Degree of Master of Science
Binary Collision of a Burning and Non-Burning Droplet of Xylene
by Rahul Gandhi
Thesis Director: Prof. Stephen Tse
Monday, October 2, 2017, 11:30 am
Engineering Building B-223
The collision behavior of a burning droplet of xylene with a non-burning droplet of xylene is studied. Two piezoelectric droplet generators were used to generate streams of isolated mono-dispersed droplets. These droplet generators were placed vertically opposite to each-other and the droplets were generated at a frequency of 6 Hz. Droplet diameters ranged from 80 microns to 95 microns and droplet velocities varied from 0.7m/s -1.5m/s for the lower droplet and from 1.5m/s - 2.5m/s for the upper droplet. The droplet streams occurred within a cuvette. The collision occurs at atmospheric pressure and a constant supply of O2 was maintained in the cuvette to facilitate the burning of the droplet. A CCD strobe was used to detect the two droplets and make them collide. The lower droplet was ignited with a spark. The collision process was recorded using a high-speed camera. The relative velocity and impact parameter of the collisions were varied by changing the supply current to the piezoelectric droplet generators and by moving the lower droplet respectively. The recorded videos of the collision process were analyzed using a MATLAB script to track the droplets and calculate their velocities and the impact parameter in each case. The collision outcomes were studied under a range of Weber numbers and for varying Impact Parameter. The post-collision behavior of the xylene flame suggests that the gas between the colliding droplets is rapidly ejected and flow pattern greatly affects the progression of the flame. Existing theoretical models fail to accurately predict the onset of the various regimes of collision.