Effect of using borax decahydrate as nanoparticles additive in blends of spirulina biodiesel/diesel on combustion characteristics and knock intensity

Abstract

Abstract In this extensive investigation, the impact of borax decahydrate as a fuel additive in a diesel single-cylinder engine was rigorously examined. Borax decahydrate was introduced at concentrations of 5, 15, 25 and 35 g in 500 ml of biodiesel, forming five unique fuel mixtures with conventional diesel: 90% diesel + 10% spirulina biodiesel (SB10), SB10 + 1 g borax decahydrate (SB10B1), SB10 + 3 g borax decahydrate (SB10B3), SB10 + 5 g borax decahydrate (SB10B5) and SB10 + 7 g borax decahydrate (SB10B7). The investigation encompassed four diverse loading conditions and yielded insightful findings. Notably, at full load, SB10B3 exhibited a higher cylinder peak pressure than diesel, reaching 69.25 bar. Heat release rate profiles demonstrated superior efficiency for SB10 at 50% load, with a cumulative heat release rate of 950 J/°CA, which is lower than the 1050 J/°CA of diesel. Knock intensity (KI) evaluations revealed that, although SB10 and SB10B1 exhibited higher KI than diesel at full load due to elevated peak pressure, SB10B7 showed no knocking across all loads, indicative of reduced in-cylinder combustion. This meticulous numerical analysis emphasizes the potential of borax decahydrate as a catalyst and enhancer, providing valuable insights into the combustion dynamics of these alternative fuel blends and their viability for sustainable and efficient engine performance. In summary, out of all the blends, SB10B3 could be a potential diesel fuel replacement fuel for compression-ignition engines.