Particles take rough with the smooth when moving in liquid suspensions

The findings from North Carolina State University, MIT and the University of Michigan are said to represent a fundamental advance in the understanding of suspensions in flow.

“We heard about problems companies were having with pumping suspensions and became curious about what was causing these problems,” said Lilian Hsiao, an assistant professor of chemical and biomolecular engineering at NC State and lead author of a paper on the work. “Given the ubiquity of these types of fluids in the industry, we were surprised that no one had systematically looked at the role of surface roughness before. That turns out to be a really important factor in how these particle-laden fluids flow.”

Using a combination of simulations and laboratory experiments, the researchers found that friction was slowing down the suspensions. According to NC State, the friction becomes significant when enough particles suspended in the liquid collide with each other; the rougher the surface of the particles, the more friction they generate when they come into contact.