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Muchidzidzo ichi, iyo hydrodynamics ye flocculation inoongororwa nekuedza uye nhamba yekuongorora kwemhirizhonga inoyerera yevheji yemunda murabhoritari chiyero paddle flocculator.Kuyerera kwemhirizhonga kunosimudzira kuunganidzwa kwechikamu kana floc kutsemuka kwakaoma uye kunotariswa nekuenzaniswa mubepa rino uchishandisa maviri emhirizhonga modhi, anoti SST k-ω uye IDDES.Mhedzisiro yacho inoratidza kuti IDDES inopa diki diki kuvandudzwa pamusoro peSST k-ω, iyo inokwana kunyatso kutevedzera kuyerera mukati me paddle flocculator.Chibodzwa chakakodzera chinoshandiswa kuongorora kuchinjika kwePIV neCFD mhedzisiro, uye kuenzanisa mhedzisiro yeCFD turbulence modhi yakashandiswa.Chidzidzo ichi zvakare chinotarisa pakuenzanisa iyo slip factor k, inova 0.18 pakumhanya kwakaderera kwe3 uye 4 rpm zvichienzaniswa neyakajairwa kukosha kwe0.25.Kuderedza k kubva pa0.25 kusvika 0.18 kunowedzera simba rinounzwa kumvura ne27-30% uye kunowedzera velocity gradient (G) nezvikamu gumi neina.Izvi zvinoreva kuti kusanganiswa kwakanyanya kunowanikwa kupfuura zvinotarisirwa, saka simba shoma rinopedzwa, uye saka kushandiswa kwesimba mu flocculation unit yemvura yekunwa yekurapa chirimwa inogona kuderera.
Mukucheneswa kwemvura, kuwedzera kwecoagulants kunoshatisa diki colloidal particles uye tsvina, izvo zvino zvinosanganiswa kuita flocculation pa flocculation stage.Mafuraki akasungwa zvakasununguka fractal aggregates of mass, ayo anobva abviswa nekugadzirisa.Particle zvivakwa uye mvura kusanganisa mamiriro anoona kugona kweiyo flocculation uye maitiro ekurapa.Flocculation inoda kubvongodzwa zvishoma kwenguva pfupi uye simba rakawanda kubvongodza mavhoriyamu makuru emvura1.
Munguva ye flocculation, iyo hydrodynamics yehurongwa hwese uye chemistry ye coagulant-particle kupindirana inotarisisa chiyero icho chinomira chimedu saizi kugoverwa chinowanikwa2.Kana zvimedu zvabonderana zvinonamatirana3.Oyegbile, Ay4 yakashuma kuti kudhumhana kunoenderana nekuyerera kwekufambisa nzira dzeBrownian diffusion, fluid shear uye musiyano wekugadzirisa.Kana maflakes akadhumhana, anokura uye anosvika kune imwe saizi muganho, izvo zvinogona kutungamirira mukuputsika, sezvo maflakes asingakwanisi kumira nesimba re hydrodynamic forces5.Mamwe eaya akatyoka maflakes anosanganiswa kuita madiki kana saizi yakafanana6.Nekudaro, maflakes akasimba anogona kuramba simba iri uye kuchengetedza saizi yavo uye kunyange kukura7.Yukselen naGregory8 vakashuma pamusoro pezvidzidzo zvine chekuita nekuparadzwa kwemaflakes uye kugona kwavo kudzoreredza, zvichiratidza kuti kusagadziriswa kunogumira.Bridgeman, Jefferson9 akashandisa CFD kufungidzira pesvedzero yemuno yekurevesa kuyerera uye kusagadzikana pakuumbwa kwefloc uye kupatsanurwa kuburikidza nemunharaunda velocity gradients.Mumatangi ane rotor blades, zvinodikanwa kusiyanisa kumhanya uko iyo aggregates inodhumhana nezvimwe zvimedu kana zvanyatso kugadzikana muchikamu checoagulation.Nekushandisa CFD uye yakaderera kutenderera kumhanya kweanosvika gumi nemashanu rpm, Vadasarukkai neGagnon11 vakakwanisa kuwana G values yekutenderera neconical blades, nekudaro kuderedza kushandiswa kwesimba kubvongodza.Nekudaro, kushanda kune yakakwira G kukosha kunogona kutungamira mukuyerera.Ivo vakaongorora mhedzisiro yekusanganisa kumhanya pakuona avhareji velocity gradient yemutyairi paddle flocculator.Vanotenderera nekumhanya kweanopfuura 5 rpm.
