【摘要】 分别采用激光全息摄影技术和高速数字摄影技术观察了柴油、甲醇和水乳化液喷雾在高温高压(773 K,3.1 MPa)环境中发生微爆现象的瞬间和全过程,证实了微爆现象的存在.由于微爆机理的复杂性,尚难以用数学方法准确描述该过程.实验分析表明:若环境温度处于“最佳温度”范围内,乳化液滴表面首先形成“无水层”,液滴内部形成一个水滴的概率很小,可能形成几个相对较大的水滴,只要其中一个较大水滴的蒸汽压力大于液滴的表面张力和环境压力之和,液滴就有可能发生微爆,微爆不仅与液滴直径、组分的质量分数和组分间的沸点差等乳化液的本身特性有关,而且环境温度和压力的影响也不容忽视.该研究可以为乳化液喷雾微爆过程的数学模拟提供参考.更多还原

【Abstract】 Laser holographic photograph technique and high-speed digital camera were respectively used to observe the instant and entire process of micro-explosion phenomenon,which occurred in the diesel,methanol and water emulsion spray at high temperature and high pressure(3.1MPa,773 K).The observation confirms that the micro-explosion exists,but it is difficult to describe the process accurately with the mathematical methods due to the complexity of micro-explosion mechanism.Experimental results show that when the ambient temperature is within the range of "optimum temperature",the surface of emulsion droplet will form the "no water zone" at first.It might be difficult to form a small water droplet within the liquid droplets,but several relatively large droplets might be formed.If the vapor pressure of one of the large water droplets is greater than the sum of the droplet surface tension and the environment pressure,droplet micro-explosion would occur.This process was not only affected by the droplet diameter,the quality of components,the boiling point difference of components,and the characteristics of the emulsion,but the influence of environmental temperature and pressure should also be considered.更多还原