醇类-生物柴油混合燃料喷雾特性的试验

Experiment on Spray Characteristics of Alcohol and Biodiesel Blends

利用高速摄影和粒子图像分析技术(PDIA)研究了生物柴油、B 20(80%,生物柴油和20%,正丁醇)、P 20(80%,生物柴油和20%,正丙醇)和E 20(80%,生物柴油和20%,乙醇)的喷雾宏观和微观特性,主要对喷雾贯穿距离、喷雾锥角、索特平均直径(SMD)和液滴尺寸分布等喷雾特性参数进行了分析.结果表明:生物柴油、B 20、P 20和E 20的喷雾贯穿距离依次减小,平均锥角依次增大.随喷射压力和环境压力的增加,燃料的影响逐渐削弱,喷雾贯穿距离和锥角主要受喷射压力和环境压力的影响.喷射压力的升高使生物柴油和醇类-生物柴油混合燃料的SMD减小,小粒径液滴所占的比例有所上升.喷射压力为80,MPa、环境压力为1,MPa时,轴向距离为50,mm处,醇类-生物柴油混合燃料相对生物柴油SMD平均减小1.6,μm(5.7%,),不同醇类-生物柴油混合燃料间SMD也依次减小,但幅度略小.醇类与生物柴油掺混可以提高喷雾质量.

Macroscopic and microscopic spray characteristics of biodiesel,B 20(80%, biodiesel-20%, n-butanol),P 20(80%, biodiesel-20%, n-propanol),E 20(80%, biodiesel-20%, ethanol),including the spray tip penetration,spray cone angle,Sauter mean diameter(SMD)and droplets size distribution,were experimentally investigated with high speed photography and particle/droplet image analysis(PDIA)methods.Experimental results show that spray tip penetration are in the order biodiesel>B 20>P 20>E 20,the spray cone angle are in the order biodiesel<B 20<P 20<E 20 under similar conditions.The influence of fuel becomes less significant under higher injection pressure and ambient pressure conditions.Increasing injection pressure leads to smaller SMD and larger fraction of droplets with small diameter.The SMD of alcohol-biodiesel blends is 1.6,μm(5.7%,)smaller than that of biodiesel.SMDs of three alcoholbiodiesel blends decrease but their differences are small at axial distance of 50,mm,injection pressure of 80,MPa,ambient pressure of 1,MPa.The results shows that biodiesel blended with alcohols can promote the spray atomization.