304 stainless hlau coiled tubing tshuaj tivthaiv, Thermodynamic tsom xam ntawm covalently thiab non-covalently functionalized graphene nanosheets nyob rau hauv round raj nruab nrog turbulators

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304 10 * 1mm Stainless hlau coiled tubing nyob rau hauv Suav teb

Loj: 3/4 nti, 1/2 nti, 1 nti, 3 nti, 2 nti

Unit Pipe Length: 6 meter

Steel Qib: 201, 304 thiab 316

Qib: 201, 202, 304, 316, 304L, 316L,

Khoom siv: STAINLESS STEEL

Qhov xwm txheej: Tshiab

Covalent thiab non-covalent nanofluids tau sim nyob rau hauv cov hlab puag ncig nruab nrog cov kab xev sib tw nrog cov kaum sab xis ntawm 45 ° thiab 90 °.Tus naj npawb ntawm Reynolds yog 7000 ≤ Re ≤ 17000, cov khoom siv thermophysical raug ntsuas ntawm 308 K. Cov qauv ntawm lub cev yog daws tau tus lej uas siv ob lub ntsuas viscosity qauv (SST k-omega turbulence).Cov concentrations (0.025 wt.%, 0.05 wt.%, thiab 0.1 wt.%) ntawm nanofluids ZNP-SDBS@DV thiab ZNP-COOH@DV tau txiav txim siab hauv kev ua haujlwm.Cov phab ntsa ntawm cov raj twisted yog rhuab ntawm qhov kub tsis tu ncua ntawm 330 K. Rau qhov tsis sib xws tau txiav txim siab hauv qhov kev tshawb fawb tam sim no: qhov hluav taws xob kub, qhov hluav taws xob hloov hluav taws xob, qhov nruab nrab Nusselt tooj, coefficient ntawm kev sib txhuam, kev poob siab, thiab kev ntsuas kev ua haujlwm.Hauv ob qho tib si (helix lub kaum sab xis ntawm 45 ° thiab 90 °), ZNP-SDBS @ DV nanofluid pom cov yam ntxwv thermal-hydraulic ntau dua li ZNP-COOH @ DV, thiab nws tau nce ntxiv nrog cov khoom loj, piv txwv li, 0.025 wt.0,05 ,wb.yog 1.19.% thiab 1.26 - 0.1 wt.%.Hauv ob qho tib si (helix lub kaum sab xis 45 ° thiab 90 °), qhov tseem ceeb ntawm cov yam ntxwv thermodynamic thaum siv GNP-COOH@DW yog 1.02 rau 0.025% wt., 1.05 rau 0.05% wt.thiab 1.02 rau 0.1% wt.
Lub tshav kub exchanger yog cov khoom siv thermodynamic 1 siv los hloov cov cua sov thaum ua haujlwm txias thiab cua sov.Lub thermal-hydraulic zog ntawm lub tshav kub exchanger txhim kho lub tshav kub hloov coefficient thiab txo qhov tsis kam ntawm cov dej ua hauj lwm.Ob peb txoj hauv kev tau tsim los txhim kho cov cua sov hloov pauv, suav nrog turbulence enhancers2,3,4,5,6,7,8,9,10,11 thiab nanofluids12,13,14,15.Twisted daim kab xev ntxig yog ib txoj hauv kev zoo tshaj plaws rau kev txhim kho cov cua sov hauv cov khoom siv hluav taws xob vim nws qhov yooj yim ntawm kev saib xyuas thiab tus nqi qis 7,16.
Nyob rau hauv ib tug series ntawm kev sim thiab xam cov kev tshawb fawb, cov hydrothermal zog ntawm mixs ntawm nanofluids thiab tshav kub exchangers nrog twisted daim kab xev inserts tau kawm.Hauv kev sim ua haujlwm, cov khoom siv hydrothermal ntawm peb yam hlau nanofluids (Ag@DW, Fe@DW thiab Cu@DW) tau kawm hauv rab koob twisted daim kab xev (STT) tshav kub exchanger17.Piv nrog rau lub hauv paus yeeb nkab, lub tshav kub hloov coefficient ntawm STT yog txhim kho los ntawm 11% thiab 67%.SST layout yog qhov zoo tshaj plaws los ntawm kev lag luam ntawm qhov pom ntawm kev ua haujlwm nrog qhov ntsuas α = β = 0.33.Tsis tas li ntawd, qhov nce ntawm 18.2% hauv n tau pom nrog Ag@DW, txawm hais tias qhov siab tshaj plaws nce siab tsuas yog 8.5%.Cov txheej txheem ntawm lub cev ntawm kev hloov hluav taws xob thiab kev poob siab hauv cov kav dej concentric nrog thiab tsis muaj coiled turbulators tau kawm siv turbulent flows ntawm Al2O3@DW nanofluid nrog yuam convection.Qhov siab tshaj plaws nruab nrab Nusselt tus naj npawb (Nuavg) thiab kev poob siab yog pom ntawm Re = 20,000 thaum lub kauj pitch = 25 mm thiab Al2O3@DW nanofluid 1.6 vol.%.Cov kev tshawb fawb hauv chaw soj nstuam kuj tau ua los kawm txog kev hloov pauv cua sov thiab kev poob siab ntawm graphene oxide nanofluids (GO@DW) ntws los ntawm ze li ntawm cov hlab ntsha nrog WC inserts.Cov txiaj ntsig tau pom tias 0.12 vol%-GO@DW nce qhov sib npaug ntawm cov cua sov hloov mus txog li 77%.Hauv lwm txoj kev tshawb fawb, nanofluids (TiO2@DW) tau tsim los kawm txog cov yam ntxwv thermal-hydraulic ntawm cov raj dimpled haum nrog cov kab xev sib tw 20.Qhov siab tshaj plaws hydrothermal efficiency ntawm 1.258 tau ua tiav siv 0.15 vol%-TiO2 @ DW embedded nyob rau hauv 45 ° inclined shafts nrog ib tug twist yam ntawm 3.0.Ib-theem thiab ob-theem (hybrid) simulation qauv coj mus rau hauv tus account qhov ntws thiab kub hloov ntawm CuO@DW nanofluids ntawm ntau yam khib nyiab (1-4% vol.%) 21.Qhov siab tshaj plaws thermal efficiency ntawm ib lub raj tso nrog ib daim kab xev twisted yog 2.18, thiab ib lub raj tso nrog ob twisted tapes nyob rau hauv tib yam mob yog 2.04 (ob-theem qauv, Re = 36,000 thiab 4 vol.