Experimental Investigation of Ranque–Hilsch Vortex Tube Performance Characteristics With High-Temperature Air

Abstract Ranque–Hilsch vortex tubes split an incoming fluid stream into two outgoing streams—one cooler and one warmer than the inlet stream, all without any supplied external power or moving parts. These impressive devices have been the subject of a great deal of research over the years, but little progress has been made in characterizing their behavior at elevated inlet temperatures. With promising potential as a thermal management device in high-temperature applications, characterization of vortex tube behavior at elevated temperatures is necessary. In the present work, a commercial Ranque–Hilsch vortex tube was modified, replacing a polymer vortex generator with a brass version to allow for higher temperature operation. Inlet total temperatures were varied between 350 K and 500 K, the highest applied to vortex tubes of which the authors are aware in the open literature, and the resulting temperature separation characteristics were examined. The high-temperature vortex tube experiments necessitated a wider range of higher Mach number inlet conditions than studied previously, and the results suggest a strong dependence of the temperature separation on the inlet Mach number. A dependence on the inlet Reynolds number was also observed, with greater sensitivity at lower Reynolds numbers.