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Hr2413591363

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IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com

IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com

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  • 1. Rahul B Patel, Dr. V. N. Bartaria , Tausif M Shaikh / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp.1359-1363 A Review On Exprimental & Numerical Investigation Of Ranque Hilsch Vortextube Rahul B Patela , Dr. V. N. Bartariab , Tausif M ShaikhcAbstract- The vortex tube or Ranque–Hilsch inlet pressure and speed. Pressure difference occursvortex tube is a simple device used in industry between tube wall and tube center because of thefor generation of cold and hot air streams from friction of the fluid circling at high speeds. Speeda single compressed air supply. This simple of the fluid near the tube wall is lower than thedevice is very efficient in separation of air speed at the tube center, because of the effects ofstreams of different temperatures and has been wall friction. As a result, fluid in the center regionthe focus of investigation since the tube’s transfers energy to the fluid at the tube wall,discovery. Different explanations for the depending on the geometric structure of the vortexphenomenon of the energy separation have been tube. The cooled fluid leaves the vortex tube fromproposed, however there has not been a the cold output side, by moving towards anconsensus in the hypothesis. The purpose of this opposite direction, compared to the main flowpaper is to present a critical review of current direction, after a stagnation point. Whereas, theexplanations on the working concept of a vortex heated fluid leaves the tube in the main flowtube. direction from the other end (Dincer et al., inAlthough many experimental and numerical press). By injecting compressed air at roomstudies on the vortex tubes have been made, the temperature circumferentially into a tube at highphysical behaviour of the flow is not fully velocity, a vortex tube can produce cold air down tounderstood due to its complexity and the lack of 223 K and hot air up to 400 K (Crocker et al.,consistency in the experimental findings. 2003).Furthermore, several different hypotheses basedon experimental, analytical, and numericalstudies have been put forward to describe thethermal separation phenomenon. Hypotheses ofpressure, viscosity, turbulence & temperatureseparation phenomenon using CFD analysis ofvortex tube are discussed in the paper, andpresumably, future research will benefit fromthis discussion.[1].Index Terms—RHVT, Thermal Separation, CFDI. INTRODUCTION Ranque discovered the effect of vortexenergy distribution and patented the first vortextube (RHVT) in 1934. In 1946, Hilsch improvedthe RHVT design and its underlying principles thatstill remain valid today (Khodorkov et al., 2003).Aljuwayhel et al. (2005) define the vortex tube as asimple device with no moving parts that is capableof separating a high-pressure flow into two lowerpressure flows of different temperatures. Thedevice consists of a simple circular tube, one ormore tangential nozzles, and a throttle valve (seeFig. 1, Cockerill, 1995).Working principle of the counter flow RHVT canbe defined as follows. Compressible fluid, which is Fig. 1 – Schematic diagram of the counter flowtangentially introduced into the vortex tube from RHVT (Cockerill, 1995).nozzles, starts to make a circular movement insidethe vortex tube at high speeds, because of the Schematic diagram of the parallel flowcylindrical structure of the tube, depending on its RHVT is shown in Fig. 2. Both hot and cold flows 1359 | P a g e
  • 2. Rahul B Patela, Dr. V. N. Bartariab ,Tausif M Shaikhc / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp.in RHVTs leave the vortex tube in the same on which physics can be applied for getting thedirection. It is not possible for cold flow to turn results. The CFD software gives one the power toback after a stagnation point. In order to separate model things, mesh them, give proper boundarythe flow in the center of the tube from the flow at conditions and simulate them with real worldthe wall, an apparatus which has a hole in the condition to obtain results. Using CFD a model cancenter is used. The temperature of hot and cold be developed which can breed to give results suchflows can be changed by back and forth movement that the model could be developed into an objectof this apparatus. In parallel flow RHVTs, hot and which could be of some use in our life.cold flows mix with each other. This mixing affectsthe temperatures of fluids negatively and causes Modeling is the mathematical physics problemtheir efficiencies to be low. For this reason, parallel formulation in terms of a continuous initialflow RHVTs are generally not preferred (Dincer, boundary value problem (IBVP)2005; Dincer et al., 2005) IBVP is in the form of Partial Differential Equations (PDEs) with appropriate boundary