| | SLO | ENG | Cookies and privacy

Bigger font | Smaller font

Search the digital library catalog Help

Query: search in
search in
search in
search in
* old and bologna study programme

Options:
  Reset


1 - 3 / 3
First pagePrevious page1Next pageLast page
1.
Numerical modeling of two-phase flow inside a wet flue gas absorber sump
Nejc Vovk, Jure Ravnik, 2023, original scientific article

Abstract: A numerical model of a flue gas scrubber sump is developed with the aim of enabling optimization of the design of the sump in order to reduce energy consumption. In this model, the multiphase flow of the continuous phase, i.e., water, and the dispersed phase, i.e., air bubbles, is considered. The air that is blown in front of the agitators, as well as the influence of the flow field of the agitators on the distribution of the dispersed phase and the recirculation pumps as outlet, is modeled. The bubble Sauter mean diameter is modeled using the population balance model. The model is used to analyze operating parameters such as the bubble retention time, the average air volume fraction, bubble Sauter mean diameter, the local distribution of the bubble size and the amount of air escaping from the pump outlets at two operating points. The purpose of the model is to simulate the two-phase flow in the sump of the flue gas scrubber using air dispersion technology with a combination of spargers and agitators, which, when optimized, reduces energy consumption by 33%. The results show that the homogeneity of air is lower in the bottom part of the absorber sump and that the amount of air escaping through recirculation pipes equals 1.2% of the total air blown into the absorber sump. The escaping air consists mainly of bubbles smaller than 6 mm. Additional operating point results show that halving the magnitude of the linear momentum source lowers the air retention, as well as the average homogeneity of the dispersed air
Keywords: flue gas scrubbing, air dispersion, numerical model, OpenFoam
Published in DKUM: 19.12.2023; Views: 212; Downloads: 14
.pdf Full text (41,41 MB)
This document has many files! More...

2.
Numerično modeliranje dvofaznega toka v rezervoarju mokrega pralnika dimnih plinov : magistrsko delo
Nejc Vovk, 2023, master's thesis

Abstract: Za termoenergetske postroje so države postavile pravila, ki narekujejo omejitve emisij zdravju škodljivih plinov. Ta pravila so povzročila razvoj tehnologij čiščenja dimnih plinov, emitiranih iz termoenergetskih postrojev. Eden največjih onesnaževalcev je žveplov dioksid (SO2), ki nastaja pri zgorevanju premoga, onesnaženega z žveplom. V magistrskem delu obravnavamo mokri kalcitni postopek, ki zahteva izgradnjo pralnika dimnih plinov. V pralniku se žveplov dioksid absorbira v kapljice vode, v katerih je raztopljen apnenec. V reakciji ki poteče, nastane kalcijev sulfid (CaSO3), ki ob prenasičenju v vodi tvori kristale. Nastala suspenzija se zbira v spodnjem delu pralnika – rezervoarju, ki skrbi za tvorbo stabilnega produkta, kalcijevega sulfata (CaSO4). Slednje je izvedeno s prisilno oksidacijo, z uporabo kombinacije razpršilnih šob in mešal (agitatorjev), ki poskrbijo za čim daljši zadrževalni čas disperzne faze. Predstavljen je numerični model rezervoarja pralnika dimnih plinov, s katerim simuliramo večfazni tok v rezervoarju. V tem modelu obravnavamo tok zvezne faze (vode) in disperzne faze (mehurčkov zraka). Modelirano je vpihovanje zraka v področje pred agitatorji, vpliv tokovnega polja agitatorjev na distribucijo disperzne faze in obtočne črpalke, kot iztok tekočine iz rezervoarja. Razvoj Sauterjevega premera mehurčkov je modeliran po populacijskem modelu. Namen izdelave modela je bil analizirati vpliv obtočnih črpalk, ki domnevno motijo učinkovito disperzijo zraka. Rezultati kažejo, da izteka največ zraka skozi obtočno črpalko v skrajni legi, skupno pa skozi obtočne črpalke uhaja 1.2 % vpihanega zraka oz. 0.03 m3/s. Preračun je izveden v odprtokodnem programskem paketu OpenFoam v10, z uporabo superračunalniške infrastrukture v okviru projekta HPC RIVR.
Keywords: pranje dimnih plinov, disperzija zraka, numerični model, OpenFoam, superračunalnik
Published in DKUM: 23.08.2023; Views: 258; Downloads: 61
.pdf Full text (4,51 MB)

3.
Numerical simulation of force interactions between rigid bodies and fluid flow
Ožbej Verhnjak, 2017, master's thesis

Abstract: Particles immersed in a fluid have always been an important researching domain in process technologies, pharmacy and fluid mechanics. It is for its practical utility in industry that the two-phase flow is still being academically researched, but in present times with a slightly different, more complex approach. Formerly all the particles have been assumed to be spheres, what simplified the models of processes physical presentation. Nowadays, however, it is clear that such an assumption makes significant errors in some fields of applications. With that reason ellipsoids were presented instead of spheres. That step also transferred computation from analytical or partially analytical to wholey numerical. This work presents the results of numerical simulation of different ellipsoids and sphere. In addition a Saffmann effect on sphere is presented as a special phenomena in fluid mechanics.
Keywords: OpenFOAM, Saffman effect, drag coefficient, sphere drag, drag on ellipsoids, forces on immersed bodies
Published in DKUM: 17.07.2017; Views: 1221; Downloads: 165
.pdf Full text (2,30 MB)

Search done in 0.11 sec.
Back to top
Logos of partners University of Maribor University of Ljubljana University of Primorska University of Nova Gorica