scholarly journals Numerical investigation on flow behavior and energy separation in a micro-scale vortex tube

2015 ◽  
Vol 19 (2) ◽  
pp. 619-630 ◽  
Author(s):  
Nader Rahbar ◽  
Mohsen Taherian ◽  
Mostafa Shateri ◽  
Sadegh Valipour
Author(s):  
Seyed Ehsan Rafiee ◽  
M. M. Sadeghiazad ◽  
Nasser Mostafavinia

The vortex tube (VT) air separator is an invaluable tool which has the ability to separate a high-pressure fluid into the cold and hot fluid streams. The hot tube is a main part of the air separator VT which the energy separation procedure happens along this part. This research has been done to analyze the effect of the convergent angle and cold orifice diameter on the thermal efficiency of a convergent vortex tube (CVT). The CVT is linked to an air pipeline with the fixed pressure of 6.5 bar. The convergent hot tube angle is varied over the range of 1 deg to 9 deg. The consideration of the main angle effect denotes that the highest thermal ability could be achieved at β = 5 deg. The laboratory setup results show this subject that the optimization of the hot tube convergent angle elevates the cooling and heating effectiveness around 32.03% and 26.21%, respectively. Experiments denoted that both cooling capability and heating effectiveness reach the highest magnitudes when the DCold is around 9 mm. After these two stages, the optimized CVT was capable of decreasing and rising air temperatures at the cold and the hot sides up to 9.05 K (42.89%) and 10.48 K (44.74%), respectively. A computational fluid dynamics (CFD) model was employed to predict the performance of the air flow inside the CVT. The numerical investigation was done by full 3D steady-state CFD-simulation using fluent6.3.26. The results show that the agreement between computation predictions and laboratory measurements is fairly good.


2017 ◽  
Vol 7 (2) ◽  
pp. 18
Author(s):  
Kiran Dattatraya Devade ◽  
Ashok T. Pise ◽  
Atul R. Urade

The vortex tube is an energy separation device that separates compressed gas stream into a low and a high temperature stream. Present work reports the flow behavior inside the vortex tube for different commonly used fluids with varied properties like Air, He, N2, CO2 and NH3. Flow behavior investigation for three-dimensional short straight-diverging vortex tube is done with CFD code (ANSYS 16.0). Different turbulent models, standard k-epsilon, Realizable k-epsilon and RNG k-epsilon are tested. Realizable k-epsilon model was then used for analysis. Flow behavior of gases with varied multi-atomic number is analyzed and compared with literature. The effect on temperature for N2 is found to be better, followed by He, CO2, Air and NH3. Energy separation for N2 is 46 % higher than all other gases. Energy separation and flow behavior inside vortex tube is analyzed and compared with literature.


2014 ◽  
Vol 18 (4) ◽  
pp. 1173-1189 ◽  
Author(s):  
Hassan Pouraria ◽  
Warn-Gyu Park

A Ranque-Hilsch vortex tube (RHVT) is a mechanical device that separates a high pressure gas stream into low pressure hot and cold streams. In this study, four different two equation turbulence models namely the standard k-?, RNG k-?, Realizable k-? and standard k-? models were compared to identify the appropriate turbulence model for studying the energy separation effect in a RHVT. Comparison between the numerical and experimental results indicates that the standard k-? model is better than other models in predicting the energy separation phenomenon. The distributions of temperature, pressure, and components of velocity have been obtained in order to understand the flow behavior inside the tube. The effect of cold outlet diameter on temperature drop and refrigeration capacity was studied. The effect of cold mass fraction on the movement of stagnation point and refrigeration capacity has been investigated. Moreover, the feasibility of improving the cooling performance of vortex tube using the cooling system was investigated. The present numerical results revealed that using the cooling system, the net energy transfer rate from cold inner region to the hot peripheral region increases, thereby improving the cooling performance of the device.


2011 ◽  
Vol 1 (4) ◽  
Author(s):  
S. Rahman ◽  
A. Mujumdar

AbstractA three-dimensional (3D) computational fluid dynamic simulation of a vortex tube is carried out to examine its flow and thermal characteristics. The aim of this work is to model the performance of the vortex tube and to capture the highly swirling compressible flow behavior inside the tube for an understanding of the well known temperature separation process. Simulations were carried out using the standard k-ɛ, k-omega, RNG k-ɛ and swirl RNG k-ɛk-ɛ turbulence models. An experimental setup was built and tested to validate the simulation results. The RNG k-ɛ turbulence model yielded better agreement between the numerical predictions and experimental data. This model captured well the essential features of the flow including formation of the outer vortex and the inner reverse vortex flow. Flow and geometric parameters that affect the flow behavior and energy separation are studied numerically. Effects of the inlet pressure, with and without an insert in the tube, are examined by numerical experiments.


2017 ◽  
Vol 22 (2) ◽  
pp. 603-612
Author(s):  
Rasoul Daneshfaraz ◽  
Ali Rezazadehjoudi ◽  
John Abraham

Sign in / Sign up

Export Citation Format

Share Document