A Review on the Numerical Analysis of Spray Combustion Characteristics of Surrogate Biodiesel

The present study conducts numerical simulation to explore the combustion characteristics and emissions of biodiesel surrogates on Palmitate Methyl Ester (PME, C17H34O2), Oleate Methyl Ester (OME, C19H36O2), and a 50:50 PME-OME mixture as representative for palm biodiesel fuel. Numerical simulations were carried out in a constant-volume chamber to evaluate spray characteristics, fuel-air mixing, and emission profiles. The results show that the surrogates performed differently: OME had the highest spray penetration, which improved atomization and combustion efficiency; PME had better fuel-air mixing, which promoted uniform combustion; and the PME-OME blend had a good balance of dispersion and penetration. Emission analysis revealed that OME produced the lowest emissions, with 25% lower CO and CO₂, 30% lower NOx, and the lowest heat release rate, 20% lower than PME, indicating controlled combustion. The 50:50 PME-OME mixture offered a balance, achieving moderate emissions (10–15% lower than PME) and the highest heat release rate (10% higher than PME), combining efficiency with reduced environmental impact. These findings show OME’s potential as a sustainable biodiesel component with a lower environmental impact and better combustion characteristics. The study also emphasizes understanding biodiesel spray combustion, which provides valuable insights for optimizing fuel formulations and engine designs to reduce emissions and improve sustainability.