Abstract
Study of the energy separation phenomenon in vortex tube (VT) at cryogenic temperature (temperature range below 123 K) has become important because of the potential application of VT as in-flight air separator in air breathing propulsion. In the present study, a CFD model is used to simulate the energy separation phenomenon in VT with gaseous air at cryogenic temperature as working fluid. Energy separation at cryogenic temperature is found to be considerably less than that obtained at normal atmospheric temperature due to lower values of inlet enthalpy and velocity. Transfer of tangential shear work from inner to outer fluid layers is found to be the cause of energy separation. A parametric sensitivity analysis is carried out in order to optimize the energy separation at cryogenic temperature. Also, rates of energy transfer in the form of sensible heat and shear work in radial and axial directions are calculated to investigate the possible explanation of the variation of the hot and cold outlet temperatures with respect to various geometric and physical input parameters.
Highlights
The Ranque-Hilsch vortex tube (VT) separates a compressed gas stream into two lower pressure streams with one stream having higher temperature and the other having lower temperature than the inlet stream
Eiamsa-ard et al [20] used a cooling water jacket to directly cool the hot tube of a VT and observed higher cold temperature separation and cooling efficiency compared to the VT without cooling
We show that work transfer in axial direction due to radial shear stress is very small throughout the VT
Summary
The Ranque-Hilsch vortex tube (VT) separates a compressed gas stream into two lower pressure streams with one stream having higher temperature and the other having lower temperature than the inlet stream. Eiamsa-ard et al [20] used a cooling water jacket to directly cool the hot tube of a VT and observed higher cold temperature separation and cooling efficiency compared to the VT without cooling They suggested that the use of cooling water jacket improves heat transfer from the axial region to the peripheral region, which leads to higher cooling efficiency. Since the published literature on experimental or theoretical investigation on energy separation at cryogenic temperature is scarce [28], the CFD model presented in our previous work [17] for the VT operating with gaseous air at normal atmospheric temperature is used here. A CFD based parametric analysis is carried out at cryogenic temperature by observing the variation of the hot outlet and cold outlet temperatures with respect to various geometric and physical input parameters in order to optimize energy separation. It may be noted that in the present study, the term “temperature” indicates “total temperature” unless otherwise specified
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
