Research Article Experimental Research on Heat Transfer...

Research ArticleExperimental Research on Heat Transfer Characteristics of CuONanofluid in Adiabatic Condition

Yu Guangbin1 Gao Dejun1 Chen Juhui1 Dai Bing1 Liu Di1 Song Ye1 and Chen Xi2

1School of Mechanical and Power Engineering Harbin University of Science and Technology Harbin Heilongjiang 150080 China2School of Mechanical Engineering The University of Melbourne Melbourne VIC 3010 Australia

Correspondence should be addressed to Chen Juhui chenjuhuihiteducn

Received 17 August 2015 Revised 23 November 2015 Accepted 28 December 2015

Academic Editor Nageh K Allam

Copyright copy 2016 Yu Guangbin et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The laminar convective heat transfer behavior of CuO nanoparticle dispersions in glycol with the average particle sizes (about70 nm) was investigated experimentally in a flow loop with constant heat flux To enhance heat exchange under high temperaturecondition and get the more accurate data we try to improve the traditional experimental apparatus which is used to test nanofluidheat transfer characteristics In the experiment five different nanoparticle concentrations (025 050 080 120 and 150)were investigated in a flow loop with constant heat fluxThe experimental results show that the heat transfer coefficient of nanofluidbecomes higher than that of pure fluid at the same Reynolds number and increased with the increasing of the mass fraction ofCuO nanoparticles Results also indicate that at very low volume concentrations nanofluid has no major impact on heat transferparameters and the pressure of nanofluids increased by the mass fraction increase

1 Introduction

With the development of industry traditional heat transferfluids such as oil water and ethylene glycol are hardly sat-isfying the requirement of modern industry transportationnuclear electronic engineering and so forthTherefore it hasbeen proposed thatmillimeter- ormicrometer-sized particlescould be suspended in industrial heat transfer fluids toemploy However it has a lot of disadvantages in heat transferfluids containing suspended particles of micrometer andmillimeter size like clogging in small passages and erosions ofthe components by abrasive reactions As a new class of engi-neered fluid nanofluids were the first pioneered by Choi andEastman in 1995 [1] it has been proposed that nanometer-sized particles could be suspended in industrial heat transferfluids such as water ethylene glycol and oil to produce anew class of engineered fluidswith high thermal conductivityBecause of the excellent thermal conductivity nanofluiddispersions are important for a number of industrial sectorsincluding transportation power generation micromanufac-turing and miniature devices [2 3]

Nanofluids as a new class of heat transfer fluids havealready been researched by many researchers in the past few

years Pak and Cho [4] investigated turbulent heat transfercharacteristics of 120574-Al

2O3water and TiO

2water nanofluid in

a circular pipe in 1998 The results indicated that when thevolume fraction of nanoparticles was 3 the heat transfercoefficient of nanofluids comparedwith purewater is reducedby 12 Kole and Dey [5] investigated the automobile coolingliquid of Al

2O3nanofluids and got the curvilinear relation-

ship between viscositytemperature and nanoparticle volumefraction Zyła and Cholewa [6 7] did the research on theunexpected behavior of viscosity of glycol-based MgAl

2O4

nanofluids and shown that nanofluids have been studiedvery intensively because they may find many applicationsin many fields including science industry and medicineRecently many researchers [8ndash10] constructed an apparatusto investigate on the pool boiling heat transfer convective heatand friction factor of nanofluid In addition there are someother researchers [11ndash14] that do lots of experiments to studythe heat transfer characteristics of nanofluid and all of themget the conclusion that comparing with base fluid nano-meter-sized particles which were suspended in the industrialheat transfer fluids have bright advantages in heat transferAlthough there are many researchers that have already focu-sed on the study of nanofluids heat transfer characteristics in

Hindawi Publishing CorporationJournal of NanomaterialsVolume 2016 Article ID 3693249 7 pageshttpdxdoiorg10115520163693249

2 Journal of Nanomaterials

Pum

pVa

lve

Flow

met

erReservoir

tank

Reservoirtank

Thermocouple

Cooling tower

Heat exchanger

2

1

Power supply

Heater

Thermocouple Pressure meterPressure meter

Figure 1 Schematic diagram of experimental apparatus

copper tube we had designed the experimental system forexample the copper tube was heated by electric resistancewire but it could not heat uniformly and the data of exper-iment is not accurate

This paper aims to consider effects of nanofluid coolanton heat transfer by improved setup and get the more accuratedata So it is better to understand the heat transfer characteris-tics of nanofluid comparedwith glycol fluid Furthermore theresults from calculation of several Nusselt correlations werecompared with the measured data Because CuO nanofluidsnot only have high thermal conductivity but also make goodcompatibility with basic liquid the cost is not too high Sotaking the factors into consideration CuO nanofluids will beselected

