omilimo porabo računalniške moči — tako uporabimo mrežno Boltzmannovo metodo za opis procesov v kompleksnih geometrijah, preprostejša področja mikrofluidne naprave pa opišemo z makroskopskim modelom. V tej nalogi predstavljamo naše delo z mrežno Boltzmannovo metodo. Najprej jo uporabimo za opis prenosa snovi v mikrobioreaktorju s strnjenim slojem sferičnih delcev. Nadaljujemo s primerjavo različnih modelov trka mrežne Boltzmannove metode in z uporabo mrežne Boltzmannove metode za modeliranje toka binarne mešanice med seboj netopnih fluidov, s pomočjo katerega teoretično načrtujemo brezmembranski mikroločevalnik. Na koncu mrežno Boltzmannovo metodo razširimo še v večnivojski model za opis reaktivne mešanice plinov v katalizirani reakciji suhega reforminga metana.

Keywords

mikroreaktorji;fluidi;večnivojsko modeliranje;mrežna Boltzmannova metoda;numerični eksperimenti;doktorske disertacije;

Data

Language:	Slovenian
Year of publishing:	2022
Typology:	2.08 - Doctoral Dissertation
Organization:	UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher:	[F. Strniša]
UDC:	66.02(043.3)
COBISS:	108519683
Views:	152
Downloads:	33
Average score:	0 (0 votes)
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Other data

Secondary language:	English
Secondary title:	Multiscale modelling of chemical and biochemical processes in microfluidic devices
Secondary abstract:	Flow devices used in chemistry and chemical manufacturing, that have at least one dimension smaller than a millimeter, may be characterized as microfluidic devices. Among characteristics that arise from this property are: high area-to-volume ratio, better efficiency, improved process control, improved heat and mass transport, and due to their small volume, reduced solvent use. Chemical engineers use modelling to gain better understanding of a process, as a tool in process scaling and optimization, and even for process control. In our field we traditionally use continuum-based models to describe processes. These models inherently neglect the particle composition of matter. It is due to microfluidic devices’ small characteristic size that the continuum assumption may not be valid when modelling them. The lattice Boltzmann method has a lot of potential for modelling of microfluidic devices as with its statistical-mechanics background it does not fully neglect the particle composition of matter, and it may be used to model fluid mechanics, and transport phenomena even in complex geometries. Due to it not being computationally very cheap it is desired to use the lattice Boltzmann method in a multiscale model setup, where it serves to solve transport phenomena in complex geometries, and the rest of the microfluidic device is modelled with a simpler macroscopic method. In this dissertation we present our work with the lattice Boltzmann method. First we use it to model mass transport in a packed-bed microbioreactor with randomly packed spherical particles. This is followed up by a study in which we compare different lattice Boltzmann collision models, and a study where we theoretically design a membrane-free microseparator by simulating the flow of a binary mixture of immiscible fluids. Finally, we expand the lattice Boltzmann method to a multiscale model of dry-reforming of methane in a catalytic reactor.
Secondary keywords:	multiscale modelling;lattice Boltzmann method;microfluidic devices;microreactors;Mikrofluidne naprave;Univerzitetna in visokošolska dela;
Type (COBISS):	Doctoral dissertation
Study programme:	1000381
Thesis comment:	Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo
Pages:	XVI, 126 str.
ID:	15357987