Prospective applications of Ranque–Hilsch vortex tubes to sustainable energy utilization and energy efficiency improvement with energy and mass separation

Abstract

The scope of this review is to highlight the potential contributions of Ranque–Hilsch vortex tubes in meeting the industrial requirements of energy efficiency improvement, sustainable energy utilization, and waste heat regeneration with its unique energy separation effect. Vortex tubes have received significant attention in recent years, as they meet the current requirements of energy conservation with their energy saving and environment-friendly operating modes. Vortex tubes have been widely exploited for the unique energy separation phenomenon and the ability to provide instant cooling and heating effects, with air as the most common working fluid. The functions fulfilled by the vortex tubes are numerous. In addition to the sole single gas-phase, there may be phase changing processes involved in vortex tubes, and the adopted purposes of vortex tubes may be broadly divided into energy separation and mass separation. The mass separation process in a vortex tube is more complex, as the phase change and component separation is interrelated. The main objective of this review relates to the analysis, carding, and construction of application and operation mechanism of vortex tubes from newly emerging research fields in order to derive a clear classification and promising techniques. Thus, the main content is divided into two parts to be summarized and discussed. The first is focused on energy or temperature separation of which the hot or cold fluid stream produced by a vortex tube is the main purpose; the second relates to the mass separation in which the mass or component separation, usually accompanied by phase change and temperature variation, is produced by a vortex tube. In each part, the operation mechanism, system configuration, performance influencing factors, and status of current techniques are introduced and described.