%).Cov uas tsis yog-Newtonian turbulent nanofluid ntws ntawm carboxymethyl cellulose (CMC) thiab tooj liab oxide (CuO) nyob rau hauv cov kav dej loj thiab cov kav dej nrog twisted inserts tau kawm.Nuavg qhia txog kev txhim kho ntawm 16.1% (rau cov kav dej loj) thiab 60% (rau cov kav dej coiled nrog qhov piv ntawm (H / D = 5)).Feem ntau, qhov qis qis-rau-ribbon piv ua rau muaj kev sib txhuam ntau dua.Nyob rau hauv ib qho kev sim, cov nyhuv ntawm cov kav dej nrog ib daim kab xev twisted (TT) thiab coils (VC) ntawm cov khoom ntawm tshav kub hloov thiab kev sib txhuam coefficient tau kawm siv CuO@DW nanofluids.Siv 0.3 vol.%-CuO@DW ntawm Re = 20,000 ua rau nws muaj peev xwm nce cov cua kub hloov hauv cov yeeb nkab VK-2 mus rau qhov siab tshaj plaws ntawm 44.45%.Tsis tas li ntawd, thaum siv ib tug twisted khub cable thiab ib tug coil insert nyob rau hauv tib lub ciam teb tej yam kev mob, lub coefficient ntawm kev sib txhuam nce los ntawm cov yam ntxwv ntawm 1.17 thiab 1.19 piv rau DW.Feem ntau, cov thermal efficiency ntawm nanofluids tso rau hauv coils yog zoo dua li ntawm nanofluids tso rau hauv cov xov hlau.Lub volumetric yam ntxwv ntawm ib tug turbulent (MWCNT @ DW) nanofluid ntws tau kawm nyob rau hauv ib tug kab rov tav raj tso rau hauv ib tug kauv hlau.Cov thermal ua haujlwm tsis zoo yog> 1 rau txhua qhov xwm txheej, qhia tias kev sib xyaw ntawm nanofluidics nrog cov coil ntxig txhim kho cov cua sov hloov tsis tas siv lub zog twj tso kua mis.Abstract-Cov yam ntxwv hydrothermal ntawm ob lub yeeb nkab hluav taws xob sib txuas nrog ntau yam ntxig ua los ntawm kev hloov kho-twisted V-shaped daim kab xev (VcTT) tau kawm nyob rau hauv cov xwm txheej ntawm cov turbulent flow ntawm Al2O3 + TiO2@DW nanofluid.Piv rau DW hauv cov raj hauv paus, Nuavg muaj kev txhim kho tseem ceeb ntawm 132% thiab kev sib txhuam coefficient txog li 55%.Tsis tas li ntawd, lub zog ua haujlwm ntawm Al2O3 + TiO2 @ DW nanocomposite nyob rau hauv ob lub yeeb nkab kub exchanger26 tau tham.Hauv lawv txoj kev tshawb fawb, lawv pom tias kev siv Al2O3 + TiO2@DW thiab TT txhim kho kev ua haujlwm zoo dua piv rau DW.Hauv concentric tubular heat exchangers nrog VcTT turbulators, Singh thiab Sarkar27 siv cov ntaub ntawv hloov theem (PCM), dispersed ib leeg / nanocomposite nanofluids (Al2O3@DW nrog PCM thiab Al2O3 + PCM).Lawv tau tshaj tawm tias kev hloov hluav taws xob thiab kev poob siab nce ntxiv vim qhov sib tw sib tw qis thiab cov nanoparticle concentration nce.Qhov loj dua V-notch qhov tob lossis qhov dav me me tuaj yeem muab cov cua sov ntau dua thiab poob siab.Tsis tas li ntawd, graphene-platinum (Gr-Pt) tau siv los tshawb xyuas cov cua sov, kev sib txhuam, thiab tag nrho cov khoom tsim tawm hauv cov raj nrog 2-TT28 inserts.Lawv txoj kev tshawb fawb tau pom tias qhov feem pua ​​​​me me ntawm (Gr-Pt) txo qis cov hluav taws xob hluav taws xob tsawg dua piv rau qhov kev sib txhuam ntau dua qhov kev loj hlob ntawm entropy.Kev sib xyaw Al2O3 @ MgO nanofluids thiab conical WC tuaj yeem suav tias yog qhov sib xyaw zoo, txij li qhov sib piv ntau ntxiv (h / Δp) tuaj yeem txhim kho qhov kev ua haujlwm ntawm hydrothermal ntawm ob lub raj kub sib hloov 29.Tus qauv naj npawb yog siv los ntsuas qhov kev txuag hluav taws xob thiab ib puag ncig kev ua haujlwm ntawm cov khoom siv hluav taws xob nrog ntau yam peb feem hybrid nanofluids (THNF) (Al2O3 + graphene + MWCNT) raug tshem tawm hauv DW30.Vim nws qhov Kev Ntsuas Ntsuas Kev Ntsuas (PEC) nyob rau hauv thaj tsam ntawm 1.42–2.35, kev sib xyaw ua ke ntawm Kev Nyuaj Siab Twisted Turbulizer Insert (DTTI) thiab (Al2O3 + Graphene + MWCNT) yuav tsum.
Txog tam sim no, me ntsis kev saib xyuas tau them rau lub luag haujlwm ntawm covalent thiab tsis-covalent functionalization hauv hydrodynamic ntws hauv cov kua dej thermal.Lub hom phiaj ntawm txoj kev tshawb no yog los sib piv cov thermal-hydraulic yam ntxwv ntawm nanofluids (ZNP-SDBS@DV) thiab (ZNP-COOH@DV) nyob rau hauv twisted daim kab xev inserts nrog helix kaum ntawm 45 ° thiab 90 °.Cov khoom siv thermophysical tau ntsuas ntawm Tin = 308 K. Nyob rau hauv rooj plaub no, peb pawg pawg tau muab coj los rau hauv tus account hauv cov txheej txheem sib piv, xws li (0.025 wt.%, 0.05 wt.% thiab 0.1 wt.%).Lub shear stress hloov nyob rau hauv 3D turbulent flow qauv (SST k-ω) yog siv los daws cov thermal-hydraulic yam ntxwv.Yog li, qhov kev tshawb fawb no ua rau muaj txiaj ntsig zoo rau kev kawm txog cov khoom zoo (kub hloov pauv) thiab cov khoom tsis zoo (siab poob ntawm kev sib txhuam), ua kom pom cov yam ntxwv thermal-hydraulic thiab optimization ntawm cov dej ua haujlwm tiag tiag hauv cov tshuab engineering.
