Professor Jun Zhang: Invention of a New Ratchet Pump

On February 3, 2015, NYU Shanghai professor of physics and mathematics Jun Zhang and Benjamin Thiria, researcher at ESPCI ParisTech, were published in research journal Applied Physics Letters.

Zhang and Thiria's article, “Ratcheting Fluid with Geometric Anisotropy,” details the surprising results of their experimental findings.

Inspired by the flight of a bird, the researchers examined the natural mastery of fluid dynamics to create a ratchet pumping mechanism. When a bird flaps its wings, air is pushed in one direction while the bird itself travels in the other, essentially causing air to be pumped backward. The newly invented ratchet pump moves fluid using vibration or shaking rather than a rotor, which has been a crucial piece in the pumps we use today.

"When a fluid is squeezed and expanded repeatedly between two sawtoothed plates, the asymmetric boundary forces the fluid to move in one direction," said Zhang. The result is an unidirectional transportation of fluid that provides an alternative means to mobilize fluids.

The reported study demonstrates the physical principles of fluid pumping without any rotational element in a system. Practical application of the ratchet pump will find their ways in industrial settings, where excessive vibrations of heavy machinery are unwanted and wasted. The pump can harvest such vibrational energy—and thus the loud noise—and convert it to useful work while improving the longevity of machines, leading to a more productive and safer working environment.

Since its publication, this work has been covered by popular media such as the magazine New Scientist, the American Institute of Physics (AIP) website, and French newspaper Le Monde.