Korpijärvi, Ahlstedt12 yakashandisa mamodhi mana akasiyana emhirizhonga kudzidza nzvimbo yekuyerera pabhenji rekuyedza tangi.Vakayera nzvimbo yekuyerera nelaser Doppler anemometer uye PIV uye vakaenzanisa zvakaverengerwa mhedzisiro neyakayerwa mhinduro.de Oliveira naDonadel13 vakakurudzira imwe nzira yekufungidzira velocity gradients kubva kuhydrodynamic zvivakwa vachishandisa CFD.Iyo nzira yakatsanangurwa yakaedzwa pamatanho matanhatu e flocculation zvichienderana nehelical geometry.yakaongorora mhedzisiro yenguva yekuchengetedza pane flocculants uye yakaronga flocculation modhi inogona kushandiswa sechishandiso chekutsigira rational cell design ine yakaderera yekuchengetedza nguva14.Zhan, You15 yakurudzira yakasanganiswa CFD uye huwandu hwehuwandu hwemhando yekutevedzera kuyerera maitiro uye floc maitiro mukuzara kwakazara flocculation.Llano-Serna, Coral-Portillo16 yakaongorora maitiro ekuyerera kweCox-type hydroflocculator mune imwe nzvimbo yekuchenesa mvura muViterbo, Colombia.Kunyangwe CFD iine zvayakanakira, pane zvakare zvipimo zvakaita sekukanganisa kwenhamba mukuverenga.Naizvozvo, chero mhinduro dzenhamba dzinowanikwa dzinofanira kunyatsoongororwa uye kuongororwa kuitira kuti iwane mhedziso dzakakomba17.Pane zvidzidzo zvishoma mumabhuku nezve dhizaini yakachinjika baffle flocculators, nepo kurudziro yekugadzirwa kwehydrodynamic flocculators inogumira18.Chen, Liao19 yakashandisa kuyedza kuseta yakavakirwa pakupararira kwechiedza chepolarized kuyera mamiriro epolarization yechiedza chakapararira kubva kune chimwe nechimwe.Feng, Zhang20 yakashandisa Ansys-Fluent kutevedzera kugoverwa kweeddy currents uye kutenderera mumunda wekuyerera weiyo coagulated plate flocculator uye inter-corrugated flocculator.Mushure mekuenzanisa mhirizhonga yekuyerera kwemvura muflocculator uchishandisa Ansys-Fluent, Gavi21 yakashandisa mhedzisiro kugadzira iyo flocculator.Vaneli naTeixeira22 vakashuma kuti hukama huri pakati pemvura inoshanduka ye spiral tube flocculators uye flocculation process ichiri kunzwisiswa zvisina kunaka kutsigira dhizaini inonzwisisika.de Oliveira naCosta Teixeira23 vakadzidza kushanda zvakanaka uye vakaratidza hydrodynamic zvimiro zve spiral chubhu flocculator kuburikidza nekuyedza fizikisi uye CFD simulations.Vatsvakurudzi vakawanda vakadzidza akakoswa machubhu reactor kana coiled tube flocculators.Nekudaro, ruzivo rwakadzama rwe hydrodynamic pamusoro pemhinduro yeaya mareactor kune akasiyana magadzirirwo uye mamiriro ekushanda achiri kushaikwa (Sartori, Oliveira24; Oliveira, Teixeira25).Oliveira naTeixeira26 vanopa mhedzisiro yepakutanga kubva kune theoretical, kuyedza uye CFD simulations ye spiral flocculator.Oliveira naTeixeira27 vakaronga kushandisa spiral coil se coagulation-flocculation reactor pamwe chete neyakajairwa decanter system.Vanoshuma kuti mibairo yakawanikwa yekubvisa turbidity inonyatso siyana neiyo inowanikwa neanowanzo shandiswa modhi yekuongorora flocculation, vachipa kungwarira kana uchishandisa mhando dzakadaro.Moruzzi na de Oliveira [28] vakaenzanisira maitiro ehurongwa hwemakamuri anoramba achiyerera pasi pemamiriro akasiyana-siyana ekushanda, kusanganisira kusiyanisa kwenhamba yemakamuri anoshandiswa uye kushandiswa kwezvakagadziriswa kana kuenzaniswa kwesero velocity gradients.Romphophak, Le Men29 PIV zviyero zvepakarepo velocities mune quasi-two-dimensional jet cleaners.Vakawana kutenderera kwakasimba kwejeti munzvimbo ye flocculation uye inofungidzirwa yemunharaunda uye pakarepo shear rates.
Shah, Joshi30 inoshuma kuti CFD inopa inonakidza imwe nzira yekuvandudza magadzirirwo uye kuwana chaiwo kuyerera maitiro.Izvi zvinobatsira kudzivirira yakawanda yekuedza setups.CFD iri kuwedzera kushandiswa kuongorora mvura netsvina yekuchenesa zvirimwa (Melo, Freire31; Alalm, Nasr32; Bridgeman, Jefferson9; Samaras, Zouboulis33; Wang, Wu34; Zhang, Tejada-Martínez35).Vaongorori vakati wandei vakaita zviedzo pazvinogona kuyedza michina (Bridgeman, Jefferson36; Bridgeman, Jefferson5; Jarvis, Jefferson6; Wang, Wu34) uye perforated disc flocculators31.Vamwe vakashandisa CFD kuongorora hydroflocculators (Bridgeman, Jefferson5; Vadasarukkai, Gagnon37).Ghawi21 yakashuma kuti ma flocculators anodhinda anoda kugadziridzwa nguva nenguva sezvo achigara achiputsika uye achida magetsi akawanda.
Kuitwa kwepaddle flocculator kunoenderana zvakanyanya neiyo hydrodynamics yedhamu.Kushaikwa kwekunzwisisa kwehuwandu hwekuyerera velocity minda mumaflocculators akadaro kunoonekwa zvakajeka mumabhuku (Howe, Hand38; Hendricks39).Iyo yese mvura yakawanda inozviisa pasi pekufamba kweiyo flocculator impeller, saka kutsvedza kunotarisirwa.Kazhinji, kumhanya kwemvura kudiki pane blade velocity ne slip factor k, iyo inotsanangurwa sereshiyo yekumhanya kwemuviri wemvura kune velocity yevhiri repaddle.Bhole40 yakataura kuti pane zvinhu zvitatu zvisingazivikanwe zvekufunga nezvazvo paunenge uchigadzira flocculator, zvinoti velocity gradient, coefficient yekukwevera, uye kumhanya kwemvura kunoenderana neblade.