Qhov yooj yim configuration yog ib tug du yeeb nkab (L = 900 mm thiab Dh = 20 mm).Inserted twisted daim kab xev qhov ntev (ntev = 20 hli, thickness = 0.5 hli, profile = 30 hli).Nyob rau hauv cov ntaub ntawv no, qhov ntev, dav, thiab stroke ntawm kauv profile yog 20 hli, 0.5 hli, thiab 30 hli, feem.Cov ntaub nplaum yog inclined ntawm 45 ° thiab 90 °.Ntau yam dej ua haujlwm xws li DW, non-covalent nanofluids (GNF-SDBS@DW) thiab covalent nanofluids (GNF-COOH@DW) ntawm Tin = 308 K, peb qhov sib txawv pawg ntau thiab sib txawv Reynolds tus lej.Cov kev ntsuam xyuas tau ua nyob rau hauv lub tshav kub exchanger.Cov phab ntsa sab nrauv ntawm lub raj kauv tau muab cua sov ntawm qhov kub thiab txias ntawm 330 K los ntsuas qhov tsis zoo rau kev txhim kho cua sov.
Ntawm daim duab.1 schematically qhia tau hais tias ib tug twisted daim kab xev insertion raj nrog rau thaj tsam tej yam kev mob thiab meshed cheeb tsam.Raws li tau hais ua ntej lawm, qhov ceev thiab siab ciam ciam yog siv rau qhov nkag thiab qhov hluav taws xob ntawm lub helix.Nyob rau ntawm qhov kub thiab txias tas li, ib qho kev mob uas tsis yog-plam yog raug rau ntawm cov yeeb nkab phab ntsa.Cov lej simulation tam sim no siv cov kev daws teeb meem siab.Nyob rau tib lub sijhawm, ib qho kev pab cuam (ANSYS FLUENT 2020R1) yog siv los hloov ib feem ntawm qhov sib txawv ntawm qhov sib npaug (PDE) rau hauv qhov system ntawm algebraic equations siv txoj kev finite ntim (FMM).Qhov thib ob-txiav txim siab txoj kev yooj yim (semi-implicit method for sequential pressure-dependent equations) yog hais txog kev tshaj tawm-siab.Nws yuav tsum tau hais tias qhov sib xyaw ntawm cov khoom seem rau qhov loj, lub zog, thiab lub zog sib npaug yog tsawg dua 103 thiab 106, raws li.
p Daim duab ntawm lub cev thiab kev suav sau: (a) helix lub kaum sab xis 90 °, (b) helix lub kaum sab xis 45 °, (c) tsis muaj helical hniav.
Ib homogeneous qauv yog siv los piav txog cov khoom ntawm nanofluids.Los ntawm kev sib xyaw nanomaterials rau hauv cov kua hauv paus (DW), cov kua dej txuas ntxiv nrog cov khoom siv thermal zoo heev yog tsim.Hauv qhov no, qhov kub thiab qhov nrawm ntawm lub hauv paus kua thiab cov nanomaterial muaj nqi tib yam.Raws li cov kev xav thiab cov kev xav saum toj no, kev ua haujlwm tau zoo ib theem ua haujlwm hauv txoj kev tshawb no.Ntau qhov kev tshawb fawb tau pom tias muaj txiaj ntsig thiab siv tau ntawm cov txheej txheem ib theem rau nanofluidic flow31,32.
Qhov ntws ntawm nanofluids yuav tsum yog Newtonian turbulent, incompressible thiab nyob ruaj ruaj.Kev ua haujlwm compression thiab viscous cua sov tsis cuam tshuam rau hauv txoj kev tshawb no.Tsis tas li ntawd, lub thickness ntawm cov phab ntsa sab hauv thiab sab nrauv ntawm cov yeeb nkab tsis suav nrog.Yog li ntawd, qhov loj, lub zog, thiab kev txuag hluav taws xob sib npaug uas txhais cov qauv thermal tuaj yeem qhia tau raws li hauv qab no:
qhov twg \(\overrightarrow{V}\) yog qhov nruab nrab tshaj tawm vector, Keff = K + Kt yog qhov zoo thermal conductivity ntawm covalent thiab noncovalent nanofluids, thiab ε yog lub zog dissipation tus nqi.Cov khoom siv hluav taws xob zoo ntawm nanofluids, suav nrog qhov ntom ntom (ρ), viscosity (μ), lub peev xwm tshwj xeeb thaum tshav kub kub (Cp) thiab thermal conductivity (k), qhia hauv lub rooj, tau ntsuas thaum lub sij hawm kev sim ntawm qhov kub ntawm 308 K1 thaum siv. nyob rau hauv cov simulators.
Cov lej simulations ntawm turbulent nanofluid flow nyob rau hauv cov pa thiab TT raj tau ua nyob rau ntawm Reynolds tooj 7000 ≤ Re ≤ 17000. Cov kev simulations thiab convective tshav kub hloov coefficients tau soj ntsuam siv Tus Mentor's κ-ω turbulence qauv ntawm shear stress transfer (SSTuls) nruab nrab. qauv Navier-Stokes, feem ntau siv hauv kev tshawb fawb aerodynamic.Tsis tas li ntawd, tus qauv ua haujlwm tsis muaj phab ntsa ua haujlwm thiab muaj tseeb nyob ze ntawm phab ntsa 35,36.(SST) κ-ω tswj kev sib npaug ntawm tus qauv turbulence yog raws li hauv qab no:
qhov twg \(S\) yog tus nqi ntawm tus nqi strain, thiab \(y\) yog qhov deb ntawm qhov chaw nyob ib sab.Meanwhile, \({\alpha}_{1}\), \({\alpha}_{2}\), \({\beta}_{1}\), \({\beta}_{2} }\), \({\beta}^{*}\), \({\sigma}_{{k}_{1}}\), \({\sigma}_{{k}_{2} }}\), \({\sigma}_{{\omega}_{1}}\) and \({\sigma}_{{\omega}_{2}}\) denote all model constants.F1 thiab F2 yog sib xyaw ua haujlwm.Faj seeb: F1 = 1 nyob rau hauv ciam txheej, 0 nyob rau hauv lub oncoming flow.
Kev ntsuas kev ua tau zoo yog siv los kawm txog kev hloov pauv hloov pauv hloov pauv hloov pauv hloov pauv, covalent thiab tsis-covalent nanofluid ntws, piv txwv li 31:
Hauv cov ntsiab lus no, (\(\rho\)), (\(v\)), (\({D}_{h}\))) thiab (\(\mu\)) yog siv rau qhov ceev, dej tshaj tawm. , hydraulic txoj kab uas hla thiab dynamic viscosity.(\(C}_{p}\, \mathrm{u}\, k\)) - cov peev txheej kub thiab thermal conductivity ntawm cov kua ntws.Tsis tas li ntawd, (\(\dot{m}\)) yog hais txog huab cua ntws, thiab (\({T}_{out}-{T}_{in}\)) yog hais txog qhov kub thiab qhov hluav taws xob sib txawv.(NFs) hais txog covalent, non-covalent nanofluids, thiab (DW) hais txog cov dej distilled (cov kua hauv paus).\({A}_{s} = \pi DL\), \({\overline{T}}_{f}=\frac{\left({T}_{out}-{T}_{in }\right)}{2}\) and \({\overline{T}}_{w}=\sum \frac{{T}_{w}}{n}\).
Cov khoom siv thermophysical ntawm lub hauv paus kua dej (DW), non-covalent nanofluid (GNF-SDBS@DW), thiab covalent nanofluid (GNF-COOH@DW) tau muab los ntawm cov ntaub ntawv luam tawm (kev sim kev tshawb fawb), Sn = 308 K, raws li qhia nyob rau hauv Table 134. Nyob rau hauv ib tug raug Nyob rau hauv ib qho kev sim kom tau ib tug uas tsis yog-covalent (GNP-SDBS@DW) nanofluid nrog paub cov pawg feem pua, tej yam grams ntawm cov thawj GNPs tau pib hnyav rau ib tug digital tshuav nyiaj li cas.Qhov hnyav piv ntawm SDBS / haiv neeg GNP yog (0.5: 1) hnyav hauv DW.Hauv qhov no, covalent (COOH-GNP@DW) nanofluids tau tsim los ntawm kev ntxiv cov carboxyl pawg rau saum npoo ntawm GNP siv qhov nruab nrab acidic nrog qhov ntim piv (1: 3) ntawm HNO3 thiab H2SO4.Covalent thiab non-covalent nanofluids tau raug tshem tawm hauv DW ntawm peb qhov sib txawv qhov hnyav xws li 0.025 wt%, 0.05 wt%.thiab 0.1% ntawm qhov hnyav.
Kev ntsuam xyuas kev ywj pheej ntawm Mesh tau ua nyob rau hauv plaub qhov sib txawv ntawm qhov sib txawv los xyuas kom meej tias qhov mesh loj tsis cuam tshuam rau qhov simulation.Nyob rau hauv rooj plaub ntawm 45 ° torsion yeeb nkab, tus naj npawb ntawm chav tsev nrog chav tsev loj 1.75 hli yog 249,033, tus naj npawb ntawm chav tsev nrog chav tsev loj 2 hli yog 307,969, cov chav tsev nrog chav tsev loj 2.25 hli yog 421,406, thiab cov naj npawb ntawm chav tsev. nrog chav tsev loj 2 .5 hli 564 940 raws.Tsis tas li ntawd, nyob rau hauv cov piv txwv ntawm 90 ° twisted yeeb nkab, tus naj npawb ntawm cov ntsiab lus nrog ib tug 1.75 hli lub ntsiab loj yog 245,531, tus naj npawb ntawm cov ntsiab lus nrog ib tug 2 mm lub ntsiab loj yog 311,584, tus naj npawb ntawm cov ntsiab lus nrog ib tug 2.25 mm lub ntsiab loj yog 422,708, thiab tus naj npawb ntawm cov ntsiab lus nrog lub ntsiab loj ntawm 2.5 hli yog feem 573,826.Qhov tseeb ntawm cov khoom siv thermal nyeem xws li (Tout, htc, thiab Nuavg) nce ntxiv vim cov ntsiab lus txo qis.Nyob rau tib lub sijhawm, qhov tseeb ntawm qhov tseem ceeb ntawm kev sib txhuam coefficient thiab kev poob siab tau pom tias tus cwj pwm txawv kiag li (Fig. 2).Daim phiaj (2) tau siv los ua cov kab sib chaws loj los ntsuam xyuas cov yam ntxwv thermal-hydraulic hauv cov ntaub ntawv simulated.
Kev ntsuas kub hloov pauv thiab kev ua haujlwm siab poob qis ntawm nws tus kheej ntawm cov mesh siv ob lub DW raj twisted ntawm 45 ° thiab 90 °.
Cov txiaj ntsig ntawm cov lej tam sim no tau raug lees paub rau kev ua haujlwm kub hloov pauv thiab kev sib txhuam coefficient siv qhov paub zoo txog kev sib raug zoo thiab kev sib npaug xws li Dittus-Belter, Petukhov, Gnelinsky, Notter-Rouse thiab Blasius.Kev sib piv tau ua raws li qhov xwm txheej 7000≤Re≤17000.Raws li daim duab.3, qhov nruab nrab thiab siab tshaj qhov yuam kev ntawm qhov kev simulation tshwm sim thiab qhov sib npaug ntawm cov cua sov hloov pauv yog 4.050 thiab 5.490% (Dittus-Belter), 9.736 thiab 11.33% (Petukhov), 4.007 thiab 7.483% (Gnelinsky), thiab 3.883% thiab 3.883% thiab Nott-Belter).Rose).Nyob rau hauv cov ntaub ntawv no, qhov nruab nrab thiab siab tshaj qhov yuam kev ntawm qhov simulation tshwm sim thiab kev sib txhuam coefficient sib npaug yog 7.346% thiab 8.039% (Blasius) thiab 8.117% thiab 9.002% (Petukhov), feem.
Thaum tshav kub kub hloov thiab hydrodynamic zog ntawm DW ntawm ntau yam Reynolds tus lej siv cov lej suav thiab kev sib raug zoo.
Tshooj lus no tham txog cov khoom siv hluav taws xob uas tsis yog-covalent (LNP-SDBS) thiab covalent (LNP-COOH) aqueous nanofluids ntawm peb qhov sib txawv pawg thiab Reynolds tus lej raws li qhov nruab nrab txheeb ze rau lub hauv paus kua (DW).Ob lub geometries ntawm coiled siv kub exchangers (helix lub kaum sab xis 45 ° thiab 90 °) yog tham txog 7000 ≤ Re ≤ 17000. Nyob rau hauv daim duab.4 qhia qhov nruab nrab kub ntawm qhov tawm ntawm nanofluid mus rau hauv lub hauv paus kua (DW) (\(\frac{{{T}_{out}}_{NFs}}{{T}_{out}}_{ DW } } \) ) ntawm (0.025% wt., 0.05% wt. thiab 0.1% wt.).(\(\frac{{{T}_{out}}_{NFs}}{{T}_{out}}_{DW}}\)) yog ib txwm tsawg dua 1, uas txhais tau hais tias qhov hluav taws xob kub yog non-covalent (VNP-SDBS) thiab covalent (VNP-COOH) nanofluids yog qis dua qhov kub ntawm qhov hluav taws xob ntawm lub hauv paus kua.Qhov txo qis tshaj plaws thiab siab tshaj plaws yog 0.1 wt%-COOH@GNPs thiab 0.1 wt%-SDBS@GNPs, feem.Qhov tshwm sim no yog vim qhov nce ntawm Reynolds tus naj npawb ntawm qhov seem tsis tu ncua, uas ua rau muaj kev hloov pauv ntawm cov khoom ntawm nanofluid (uas yog, ntom thiab dynamic viscosity).
