Chemical Engineering

2 open-access papers in Chemical Engineering, free to watch.

5:30

Self-limiting turbulent drag reduction via a viscoelastic lubricating layer

Emanuele Milocco, Alessio Roccon, Alfredo Soldati

A thin slippery layer can make turbulent flow move more easily, but making that layer more elastic eventually makes almost no further difference. The surprising reason is that the layer starts suppressing the motion it needs to work. What if making a lubricating polymer layer more elastic eventually makes it less useful? This study finds that drag reduction rises toward roughly twenty-four percent, then largely stalls because the polymers suppress the turbulence that stretches them.

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3:06

Significant heat-transfer enhancement via polymer additives in two-dimensional sheared convection

Guanhan Li, Lu Zhu, Rich. R. Kerswell

Cooling powerful electronics is becoming harder, and air alone may not be enough. This study finds that adding polymers to flowing liquid can, under the right conditions, make heat move dramatically faster. What if adding a tiny amount of polymer could turn an ordinary channel flow into a heat-transfer machine? This study finds that the answer depends on whether the polymer stress forms the right kind of hook.

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