Camp41 inoshuma kuti kana uchifunga nezvemichina yekumhanya kwazvo, kumhanya kunenge 24% yerotor kumhanya uye yakakwira se32% kune yakaderera kumhanya michina.Mukushaikwa kwesepta, Droste naGer42 vakashandisa ak kukosha kwe0.25, nepo septa, k kubva pa0 kusvika ku0.15.Howe, Hand38 inoratidza kuti k iri pakati pe0.2 kusvika 0.3.Hendrix39 yakabatanidza iyo slip factor nekumhanyisa kutenderera ichishandisa empirical formula uye yakagumisa kuti slip factor yaivewo mukati meiyo yakagadzwa neCamp41.Bratby43 yakashuma kuti k ingangoita 0.2 yekumhanyisa kumhanya kubva 1.8 kusvika 5.4 rpm uye inowedzera kusvika 0.35 yeimpeller kumhanya kubva 0.9 kusvika 3 rpm.Vamwe vaongorori vanotaura huwandu hwakasiyana hwekudhonza coefficient (Cd) kukosha kubva pa1.0 kusvika 1.8 uye inotsvedza coefficient k values kubva pa0.25 kusvika 0.40 (Feir naGeyer44; Hyde naLudwig45; Harris, Kaufman46; van Duuren47; uye 4 Brat8by naMarais8by )Mabhuku haaratidze kufambira mberi kwakakosha mukutsanangura uye kuenzanisa k kubva pabasa reCamp41.
Iyo flocculation process yakavakirwa panyonganyonga yekugonesa kukondera, uko velocity gradient (G) inoshandiswa kuyera turbulence/flocculation.Kusanganisa inzira yekukurumidza uye yakaenzana kuparadzira makemikari mumvura.Dhigirii yekusanganisa inoyerwa nevelocity gradient:
uko G = velocity gradient (sec-1), P = simba rekuisa (W), V = vhoriyamu yemvura (m3), μ = dynamic viscosity (Pa s).
Iyo yakakwirira iyo G kukosha, iyo yakanyanya kusanganiswa.Kunyatso kusanganisa kwakakosha kuti uve nechokwadi chekuti yunifomu coagulation.Zvinyorwa zvinoratidza kuti zvakakosha dhizaini paramita kusanganisa nguva (t) uye velocity gradient (G).Iyo flocculation process yakavakirwa panyonganyonga yekugonesa kukondera, uko velocity gradient (G) inoshandiswa kuyera turbulence/flocculation.Yakajairika dhizaini kukosha kweG ndeye 20 kusvika 70 s-1, t i15 kusvika 30 maminetsi, uye Gt (dimensionless) ndeye 104 kusvika 105. Fast musanganiswa matangi anoshanda zvakanyanya neG kukosha kwe700 kusvika 1000, nekugara kwenguva. anenge 2 maminitsi.
uko P ndiro simba rinopihwa kumvura nechero flocculator blade, N ndiyo inotenderera, b ndiyo kureba kweblade, ρ ndiko kuwanda kwemvura, r ndiyo radius, uye k ndiyo inotsvedza coefficient.Iyi equation inoiswa kune yega yega blade uye mibairo inopfupikiswa kupa iyo yakazara simba yekuisa ye flocculator.Kunyatsoongorora kweiyi equation kunoratidza kukosha kweiyo slip factor k mukugadzira maitiro epaddle flocculator.Mabhuku haatauri kukosha chaiko kwe k, asi panzvimbo pezvo anokurudzira siyana sezvakambotaurwa.Nekudaro, hukama pakati pesimba P uye inotsvedza coefficient k is cubic.Saka, chero ma parameter ese akafanana, semuenzaniso, kuchinja k kubva ku0,25 kusvika 0.3 kuchaita kuti kuderera kwesimba rinopfuudzwa kumvura kune blade ne20%, uye kuderedza k kubva 0.25 kusvika 0.18 kuchamuwedzera.by about 27-30% per vane Simba rinopihwa kumvura.Pakupedzisira, mhedzisiro ye k pane inogadzika paddle flocculator dhizaini inoda kuongororwa kuburikidza nehunyanzvi quantification.
Yakarurama empirical quantification yekutsvedza inoda kuyerera kwekuona uye simulation.Naizvozvo, zvakakosha kutsanangura tangential kumhanya kweblade mumvura pane imwe nhanho yekutenderera pamatanho akasiyana eradial kubva kune shaft uye pakadzika kwakasiyana kubva pamusoro pemvura kuitira kuti uongorore mhedzisiro yenzvimbo dzakasiyana dzeblade.
Muchidzidzo ichi, iyo hydrodynamics ye flocculation inoongororwa nekuedza uye nhamba yekuongorora kwemhirizhonga inoyerera yevheji yemunda murabhoritari chiyero paddle flocculator.Zviyero zvePIV zvinorekodhwa pane flocculator, zvichigadzira nguva-avhareji velocity contours inoratidza kukurumidza kwezvikamu zvemvura zvakatenderedza mashizha.Uye zvakare, ANSYS-Fluent CFD yakashandiswa kutevedzera kutenderera kuyerera mukati meiyo flocculator uye kugadzira nguva-avhareji velocity contours.Iyo yakaguma CFD modhi yakasimbiswa nekuongorora tsamba pakati pePIV neCFD zvawanikwa.Chinangwa chebasa iri pakuenzanisa slip coefficient k, iri dimensionless dhizaini parameter ye paddle flocculator.Basa rinoratidzwa pano rinopa hwaro hutsva hwekuenzanisa slip coefficient k nekumhanya kwakaderera kwe3 rpm uye 4 rpm.Mhedzisiro yemhedzisiro inobatsira mukunzwisisa zvirinani kweiyo hydrodynamics ye flocculation tank.
Murabhoritari flocculator ine yakavhurika pamusoro rectangular bhokisi rine hurefu hwese 147 cm, kureba 39 cm, hupamhi hwese 118 cm, uye kureba kwese 138 cm (Fig. 1).Nzira huru yekugadzira yakagadzirwa neCamp49 yakashandiswa kugadzira laboratory scale paddle flocculator uye kushandisa nheyo dzekuongorora kwedimensional.Nzvimbo yekuyedza yakavakwa paEnvironmental Engineering Laboratory yeLebanese American University (Byblos, Lebanon).
