TJ348 : An Experimental Investigation on Non-Newtonia Drop Impact onto Solid Surfaces
Thesis > Central Library of Shahrood University > Mechanical Engineering > MSc > 2015
Authors:
Abstarct: Drop impact onto solid surfaces is among on the complicate and yet interesting issues in fluid dynamic science that is a key element of a wide variety of phenomena encountered in technical applications, such as ink-jet printing, spray coating, soil erosion, spray cooling and crop spraying. In the present work, the impact dynamics of Boger drops on dry solid surfaces is investigated and compared with that of Newtonian drops. The effects of liquid viscosity, surface wettability and impact velocity on the spreading and receding behavior of the drops were investigated experimentally. Water, glycerin drops (Newtonian liquids), and polyacrylamide drops (Non-Newtonian liquids) were impinged upon plaxiglas and glass substrate, which have hydrophilic properties, at the impact velocities 4.03 and 4.22 m/s. The polyacrylamide drops spread out more widely and receded more rapidly than the glycerin drops. The impact velocity and the liquid viscosity had a dominant effect on the spreading phase. In contrast, the surface wettability had only a minor effect on the spreading phase but a very significant effect on the receding phase. The effect of the impact velocity on the receding phase was limited to the low-viscosity drops. That is, when the low-viscosity drops impacted on a hydrophilic substrate, the receding velocity increased greatly with higher impact velocity. On the other hand, drop receding was significantly suppressed on the glass and plaxiglas substrates. Suppression of drop receding was more prominent with the liquid having a lower viscisity.
Keywords:
#Drop impact #Solid surface #Boger fluid #Viscosity #Wettability #Impact velocity
Keeping place: Central Library of Shahrood University
Visitor:
Keeping place: Central Library of Shahrood University
Visitor: