IMPACT OF PHYSICAL PROPERTIES OF DIESEL AND BIODIESEL MIXTURE ON CHARACTERISTICS OF FUEL SPRAYING

Uporaba alternativnih goriva u motorima s unutarnjim izgaranjem postaje sve atraktivnija, sa stajališta štednje energije, smanjenja emisije reguliranih zagađivača u ispušnim plinovima te smanjenja emisije CO2 u okoliš. Kod dizelovih motora, od alternativnih goriva, najviše se radi na uporabi biodizelskog goriva i njegovih mješavina s dizelskim gorivom. Također, nije zanemariva ni uporaba mješavina tekućih i plinovitih goriva (D2 i CNG). Uporaba biodizelskog goriva i njegovih mješavina s dizelskim gorivom u motorima, zbog različitih fizikalnih i kemijskih osobina, ima značajan utjecaj na procese u motoru, od pripreme smjese zrak-gorivo do procesa izgaranja (različito vrijeme pritajenog izgaranja, različita brzina oslobađanja topline, itd.). Za optimalan rad motora, u prvom redu procesa izgaranja, potrebno je poznavati sve utjecajne parametre, koji su posljedica uporabe novog goriva. U ovom radu je napravljena detaljna analiza utjecaja fizikalnih osobina biodizela i njegovih mješavina s dizelskim gorivom, na karakteristike mlaza raspršenog goriva koji ima dominantan utjecaj na proces miješanja goriva i zraka. Rezutati prikazani u ovom radu su kombinacija eksperimentalnih i računskih rezultata, dobivenih pomoću vlastito razvijenog računarskog programa.The use of alternative fuels in internal combustion engines is becoming increasingly attractive, both from the standpoint of energy saving as well as the reduction of emissions of regulated pollutants in the exhaust gases and the reduction of CO2 emissions into the environment. Regarding alternative fuels in diesel engines, most of the work is based on the use of biodiesel and their blends with diesel fuel. Also, the use of a mixture of liquid and gaseous fuels (D2 and CNG) is not negligible. The use of biodiesel and their blends with diesel fuel in the engines, due to variety of physical and chemical properties, has a significant influence on the processes in the engine, from the preparation of the air-fuel mixture to the combustion process (different combustion time, different heat release rate, etc.). For optimum engine performance, but primarily the combustion process, it is necessary to know all influential parameters, which are the result of the use of the new fuel. This paper presents a detailed analysis of the impact of physical properties of biodiesel and their blends with diesel fuel, on the characteristics of the atomized fuel spray which has a dominant influence on the mixing of fuel and air. The results presented in this paper are combination of experimental and computational results, obtained using a self developed computer program