In the pharmaceutical and food industries, one major roadblock to operational efficiency has been the inability to understand the particulars of granular flow.

Recently, however, researchers at MIT have come up with a new theoretical model to account for these complicated flow issues that promises to help engineers design perfected systems for increased productivity.

This could mean some major savings to the industry, explained Ken Kamrin, assistant professor at MIT.

"It has been estimated that we waste about 40% of the capacity of most industrial plants due to inefficiencies in handling granular materials," he said.

In the pharmaceutical industry for instance, he said, workers "must deal with pills and powders on a daily basis. They lose millions of dollars on handling processes alone."

In the past, because of the knowledge gap, the rough pills, grains and powders of the industry were generally expected to flow through production like water, cutting smooth and predictable paths through their course of chutes and vats and silos.

The problem, of course, is that these materials are not water and stubbornly refuse to act like they are, leading to costly and often dangerous blockages, not to mention severely limited production efficiency.

Until MIT's breakthrough, though, scientists just didn't know any other way to think about grains.

"The basic equations governing water flow have been known for a century," Kamrin said. But "there hasn't been something similar for sand, where I can give you a cup full of sand and tell you which equations will be necessary to predict how it will squish around if I squeeze the cup."

This has been due to the complicated nature of grains in motion, which Kamrin noted exhibit characteristics of fluid, solid and gas at various stages. As a result, engineers have been unable to accurately predict the flow of such materials and have instead relied on "rule of thumb" approximations. This has prevented manufacturers from optimizing their production cycles.

The new research could change that.

By updating the basic equations for the water flow continuum to factor in the complications larger grain sizes add to flow, Kamrin explained, the computer-run models can now accurately predict flow paths of various grain types, which will help engineers better design chutes and troughs to prevent blockages.

With this new model, he said, "we hope that in understanding how grains flow, we can start to optimize these processes better."






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