RANQUE-HILSCH VORTEX TUBE AS AN EDUCATIONAL TOOL FOR CLASSICAL THERMODYNAMICS TEACHING

Abstract

A vortex or Ranque-Hilsch tube is a moving parts-free device that splits a compressed air stream into a cold and a hot stream at its two extremities. Although there exist some theoretical approaches based on internal shock and expansion waves as well as Maxwell velocity distribution, a final word on the phenomenon to explain the thermal energy splitting has not been reached yet. Nevertheless, from the classical Thermodynamics point-of-view, the conservation laws of mass and energy along with the Second Law validation applied to a control volume enveloping the vortex must be fulfilled. Consequently, such a simple device may be an outstanding tool for hands-on laboratory teaching of engineering Thermodynamics. In accordance with that, an educational laboratory test rig was conceived to carry out experiments to demonstrate the fundamental laws: mass and energy conservations, and the Second Law constraint. As a secondary goal, students can be acquainted with flow, pressure, and temperature measuring techniques, along with obtaining thermodynamic properties, computing, and data-reducing procedure as part of the testing as well. In addition, the coefficient of performance in refrigeration and heat pump operation modes can be obtained and a proper discussion of the vortex tube working principle can be fostered.