Cov duab 5 thiab 6 qhia qhov nruab nrab ntawm cov cua kub hloov pauv ntawm nanofluid rau hauv paus kua (DW) ntawm (0.025 wt.%, 0.05 wt.% thiab 0.1 wt.%).Qhov nruab nrab ntawm cov khoom siv hluav taws xob hloov pauv ib txwm muaj ntau dua 1, uas txhais tau hais tias cov khoom siv hluav taws xob hloov pauv ntawm cov khoom tsis-covalent (LNP-SDBS) thiab covalent (LNP-COOH) nanofluids tau txhim kho dua piv rau cov kua hauv paus.0.1 wt%-COOH@GNPs thiab 0.1 wt%-SDBS@GNPs ua tiav qhov qis tshaj thiab siab tshaj qhov nce, feem.Thaum Reynolds tus naj npawb nce vim muaj kev sib xyaw ua kua ntau dua thiab muaj kev kub ntxhov hauv cov yeeb nkab 1, kev ua haujlwm kub hloov tau zoo dua.Cov kua dej los ntawm qhov sib txawv me me mus txog qhov nrawm dua, ua rau cov txheej txheem thinner / tshav kub ciam teb, uas ua rau nce tus nqi ntawm cov cua sov.Ntxiv ntau nanoparticles rau cov kua hauv paus tuaj yeem muaj txiaj ntsig zoo thiab tsis zoo.Cov txiaj ntsig muaj txiaj ntsig suav nrog kev sib tsoo nanoparticle nce ntxiv, cov dej zoo thermal conductivity xav tau, thiab txhim kho cov cua sov hloov.
Thaum tshav kub kub hloov coefficient ntawm nanofluid mus rau lub hauv paus kua nyob ntawm Reynolds tooj rau 45 ° thiab 90 ° hlab.
Nyob rau tib lub sijhawm, qhov kev cuam tshuam tsis zoo yog qhov nce hauv dynamic viscosity ntawm nanofluid, uas txo cov kev txav mus los ntawm nanofluid, yog li txo qhov nruab nrab Nusselt tooj (Nuavg).Qhov nce thermal conductivity ntawm nanofluids (ZNP-SDBS@DW) thiab (ZNP-COOH@DW) yuav tsum yog vim Brownian motion thiab microconvection ntawm graphene nanoparticles raug tshem tawm hauv DW37.Lub thermal conductivity ntawm nanofluid (ZNP-COOH@DV) yog siab dua li ntawm nanofluid (ZNP-SDBS@DV) thiab dej distilled.Ntxiv ntau nanomaterials rau cov kua hauv paus ua rau lawv cov thermal conductivity (Table 1) 38.
Daim duab 7 qhia txog qhov nruab nrab coefficient ntawm kev sib txhuam ntawm nanofluids nrog lub hauv paus kua (DW) (f (NFs) / f (DW)) hauv huab hwm coj feem pua ​​(0.025%, 0.05% thiab 0.1%).Qhov nruab nrab kev sib txhuam coefficient yog ib txwm ≈1, uas txhais tau hais tias tsis yog-covalent (GNF-SDBS@DW) thiab covalent (GNF-COOH@DW) nanofluids muaj qhov sib txhuam coefficient zoo li cov kua hauv paus.Lub tshuab hluav taws xob uas muaj qhov chaw tsawg dua ua rau muaj kev cuam tshuam ntau dua thiab ua rau muaj kev sib txhuam ntau dua 1.Yeej, cov coefficient ntawm kev sib txhuam nce me ntsis nrog nce loj feem ntawm nanofluid.Qhov kev sib txhuam ntau dua yog tshwm sim los ntawm kev ua kom muaj zog viscosity ntawm nanofluid thiab nce shear kev nyuaj siab rau ntawm qhov chaw nrog ntau dua qhov loj ntawm nanographene hauv cov kua hauv paus.Table (1) qhia tau hais tias qhov dynamic viscosity ntawm nanofluid (ZNP-SDBS@DV) yog siab dua li ntawm nanofluid (ZNP-COOH@DV) ntawm tib qhov hnyav feem pua, uas yog txuam nrog qhov sib ntxiv ntawm cov teebmeem saum npoo.Cov tshuaj nquag ntawm cov tsis-covalent nanofluid.
Ntawm daim duab.8 qhia nanofluid piv rau cov kua hauv qab (DW) (\(\frac{{\Delta P}_{NFs}}{{\Delta P}_{DW}}\)) ntawm (0.025%, 0.05% thiab 0.1% ).Cov uas tsis yog-covalent (GNPs-SDBS@DW) nanofluid tau pom qhov poob siab dua qhov nruab nrab, thiab nrog rau qhov nce hauv huab hwm coj feem pua ​​​​rau 2.04% rau 0.025% wt., 2.46% rau 0.05% wt.thiab 3.44% rau 0.1% wt.nrog cov ntaub ntawv loj (helix lub kaum sab xis 45 ° thiab 90 °).Lub caij no, nanofluid (GNPs-COOH@DW) pom qhov poob qis nruab nrab, nce los ntawm 1.31% ntawm 0.025% wt.mus txog 1.65% ntawm 0.05% wt.Qhov nruab nrab siab poob ntawm 0.05 wt.% -COOH@NP thiab 0.1 wt.% -COOH@NP yog 1.65%.Raws li tuaj yeem pom, qhov kev poob siab nce nrog nce Re naj npawb hauv txhua kis.Ib qho kev nce siab poob ntawm qhov siab Re qhov tseem ceeb yog qhia los ntawm kev tso siab ncaj qha rau ntawm qhov ntim ntws.Yog li ntawd, tus lej Re ntau dua hauv lub raj ua rau lub siab poob siab dua, uas yuav tsum tau nce lub zog ntawm lub twj tso kua mis 39,40.Tsis tas li ntawd, kev poob siab yog siab dua vim qhov kev siv ntau dua ntawm eddies thiab turbulence generated los ntawm qhov loj dua qhov chaw, uas ua rau kom muaj kev sib cuam tshuam ntawm lub siab thiab inertia rog nyob rau hauv ciam teb txheej 1.