Firstly the theory of experiment and data parameter isdiscussed in Section 2 Secondly Section 3 provides the detai-led theory of conducted heat Thirdly in Section 4 the rela-tionship between Reynolds number and heat transfer coef-ficient (including pressure and flow) would be introducedFinally some concluding remarks are made in Section 5

2 The Building of Experimental System

21 Schematic Diagram of Experimental Setup As is shown inFigure 1 the reservoir tank (about 5 liters) was made of poly-methylmethacrylate and intended to hold the preparationof nanofluid while being equipped with the thermocoupleof the accuracy of 01∘C and the pressure of intakeouttakewas measured by the pressure meter A flow meter recordedthe nanofluids quantity of flow the bypass line was used todischarge liquid The copper tube with an inner diameter of25mm and an external diameter of 30mm and a length of1000mm was used as the test section the copper tube casingwas full of ethylene glycol The tube surface was covered withheat preservation material of aluminum silicate and a fiberglass tape the tube was fixed by flange plates on both endsand gauze with asbestos was located in the middle which hasthe function of preserving heat

Therewere two pyroelectric sensors (one has the accuracyof 01∘C another has the accuracy of 1∘C) in the test sectionthey were used to measure the tube wall and fluid tempera-ture In order to control the fluid flow rate a valve was usedThe first circulatory systemwasmade up of the reservoir tankand the test section the system could measure the heat trans-fer coefficient of the nanofluid Secondly circulatory systemwas a heat exchanger and a cooling tank the function was topreserve constant temperature at the inlet of the test sectionThe third circulatory system was a heating device and a testsection the main function of that was to heat ethylene glycolwhich was located in the middle of the sleeve and the coppertube to preserve a constant temperature of the tube wall

22 The Experimental Step In this section the nanofluidwith 50sim60 nmCuO particles will be prepared different massfractions for the experiment and there are four steps that willbe followed before analyzing the test data

(1) Check out the air tightness of the test device

(2) By making nanofluid with ldquotwo stepsrdquo andmeasuringlittle nanoparticles and dispersant they were addedinto the glycol fluid andmixed in 120minutesmakinguse of ultrasonic shaking in 150minutes in order to getnanofluid suspension and we will use sodium dodec-yl-benzenesulfonate (SDBS) as a dispersant Further-more we observed the effect of nanofluid stabilitywith different volume fraction of SDBS In order toobtain stability nanofluid we used sodium dodecyl-benzenesulfonate (SDBS) as a dispersantThe volumeof SDBS has a great impact on the stability of CuO-glycol nanofluid By increasing the volume of SDBSthe stability of CuO-glycol is better

(3) Measured nanofluid was added into the system theexport and import of the test section and the tubewall temperature were constant until making use ofthe heat device heating copper tube equably

Journal of Nanomaterials 3

(4) The heat sensor and thermocouple marked correspo-nding temperature each measurement was repeatedto measure different mass fraction nanofluid Finallywe analyzed the measured data

23 The Data of Convective Heat Transfer Analysis In orderto obtain heat transfer parameters nanofluid properties suchas density specific heat viscosity and thermal conductivityshould be measured or calculated by theoretical models

Density and specific heat are given byWang andMujum-dar [15]

Density 120588nf = (1 minus 120593) 120588bf + 120593120588np (1)

Heat capacitance is as follows

119862119901nf =

(1 minus 120593) 120588bf119862119901bf + 120593120588np119862119901np

120588nf (2)

Dynamic viscosity of nanofluid is as follows

120583nf = (1 + 25120593) 120583bf (3)

Reynolds number and thermal conductivity are given asfollows

The thermal conductivity of nanoparticles is given byCorcione [16]

119896nf119896bf= 1 + 44119877

119890

04

np119875119903066

bf (119879

119879119891119903

)

10

(119896np

119896bf)

003

120593066

119875119903bf=120583bf119862119901bf

119896

(4)

where 119879119891119903is freezing point of base fluid (about 27316 K)

Reynolds number is given as follows

Renp =120588bf119881119889np

120583bf=2120588bf120581119861119879

1205871205832bf119889np (5)

where 120581119861is Boltzmannrsquos constant (138066 times 10minus23 JK) This

correlation is applicable for nanoparticles diameter between10 nm and 150 nm volume concentration between 02 and9 and nanofluid temperature between 294K and 324K