conditions and initial conditions. Modeling includes: 1. Geometry and domain 2. Coordinates 3. Governing equations 4. Flow conditions 5. Initial and boundary conditions 6. Selection of models for different applications Solve the Navier-Stokes equations (3D in Cartesian coordinates) . Fig. 2 – Schematic diagram of the parallel flow RHVT (Dincer et al., 2005). Computational fluid dynamics techniques have revolutionized engineering design in several In the conventional vortex tube, important areas, notably in analysis of fluid flowcompressed gas enters directly a circular flow technology. CFD can also be used as a minimalpassage with equal section area from a straight adequate tool for design of engineeringpipe, which can cause a sudden change of flow components. A careful scanning of variousdirection at the joint between the straight pipe and numerical investigations on the mechanism ofthe circular flow passage. The sudden change thermal separation in vortex tubes indicate thatwould lead to the generation of eddies, which cause barring a few ,no serious attempts have been madeenergy loss. The sudden change of flow velocity to use CFD techniques to simulate the flow patternsand the eddy generated by this change can also of vortex tubes.cause the energy loss. It is important to have a highperipheral velocity in the portion of the tube A detailed analysis of various parametersimmediately after the nozzle; the curve of the of the vortex tube has been carried out throughnozzle affects the performance of vortex tubes (Wu CFD techniques to simulate the phenomenon ofet al., 2007). flow pattern, thermal separation, pressure gradientRHVTs are used, among others, for cooling, etc. so that they are comparable with theheating, drying and snow production. Their cooling experimental results.capability is used, e.g., in dehumidifying gassamples, chilling of environmental chambers, The vortex tube was first observed bycooling of food, welding, and air climate control Ranque. Later, Hilsch did some experimental andprocesses. Although, they are not very efficient as a theoretical studies to increase the efficiency of thecooling device, they can be very useful in certain vortex tube. Fulton explained the energy separation.applications as they are small, simple to make and He proposed that the inner layer heat the outer layerrepair, and require no electrical or chemical power meanwhile expanding and growing cold. Reynoldssource. Nowadays, RHVTs are produced by did the numerical analysis of vortex tube. Lewellendifferent commercial companies with a wide range arrived at the solution by combining the threeof applications (Dincer et al., 2008). [2] Navier-stokes equations for an incompressible fluid in a strong rotating axisymmetric flow with a radialII. INTRODUCTION TO CFD sink flow. Linderstorm-lang examined the velocityMODELLING and thermal fields in the tube. He calculated the CFD is concerned with numerical solution axial and radial gradients of the tangential velocityof differential equations governing transport of profile from prescribed secondary flow functionsmass, momentum and energy in moving fluid. on the basis of a zero-order approximation to theUsing CFD, one can build a computational model 1360 | P a g e
  • 3. Rahul B Patel, Dr. V. N. Bartaria , Tausif M Shaikh / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp.1359-1363momentum equations developed by Lewellen for an parameters for obtaining the maximum hot gasincompressible flow. temperature and minimum cold gas temperature are obtained through CFD analysis and validated Schlenz investigated numerically in a uni- through experiments. The coefficient offlow vortex tube, the flow field and the process of performance (COP) of the vortex tube as a heatenergy separation. Calculations were carried out engine and as a refrigerator has been calculated.assuming a 2D axisymmetric compressible flowand using the Galerkins approach with a zero- Ahmet Murat Pinar et al, [6] were carriedequation turbulence model to solve the mass, out Optimization of counter flow Ranque–Hilschmomentum, and energy conservation equations to vortex tube performance using Taguchi method.calculate the flow and thermal fields. Amitani used This study discusses the application of Taguchithe mass, momentum and energy conservation method in assessing maximum temperatureequation in a 2D model of a counter flow vortex gradient for the Ranque–Hilsch counter flow vortextube with a short length, with an assumption of a tube performance. The experiments were plannedhelical motion in an axial direction for an invicid based on Taguchi’s L27 orthogonal array with eachcompressible perfect fluid. Flohlingsdorf and Unger trial performed under different conditions of inletused the CFX system with the k-ϵ model to study pressure, nozzle number and fluid type. Signal-to-the velocity profile and energy separation in a noise ratio (S/N) analysis, analysis of variancevortex tube. Aljuwahel reported that RNG k-ϵ is (ANOVA) and regression