A study of fluid flow simulation in convergentdivergent

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IOP Conference Series: Mterils Science nd Engineering PAPER OPEN ACCESS A study of fluid flow simultion in convergentdivergent nozzles To cite this rticle: I Olru 2015 IOP Conf. Ser.: Mter. Sci. Eng. 95 012048 View the rticle online for updtes nd enhncements.

1 IOP Conference Series: Mterils Science nd Engineering PAPER OPEN ACCESS A study of fluid flow simultion in convergentdivergent nozzles To cite this rticle: I Olru 2015 IOP Conf. Ser.: Mter. Sci. Eng View the rticle online for updtes nd enhncements. Relted content - A study on fluid flow simultion in the cooling systems of mchine tools I Olru - Permeility Estimtion of Porous Rock y Mens of Fluid Flow Simultion nd Digitl Imge Anlysis C W Winrdhi, F I Muln nd F D E Ltief - A study of the cooling systems nd fluid flow simultion in metl cutting processing I Olru This content ws downloded from IP ddress on 28/09/2018 t 02:37

2 A study of fluid flow simultion in convergent divergent nozzles I Olru 1 1 Vsile Alecsndri University of Bcu, 157 Cle Mrsesti, Romni E-mil: ionelo@u.ro Astrct. A study of geometry nozzle is prticulrly importnt in optimizing the quntity of coolnt in terms to minimize tht quntity or coolnt cn e used for luriction of mchines moving prts. Coolnts cn e from the simplest (wter, ir) s well s mixture of liquid (emulsions) to chieve good cooling in function of temperture tht develops in the re concerned. The study from this pper proposes n nlysis nd simultion of flow through the convergent-divergent nozzle type to optimize them nd to use minimum quntity of coolnt or luricnt. This study is focus on the nlysis of cooling systems for cutting processes on mchine tools. 1. Introduction In industril pplictions, coolnts re used for different working situtions. The cooling fluid is sent in the re to e cooled in prticulr y mens of nozzles. A nozzle is generlly device tht increses the velocity of fluid flow t the expense of this pressure, the flow of fluid through nozzles my e regrded s ditic expnsion. The nozzles hve specil geometry to send smll mount of liquid ut to hve good cooling effect [1]. Cooling cpcity is property of liquid cooling/luriction nd is due to evcution of het generted in the cutting process, helps to reduce of the temperture of the tool, of the piece nd the whole cutting system. With luriction fluids re reduced friction forces etween the chip nd rke fce nd etween the seting fce nd the mchined surfce. Cutting fluid is drwn on the chips surfces with high dhesion forces, forming film with lrge surfce pressure resistnce. Wshing effect of cooling liquids, led to the removl of smll chips, metl dust, etc. [2]. Cooling liquids or luricnts used eqution specil ttention, greter quntity of liquid consumed cn e hrmful environment, lrger quntity of fluid cn generte high production costs, depending on their chemicl composition nd rection with vrious heted zones of the process my e hrmful to the opertor [3]. Coolnts must hve the following properties: does not ffect seling prts of mchine tool, to e stle nd comptile with the mterils used nd the type of processing, should not e toxic, nd not smoke in contct with cold zone nd to e with low flmmility [4]. The cutting surfces luriction cn e chieved under continuous hydrodynmic film, semi-liquid friction nd friction limit. In hydrodynmic luriction regimes, the sliding surfces re seprted y thick lyer of fluid nd re sufficiently high to prevent the contct etween oth surfces [5]. Content from this work my e used under the terms of the Cretive Commons Attriution 3.0 licence. Any further distriution of this work must mintin ttriution to the uthor(s) nd the title of the work, journl cittion nd DOI. Pulished under licence y Ltd 1

3 In industril pplictions re used the following types of coolnts nd luricnts: wter, ir, oil, wter-immiscile oils, fluids emulsifile in queous solutions or orgnic compounds or inorgnic nd suspensions or solid luricnt pstes. The emulsion is system consisting of two immiscile phses or prtilly miscile with one phse dispersed in the other stte. Wter nd oil phses cn form type of emulsions with wter s minly fluid nd oil s secondry fluid or oil s minly fluid nd wter like secondry fluid, however only the min fluid wter emulsions cn dilute the oil. Approprite nozzle geometry could use minimum quntity of coolnt tht cn ccurtely e sent to the re to e cooled [6]. 2. Design of nozzles For simultions in this pper were considered four types of nozzles: the first type serves s the output surfce of the working fluid series of smll dimeter holes. In figure 1 ws rted nozzle numer 1 nd is used minly when cooling fluid with low viscosity. In the cse of using fluid with high viscosity or emulsion cn e used nozzle geometries denoted y 2 nd 3 in figure 1. The nozzle with numer 4 is simple nd cn e found on mny types of mchine tools [7]. Nozzle 1. Nozzle 2. Nozzle 3. Nozzle 4. Figure 1. Different type of nozzles used for simultions. Figure 1 shows the geometric dimensions for ech nozzle, nozzle numer 3 is venture type eing of convergent-divergent type, nozzle numer 1 nd 2 only shows flttening of frontl re to e le to direct the fluid jet s ccurtely in the re to e cooled nd to e luricted if is necessry. 3. Fluid flow simultions The simultions re performed using specilized progrm with finite element which nlysis the flow through the different nozzles with different operting prmeters nd different geometries of convergent-divergent nozzle. These simultions cn e compred to rel working conditions on the mchine tool system. Mthemticl model cn egin from reltion etween pressure nd velocity of fluid, in the nozzle the distnces hve smll vlues the forces of grvity cn e neglected compred to inertil forces nd pressure forces nd hve Bernoulli expression for the fluid [8]: 2

As cn e seen in figure 2 the velocities of the working fluid increses in re in which we hve holes for guiding the fluid jet.