3 The Theory of Conducted Heat

31 Parameter Calculation With the convective heat transferbetween nanofluid and copper tube wall the temperature ofnanofluid has changed on the inlet of the copper tube andoutlet of the copper tube Consider

= 119902119862119901nfΔ119879

Δ119879 = 119879out minus 119879in

119902 = 119878 sdot V sdot 120588nf

119878 =120587119889ℎ

2

4

V =119902V

119904

(6)

where is generated heat where119862119901nf is the nanofluid specific

heat and Δ119879 is the temperature difference of inlet copperand outlet copper 119902 is the average nanofluid mass flow 119878 iscross-sectional area of copper tube V is the average velocityof nanofluid in the test section and 119902V is the average volumeflow

The nanofluid convective heat transfer coefficient ℎ andNu are calculated as follows [17] (which was given by Incr-opera and DeWitt)

ℎ =11990210158401015840

119879w minus 119879f

11990210158401015840=

Nu = ℎ119897119896nf

(7)

where is the surface area of test copper tube = 120587119889 sdot 119871 119879wis the average temperature of copper tube wall and 119879f is theaverage temperature of nanofluid Consider

119879w =3

sum

119894=1

119879119894

3

119879f =(119879out + 119879in)

2

(8)

The arbitrary119909heat transfer coefficient in the test section ℎ(119909)is calculated as follows

ℎ (119909) =11990210158401015840

119879w (119909) minus 119879f (119909) (9)

where 119879w(119909) is the arbitrary 119909 of copper tube wall temper-ature and 119879f(119909) is the arbitrary 119909 temperature of nanofluidConsider

119879f (119909) = 119879in +11990210158401015840

120588nf119862119901nfV119878119897 (10)

32 Uncertainty The uncertainty of averaged heat transfercoefficient is defined as follows

120575119877 =

119873

sum

119894=1

(120597119877

120597119909119894

120575119909119894)

2

12

(11)

The values of uncertainties were calculated in differ-ent Reynolds numbers and nanoparticles volume fractionsAccording to formula (11) we can get the uncertainties asTable 1

4 Experimental Results and Discussion

41 The Effect of Nanofluid Stability with Different VolumeFraction of Dispersant Figure 2 shows the typical microgra-phs obtained by transmission electronmicroscopy (TEM) forthe CuO nanoparticles that were used in this study Figure 2confirms that the average size is 70 nm


Table 1 The uncertainties

Parameter UncertaintyThermocouple plusmn51Pyroelectric sensor plusmn05Quantity of flow plusmn27Pressure plusmn45Transfer coefficient plusmn76Test section plusmn42

42 Reynolds Number Mass Fraction and Heat Transfer Coef-ficient A typical set of results are shown in Figure 3 for mea-surements at 20∘C The effective thermal conductivity of thenanofluid increases approximately linearly with particle vol-ume fraction but decreases with increasing particle sizes [1819] By the reason of the fact that nanoparticles size is bigthe nanofluid thermal conductivity is not obvious at 050To obtain a comprehensive understanding of the mechanismbehind this phenomenon we also tested the samples withhigher CuO concentration and its heat transfer mechanismis similar to concentration at 120 (as the result is similar inthe following Figures 4 5 and 6 we did not introduce it) Asis shown in Figure 3 for low volume of CuO nanoparticles inglycol fluid there are no major changes in heat transfer coef-ficient As the volume of CuOnanoparticles and the Reynoldsnumber are increasing however the heat transfer coefficientof nanofluid has an obvious increase

To obtain more data of experiment we also measure thearbitrary of heat transfer coefficient in copper tube which isillustrated in Figure 4 at the temperature of 20∘C

As is shown in Figure 4 the heat transfer coefficient ofentrance has an obvious difference in other placesThemajorreason is that it has a fierce Brownian movement in entrance[20 21]

43 Reynolds Number Mass Fraction and Wall TemperatureIn the third closed-loop system shutdown valve 1 and openvalve 2 lead ethylene glycol flow into the water tank as shownin Figure 5

Although there is no major effect on wall temperature inlow nanoparticle concentrations in higher volume fractionsnanoparticles affect wall temperature By increasing nanopar-ticle concentrations wall temperature decreases The rea-son behind this behavior is higher thermal conductivity ofnanofluid in comparison to glycol fluid

44TheNusselt Number ofNanofluid inDifferentNanoparticleConcentrations and Different Reynolds Number Variation ofNusselt number with different particle concentrations at Re =2600 is illustrated in Figure 6 It is evident that CuOnanopar-ticles suspended in ethylene glycol enhance the Nusseltnumber except for 025 and 05 volume fractions

45 The Resistance along the Project The resistance along theprojectwas reflected by the pressure variationwith nanofluids

