Spray characteristics of biodiesel/blends in a high pressure constant volume spray chamber

The spray characteristics of the fuel greatly influence emissions from diesel engines. Spray development plays an important role in improving the combustion and emission characteristics of a fuel because it directly affects the air–fuel mixture formation. Spray characteristics of the fuel mainly depend on fuel injection pressure, fuel density, fuel viscosity, ambient pressure and temperature. Among these, the effect of ambient pressure is very important parameter directly affecting spray pattern. This study investigates the effect of ambient pressure on spray characteristics such as spray tip penetration, cone angle and spray area in a constant volume spray chamber by employing spray visualization and image processing techniques. The fuels used for the investigation are Karanja biodiesel (KB100), diesel (KB0) and blends (KB5 and KB20). The results of macro-analysis show that with increasing ambient pressure, spray tip penetration decreases, and cone angle and spray area increase. Comparing Karanja biodiesel and blends with diesel, B100 gives highest spray tip penetration, cone angle and spray area followed by KB20, KB5 and diesel respectively because of fuel density differences.