'Shocking' discovery may improve diesel engines

Washington, March 13 (IANS) Scientists have found the interaction between shock waves created by high-pressure supersonic fuel jets. The discovery may lead to cleaner and more efficient internal combustion engines as well as advances in high-speed jet cleaning, machining and mining.

Shock waves have been studied in the past but high-pressure liquid jets created by micrometre sized nozzles can also reach supersonic speeds.

'Shock waves occur in nature and have been studied for many years, but it has been difficult to examine the internal structure of shock waves created by high-pressure fuel jets,' Argonne National Lab scientist Jin Wang said.

'High-intensity X-rays can penetrate the normally opaque jet stream allowing us to see the spray's internal structure and the gaseous environment around the jet, where the shock waves are generated.'

Due to the supersonic spray's opaque nature, scientists have been unable to examine the internal structure of these jets and that has limited the improvement of high-pressure and high-speed jets and spray technologies, which are essential for fuel combustions, paint sprays and industrial sprays.

Using high-intensity X-rays created by the Advanced Photon Source and High Energy Synchrotron Source at Cornell University, scientists were able to examine the interaction between the shock waves and liquid jets with a time resolution a millionth of a second, said a Cornell release.

The study was reported in Physical Review Letters.