scholarly journals Computational Fluid Dynamic Prediction and Physical Mechanisms Consideration of Thermal Separation and Heat Transfer Processes Inside Divergent, Straight, and Convergent Ranque–Hilsch Vortex Tubes

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Adib Bazgir ◽  
Nader Nabhani ◽  
Bahamin Bazooyar ◽  
Ali Heydari
Keyword(s):  
Vortex Tube ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Numerical Data ◽  
Dynamic Prediction ◽  
Temperature Separation ◽  
Flow Phenomena ◽  
Stream Lines ◽  
Physical Phenomena ◽  
Vortex Tubes

AbstractThe design of Ranque–Hilsch vortex tube (RHVT) seems to be interesting for refrigeration and air conditioning purposes in industry. Improving thermal efficiency of the vortex tubes could increase the operability of these innovative facilities for a wider heat and cooling demand to this end; it is of an interest to understand the physical phenomena of thermal and flow patterns inside a vortex tube. In this work, the flow phenomena and the thermal energy transfer in RHVT are studied for three RHVT: straight, divergent, and convergent vortex tubes. A three-dimensional numerical analysis of swirling or vortex flow is performed, verified, and validated against previous experimental and numerical data reported in literature. The flow field and the temperature separation inside an RHVT for different configuration of straight, five angles of divergent hot tube (1 deg, 2 deg, 3 deg, 4 deg, and 6 deg) and five angle of convergent hot tube (0.5 deg, 0.8 deg, 1 deg, 1.5 deg, and 2 deg) are investigated. The thermal performance for all investigated RHVTs configuration is determined and quantitatively assessed via visualizing the stream lines for all three scenarios.

Investigation of Temperature Separation Inside Various Models of Ranque–Hilsch Vortex Tube: Convergent, Straight, and Divergent With the Help of Computational Fluid Dynamic Approach

2018 ◽  
Vol 10 (5) ◽  
Author(s):  
Adib Bazgir ◽  
Nader Nabhani
Keyword(s):  
Computational Fluid Dynamic ◽  
Vortex Tube ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Numerical Data ◽  
Coefficient Of Performance ◽  
Tube Length ◽  
Operational Parameters ◽  
Temperature Separation ◽  
Isentropic Efficiency

In this paper, a Ranque–Hilsch vortex tube (RHVT) has been optimized utilizing convergent (φ), straight, and divergent (θ) axial angles for hot-tube. Effects of divergent (θ) and convergent (φ) angles on the flow behavior have been investigated by computational fluid dynamic (CFD) techniques. By using a renormalization group (RNG) k–ε turbulence model based on finite volume method, all the computations have been carried out. The isentropic efficiency (ηis) and coefficient of performance (COP) of machine was studied under five different divergent angles (θ), namely 1 deg, 2 deg, 3 deg, 4 deg, and 6 deg, two different convergent (φ) angles (φ) namely 1 deg and 2 deg adjusted to the hot-tube. Furthermore, some geometrical and operational parameters including cold outlet diameter, hot-tube length, and different inlet pressures and mass flow rates have been analyzed in detail (spanwisely) in order to optimize the cooling efficiency of vortex tube (straight). The results show that utilizing the divergent hot-tubes increases the isentropic efficiency (ηis) and COP of device for most values of inlet pressures, and helps to become more efficient than the other shape of vortex tubes (straight and convergent). Finally, some results of the CFD models have been validated by the available experimental and numerical data, which show reasonable agreement, and others are compared qualitatively.

Aerodynamic and thermal characteristics of a maxwell type vortex tube

2011 ◽  
Vol 1 (4) ◽  
Author(s):  
S. Rahman ◽  
A. Mujumdar
Keyword(s):  
Vortex Tube ◽  
Fluid Dynamic ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Turbulence Models ◽  
Computational Fluid Dynamic Simulation ◽  
Energy Separation ◽  
Numerical Predictions ◽  
Temperature Separation

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.