Iyo horizontal axis iri pahurefu hwemasendimita makumi matanhatu kubva pasi uye inogara mavhiri maviri epaddle.Gumbo rega rega repaddle rine 4 paddles ine 3 paddles pane yega yega paddles anokwana gumi nemaviri.Flocculation inoda kubvongodzwa zvinyoro pane yakaderera kumhanya kwe2 kusvika 6 rpm.Iyo inonyanya kusanganisa kumhanya mumaflocculators ndeye 3 rpm uye 4 rpm.Iyo laboratory scale flocculator kuyerera yakagadzirirwa kumiririra kuyerera mu flocculation tank compartment yeinonwa mvura yekurapa chirimwa.Simba rinoverengwa pachishandiswa equation yechinyakare 42.Pamamhanyiro ese ari maviri, sipidhi gradient \(\stackrel{\mathrm{-}}{\text{G}}\) inopfuura 10 \({\text{sec}}^{-{1}}\) , nhamba yeReynolds inoratidza mhirizhonga inoyerera (Tafura 1).
PIV inoshandiswa kuwana kwakaringana uye kuwanda kuyerwa kwe fluid velocity vectors panguva imwe chete pane yakakura kwazvo nhamba ye50.Iyo yekuyedza setup yaisanganisira lab-scale paddle flocculator, LaVision PIV system (2017), uye Arduino yekunze laser sensor trigger.Kugadzira nguva-avhareji velocity profiles, mifananidzo yePIV yakanyorwa zvakatevedzana panzvimbo imwe chete.Iyo PIV sisitimu inogadziriswa zvekuti nzvimbo yainonangwa iri pakati pehurefu hwechimwe nechimwe chemashizha matatu erumwe ruoko rwepaddle.Iyo yekunze inokonzeresa ine laser inowanikwa kune rimwe divi reiyo flocculator upamhi uye sensor inogamuchira kune rimwe divi.Nguva imwe neimwe iyo flocculator ruoko inovhara nzira yelaser, chiratidzo chinotumirwa kuPIV system kutora mufananidzo nePIV laser uye kamera yakawiriraniswa neinogoneka nguva unit.Pamusoro pemuonde.2 inoratidza kuiswa kwePIV system uye maitiro ekutora mufananidzo.
Kurekodhwa kwePIV kwakatangwa mushure mekunge flocculator yashandiswa kwe5-10 min kuti iite kuti kuyerera kuwedzere uye funga iyo yakafanana refractive index field.Calibration inowanikwa nekushandisa calibration plate yakanyudzwa mu flocculator uye yakaiswa pakati pehurefu hweblade yekufarira.Gadzirisa nzvimbo yePIV laser kuti iite jira rakapfava rakananga pamusoro peiyo calibration plate.Rekodha zviyero zvakayerwa kune yega yega yekutenderera kumhanya kwechero rega, uye kumhanya kutenderera kwakasarudzwa kuyedza 3 rpm uye 4 rpm.
Kune ese marekodha ePIV, nguva yepakati pakati pemalaser pulses maviri yakaiswa muchikamu kubva pa6900 kusvika 7700 µs, iyo yakabvumira kadiki diki kutamiswa kwe5 pixels.Mayedzo emutyairi akaitwa pahuwandu hwemifananidzo inodiwa kuti uwane zviyero zveavhareji yenguva.Vector statistics yakaenzaniswa yemasampuli ane 40, 50, 60, 80, 100, 120, 160, 200, 240, uye 280 mifananidzo.Saizi yesaizi yemifananidzo mazana maviri nemakumi mana yakawanikwa ichipa yakagadzikana-yepakati-yenguva mhinduro zvakapihwa kuti mufananidzo wega wega une maforemu maviri.
Sezvo kuyerera mu flocculator kune mhirizhonga, hwindo diki rekubvunzurudza uye nhamba huru yezvimedu zvinodiwa kugadzirisa zvimiro zvidiki zvinonetsa.Kudzokororwa kwakati wandei kwekudzikisira saizi kunoiswa pamwe neyakachinjika-yekubatanidza algorithm kuti ive nechokwadi.Hwindo rekutanga rekuvhota saizi ye48 × 48 pixels ine 50% kupindirana uye imwe nzira yekugadzirisa yakateverwa neyekupedzisira yekuvhota hwindo saizi ye32 × 32 pixels ine 100% kupindirana uye maviri ekugadzirisa maitiro.Pamusoro pezvo, girazi hollow spheres raishandiswa sezvimedu zvembeu mukuyerera, izvo zvaibvumira kanenge 10 zvimedu pahwindo rekuvhota.Kurekodha kwePIV kunokonzereswa neinokonzeresa sosi muProgrammable Timing Unit (PTU), iyo ine basa rekushandisa uye kuwiriranisa iyo laser sosi uye kamera.
Iyo yekutengesa CFD package ANSYS Fluent v 19.1 yakashandiswa kugadzira iyo 3D modhi uye kugadzirisa iwo ekutanga kuyerera equations.
Kushandisa ANSYS-Fluent, modhi ye3D yerabhoritari-scale paddle flocculator yakagadzirwa.Iyo modhi inogadzirwa muchimiro chebhokisi rectangular, rine maviri epaddle mavhiri akaiswa pane yakachinjika axis, senge yerabhoritari modhi.Iyo modhi isina freeboard ndeye 108 cm kureba, 118 cm yakafara uye 138 cm kureba.Ndege yakachinjika cylindrical yakawedzerwa kutenderedza musanganisi.Cylindrical plane generation inofanira kushandisa kutenderera kwemusanganisi wose panguva yekuisa uye kutevedzera iyo inotenderera inoyerera munda mukati me flocculator, sezvakaratidzwa muFig. 3a.
