中文摘要：

采用高速可控闪光摄影技术搭建了喷油器喷孔内流动及近场喷雾可视化试验装置，针对柴油、汽油、乙醇柴油、生物柴油4种燃料，对实际尺寸的透明喷油器喷孔内的流动及近场喷雾进行了对比试验研究。试验研究结果表明：所有试验燃料喷孔内均呈现空穴流动，低运动粘度、高饱和蒸气压的燃料空穴生成时刻更早、空穴强度更强；喷孔空穴强度较大的燃料具有更大的近场喷雾锥角；喷射结束后喷孔内会产生气体倒流现象并形成初始气泡，初始气泡体积随燃料表面张力的减小而增大。同时发现，针阀运动会对压力室和喷孔内的流动产生极大的扰动并影响其流动形态。

英文摘要：

A visualization experimental apparatus with high speed controlled flash photography techniques was developed to investigate the flow in the hole of diesel injection nozzles and the spray construction near orifice. The experiments were performed with the transparent actual nozzles for diesel, gasoline, ethanol diesel fuel and biodiesel. The results indicate that the cavitation films could be observed in the hole for all fuels. The initial cavitation was appeared earlier and the cavitation intensity was stronger for the fuel which had lower viscosity and higher saturated vapor pressure. There was larger spray cone angle with stronger cavitation intensity. After the jet was finished, the gas backflow phenomenon could be observed in the hole and the initial bubble would be produced. And the initial bubble size could increase with the reduction of fuel surface tension. The flow status in the pressure chamber and hole was greatly affected by the movement of needle.