Unsteady Interaction of Labyrinth Seal Leakage Flow and Downstream Stator Flow in a Shrouded 1.5 Stage Axial Turbine

2005 ◽  
Author(s):  
P. Peters ◽  
J. R. Menter ◽  
H. Pfost ◽  
A. Giboni ◽  
K. Wolter
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Numerical Data ◽  
Labyrinth Seal ◽  
Rotor Blades ◽  
Navier Stokes ◽  
Experimental Program ◽  
Leakage Flow ◽  
Axial Turbine ◽  
Flow Phenomena

This paper presents the results of experimental and numerical investigations into the flow in a 1.5-stage low-speed axial turbine with shrouded rotor blades and a straight through labyrinth seal. The paper focuses on the time dependent influence of the leakage flow on the downstream stator flow field. The experimental program consists of time accurate measurements of the three-dimensional properties of the flow through ten different measurement planes in the stator passage. The measurements were carried out using pneumatic five-hole probes and three dimensional hot-wire probes at the design operating point of the turbine. The measurement planes extend from the shroud to the casing. The complex three-dimensional flow field is mapped in great detail by 4,800 measurement points and 20 time steps per blade passing period. The time-accurate experimental data of the ten measurement planes was compared with the results of unsteady, numerical simulations of the turbine flow. The 3D-Navier-Stokes Solver CFX-TASCflow was used. The experimental and numerical results correspond well and allow detailed analysis of the flow phenomena. Additionally numerical data behind the rotor is used to connect the entry of the leakage flow with the flow phenomena in the downstream stator passage and behind it. The leakage flow causes strong fluctuations of the flow in the downstream stator. Above all, the high number of measurement points reveals both the secondary flow phenomena and the vortex structures within the blade passage. The time-dependence of both the position and the intensity of the vortices influenced by the leakage flow is shown. The paper shows that even at realistic clearance heights the leakage flow influences considerable parts of the downstream stator and gives rise to negative incidence and flow separation. Thus, labyrinth seal leakage flow should be taken properly into account in the design or optimization process of turbines.

Investigations of Energy Separation Effect in Vortex Tube for Natural Gases

2013 ◽  
Vol 397-400 ◽  
pp. 205-208
Author(s):  
Wen Chuan Wang ◽  
Xiang Jun Fang ◽  
Shi Long Liu ◽  
Wen Long Sun
Keyword(s):  
Mass Fraction ◽  
Vortex Tube ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Energy Separation ◽  
Separation Effect ◽  
Natural Gases ◽  
Temperature Separation ◽  
Total Temperature ◽  
Cold Mass

This paper aims to investigate fixed composition natural gases including N2, CH4 and C2H4 energy separation effect in vortex tube. Energy separation phenomena of those gases were investigated by means of three-dimensional Computational Fluid Dynamics (CFD) method. Flow fields of natural gases in fixed inlet boundary conditions were simulated. The results main factors were found that affect the energy separation with cold mass fraction being 0.7 and pressure drop ratio being 3.90. At the same time, this paper has illustrated the effects and tendencies of energy separation with gases in the tube under the same cold mass flow fraction and cold pressure ratio. The results show mixture gases total temperature difference effect is unchanged varied with the cold mass fraction; CH4% has no effect on the vortex cold end temperature separation, but varied of CH4% has an influence in total temperature and hot end separation effect; total temperature separation effect of CH4% was divided into two sections, one is0%-80%, and the other 80%-100%.

Unsteady flow interactions between an advected cylindrical vortex tube and a spherical particle

1995 ◽  
Vol 288 ◽  
pp. 123-155 ◽  
Author(s):  
Inchul Kim ◽  
Said Elghobashi ◽  
William A. Sirignano
Keyword(s):  
Spherical Particle ◽  
Vortex Tube ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Incompressible Viscous Flow ◽  
Cylindrical Vortex ◽  
Maximum Fluctuation ◽  
Flow Interactions ◽  
Flow Phenomena