Feem ntau, cov kev ntsuas kev ua tau zoo (PEC) rau cov uas tsis yog-covalent (VNP-SDBS@DW) thiab covalent (VNP-COOH@DW) nanofluids tau qhia hauv daim duab.9. Nanofluid (ZNP-SDBS@DV) tau pom cov txiaj ntsig PEC siab dua (ZNP-COOH@DV) nyob rau hauv ob qho tib si (helix lub kaum sab xis 45 ° thiab 90 °) thiab nws tau txhim kho los ntawm kev nce cov feem ntau, piv txwv li, 0.025 wt.%.yog 1.17, 0.05 wt.% yog 1.19 thiab 0.1 wt.% yog 1.26.Lub caij no, PEC tus nqi siv nanofluids (GNPs-COOH@DW) yog 1.02 rau 0.025 wt%, 1.05 rau 0.05 wt%, 1.05 rau 0.1 wt%.nyob rau hauv ob qho tib si (helix lub kaum sab xis 45 ° thiab 90 °).1.02 ib.Raws li txoj cai, nrog kev nce hauv Reynolds tus lej, thermal-hydraulic efficiency txo qis.Raws li Reynolds tus lej nce, qhov txo qis hauv thermal-hydraulic efficiency coefficient yog txuam nrog kev nce hauv (NuNFs / NuDW) thiab txo qis (fNFs / fDW).
Hydrothermal zog ntawm nanofluids nrog rau cov kua hauv paus nyob ntawm Reynolds tus lej rau cov hlab nrog 45 ° thiab 90 ° kaum.
Tshooj lus no tham txog cov khoom siv hluav taws xob ntawm dej (DW), uas tsis yog-covalent (VNP-SDBS@DW), thiab covalent (VNP-COOH@DW) nanofluids ntawm peb qhov sib txawv pawg ntau thiab Reynolds tus lej.Ob lub coiled siv hluav taws xob sib hloov geometries tau txiav txim siab nyob rau hauv thaj tsam 7000 ≤ Re ≤ 17000 nrog rau cov kav dej ib txwm siv (helix kaum sab xis 45 ° thiab 90 °) los ntsuas qhov nruab nrab thermal-hydraulic kev ua tau zoo.Ntawm daim duab.10 qhia qhov kub ntawm cov dej thiab nanofluids ntawm qhov hluav taws xob raws li qhov nruab nrab siv (helix lub kaum sab xis 45 ° thiab 90 °) rau ib qho yeeb nkab (\(\frac{{{T}_{out}}_{Twisted}}{{ {T} _{out}}_{Regular}}\)).Non-covalent (GNP-SDBS@DW) thiab covalent (GNP-COOH@DW) nanofluids muaj peb qhov sib txawv qhov hnyav xws li 0.025 wt%, 0.05 wt% thiab 0.1 wt%.Raws li qhia hauv daim duab.11, tus nqi nruab nrab ntawm qhov hluav taws xob kub (\(\frac{{{T}_{out}}_{Twisted}}{{T}_{out}}_{Plain}}\)) > 1, qhia tau hais tias (45 ° thiab 90 ° helix lub kaum sab xis) qhov kub ntawm qhov hluav taws xob ntawm qhov hluav taws xob sib hloov yog qhov tseem ceeb dua li cov yeeb nkab ua ke, vim qhov kev siv zog ntau dua thiab kev sib xyaw ua kua zoo dua.Tsis tas li ntawd, qhov kub thiab txias ntawm qhov hluav taws xob ntawm DW, uas tsis yog-covalent thiab covalent nanofluids poob nrog nce Reynolds tus lej.Lub hauv paus kua dej (DW) muaj qhov ntsuas qhov hluav taws xob siab tshaj plaws.Lub caij no, tus nqi qis tshaj yog hais txog 0.1 wt%-SDBS@GNPs.Non-covalent (GNPs-SDBS@DW) nanofluids pom qhov nruab nrab qhov hluav taws xob qis dua piv rau covalent (GNPs-COOH@DW) nanofluids.Txij li thaum daim kab xev twisted ua rau cov dej ntws ntau sib xyaw, qhov ze ntawm phab ntsa cua sov tuaj yeem yooj yim dua los ntawm cov kua, ua rau tag nrho qhov kub thiab txias.Qhov qis dua twist-rau-kab kab xev ua rau muaj kev nkag tau zoo dua thiab yog li kev hloov cua sov zoo dua.Ntawm qhov tod tes, nws tuaj yeem pom tias daim kab xev dov tswj qhov kub thiab txias tiv thaiv phab ntsa, uas nyob rau hauv lem nce Nuavg.Rau kev sib tw daim kab xev ntxig, tus nqi ntau dua Nuavg qhia tau tias hloov pauv cov cua sov hauv lub raj 22.Vim yog txoj hauv kev nce ntxiv thiab kev sib xyaw ntxiv thiab kev kub ntxhov, lub sijhawm nyob hauv tsev nce, uas ua rau muaj qhov kub thiab txias ntawm cov kua hauv qhov hluav taws xob 41.
Reynolds cov naj npawb ntawm ntau yam nanofluids txheeb ze rau qhov hluav taws xob kub ntawm cov pa raj (45 ° thiab 90 ° helix kaum).
Thaum tshav kub kub hloov coefficients (45 ° thiab 90 ° helix lub kaum sab xis) piv rau Reynolds tus lej rau ntau yam nanofluids piv rau cov pa roj carbon monoxide.
Lub ntsiab mechanism ntawm enhanced coiled daim kab xev thaum tshav kub kub hloov lwm lub tsev yog raws li nram no: 1. Txo cov hydraulic txoj kab uas hla ntawm lub tshav kub exchanger tube ua rau kom ib tug nce nyob rau hauv khiav ceev thiab curvature, uas nyob rau hauv lem nce shear stress ntawm phab ntsa thiab txhawb nqa theem nrab zog.2. Vim tias qhov thaiv ntawm daim kab xev winding, qhov ceev ntawm cov yeeb nkab phab ntsa nce, thiab lub thickness ntawm cov ciam txheej txo.3. Kauv ntws tom qab txoj siv twisted ua rau kev nce ceev.4. Induced vortices txhim kho cov kua sib tov ntawm nruab nrab thiab ze-phab ntsa cheeb tsam ntawm lub flow42.Ntawm daim duab.11i siv.12 qhia txog cov khoom siv hluav taws xob hloov hluav taws xob ntawm DW thiab nanofluids, piv txwv li (kub hloov pauv coefficient thiab nruab nrab Nusselt tus lej) raws li qhov nruab nrab siv cov hlua khi hlua khi piv rau cov pa roj carbon monoxide.Non-covalent (GNP-SDBS@DW) thiab covalent (GNP-COOH@DW) nanofluids muaj peb qhov sib txawv qhov hnyav xws li 0.025 wt%, 0.05 wt% thiab 0.1 wt%.Nyob rau hauv ob qho tib si kub exchangers (45 ° thiab 90 ° helix lub kaum sab xis) qhov nruab nrab ntawm tshav kub hloov kev ua tau zoo yog> 1, qhia txog kev txhim kho nyob rau hauv tshav kub hloov coefficient thiab nruab nrab Nusselt tooj nrog coiled hlab piv rau cov pa pa.Non-covalent (GNPs-SDBS@DW) nanofluids pom tau tias qhov nruab nrab kub hloov pauv tau zoo dua li covalent (GNPs-COOH@DW) nanofluids.Ntawm Re = 900, 0.1 wt% kev txhim kho hauv kev hloov pauv hluav taws xob -SDBS@GNPs rau ob lub tshav kub hloov pauv (45 ° thiab 90 ° helix lub kaum sab xis) yog qhov siab tshaj plaws nrog tus nqi ntawm 1.90.Qhov no txhais tau hais tias cov nyhuv TP zoo ib yam tseem ceeb dua ntawm cov kua dej qis dua (Reynolds tus lej) 43 thiab ua rau muaj kev kub ntxhov.Vim yog qhov kev taw qhia ntawm ntau lub vortices, cov cua sov hloov coefficient thiab nruab nrab Nusselt tus naj npawb ntawm TT raj yog siab dua li cov pa raj, uas ua rau cov txheej txheem nyias nyias.Puas yog lub xub ntiag ntawm HP ua rau muaj kev kub ntxhov, kev sib xyaw ntawm cov kua dej ua haujlwm thiab kev hloov hluav taws xob zoo dua piv rau cov kav dej hauv paus (tsis suav nrog cov ntaub nplaum sib tw) 21.