Figure 2 Typical TEMmicrographs of CuO nanoparticles

500 1000 1500 2000

400

800

1200

1600

2000The rate of change

Re

Glycol exp025 exp050 exp080 exp120 exp150 exp

Glycol fit025 fit050 fit080 fit120 fit150 fit

h(W

m2

K)

Figure 3 Convective heat transfer coefficient of CuOglycol nano-fluids with different mass fraction under laminar flow

which was shown in Figure 6 And the relationship pressurewith resistance is

119891 =2Δ119875119889h119897120588nfV

(12)

where 119891 is the resistance along the project Δ119875 is the pressuredrop of CuO-glycol 119889h is the hydraulic diameter 119897 is testsection length and V is velocity of flow

In Figure 7 the pressure of nanofluids increased by themass fraction increase The major reason is that the higherparticle volume fraction has a higher viscosity and its frictioncoefficient is also higher than the low particle volume fractionnanofluids At the concentration of the CuO-glycol nanofluidfrom 080 to 120 although its pressure is higher thanothers the differential pressure is not very obvious Howeverin the heat transfer aspect the higher particle volume fractionnanofluid has a large obvious difference with the low onesAlthough the pressure drop increases would lead to the lossof pimp power the heat transfer coefficient increases signif-icantly That is to say its thermal conductivity is higher thanthe low ones So when the range of the CuO-glycol nanofluid


Glycol exp025 exp050 exp080 exp120 exp

Glycol fit025 fit050 fit080 fit120 fit

1600

1400

1200

1000

800

60002 06 1 14

Distance (m)

h(x)

(Wm

2K)

The h(x) veracity

Figure 4 Tube axial convective heat transfer coefficient of CuOglycol nanofluids with different mass fractions



65

55

45

35

Tem

pera

ture

(∘C)

500 1000 1500 2000 2500

Re

Temperature of Reynolds number

Figure 5 Measure the wall temperature

120

100

80

60

400 04 08 12

Distance X (m)

Nu



Re = 2600

Figure 6 Tube axial local Nusselt number coefficient of CuOglycolnanofluids with different mass fractions



6000

5000

4000

3000

2000

1000

00 500 1000 1500 2000

Re

Pres

sure

dro

p (p

a)

Pressure variation

Figure 7 Pressure drop of CuO-glycol

concentration is from 080 to 120 its positive effects aremuch higher than negative effects

5 Conclusions

(1) CuO nanoparticles make the heat transfer intensity of thefluid increase obviously in glycol fluid It is observed thatby increasing Reynolds number the heat transfer coefficient


increases especially the inlet which is very obvious Addingmoderate dispersant can ease nanoparticles aggregationeffectively and enable it to be steady

(2) For higher volume fractions of CuOnanoparticle walltemperature decreases and heat transfer increases

(3) For low concentration of CuO nanofluid there is nosignificant change in wall temperature heat transfer coeffi-cient and Nusselt number By increasing the mass fraction ofCuOnanofluids wall temperature decreases and heat transfercoefficient and Nusselt number increase

(4) As nanofluids greatly increase the heat transfer coef-ficient of base liquid compared to the defect taken by thevolume of nanoparticle its high heat transfer coefficientwould bringmore advantages So increasing appropriately theparticle volume fraction would be beneficial to the enhance-ment of heat transfer

Nomenclature

119862119901 Specific heat (Jkg)

119863 Diameter of particles (nm)119889h Hydraulic diameter (mm)Nu Nusselt numberPr Prandtl number Generated heat (W)Re Reynolds number120581 Boltzmann constant (JK)120583 Viscosity (kgsm)120593 Nanoparticles concentrationV Velocity of flow (m)bf Base fluidnp Nanoparticlesℎ Heat transfer coefficient (Wm2)119896 Thermal conductivity (Wm)119897 Test section length (mm)119901 Power (W)11990210158401015840 Heat flux (Wm2)119889in Inner diameter (mm)119879 Temperature (∘C)120588 Density (kgm3)119902V Average volume flow119871 Test section length (mm)

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Authorsrsquo Contribution

Chen Juhui and Yu Guangbin contributed equally to thiswork

Acknowledgments

This research was supported by the National Natural ScienceFoundation of China (51406045) and the Key Program ofNational Natural Science Foundation of Heilongjiang (no

ZD201309) and the project was supported by the MajorInternational Joint Research Program of China (Grant no2014DFB70120) the Outstanding Youth Science Fund ofHeilongjiang (Grant no JC201420) and National NaturalScience Foundation of Heilongjiang Province (E201441)