The unsteady, three-dimensional, incompressible, viscous flow interactions between a vortical (initially cylindrical) structure advected by a uniform free stream and a spherical particle held fixed in space is investigated numerically for a range of particle Reynolds numbers 20 ≤ Re ≤ 100. The counter-clockwise rotating vortex tube is initially located ten sphere radii upstream from the sphere centre. The finite-difference computations yield the flow properties and the temporal distributions of lift, drag, and moment coefficients of the sphere. Initially, the lift force is positive owing to the upwash on the sphere, then becomes negative owing to the downwash as the vortex tube passes the sphere. Varying the size of the vortex core (σ) shows that the r.m.s. lift coefficient is linearly proportional to the circulation of the vortex tube at small values of σ. At large values of σ, the r.m.s. lift coefficient is linearly proportional to the maximum fluctuation velocity (vmax) induced by the vortex tube but independent of σ. For intermediate values of σ, the r.m.s. lift coefficient depends on both σ and vmax (or equivalently both σ and the circulation). We observe some interesting flow phenomena in the near wake as a function of time owing to the passage of the vortex tube.

Design of a rotor blade tip for the investigation of dynamic stall in the transonic wind-tunnel Göttingen

2016 ◽  
Vol 120 (1232) ◽  
pp. 1509-1533 ◽  
Author(s):  
B. Lütke ◽  
J. Nuhn ◽  
Y. Govers ◽  
M. Schmidt
Keyword(s):  
Experimental Data ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Numerical Data ◽  
Dynamic Stall ◽  
Navier Stokes ◽  
Fe Model ◽  
Stress Distributions ◽  
Cfd Simulations ◽  
Blade Tip

ABSTRACTThe aerodynamic and structural design of a pitching blade tip with a double-swept planform is presented. The authors demonstrate how high-fidelity finite element (FE) and computational fluid dynamic (CFD) simulations are successfully used in the design phase. Eigenfrequencies, deformation, and stress distributions are evaluated by means of a three-dimensional (3D) FE model. Unsteady Reynolds-averaged Navier-Stokes (RANS) simulations are compared to experimental data for a light dynamic stall case atMa= 0.5,Re= 1.2 × 106. The results show a very good agreement as long as the flow stays attached. Tendencies for the span-wise location of separation are captured. As soon as separation sets in, discrepancies between experimental and numerical data are observed. The experimental data show that for light dynamic stall cases atMa= 0.5, a factor of safety ofFoS= 2.0 is sufficient if the presented simulation methods are used.

scholarly journals Numerical simulation of different turbulence models aiming at perdicting the flow and temperature separation in a Ranque-Hilsch vortex tube

2014 ◽  
Vol 18 (4) ◽  
pp. 1159-1171
Author(s):  
Hossein Azizi ◽  
Reza Saleh ◽  
Mohsen Kahrom ◽  
Reza Andalibi
Keyword(s):  
Vortex Tube ◽  
Turbulence Models ◽  
Swirl Flow ◽  
Experimental Results ◽  
Navier Stokes ◽  
Temperature Separation ◽  
Experiment Validation ◽  
Performance Curves ◽  
Mass Fractions ◽  
Flow Phenomena

A computational fluid dynamics (CFD) model is used to compare the effect of different Reynolds Averaged Navier-Stokes (RANS) based turbulence models in predicting the temperature separation and power separation in a Ranque-Hilsch vortex tube. Three first order turbulence models (standard k-?, Renormalized group RNG and shear stress transport (SST) K-? model) together with a second order numerical scheme are surveyed in the present work. The simulations are done in 2D steady, axisymetric with high swirl flow model. The performance curves (hot and cold outlet temperatures and power separation versus hot outlet mass fraction) obtained by using these turbulence models are compared with the experimental results in different cold mass fractions. The aim is to select an appropriate turbulence model for the simulation of the flow phenomena. Because of large discrepancy between 2D and experiment, validation in 3D model is also considered. The performance analysis shows that among all the turbulence models investigated in this study, temperature separation predicted by the Renormalized group RNG model is closer to the experimental results.

scholarly journals Effect of secondary swirl in supersonic gas and plasma flows in the self-vacuuming vortex tube