Nruab Nrab Nusselt tus naj npawb (helix lub kaum sab xis 45 ° thiab 90 °) piv rau Reynolds tus naj npawb rau ntau yam nanofluids piv rau cov pa pa.
Daim duab 13 thiab 14 qhia qhov nruab nrab coefficient ntawm kev sib txhuam (\(\frac{{f}_{Twisted}}{{f}_{Plain}}\)) thiab siab poob (\(\frac{{\Delta P}) _ {Twisted}}{{\Delta P}_{Plain}}\}} txog 45 ° thiab 90 ° rau cov kav dej ib txwm siv DW nanofluids, (GNPs-SDBS@DW) thiab (GNPs-COOH@DW) ion exchanger muaj ( 0.025 wt %, 0.05 wt % and 0.1 wt %). { {f}_{ Plain} }\)) thiab siab poob (\(\frac{{ \Delta P}_{Twisted}}}{{\Delta P }_{Plain}}\}) txo qis, qhov sib txhuam coefficient thiab siab poob siab dua ntawm Reynolds cov lej Qhov nruab nrab kev sib txhuam coefficient thiab siab poob yog nyob nruab nrab ntawm 3.78 thiab 3.12 Qhov nruab nrab kev sib txhuam coefficient thiab siab poob qhia tias (45 ° helix lub kaum sab xis thiab 90 °) kub exchanger raug nqi peb zaug siab dua li cov kav dej ib txwm siv. Tsis tas li ntawd, thaum cov dej ua haujlwm ntws ntawm qhov nrawm dua, cov coefficient ntawm kev sib txhuam txo qis. Kev txo qis, uas ua rau txo qis hauv cov nyhuv dynamic viscosity ntawm thaj chaw cuam tshuam, txo qis hauv qhov nrawm nrawm thiab shear stresses thiab, yog li ntawd, txo qhov coefficient ntawm kev sib txhuam 21.Kev txhim kho thaiv kev cuam tshuam vim muaj TT thiab qhov nce swirl ua rau muaj kev poob siab ntau dua rau cov kav dej heterogeneous TT dua li cov kav dej hauv paus.Tsis tas li ntawd, rau ob qho tib si hauv paus yeeb nkab thiab TT yeeb nkab, nws tuaj yeem pom tias qhov kev poob siab nce ntxiv nrog qhov ceev ntawm cov kua dej ua haujlwm 43.
Coefficient ntawm kev sib txhuam (45 ° thiab 90 ° helix lub kaum sab xis) piv rau Reynolds tus naj npawb rau ntau yam nanofluids piv rau cov pa pa.
Kev poob siab (45 ° thiab 90 ° helix lub kaum sab xis) raws li kev ua haujlwm ntawm Reynolds tus lej rau ntau yam nanofluids txheeb ze rau lub raj pa.
Hauv cov ntsiab lus, Daim duab 15 qhia txog kev ntsuas kev ua tau zoo (PEC) rau cov khoom siv hluav taws xob sib hloov nrog 45 ° thiab 90 ° cov kaum sib piv rau cov hlab (\(\frac{{PEC}_{Twisted}}{{PEC}_{ Plain}}} \ ) ) hauv (0.025 wt.%, 0.05 wt.% thiab 0.1 wt.%) siv DV, (VNP-SDBS@DV) thiab covalent (VNP-COOH@DV) nanofluids.Tus nqi (\(\frac{{PEC}_{Twisted}}{{PEC}_{Plain}}}\)) > 1 nyob rau hauv ob qho tib si (45 ° thiab 90 ° helix lub kaum sab xis) nyob rau hauv lub tshav kub exchanger.Ntxiv rau, (\(\frac{{PEC}_{Twisted}}{{PEC}_{Plain}}\)) nce mus txog nws tus nqi zoo tshaj ntawm Re = 11,000.Lub 90 ° kub exchanger qhia tau hais tias ib tug me ntsis nce nyob rau hauv (\ (\ frac{{PEC}_{Twisted}}{{PEC}_{ Plain}}\)) piv rau 45 ° kub exchanger., Ntawm Re = 11,000 0.1 wt%-GNPs@SDBS sawv cev siab dua (\(\frac{{PEC}_{Twisted}}{{PEC}_{Plain}}\))) qhov tseem ceeb, xws li 1.25 rau 45 ° tshav kub exchanger ces kaum thiab 1.27 rau 90 ° kaum cua sov exchanger.Nws yog ntau dua ib qho ntawm tag nrho cov feem pua ​​​​ntawm cov feem ntau, uas qhia tau hais tias cov kav dej nrog twisted daim kab xev inserts yog superior rau cov pa kav.Qhov tseem ceeb, qhov hloov pauv tau zoo dua los ntawm cov kab xev ntxig ua rau muaj kev sib txhuam loj zuj zus ntxiv22.
Kev ua tau zoo rau Reynolds tus naj npawb ntawm ntau yam nanofluids nyob rau hauv kev sib raug zoo rau cov pa raj (45 ° thiab 90 ° helix lub kaum sab xis).
