Design of Supersonic Nozzles for Ultra-Rapid Quenching of Metallic Vapours

CSIRO has been experimenting with supersonic flows as a method of
rapidly quenching metallic vapors. Cooling rates above one million degrees
per second have been achieved. The supersonic flow conditions are
achieved through adiabatic expansion of the gas through a Laval nozzle
into a vacuum chamber. This paper will describe the basic physics of the
process, outlining the CFD modeling of flow in the nozzle, the effects of
different flow conditions on the condensation process and discuss the practical
design issues associated with operating supersonic nozzles.