Optical investigation on spray and combustion by using biodiesel-diesel-butanol blend fuel

An optical constant volume chamber simulated HTHP ambient condition was employed by using biodiesel-diesel-butanol blends.With high-speed camera and synchronized copper vapor laser,recorded fuel spray and combustion process,measured liquid jet penetration length and heat release rate under variable ambient temperature and fuel composition conditions.Results shown that micro-explosion existed during B10S80N10 fuel spray process at 800 K and 900 K ambient temperature.It resulted in tip of the spray jet erupted into a plume and made jet penetration length sudden drop.With ambient temperature increasing,burn process converted from premixed combustion to diffusion combustion,and the micro-explosion became weak and disappeared.