3D ANSYS-inotsetseka uye modhi geometry dhiyagiramu, ANSYS-inotsetseka flocculator muviri mesh pane ndege inofarira, ANSYS-inotsetseka dhayagiramu pandege yekufarira.
Iyo modhi geometry ine matunhu maviri, imwe neimwe iine mvura.Izvi zvinowanikwa uchishandisa zvine musoro kubvisa basa.Kutanga bvisa humburumbira (kusanganisira musanganisi) kubva mubhokisi kumiririra mvura.Wobva wabvisa musanganisi kubva muhumburumbira, zvichikonzera zvinhu zviviri: musanganisi uye mvura.Pakupedzisira, sliding interface yakashandiswa pakati penzvimbo mbiri: cylinder-cylinder interface uye cylinder-mixer interface (Fig. 3a).
Iyo meshing yemamodheru akavakirwa yakapedzwa kuti isangane nezvinodiwa zvemodhiyo yemhirizhonga iyo ichashandiswa kumhanyisa manhamba ekuenzanisa.Mesh isina kuumbwa ine mitsara yakawedzerwa pedyo nenzvimbo yakasimba yakashandiswa.Gadzira mitsara yekuwedzera yemadziro ese ane mwero wekukura we 1.2 kuona kuti yakaoma mafambiro ekuyerera anotorwa, nehupamhi hwekutanga hwe \(7\mathrm{ x {10}^{-4}\) m kuona kuti \ ( {\ chinyorwa {y))^{+}\le 1.0\).Saizi yemuviri inogadziriswa uchishandisa tetrahedron yakakodzera nzira.Saizi yekumberi yemativi maviri ane saizi ye2.5 × \({10}^{-3}\) m inogadzirwa, uye saizi yepamberi yemusanganisi ye9 × \({10}^{-3}\ ) m inoshandiswa.Iyo yekutanga yakagadzirwa mesh yaive ne2144409 zvinhu (Fig. 3b).
A two-parameter k–ε turbulence modhi yakasarudzwa seyokutanga base modhi.Kuti unyatso kutevedzera kutenderera kuyerera mukati meiyo flocculator, imwe yakawedzera kudhura modhi yakasarudzwa.Iyo mhirizhonga inoyerera mukati meiyo flocculator yakaongororwa nenhamba uchishandisa maviri eCFD modhi: SST k-ω51 uye IDDES52.Mhedzisiro yemhando mbiri idzi dzakaenzaniswa neyekuyedza PIV mhedzisiro yekusimbisa mamodheru.Chekutanga, iyo SST k-ω turbulence modhi imbiri-equation turbulent viscosity modhi yemashandisirwo emagetsi emagetsi.Iyi imhando yakasanganiswa inosanganisa iyo Wilcox k-ω uye k-ε modhi.Basa rekusanganisa rinoita Wilcox modhi padyo nemadziro uye k-ε modhi mukuyerera kuri kuuya.Izvi zvinovimbisa kuti iyo chaiyo modhi inoshandiswa munzvimbo yese yekuyerera.Iyo inofanotaura nenzira kwayo kuyerera kuparadzaniswa nekuda kwekuipa kwekumanikidza gradients.Kechipiri, iyo Advanced Deferred Eddy Simulation (IDDES) nzira, yakashandiswa zvakanyanya muIndividual Eddy Simulation (DES) modhi ine SST k-ω Rans (Reynolds-Averaged Navier-Stokes) modhi, yakasarudzwa.IDDES ihybrid RNS-LES (hombe eddy simulation) iyo inopa inochinjika uye mushandisi-ane hushamwari kugadzirisa kuyera (SRS) simulation modhi.Iyo yakavakirwa paiyo LES modhi yekugadzirisa hombe eddies uye kudzokera kuSST k-ω kutevedzera madiki madiki.Statistical ongororo yemhedzisiro kubva kuSST k–ω uye IDDES simulations yakaenzaniswa neiyo PIV mhedzisiro yekusimbisa modhi.
A two-parameter k–ε turbulence modhi yakasarudzwa seyokutanga base modhi.Kuti unyatso kutevedzera kutenderera kuyerera mukati meiyo flocculator, imwe yakawedzera kudhura modhi yakasarudzwa.Iyo mhirizhonga inoyerera mukati meiyo flocculator yakaongororwa nenhamba uchishandisa maviri eCFD modhi: SST k-ω51 uye IDDES52.Mhedzisiro yemhando mbiri idzi dzakaenzaniswa neyekuyedza PIV mhedzisiro yekusimbisa mamodheru.Chekutanga, iyo SST k-ω turbulence modhi imbiri-equation turbulent viscosity modhi yemashandisirwo emagetsi emagetsi.Iyi imhando yakasanganiswa inosanganisa iyo Wilcox k-ω uye k-ε modhi.Basa rekusanganisa rinoita Wilcox modhi padyo nemadziro uye k-ε modhi mukuyerera kuri kuuya.Izvi zvinovimbisa kuti iyo chaiyo modhi inoshandiswa munzvimbo yese yekuyerera.Iyo inofanotaura nenzira kwayo kuyerera kuparadzaniswa nekuda kwekuipa kwekumanikidza gradients.Kechipiri, iyo Advanced Deferred Eddy Simulation (IDDES) nzira, yakashandiswa zvakanyanya muIndividual Eddy Simulation (DES) modhi ine SST k-ω Rans (Reynolds-Averaged Navier-Stokes) modhi, yakasarudzwa.IDDES ihybrid RNS-LES (hombe eddy simulation) iyo inopa inochinjika uye mushandisi-ane hushamwari kugadzirisa kuyera (SRS) simulation modhi.Iyo yakavakirwa paiyo LES modhi yekugadzirisa hombe eddies uye kudzokera kuSST k-ω kutevedzera madiki madiki.Statistical ongororo yemhedzisiro kubva kuSST k–ω uye IDDES simulations yakaenzaniswa neiyo PIV mhedzisiro yekusimbisa modhi.
Shandisa kudzvanywa-kwakavakirwa kwenguva pfupi solver uye shandisa giravhiti munzira yeY.Kutenderera kunowanikwa nekupa mesh kufamba kune musanganisi, uko kwakabva axis yekutenderera iri pakati peiyo axis yakachinjika uye kwainotenderera axis iri munzira yeZ.Iyo mesh interface inogadzirwa kune ese ari maviri modhi geometry interfaces, zvichikonzera maviri anosungirirwa mabhokisi edge.Sezviri muhunyanzvi hwekuyedza, kumhanya kwekutenderera kunoenderana ne3 uye 4 marevolutions.
Mamiriro emuganhu wemadziro emusanganisi uye flocculator akaiswa pamadziro, uye kuvhurika kwepamusoro kweiyo flocculator kwakaiswa nekubuda ne zero gauge pressure (Fig. 3c).SIMPLE pressure-velocity communication scheme, discretization of the gradient space of second-order function with all parameters based on little squares elements.Chiyero chekubatanidza chemarudzi ese ekuyerera ndicho chikero chasara 1 x \({10}^{-3}\).Iyo yakawanda nhamba yekudzokorora pane imwe nguva nhanho ndeye 20, uye nhanho yenguva saizi inoenderana nekutenderera kwe0.5 °.Mhinduro inoshanduka pa 8th iteration ye SST k–ω modhi uye pa 12th iteration uchishandisa IDDES.Mukuwedzera, nhamba yematanho enguva yakaverengerwa kuitira kuti musanganisi aite kanenge ka12 marevolutions.Shandisa data sampling yehuwandu hwenguva mushure mekutenderera kwe3, iyo inobvumira kuenzanisa kwekuyerera, kufanana nekuedza maitiro.Kuenzanisa kubuda kwemalopu ekumhanya kwechimurenga chega chega kunopa mibairo yakangofanana pamarendurudzo mana ekupedzisira, zvichiratidza kuti nzvimbo yakatsiga yasvikwa.Iwo marevs ekuwedzera haana kunatsiridza ari epakati sipidhi contours.
Nhanho yenguva inotsanangurwa maererano nekutenderera kwekutenderera, 3 rpm kana 4 rpm.Nhanho yenguva inonatswa kusvika panguva inodiwa kutenderedza musanganisi ne 0.5 °.Izvi zvinoshanduka kuve zvakakwana, sezvo mhinduro ichichinjika nyore, sezvakatsanangurwa muchikamu chakapfuura.Saka, maverengero enhamba emhando dzese dzemhirizhonga akaitwa pachishandiswa nhanho yenguva yakagadziridzwa ye0.02 \(\stackrel{\mathrm{-}}{7}\) ye3 rpm, 0.0208 \(\stackrel{\mathrm{-} {3}\) 4 rpm.Kune yakapihwa nhanho yenguva yekukwenenzvera, iyo Courant nhamba yesero inogara iri pasi pe1.0.
Kuongorora kutsamira kwemodhi-mesh, mhedzisiro yakatanga kuwanikwa uchishandisa yekutanga 2.14M mesh uyezve yakakwenenzverwa 2.88M mesh.Kukwenenzvera kwegridi kunowanikwa nekudzikisa ukuru hwesero remusanganisi muviri kubva pa9 × \({10}^{-3}\) m kusvika 7 × \({10}^{-3}\) m.Kune ekutanga uye akacheneswa meshes emhando mbiri mhirizhonga, avhareji kukosha kwevelocity modules munzvimbo dzakasiyana dzakatenderedza blade dzakaenzaniswa.Musiyano wepakati pakati pezvabuda i1.73% yeSST k–ω modhi uye 3.51% yeIDDES modhi.IDDES inoratidza mutsauko wepamusoro wepakati nekuti ihybrid RNS-LES modhi.Misiyano iyi yaionekwa se isingakoshi, saka simulation yakaitwa pachishandiswa mesh yepakutanga ine 2.14 miriyoni zvinhu uye kutenderera nguva nhanho ye0.5 °.
Kuberekwazve kwemigumisiro yekuedza kwakaongororwa nekuita imwe neimwe yezviyero zvitanhatu kechipiri uye nekuenzanisa migumisiro.Enzanisa kumhanyisa kukosha pakati peblade mune maviri akatevedzana ekuedza.Avhareji yepakati mutsauko pakati pemapoka maviri ekuedzwa yaive 3.1%.Iyo PIV system zvakare yakazvimiririra yakadzokororwa pakuedza kwega kwega.Enzanisa kumhanya kwakaverengerwa kwakaverengerwa pakati peblade yega yega nePIV kumhanya panzvimbo imwe chete.Kuenzanisa uku kunoratidza mutsauko nemhosho yepamusoro muzana ye6.5% yeblade 1.
Usati waverengera iyo inotsvedza chinhu, zvinodikanwa kuti unzwisise nesainzi pfungwa yekutsvedza mune paddle flocculator, izvo zvinoda kudzidza kuyerera chimiro chakatenderedza paddles ye flocculator.Sezvineiwo, iyo inotsvedza coefficient yakavakirwa mudhizaini yemapaddle flocculators kuti atarise kumhanya kwemablades ane chekuita nemvura.Mabhuku anokurudzira kuti kumhanya uku kuve 75% yekumhanya kweblade, saka magadzirirwo mazhinji anowanzo shandisa ak ye0.25 kuzvidavirira pakugadzirisa uku.Izvi zvinoda kushandiswa kwevelocity streamlines inotorwa kubva kuPIV kuyedza kuti unzwisise zvizere iyo inoyerera velocity ndima uye kudzidza iyi slip.blade 1 ndiro blade remukati-kati riri pedyo neshaft, blade 3 ndiro rekunze, uye blade 2 ndiro repakati.
Velocity inoyerera pablade 1 inoratidza kutenderera kwakananga kuyerera kwakatenderedza blade.Aya maitiro ekuyerera anobuda kubva pane imwe nzvimbo kurudyi rweblade, pakati pe rotor uye blade.Tichitarisa nzvimbo inoratidzwa nebhokisi dzvuku rine madota muMufananidzo 4a, zvinonakidza kuona chimwe chikamu chekutenderera kuyerera kumusoro uye kutenderedza blade.Kuyerera kwekuona kunoratidza kuyerera kudiki munzvimbo yekudzokorora.Kuyerera uku kunosvika kubva kurutivi rwerudyi rweblade pahupamhi hwemasendimita matanhatu kubva kumagumo eshizha, zvichida nekuda kwesimba rekutanga blade reruoko rinotangira blade, iro rinoonekwa mumufananidzo.Kuyerera kwekuona pa4 rpm kunoratidza maitiro akafanana uye chimiro, sezviri pachena nekumhanya kwakanyanya.
Velocity munda uye magirafu azvino emablades matatu paviri kutenderera kumhanya kwe3 rpm uye 4 rpm.Ivhareji yekumhanya kwema blades matatu pa 3 rpm i 0.15 m / s, 0.20 m / s uye 0.16 m / s zvichienderana, uye iyo yakawanda yevhareji yekumhanya pa 4 rpm ndeye 0.15 m / s, 0.22 m / s uye 0.22 m / s, zvichiteerana.pamapepa matatu.
Imwe nzira yehelical flow yakawanikwa pakati pevane 1 uye 2. Munda wevector unoratidza zvakajeka kuti mvura inoyerera inofamba ichikwira kumusoro kubva pasi pevheti 2, sezvinoratidzwa nekutungamira kwevector.Sezvinoratidzwa nebhokisi rine madoti mumufananidzo 4b, mavheji aya haaendi akakwira kumusoro kubva pachiso cheblade, asi anotendeukira kurudyi uye zvishoma nezvishoma achidzika.Pamusoro pe blade 1, mavheji anodzika anosiyaniswa, ayo anoswedera kune ese maviri blade uye anoatenderedza kubva kune recirculation kuyerera kwakaumbwa pakati pavo.Iyo yakafanana yekuyerera chimiro yakatemerwa pane ese ari maviri ekutenderera kumhanya neakakwira kumhanya amplitude ye4 rpm.
Munda wevelocity we blade 3 hauiti mupiro wakakosha kubva kune velocity vector yeblade yapfuura inobatanidza kuyerera pasi pe blade 3. Kuyerera kukuru pasi pe blade 3 kunokonzerwa ne vertical velocity vector inokwira nemvura.
Velocity vectors pamusoro pepamusoro pe blade 3 inogona kugoverwa mumapoka matatu, sezvinoratidzwa mumufananidzo 4c.Seti yekutanga ndiyo iri pamucheto wekurudyi weblade.Chimiro chekuyerera munzvimbo iyi chakananga kurudyi uye kumusoro (kureva kune blade 2).Boka rechipiri ndiro pakati pebadza.Velocity vector yenzvimbo iyi inonangidzirwa kumusoro, pasina kana kutsauka uye pasina kutenderera.Kuderera kwekukosha kwevelocity kwakatemwa nekuwedzera kwekukwirira pamusoro pekupedzisira kweblade.Kune boka rechitatu, riri kuruboshwe rworuboshwe rwemashizha, kuyerera kunobva kwananga kuruboshwe, kureva kumadziro e flocculator.Yakawanda yekuyerera inomiririrwa nevelocity vector inokwira kumusoro, uye chikamu chekuyerera chinoenda chakatwasuka pasi.
Mhando mbiri dzemhirizhonga, SST k–ω neIDDES, dzakashandiswa kugadzira avhareji yenguva-yevhavha profiles ye3 rpm uye 4 rpm mublade inoreva kureba ndege.Sezvinoratidzwa muMufananidzo 5, kugadzikana kunowanikwa kuburikidza nekuwana kufanana kwakakwana pakati pevelocity contours yakagadzirwa nekutenderera kunotevera.Mukuwedzera, nguva-yevhareji velocity contours yakagadzirwa neIDDES inoratidzwa muFig. 6a, nepo nguva-yevhareji yevheji profiles yakagadzirwa neSST k - ω inoratidzwa muFig. 6a.6b.
Uchishandisa IDDES uye nguva-avhareji velocity loops inogadzirwa neSST k–ω, IDDES ine chikamu chepamusoro chevelocity loops.
Nyatsoongorora purogiramu yekukurumidza yakagadzirwa neIDDES pa3 rpm sezvakaratidzwa muMufananidzo 7. Musanganisi anotenderera newachi uye kuyerera kunokurukurwa maererano nemashoko anoratidzwa.
