20.500.12556/DKUM-42965 Obravnava zaprtega stanja igle med posameznimi vbrizgi v dizelskem injektorju Treatment of closed needle condition between injection events in a diesel injector Magistrska naloga obravnava numerično metodo, s katero je mogoče popisati tokovne razmere v sodobnem dizelskem injektorju tako v času posameznih vbrizgov kot tudi v času med njimi, kadar se smatra, da je tok tekočine popolnoma prekinjen. Metoda je namenjena natančni analizi tokovnih razmer v dizelskem injektorju, ki jih je eksperimentalno nemogoče obravnavati v takšnem obsegu, saj so dizelski injektorji, zlasti izstopna izvrtina na njih, ki je ključni del obravnave, dimenzijsko izredno majhni in skoraj nedostopni za merilno opremo. Vbrizg goriva je pri sodobnih motorjih razdeljen v več pod-vbrizgov. Lahko je sestavljen iz pred-vbrizga, glavnega vbrizga in po-vbrizga. Med posameznimi pod-vbrizgi je tok tekočine z injektorsko iglo večkrat ustavljen. Ravno ta prekinitev je bila v predhodnih simulacijah zanemarjena in vsako stopnjo vbrizga je bilo mogoče računati le ločeno kot posamezno simulacijo. Metoda, predstavljena v magistrski nalogi, omogoča preračun več pod-vbrizgov v eni sami simulaciji in pri tem ne zanemarja obdobja, ko je tok tekočine prekinjen. Metodologija je bila razvita v komercialnem CFD programu AVL FIRE. The Master’s Thesis deals with the numerical method which can describe flow field conditions of a modern diesel injector at the time of injection and also at the time in between injections when the flow is supposed to be fully blocked by a closed needle. The method is intended for detailed analysis of flow field conditions in a diesel injector, which is experimentally impossible to such extent. Diesel injector dimensions and particularly the spray hole, which is the key part of the nozzle, is dimensionally small and virtually inaccessible with measurement equipment. In modern engines fuel injection is split in sub-injection events. It may consist of pre-injection, main-injection and post-injection. During the entire duration of injection the flow is blocked several times by the needle. Sequence of several sub-injection events could not be treated in the past, as the closed needle position could not be handled. Closed needle period has been neglected in previous simulations and each part of injection has been calculated separately as a stand-alone simulation for open needle condition only. With the method presented here, it is possible to calculate several sub-injection events in one single simulation, also including the period between sub-injections when the fluid flow is blocked. The methodology has been developed using the commercial CFD program AVL FIRE. dizelski injektor vbrizg goriva pred-vbrizg po-vbrizg glavni vbrizg zaprto stanje igle pretok v šobi diesel injector fuel injection pre-injection main-injection post-injection closed needle injector flow true true false [J. Štrucl] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2013-11-07 20:57:22 2013-12-12 14:42:06 2022-05-08 03:07:09 2021-04-27 03:17:34 2013 0 Maribor 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 [519.6:532.5]621.43.038(043.2) 17627670 URN:SI:UM:DK:LZPFI5NF MAG_Strucl_Jure_2013.pdf MAG_Strucl_Jure_2013.pdf 1 8FB885E00CB344DFE0E9C2F810560D0A a42de0988eca2b6d33dfd894dc48c46732b37cc7c7601d7d9f74cae1c043c089 8761b1be-7c0a-11eb-bb7a-00155d0001ca https://dk.um.si/Dokument.php?lang=slv&id=60505 Fakulteta za strojništvo 0 0 0