Vortex tubes are commonly used as refrigeration devices. We show that the t
hermal and fluid dynamics of the vortex tube bear the signature of a classi
c cooling cycle, and quantify its performance as a thermodynamic machine. I
n the process, we develop simple analytic formulas for the temperature and
pressure profiles within the tube. The principal model predictions compare
favorably against experimental measurements. (C) 2000 American Institute of
Physics. [S0021-8979(00)05719-4].