Boiling water without bubbles
06 Oct 2012
Every cook knows that boiling water bubbles, right? New research from Northwestern University turns that notion on its head.
''We manipulated what has been known for a long, long time by using the right kind of texture and chemistry to prevent bubbling during boiling,'' said Neelesh A. Patankar, professor of mechanical engineering at Northwestern's McCormick School of Engineering and Applied Science and co-author of the study.
This discovery could help reduce damage to surfaces, prevent bubbling explosions and may someday be used to enhance heat transfer equipment, reduce drag on ships and lead to anti-frost technologies.
Published last month in the journal Nature, the research outlines how a specially engineered coated surface can create a stable vapour cushion between the surface and a hot liquid and eliminate the bubbles that are created during boiling.
This phenomenon is based on the Leidenfrost effect. In 1756 the German scientist Johann Leidenfrost observed that water drops skittered on a sufficiently hot skillet, bouncing across the surface of the skillet on a vapour cushion or film of steam. The vapour film collapses as the surface falls below the Leidenfrost temperature. When the water droplet hits the surface of the skillet, at 100 degrees Celsius, boiling temperature, it bubbles.
To stabilise a Leidenfrost vapour film and prevent bubbling during boiling, Patankar collaborated with Ivan U Vakarelski of King Abdullah University of Science and Technology, Saudi Arabia.
