Experimental study of the flow structure in a vortex tube

Abstract

With the single injection, a vortex tube generates cold and hot stream from two exits respectively, which was first found and investigated by Ranque. Different explanations for the temperature separation in a vortex tube have been proposed since the invention of the device. However, due to the difference and conflicts among those explanations, a clarification of the thermal separation is still required. Understanding of the flow behaviour inside a vortex tube is an essential requirement in exploring the thermal separation. This paper reports on an experimental study in progress exploring the flow structure in a vortex tube. Flow properties in a vortex tube are measured and used to clarify the flow structure inside the tube. The velocity distributions along the tube are presented, which are different from previous studies. The transition from a forced vortex at the cold end to a free vortex near the hot end was first observed, which agrees with the author's previous study. The flow structures found in this research show positive supports for the proposed hypothesis of the temperature separation in the vortex tube.