Isolated Droplet Combustion Study of Malaysian Palm Biodiesel-Diesel Blends

Malaysian palm biodiesel is one of the attractive biofuels for petroleum diesel due to its zero-sulphur content (i.e., non-toxic), renewable capability, and similar physicochemical properties. Recent studies have reported significant improvement in the performance and emission characteristics of diesel engines by leveraging the blending composition between palm biodiesel and diesel. However, the fundamental aspects of combustion performance due to the blending effects of Malaysian palm biodiesel remain unexplored. This study aims to investigate the isolated droplet combustion behaviour of palm biodiesel-diesel blends at various blending compositions through a time-based image capturing method. Experimental results show that palm biodiesel-diesel blend with 60% palm biodiesel content (B60) and above produce a more prominent blue flame, which indicates cleaner and more complete combustion. The ignition delay (ID) increased when the palm biodiesel content is increased. Similarly, the burn rate constant for palm biodiesel-diesel blends increased with increasing palm biodiesel content. The combustion duration of palm biodiesel-diesel blends increased slightly when the palm biodiesel content is raised to 40% (B40) but decreased significantly when the palm biodiesel content is at 60% and above. Overall results suggest B60 is the optimum blend, which could potentially improve the performance and emissions of diesel-powered vehicles.