Numerical simulation of fuel flow and cavitation phenomena due to the high pressure fuel injection

Tema ovog rada je usporedba rezultata numeričkih simulacija brizgaljke korištenjem k - ε i k - zeta - f modela turbulencije. Diskretizirana je 1/12 modela brizgaljke te se područje interesa odnosi na izlazni dio sapnice. Za numeričke simulacije korišten je programski paket FIRE® ustupljen od strane AVL-a. Kao rezultat rada prikazana je promjena određenih fizikalnih veličina (tlak, brzina, volumni udio faza, itd.) u ovisnosti o zakretu koljenastog vratila za oba modela turbulencije. Prikazani su maseni protoci na izlazu iz brizgaljke te se pokazalo da su odstupanja između simulacija relativno mala. Najveće razlike odnose se na maseni protok isparene faze za koju k - ε model turbulencije daje manje vrijednosti. Razlike ukupnog masenog protoka su neznatne, pošto je maseni protok isparene faze tri reda veličine manji od masenog protoka tekuće faze. Najbolje slaganje u rezultatima imamo kod prikaza polja apsolutne brzine, dok su najmanja slaganja uočena kod prikaza turbulentne kinetičke energije i energije disipacije.In this thesis the numerical simulations of in-nozzle multiphase flow was performed in CFD tool FIRE. The results were compared for two different turbulence models, k - ε and k - zeta - f turbulence model. Discretization was done on a 1/12 piece of a whole injector model. The discussion was focused on results in the nozzle outlet region. Changes of some physical quantities (pressure, velocity...) were presented and described in dependence of crankangle and mass flow across outlet selection was presented on diagram. A relatively small differences could be noticed between the two simulations. The biggest differences in vapour phase development were demonstrated in the conclusion part. The k - ε turbulence model results in lower values of vapour phase than the k - zeta - f model. The differences between the total mass flow are negligible because the values of vapour phase are three order of magnitude lower than values of the liquid phase. Similar results were obtained for velocity field whilst the big discrepancies were noticed for turbulence kinetic energy and dissipation rate