2018 ◽  
Vol 209 ◽  
pp. 00020 ◽  
Author(s):  
Vyacheslav Volov ◽  
Anton Lyaskin
Keyword(s):  
Pressure Drop ◽  
Shock Waves ◽  
Energy Loss ◽  
Flow Structure ◽  
Vortex Tube ◽  
Extreme Values ◽  
The Self ◽  
Temperature Separation ◽  
Loss Estimations ◽  
Vortex Tubes

This article presents the results of simulation for a special type of vortex tubes – self-vacuuming vortex tube (SVT), for which extreme values of temperature separation and pressure drop are realized. The main results of this study are the flow structure in the SVT and energy loss estimations on oblique shock waves, gas friction, instant expansion and organization of vortex bundles in SVT.

scholarly journals Comparison of an analytical and computational fluid-dynamics models of a commercial Ranque-Hilsch vortex tube operating with Air and Methane

2019 ◽  
Vol 9 (2) ◽  
pp. 61-71
Author(s):  
Luz Marlen Ahumada ◽  
Antonio José Bula Silvera ◽  
Kevin Andres Melendez Valencia ◽  
Julio Medina Suarez
Keyword(s):  
Analytical Model ◽  
Vortex Tube ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Vortex Generator ◽  
Preliminary Information ◽  
Industrial Implementation ◽  
Inlet Conditions ◽  
Dynamics Models

This paper presents a comparison between the behavior predicted by a computational fluid-dynamic model (CFD) and an analytical model for a commercial vortex tube using air and methane as working fluids, in addition to a three-dimensional mesh for this purpose. The numerical simulation of the turbulent, compressible and high vorticity flow was carried out using RANS equations, the Realizable k-e turbulence model and STAR-CCM+ as software for the equations solution. The variables measured in this work were temperature, pressure and velocity at the exit nozzles of the vortex generator and the tube discharges, resulting in errors of less than 16% between CFD and the analytical model. This numerical study represents a first approximation of the vorticityphenomenon and has been developed in order to establish a prototype simulation model that provides, under certain inlet conditions to the process, preliminary information on the vortex tube industrial implementation for obtaining liquefied natural gas.

scholarly journals NUMERICAL INVESTIGATION OF THE EFFECTS OF GEOMETRICAL PARAMETERS ON THE VORTEX SEPARATION PHENOMENON INSIDE A RANQUE-HILSCH VORTEX TUBE USED AS AN AIR SEPARATOR IN A HELICOPTER’S ENGINE

Aviation ◽  
2018 ◽  
Vol 22 (1) ◽  
pp. 13-23 ◽  
Author(s):  
Adib Bazgir ◽  
Nader Nabhani
Keyword(s):  
Vortex Tube ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Geometrical Parameters ◽  
Cfd Model ◽  
Steady State Condition ◽  
Axial Angle ◽  
Temperature Reduction ◽  
Vortex Separation

Air separators are fitted to helicopter engine intakes to remove potentially harmful dust from the influent air. Their use is necessary in desert environments to eliminate the risk of rapid engine wear and subsequent power deterioration. However, their employment is concomitant with an inherent loss in inlet pressure and, in some cases, auxiliary power. There are three main technologies: vortex tubes, barrier filters, and integrated inlet particle separators. In this work, a vortex tube is investigated numerically. The study was conducted on the number and axial angle of inlet nozzles. Two and three-dimensional models are investigated at a steady state condition then the standard k-ε turbulence model is utilised for determining the flow and temperature fields. The finite volume method base on a Computational Fluid Dynamic (CFD) model is verified through the comparison with experimental data and numerical results of a vortex tube, reported in literature sources. Increasing the number of inlet nozzles, increases the sensitivity of the temperature reduction and the highest possible temperature reduction can be obtained. A vortex tube with an axial angle inlet nozzle of yields better performance. The numerical simulation results indicated that the CFD model is capable of predicting the vortex separation phenomenon inside a Ranque-Hilsch vortex tube with different geometrical parameters.

Sign in / Sign up

Export Citation Format

Share Document