Experimental Study On The Combustion Characteristics Of Benzyl Azides-diesel Blend Droplet

To further increase the power density of diesel engine, high efficiency and rapid combustion of fuel have become the key factor and meanwhile one of the technological bottlenecks. From the perspective of fuel design method, the liquid phase reaction of benzyl azides offers an effitive way for improving the fuel atomization and burning rate. Therefore, this study blend benzyl azides with diesel, and investigated the burning characteristics through the single droplet burning experiment of the blend fuel. The comprehensive burning characteristics of benzyl azides-diesel blend has been gained.For the experimental study, this paper established a complete method of droplet free falling burning technique including equipment design and selection of each system, test procedure development, data acquisition and post-processing method and stability and error analysis, which provided an accurate approach with varied conditions for experimental investigation.Based on the experimental method establishment, the burning characteristics of benzyl azides-diesel blend and the effect of benzyl azides fraction, initial droplet diameter and ambient oxygen concentration to the burning characteristics have been investigated. The main conclusions are as following: 1. the flame of benzyl azides-diesel blend exhibited yellow luminous, which indicate strong sooting peopensity during burning. With the burning continuing, the occurance of liquid phase reaction increased the droplet burning rate and caused the micro-explosion in the tail region of flame, and thus shorten the burning duration. 2. When the initial droplet diameter increased, the increase of droplet temperature slowed down and didn’t reach the luquid phase reaction temperature, which decreased the burning rate and prolonged the ignition delay time. Therefore, there is no micro-explosion during the whole burning process for bigger droplet. 3. When the ambient oxygen concentration increased, the micro-explosion strength of smaller droplet increased, flame lay nearer to the droplet and with a shorter length vertically and horizontally. When the ambient oxygen concentration and the initial droplet diameter changed at the same time, the burning characteristics of benzyl azides-diesel blend are subject to liquid phase reaction and ambient condition respectively, depending on whether the droplet temperature reached the liquid phase reaction temperature or not. 4. When the benzyl azides fraction increased, the burning rate of bigger droplet slight increased, which caused the shorter ignition delay time.