Engineering news
Researchers at the University of Waterloo in Canada developed the model, which could improve the safety of hydraulic systems used for pipelines, water turbines and other applications.
The team investigated a phenomenon known as cavitation, the formation and collapse of destructive gas-filled bubbles resulting from rapid pressure changes in liquids. When the bubbles implode, they temporarily create high temperatures, high-speed ‘micro-jets’ and shockwaves.
“The growth and collapse of cavitation bubbles are fascinating,” said mechanical engineer Zhao Pan, who led the research. “They are usually small and fast, but they can cause serious damage even on surfaces such as hard alloys and glass.”
The researchers developed a theoretical model to predict the formation and size of particularly damaging large bubbles, based on the acceleration and velocity of fluid flow. Experiments using high-speed photography validated the theory.
“Information provided by the model could help engineers design hydraulic systems and develop operation guidelines to minimise wear and tear, avoid major failures, and improve the reliability of the technology,” a research announcement said.
Cavitation is a common culprit in damaged water pipes and ship propellers, for example. In extreme cases, it has led to disastrous pipe failures in hydropower plants.
“On the other hand, the power of these bubbles can also be harnessed for good,” Pan said. “Cavitation can be used to break up kidney stones, kill bacteria without using chemicals, and even in the production of beer and chocolate.”
Pan previously worked with researchers in Japan and the United States on a new theory of small cavitation bubbles caused by the acceleration of liquids. The recent work extends those results to the prediction of large bubbles.
A paper on the research appears in Journal of Fluid Mechanics. Pan collaborated on the new study with researchers from Tsinghua University in China.
Want the best engineering stories delivered straight to your inbox? The Professional Engineering newsletter gives you vital updates on the most cutting-edge engineering and exciting new job opportunities. To sign up, click here.
Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.