log(den) - 4ms.mpg

This simulation shows the the gas density: hot colours (red, yellow) indicating high density and cold colours (green, blue) indicating low density. The gas is injected through a nozzle at Mach 2 (twice the speed of sound) at left and a jet develops over the next 4 milliseconds as the gas propagates towards the object to be coated, shown in white, on the right. Above and below this object are the ports which lead to the vacuum pump.

A shock wave structure forms near the nozzle but the gas density is very uniform over the top surface of the object, which is the surface we want to coat. This simulation represents only the first 4 milliseconds, after which the injection is shut off and the jet dissipates, and the density becomes more uniform still.

The simulation is done by dividing the reactor into 300,000 cells and solving equations which describe the conservation of mass, momentum and energy, and the variation of pressure with temperature and density, in each cell. The same kind of simulation is used (by other groups) to simulate the flow in rocket propulsion systems and over the outside of spaceplanes, to determine their flight paths.
from http://www.radionz.co.nz/national/programmes/ourchangingworld
Thanks to Dr Mark Jeremy, Dr Hadley Cave and Mr Lim Chin Wai.

Category:

Science & Technology

Tags:

• logden
• 4ms