1. Obravnavanje curka plinskega oljaMartin Volmajer, Breda Kegl, 2001, review article Abstract: V prispevku je obravnavan proces vbrizgavanja goriva in karakteristike curka dizelskega motorja z uporabo programa računske dinamike tekočin FIRE. Natančnost rezultatov, dobljenih s tem programom, je v veliki meri odvisna od pravilno postavljenih začetnih pogojev. Določevanje nekaterih pogojev je precej zahtevno, saj jih lahko določimo le na temelju izkušenj ali zahtevanih meritev v laboratoriju. V tem prispevku so na podlagi številnih zgledov in primerjav z rezultati, dobljenimi z znanimi empiričnimi izrazi za srednji Sauterjev premer kapljic, podane smernice za postavljanje začetnih pogojev.
Published in DKUM: 10.07.2015; Views: 1503; Downloads: 29
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2. Obravnavanje curka plinskega olja in nadomestnih gorivMartin Volmajer, Breda Kegl, 2004, other scientific articles Abstract: V prispevku je obravnavana numerična analiza curkov plinskega olja in nekaterih nadomestnih goriv. Z uporabo paketa računske dinamike tekočin FIRE so bile določene karakteristike curkov (velikost kapljic in domet) plinskega olja, biodizla in odpadnega rastlinskega olja. Nekatere vrednosti karakterističnih veličin curka so bile primerjane tudi z vrednostmi, izračunanimi z uporabo znanih empiričnih modelov za določitev karakteristik curka. Analize so bile izvedene za dva tipa vbrizgalnih šob oz. vbrizgalnih sistemov (neposredni in posredni). V primeru slednjega so rezultati numerične analize primerjani še s fotografijami curka.
Published in DKUM: 10.07.2015; Views: 905; Downloads: 53
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3. Coupled simulations of nozzle flow, primary fuel jet breakup, and spray formationEberhard von Berg, Wilfried Edelbauer, Aleš Alajbegović, Reinhard Tatschl, Martin Volmajer, Breda Kegl, Lionel C. Ganippa, 2005, original scientific article Abstract: Presented are two approaches for coupled simulations of the injector flow withspray formation. In the first approach the two-fluid model is used within the injector for the cavitating flow. A primary breakup model is then applied at the nozzle orifice where it is coupled with the standard discrete droplet model. In the second approach the Eulerian multi-fluid model is applied for both the nozzle and spray regions. The developed primary breakup model, used in both approaches, is based on locally resolved properties of the cavitating nozzle flow across the orifice cross section. The model provides the initial droplet size and velocity distribution for the droplet parcels released from the surface of a coherent liquid core. The major feature of the predictions obtained with the model is a remarkable asymmetry of the spray. This asymmetryis in agreement with the recent observations at Chalmers University where they performed experiments using a transparent model scaled-up injector.The described model has been implemented into AVL FIRE computational fluid dynamics code which was used to obtain all the presented results.
Keywords: internal combustion engines, fuel injection, simulations
Published in DKUM: 01.06.2012; Views: 1779; Downloads: 95
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