Energy separation for Ranque-Hilsch vortex tube: A short review

In this article, the development of the energy separation for the vortex tube has been briefly reviewed. This review mainly focuses on three aspects, they are the energy separation principle, the design criteria of vortex tubes, and practical application. First, the research progress on the energy separation principle of the vortex tube from several aspects has been introduced, such as friction, pressure gradient, acoustic streaming, secondary circulation and multi-circulation theory. In addition, the control factors that affecting the performance of the vortex tube were summarized. Furthermore, due to its simple structure, safety and stability, the vortex tube is widely used in the field of refrigerating and heating, mixture separation. This survey, while extensive cannot cover all papers, some selection is necessary. The purpose of this review aims to summarize the important works of literature on the energy separation of vortex tube as well as identify limitations to existing studies and directions for future research.