The Hilsch vortex tube was investigated at low operating pressures (gauge pressures less than one atmosphere). A mathematical analysis by Burkhardt was extended to include this pressure range. Except for differences in magnitude, the experimental results were essentially the same as those previously reported in the literature for high pressure tests. However, because of low flow rates, heat exchanges with the environment had a more pronounced effect. The dependence of Hilsch tube heating or cooling upon the specific heat ratio of the working gas was derived for low operating pressures. This result was experimentally verified for argon and air.
Proceedings of the Iowa Academy of Science
©1961 Iowa Academy of Science, Inc.
Lorenz, Philip J.; Ericson, Gerald D.; and Hayes, James D.
"The Hilsch Tube: Low-Pressure Effects,"
Proceedings of the Iowa Academy of Science, 68(1), 443-451.
Available at: https://scholarworks.uni.edu/pias/vol68/iss1/62