4 2 v p z Const. 2g (1) In wht follows we hve presented in figure 2 velocity distriutions long the nozzle noted down for numer 1 [9, 10]. Figure 2. Velocity vrition long the nozzle no. 1 for two working fluids:. wter;. ir. As cn e seen in figure 2 the velocities of the working fluid increses in re in which we hve holes for guiding the fluid jet. Velocities vlues re s is norml smller for wter thn for ir. Figure 3. Velocity vrition long the nozzle no. 2 for two working fluids:. wter;. ir. For simultions in this pper were chosen the two fluids due their simplicity, to their low cost nd their different properties. Figure 3 presents digrms velocities for nozzle numer 2. 3

5 Figure 4. Velocity vrition long the nozzle no. 3 for two working fluids:. wter;. ir. For this type of nozzle (figure 3) een renounced t the holes in the outlet of the fluid, prcticlly in this re is performed only flttening of the jet of fluid this will record higher vlues of velocities in this re. Figure 5. Velocity vrition long the nozzle no. 4 for two working fluids:. wter;. ir. Figures 4 nd 5 show convergent-divergent nozzle nd simply convergent nozzle used for cooling with wide rnge of coolnts ecuse it is not importnt the working fluid viscosity. Simultions were performed using SolidWorks softwre, initil geometries were estlished for ll four nozzles studied in this pper nd ll kinds of nozzles hve min dimensions similr to e le to nlyse etter them. As input prmeters for simultions we used the two coolnts with their physicl fetures, for ll types of nozzles hve e chosen 3 r t input pressure, nd t the exit of the nozzle ws set the tmospheric pressure ecuse the fluid jet is open to the tmosphere. Figure 6 presents the vrition of the velocities chrts in usle length of nozzles, for etter illustrtion were grouped y the working fluid used. 4

6 Figure 6. Velocity nlysis long the nozzle for two working fluids:. wter;. ir. The nozzle 3 convergent-divergent type shows grph it different from the other three chrts ecuse it hs the middle re where the fluid velocity increses with decresing pressure, which is more pronounced for wter. The ir does not hve the sme friction forces with wll, the chrt resulted pproximtely s for other types of nozzles, registering n increse of ir velocity in the exit re. With computer softwre could simulte the flow inside the chosen nozzle were not tken into ccount other elements which re not relevnt to the study such s: working fluid temperture, convection phenomen of fluid nd wll nozzle, conduction phenomenon trough mteril, ws considered perfect fluid, wll roughness ws neglected nd lod loses of nozzle ecuse it hs reltively smll length. 4. Conclusions After simultions for severl nozzle geometries cn e concluded from the nlysis of flow in the nozzle is very importnt, following this nlysis cn optimize the size nd shpe of the nozzles so tht the cooling fluid to e distriuted more efficiently in the processed re. A specil importnce presents the choice of cooling fluid depending on the geometry of the nozzle so s to eliminte hydrulic lockges tht my rise nd cn led to incresed fluid pumping power nd thus to higher consumption of luricnt or cooling fluid. Correct distriution of the fluid in the re leds to luricnt sving, it no longer wsted, it is recognized tht some coolnt cn e quite expensive, so choosing the right nozzle depending on the physicl properties of the luricnt is lso importnt. Fluid jets re used in mny industries; this pper ims to study the jets of fluid tht pss through the nozzles prticulrly used in mchine uilding industry, with those type of nozzles is performed cooling of mchining zone. In this sense hve een mde mny specific studies to reserch how fluid leves the nozzle nd how it wet in the processing re to chieve n eqution cooling when is used smll quntity of luricnt. Study the wy in which the fluid flows through the nozzle y computer simultion. In mechnicl cutting process is very importnt to study the cooling fluid jet using miniml quntity of fluid. This nlysis rings more clrifiction on the cooling fluid flow inside the nozzle nd cn e nlyzing chrts speeds, pressure or ny nlysis on how the vortex flow is formed nd the influence of nozzle geometry on fluid distriution in the processed re. References [1] Kurnosov N E nd Trnopolskii A V 2007 Air Liquid Luricnt nd Coolnt Aerosols in Mchining Russin Engineering Reserch 27(10) pp [2] Nedelcu D-I nd Olru I 2013 Study of Cooling Prmeters using Fluid Jet in Milling Process Simultion Applied Mechnics nd Mterils 371 (Switzerlnd: Trns Tech Pulictions) pp

7 [3] Ryzhkin A A, Shuchev K G, Aliev M M nd Gusev V V 2008 Dissiptive Properties of Luricnt nd Coolnt Fluid in Cutting nd Friction Russin Engineering Reserch 28(12) pp [4] Rozti A nd Tfti D K 2008 Effect of coolnt minstrem lowing rtio on leding edge film cooling flow nd het trnsfer LES investigtion Interntionl Journl of Het nd Fluid Flow 29 pp [5] Olru I 2013 The Fluid Flow Simultion through to Convergent Nozzle Journl of Engineering Studies nd Reserch 19(2) pp [6] Liu J, Hn R, Zhng L nd Guo H 2007 Study on luricting chrcteristic nd tool wer with wter vpor s coolnt nd luricnt in green cutting Wer 262 pp [7] Olru I 2013 The Fluid Flow Simultion through to Venturi Nozzle Journl of Engineering Studies nd Reserch 19(1) pp [8] Florescu I, Florescu D nd Olru I 2003 Fluid mechnics nd hydrulic mchines Lortory Guidnce (in romnin) (Chişinău: Editur Tehnic Info) [9] Informtion on SolidWorks: Accessed 19/01/2015 [10] Informtion on SolidWorks Tutorils: Accessed 23/02/2015 6

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