Effects of Ambient Pressure in a Constant Volume Spray Chamber on the Characteristics of Biodiesel-Mixed Sprays

Abstract

The output of diesel engine combustion is strongly influenced by the characteristics of the fuel spray. An important role in the process of forming a mixture of fuel and air is to develop the characteristics of fuel spray, which will directly affect the combustion and emissions process. The characteristics of fuel spray depend on fuel injection pressure, fuel viscosity, fuel density, ambient pressure, and temperature. Among the parameters that are very important and directly affect the shape of the spray is ambient pressure. With injection pressure set at 200 Bar and all experiments with spray pressure chamber 1 Bar, 4 Bar, 7 Bar and 9 Bar. This study investigated the effect of ambient pressure on spray characteristics such as spray tip penetration, cone angle, spray time and spray area in constant volume spray chamber by using spray visualization. Biodiesel from nyamplung oil was varied in this study BD 20 (20% nyamplung oil, 80% diesel oil), BD 40 (40% nyamplung oil, 60% diesel oil), BD 60 (60% nyamplung oil, 40% diesel oil) and pure diesel D 0. The record of fuel mixture was immortalized using a high-speed camera, iso speed 800, exposure time 1/125 sec. The results fo the macro-analysis showed that with increasing spray pressure level will cause spray tip penetration decreases but cone angle and spray area will increase. BD 60 gives penetration of the longest spray tip, cone angle and spray area widest while BD 20 and D 0 diesel have similar sprayed characteristics.