analysis were carried outbetter than k-ϵ when he studied the energy in order to determine the effects of processseparation and the flow phenomenon in a counter parameters and optimal factor settings. Finally,flow vortex tube using CFD in Fluent. T. Farouk confirmation tests verified that Taguchi methodand B. Farouk introduced the large eddy simulation achieved optimization of counter flow Ranque–(LES) technique to predict the flow fields and the Hilsch vortex tube performance with sufficientassociated temperature separation within a counter- accuracy.flow vortex tube for several cold mass fractions.However, most of the computations found in the Tanvir Farouk et al, [7] carried outliterature used simple or the first-order turbulence Simulation of gas species and temperaturemodels which are considered unsuitable for separation in the counter-flow Ranque–Hilschcomplex, compressible vortex tube flows. The vortex tube using the large eddy simulationpresent work presents a two-dimensional numerical technique.A computational fluid dynamic model isinvestigation of flow and temperature separation used to predict the species and temperaturebehaviours inside a flow vortex tube.[3] separation within a counter flow Ranque–Hilsch vortex tube. The large eddy simulation (LES)III. EXPRIMENTAL & NUMRICAL technique was employed for predicting the gas flowANALYSIS and temperature fields and the species mass From 1934, almost 200-215 articles are fractions (nitrogen and helium) in the vortex tube.published on Ranque Hilsch vortex tube. Not all the A vortex tube with a circumferential inlet stream ofarticles are directly related to our work, especially, nitrogen–helium mixture and an axial (cold) outletthose articles which were focused on computational stream and a circumferential (hot) outlet streamwork. Many articles addressed experimental was considered. The temporal evolutions of thefindings and remaining discussed various theories axial, radial and azimuthal components of theexplaining energy separation phenomenon. In this velocity along with the temperature, pressure andsubsection, we are going to discuss only those mass density and species concentration fieldsarticles (experimental and/or theoretical work) within the vortex tube are simulated. Even though awhich are directly related to current work.[4] large temperature separation was observed, only a very minimal gas separation occurred due to Upendra Behera et al, [5] were carried out diffusion effects. Correlations between theCFD analysis and experimental investigations fluctuating components of velocity, temperaturetowards optimizing the parameters of Ranque– and species mass fraction were calculated toHilsch vortex tube. Computational fluid dynamics understand the separation mechanism. The inner(CFD) and experimental studies are conducted core flow was found to have large values of eddytowards the optimization of the Ranque–Hilsch heat flux and Reynolds’s stresses. Simulations werevortex tubes. Different types of nozzle profiles and carried out for varying amounts of cold outlet massnumber of nozzles are evaluated by CFD analysis. flow rates. Performance curves (temperatureThe swirl velocity, axial velocity and radial separation/gas separation versus cold outlet massvelocity components as well as the flow patterns fraction) were obtained for a specific vortex tubeincluding secondary circulation flow have been with a given inlet mass flow rate.evaluated. The optimum cold end diameter (dc) andthe length to diameter (L/D) ratios and optimum 1361 | P a g e
  • 4. Rahul B Patela, Dr. V. N. Bartariab ,Tausif M Shaikhc / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp. Fig. 1. Time averaged total temperature contours for the vortex tube in the r–x plane(case 1). Time averaging was performed between 0.4 and 0.8 s Fig. 1. Schematic diagram of a counter-flow Ranque–Hilsch vortex tube. K. Dincer et al, [9] were carried out Experimental Fig. 2. Time averaged helium mass fraction investigation of performance of hot cascade type contours for the vortex tube in the r–x plane Ranque-Hilsch vortex tube and exergy analysis. In(case 1). Time averaging was performed between this study, three Ranque-Hilsch vortex tubes were 0.4 and 0.8 s. used, which have 9 mm inside diameter and length/diameter ratio was 15. Their performances S. Eiamsa-ard [8] was carried out were examined as one of the classical RHVT andExperimental investigation of energy separation in other was hot cascade type RHVT. Performancea counter-flow Ranque–Hilsch vortex tube with analysis was according to temperature differencemultiple inlet snail entries. The energy/ between the hot outlet and the inlet (ΔThot). TheTemperature separation phenomenon and cooling ΔThot values of hot cascade type Ranque-Hilschefficiency characteristics in a counter-flow vortex tubes were greater than the ΔThot values ofRanque–Hilsch vortex tube (RHVT) are classical RHVT, which were determinedexperimentally studied. The ascertainment focuses