Pamusoro pemuonde.7 inogona kuonekwa kuti pamusoro pechidzitiro 3 muI quadrant pane kuparadzaniswa kwekuyerera, sezvo kuyerera kusingadzvinyiriri nekuda kwekuvapo kwegomba repamusoro.Mu quadrant II hapana kupatsanurwa kwekuyerera kunoonekwa, sezvo kuyerera kunogumira zvachose nemadziro e flocculator.Mu quadrant III, mvura inotenderera pane yakanyanya kuderera kana yakaderera kumhanya kupfuura mune yapfuura quadrants.Mvura iri mumaquadrants I ne II inofambiswa (kureva kutenderedzwa kana kusundirwa kunze) ichidzika pasi nekuita kwemusanganisi.Uye mu quadrant III, mvura inosundirwa kunze nemashizha eagitator.Zviripachena kuti huwandu hwemvura munzvimbo ino hunopesana nesleeve yeflocculator iri kusvika.Iyo inotenderera inoyerera mune iyi quadrant yakaparadzaniswa zvachose.Kune quadrant IV, yakawanda yemhepo iri pamusoro pe vane 3 inonangidzirwa kumadziro eflocculator uye zvishoma nezvishoma inorasikirwa nehukuru hwayo sezvo hurefu hunowedzera kusvika pakuvhurwa kwepamusoro.
Mukuwedzera, nzvimbo yepakati inosanganisira maitiro akaoma ekuyerera anotonga quadrants III uye IV, sezvinoratidzwa neblue dotted ellipses.Iyi nzvimbo yakanyorwa haina chekuita nekutenderera kuyerera mupaddle flocculator, sezvo kutenderera kwekufamba kunogona kuzivikanwa.Izvi zvinopesana ne quadrants I uye II apo pane kupatsanurwa kwakajeka pakati pekuyerera kwemukati uye kutenderera kuzere.
Sezvinoratidzwa mufig.6, kuenzanisa migumisiro yeIDDES uye SST k-ω, musiyano mukuru pakati pevelocity contours ndiyo hukuru hwevheji pakarepo pasi pe blade 3. SST k-ω muenzaniso unoratidza zvakajeka kuti kuwedzerwa kwepamusoro-velocity kuyerera kunotakurwa neblade 3. zvichienzaniswa neIDDES.
Imwe misiyano inogona kuwanikwa muquadrant III.Kubva kuIDDES, sezvambotaurwa, kutenderera kuyerera kuparadzaniswa pakati pemaoko eflocculator kwakacherechedzwa.Zvisinei, nzvimbo iyi inobatwa zvakasimba nechepasi velocity inoyerera kubva kumakona uye mukati mekutanga blade.Kubva kuSST k–ω yenzvimbo imwe chete, mitsetse yecontour inoratidza manyawi akareba kana ichienzaniswa neIDDES nekuti hapana kuyerera kunobva kune mamwe matunhu.
Kunzwisisa kwemhando yevelocity vector minda uye mitsetse inodiwa kuti unzwisise kwakaringana maitiro ekuyerera uye chimiro.Tichifunga kuti chipande chega chega chakafara masendimita mashanu, nzvimbo nomwe dzekumhanya dzakasarudzwa pahupamhi kuti dzipe mufananidzo wekumhanya unomiririra.Pamusoro pezvo, kunzwisiswa kwehuwandu hwehukuru hwekumhanya sebasa rehurefu pamusoro penzvimbo yeblade inodiwa nekuronga chimiro chevelocity zvakananga pamusoro pese pese pese uye nepamusoro pechinhambwe chinoramba chiri 2.5 cm vertically kusvika paurefu hwemasendimita gumi.Ona S1, S2 uye S3 mumufananidzo kuti uwane rumwe ruzivo.Appendix A. Mufananidzo 8 unoratidza kufanana kwepamusoro velocity kuparadzirwa kweblade imwe neimwe (Y = 0.0) yakawanikwa uchishandisa PIV miedzo uye ANSYS-Fluent kuongorora uchishandisa IDDES uye SST k-ω.Mhando mbiri dzenhamba dzinoita kuti zvikwanise kunyatso tevedzera kuyerera kwechimiro pamusoro peiyo flocculator blades.
Velocity kugovera PIV, IDDES uye SST k–ω panzvimbo yeblade.Iyo x-axis inomiririra hupamhi hwebepa rega rega mumamilimita, ine mavambo (0 mm) inomiririra kuruboshwe rwebepa uye kumagumo (50 mm) inomiririra kurudyi kwepepa.
Zvinonyatsoonekwa kuti kukurumidza kugoverwa kwemashizha 2 ne3 kunoratidzwa muFig.8 uye Fig.8.S2 uye S3 muAppendix A inoratidza maitiro akafanana nehurefu, nepo blade 1 ichichinja yakazvimiririra.Velocity profiles ye blades 2 ne3 inova yakanyatsotwangana uye ine maamplitude akafanana pakureba kwemasendimita gumi kubva kumagumo eblade.Izvi zvinoreva kuti kuyerera kunova kwakafanana panguva ino.Izvi zvinonyatsoonekwa kubva mumigumisiro yePIV, iyo yakanyatsogadzirwa neIDDES.Zvichakadaro, iyo SST k-ω mhedzisiro inoratidza mimwe misiyano, kunyanya pa 4 rpm.
Izvo zvakakosha kuti uzive kuti blade 1 inochengetedza chimiro chakafanana cheiyo velocity profiles munzvimbo dzese uye haina kujairika mukukwirira, sezvo swirl inoumbwa pakati pemusanganisi ine yekutanga blade yemaoko ese.Zvakare, zvichienzaniswa neIDDES, PIV blade kumhanya profiles 2 uye 3 yakaratidza yakakwira nhanho dzepamusoro munzvimbo zhinji kusvika dzave dzakada kuenzana pa10 cm pamusoro penzvimbo yeblade.
Nguva yekutumira: Zvita-27-2022