Cov ntawv ntxiv A qhia txog kev hloov pauv rau 45 ° thiab 90 ° cov khoom siv hluav taws xob ntawm Re = 7000 siv DW, 0.1 wt%-GNP-SDBS@DW thiab 0.1 wt%-GNP-COOH@DW.Cov streamlines nyob rau hauv lub dav hlau transverse yog qhov zoo tshaj plaws feature ntawm cov nyhuv ntawm twisted ribbon inserts ntawm lub ntsiab ntws.Kev siv 45 ° thiab 90 ° cov khoom siv hluav taws xob sib txawv qhia tau hais tias qhov nrawm ntawm thaj tsam ze ntawm phab ntsa yog kwv yees li qub.Meanwhile, Appendix B qhia qhov ceev contours rau 45 ° thiab 90 ° kub exchangers ntawm Re = 7000 siv DW, 0.1 wt%-GNP-SDBS@DW thiab 0.1 wt%-GNP-COOH@DW.Lub voj voj voog nyob hauv peb qhov chaw sib txawv (slices), piv txwv li Plain-1 (P1 = −30mm), Plain-4 (P4 = 60mm) thiab Plain-7 (P7 = 150mm).Qhov khiav nrawm ze ntawm cov yeeb nkab phab ntsa yog qhov qis tshaj plaws thiab cov dej nrawm nrawm nce mus rau qhov nruab nrab ntawm cov yeeb nkab.Tsis tas li ntawd, thaum dhau los ntawm cov pa cua, thaj tsam ntawm qhov qis qis nyob ze ntawm phab ntsa nce.Qhov no yog vim qhov kev loj hlob ntawm hydrodynamic ciam txheej txheej, uas ua rau kom cov thickness ntawm lub low-velocity cheeb tsam nyob ze ntawm phab ntsa.Tsis tas li ntawd, nce tus naj npawb ntawm Reynolds nce qib kev tshaj tawm tag nrho hauv txhua ntu hla, yog li txo qhov tuab ntawm thaj av qis qis hauv channel39.
Covalently thiab non-covalently functionalized graphene nanosheets tau soj ntsuam nyob rau hauv twisted daim kab xev inserts nrog helix kaum ntawm 45 ° thiab 90 °.Lub tshav kub exchanger yog suav nrog kev daws teeb meem siv SST k-omega turbulence qauv ntawm 7000 ≤ Re ≤ 17000. Cov khoom siv thermophysical yog xam ntawm Tin = 308 K. Ib txhij ua kom sov cov phab ntsa twisted raj ntawm qhov kub thiab txias ntawm 330 K. COOH@DV) yog diluted nyob rau hauv peb loj npaum li cas, piv txwv li (0.025 wt.%, 0.05 wt.% thiab 0.1 wt.%).Txoj kev tshawb fawb tam sim no suav txog rau 6 yam tseem ceeb: qhov hluav taws xob kub, hluav taws xob hloov hluav taws xob, qhov nruab nrab Nusselt tus lej, coefficient ntawm kev sib txhuam, kev poob siab, thiab kev ntsuas kev ua haujlwm.Nov yog cov txiaj ntsig tseem ceeb:
Qhov nruab nrab qhov hluav taws xob kub (\({{T}_{out}}_{Nanofluids}\)/\({T}_{out}}_{Basefluid}\))) yog ib txwm tsawg dua 1, uas txhais tau tias non-spread Lub qhov hluav taws xob kub ntawm valence (ZNP-SDBS@DV) thiab covalent (ZNP-COOH@DV) nanofluids qis dua li cov kua hauv paus.Meanwhile, qhov nruab nrab qhov hluav taws xob kub (\({{T}_{out}}_{Twisted}\)/\({{T}_{out}}_{Plain}\))) tus nqi > 1, qhia rau Qhov tseeb tias (45 ° thiab 90 ° helix lub kaum sab xis) qhov hluav taws xob qhov hluav taws xob yog siab dua nrog cov pa roj.
Nyob rau hauv ob qho tib si, qhov nruab nrab qhov tseem ceeb ntawm cov khoom hloov hluav taws xob (nanofluid / base fluid) thiab (twisted tube / li qub tube) ib txwm qhia> 1.Non-covalent (GNPs-SDBS@DW) nanofluids pom qhov nruab nrab siab dua ntawm kev hloov hluav taws xob, sib xws rau covalent (GNPs-COOH@DW) nanofluids.
Qhov nruab nrab kev sib txhuam coefficient (\({f}_{Nanofluids}/{f}_{Basefluid}\)) ntawm non-covalent (VNP-SDBS@DW) thiab covalent (VNP-COOH@DW) nanofluids yog ib txwm ≈1 .kev sib txhuam ntawm non-covalent (ZNP-SDBS@DV) thiab covalent (ZNP-COOH@DV) nanofluids (\({f}_{Twisted}/{f}_{Plain}\)) ib txwm > 3.
Hauv ob qho tib si (45 ° thiab 90 ° helix lub kaum sab xis), nanofluids (GNPs-SDBS@DW) pom ntau dua (\({\Delta P}_{Nanofluids}/{\Delta P}_{Basefluid}\))) 0.025 wt .% rau 2.04%, 0.05 wt.% rau 2.46% thiab 0.1 wt.% rau 3.44%.Lub caij no, (GNPs-COOH@DW) nanofluids pom qis dua (\({\Delta P}_{Nanofluids}/{\Delta P}_{Basefluid}\)) los ntawm 1.31% rau 0.025 wt.% rau 1.65% yog 0.05 % los ntawm qhov hnyav.Tsis tas li ntawd, qhov poob siab nruab nrab (\({\Delta P}_{Twisted}/{\Delta P}_{Plain}\) ntawm non-covalent (GNPs-SDBS@DW) thiab covalent (GNPs-COOH@DW ))) nanofluids ib txwm > 3.
Hauv ob qho tib si (45 ° thiab 90 ° helix lub kaum sab xis), nanofluids (GNPs-SDBS@DW) pom qhov siab dua (\({PEC}_{Nanofluids}/{PEC} _{Basefluid}\)) @DW tus nqi) , xws li 0.025 wt.% - 1.17, 0.05 wt.% - 1.19, 0.1 wt.% - 1.26.Hauv qhov no, qhov tseem ceeb ntawm (\({PEC}_{Nanofluids}/{PEC}_{Basefluid}\)) siv (GNPs-COOH@DW) nanofluids yog 1.02 rau 0.025 wt.%, 1.05 rau 0. ,,05 wb.% thiab 1.02 yog 0.1% los ntawm qhov hnyav.Tsis tas li ntawd, ntawm Re = 11,000, 0.1 wt%-GNPs@SDBS tau pom cov txiaj ntsig siab dua (\({PEC}_{Twisted}/{PEC}_{Plain}\)), xws li 1.25 rau 45 ° helix lub kaum sab xis thiab 90 ° helix lub kaum sab xis 1.27.
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