experimentally. The total inlet exergy, total outleton the effects of the multiple inlet snail entries exergy, total lost exergy and exergy efficiency of(N=1 to 4 nozzles), cold orifice diameter ratios hot stream were investigated by using experimental(d/D=0.3 to 0.7) and inlet pressures (Pi=2.0 and 3.0 data. In both the classical RHVT and hot cascadebar). The experiments using the conventional type RHVT, it was found that as fraction of coldtangential nozzles (N=4), are also performed for flow increases the total lost exergy decreases. Itcomparison. The experimental results reveal that was also found that, the hot cascade type RHVTthe RHVT with the snail entry provides greater cold more exergy efficiency of hot outlet than theair temperature reduction and cooling efficiency classical RHVT. Excess ΔThot value of hot cascadethan those offered by the RHVT with the type Ranque-Hilsch vortex tube causes the excessconventional tangential inlet nozzle under the same exergy efficiency of hot outlet.cold mass fraction and supply inlet pressure. Theincrease in the nozzle number and the supply H.M. Skye et al, [10] were carried outpressure leads to the rise of the swirl/vortex Comparison of CFD analysis to empirical data in aintensity and thus the energy separation in the tube. Commercial vortex tube. This paper presents a comparison between the performance predicted by a computational fluid dynamic (CFD) model and 1362 | P a g e
  • 5. Rahul B Patel, Dr. V. N. Bartaria , Tausif M Shaikh / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 2, Issue 4, July-August 2012, pp.1359-1363experimental measurements taken using a [2] K. Dincer et al, were carried outcommercially available vortex tube. Specifically, ―Experimental investigation of thethe measured exit temperatures into and out of the performance of a Ranque–Hilsch Vortexvortex tube are compared with the CFD model. The tube with regard to a plug located at thedata and the model are both verified using global hot outlet‖.mass and energy balances. The CFD model is a [3] Prof. R. K. Sahoo et al, were carried outtwo-dimensional (2D) steady axisymmetric model ―Numerical Analysis in Ranque-Hilsch(with swirl) that utilizes both the standard and Vortex tube.‖renormalization group (RNG) k-epsilon turbulence [4] Sachin U. Nimbalkar et al, were carriedmodels. While CFD has been used previously to out ―Quantitative observations on multipleunderstand the fluid behavior internal to the vortex flow structures inside Ranque Hilschtube, it has not been applied as a predictive model vortex tube.‖of the vortex tube in order to develop a design tool [5] Upendra Behera et al, were carried outthat can be used with confidence over a range of ―CFD analysis and experimentaloperating conditions and geometries. The objective investigations towards optimizing theof this paper is the demonstration of the successful parameters of Ranque–Hilsch vortexuse of CFD in this regard, thereby providing a tube.‖powerful tool that can be used to optimize vortex [6] Ahmet Murat Pinar et al, were carried outtube design as well as assess its utility in the ―Optimization of counter flow Ranque–context of new applications. Hilsch vortex tube performance using Taguchi method.‖ [7] Tanvir Farouk et al, were carried out ―Simulation of gas species and temperature separation in the counter-flow Ranque–Hilsch vortex tube using the large eddy simulation technique.‖ [8]. S.Eiamsa-ard was carried out ―Experimental investigation of energy separation in a Counter- flow Ranque– Hilsch vortex tube with multiple inlet snail entries.‖ Fig. 3. Picture of vortex tube used for [9] .K. Dincer et al, were carried out experiment. ―Experimental investigation of performance of hot cascade type Ranque-IV. CONCLUSION:- Hilsch vortex tube and exergy analysis.‖ The issue concerned in all explanations is [10]. H.M. Skye et al, were carried outthe energy transfer between different layers. When Comparison of CFD analysis to empiricallittle energy is transferred from the inner flow to data in a Commercial vortex tube.the outer flow, the temperature drop of cold air canbe considered to be the result of sudden expansionnear the entrance, and the temperature rise of hotair might be the result of friction of the multi-circulation near the hot exit. Therefore, clarificationof the energy transfer between different layers is auseful approach in the investigation of the vortextube. Clear understanding of the flow structureinside the vortex tube is required for furtherinvestigation, especially the region near theentrance in which sudden expansion is consideredas the governing process and the region near theexit in which multi-circulation may be formed.From the above study I am much more interested towork on Experimental & Numerical investigationof Ranque-Hilsch vortex tube using CFD.V. REFERENCES [1] Yunpeng Xue et al, were carried out ―A critical review of temperature separation in a vortex tube‖. 1363 | P a g e

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