References

[1] S U S Choi and J A Eastman ldquoEnhancing thermal con-ductivity of fluids with nanoparticlesrdquo in Proceedings of theInternational Mechanical Engineering Congress and Exhibitionpp 99ndash103 San Francisco Calif USA November 1995

[2] P Garg J L Alvarado C Marsh T A Carlson D A KesslerandKAnnamalai ldquoAn experimental study on the effect of ultra-sonication on viscosity and heat transfer performance of multi-wall carbon nanotube-based aqueous nanofluidsrdquo InternationalJournal of Heat and Mass Transfer vol 52 no 21-22 pp 5090ndash5101 2009

[3] B Rimbault C T Nguyen and N Galanis ldquoExperimentalinvestigation of CuO-water nanofluid flow and heat transferinside a microchannel heat sinkrdquo International Journal of Ther-mal Sciences vol 84 pp 275ndash292 2014

[4] B C Pak and Y I Cho ldquoHydrodynamic and heat transfer studyof dispersed fluids with submicron metallic oxide particlesrdquoExperimental Heat Transfer vol 11 no 2 pp 151ndash170 1998

[5] M Kole and T K Dey ldquoViscosity of alumina nanoparticlesdispersed in car engine coolantrdquo Experimental Thermal andFluid Science vol 34 no 6 pp 677ndash683 2010

[6] G Zyła M Cholewa and A Witek ldquoRheological properties ofdiethylene glycol-based MgAl

2O4nanofluidsrdquo RSC Advances

vol 3 no 18 pp 6429ndash6434 2013[7] G Zyła and M Cholewa ldquoOn unexpected behavior of viscosity

of diethylene glycol-basedMgAl2O4nanofluidsrdquoRSCAdvances

vol 4 no 50 pp 26057ndash26062 2014[8] T I Kim Y H Jeong and S H Chang ldquoAn experimental study

on CHF enhancement in flow boiling using Al2O3nano-fluidrdquo

International Journal of Heat andMass Transfer vol 53 no 5-6pp 1015ndash1022 2010

[9] M Kole and T K Dey ldquoInvestigations on the pool boilingheat transfer and critical heat flux of ZnO-ethylene glycolnanofluidsrdquo Applied Thermal Engineering vol 37 pp 112ndash1192012

[10] H Ramakrishna R Shrikantha and R Ranapratap ldquoExperi-mental investigations of pool boiling heat transfer characteris-tics on a vertical surface using CuO nanoparticles in distilledwaterrdquo Heat Transfer Engineering vol 35 no 14-15 pp 1279ndash1287 2014

[11] Y Abbassi M Talebi A S Shirani and J Khorsandi ldquoExper-imental investigation of TiO

2Water nanofluid effects on heat

transfer characteristics of a vertical annulus with non-uniformheat flux in non-radiation environmentrdquo Annals of NuclearEnergy vol 69 pp 7ndash13 2014

[12] V T Perarasu M Arivazhagan and P Sivashanmugam ldquoHeattransfer of TiO

2water nanofluid in a coiled agitated vessel with

propellerrdquo Journal of Hydrodynamics vol 24 no 6 pp 942ndash9502012

[13] C T Nguyen N Galanis G Polidori S Fohanno C VPopa and A Le Bechec ldquoAn experimental study of a confinedand submerged impinging jet heat transfer using Al

2O3-water

nanofluidrdquo International Journal ofThermal Sciences vol 48 no2 pp 401ndash411 2009


[14] S Mitra S K Saha S Chakraborty and S Das ldquoStudyon boiling heat transfer of water-TiO

2and water-MWCNT

nanofluids based laminar jet impingement on heated steelsurfacerdquoAppliedThermal Engineering vol 37 pp 353ndash359 2012

[15] X-Q Wang and A S Mujumdar ldquoHeat transfer characteristicsof nanofluids a reviewrdquo International Journal of Thermal Sci-ences vol 46 no 1 pp 1ndash19 2007

[16] M Corcione ldquoEmpirical correlating equations for predictingthe effective thermal conductivity and dynamic viscosity ofnanofluidsrdquo Energy Conversion and Management vol 52 no 1pp 789ndash793 2011

[17] K Seung-Won J Jae-Jun and L Tae-Hee ldquoCandidate pointsand representative cross-validation approach for sequentialsamplingrdquo Korea Science vol 44 pp 367ndash373 1996

[18] S Lee S U-S Choi S Li and J A Eastman ldquoMeasuringthermal conductivity of fluids containing oxide nanoparticlesrdquoASME Journal of Heat Transfer vol 121 no 2 pp 280ndash288 1999

[19] H Xie J Wang and T Xi ldquoThermal conductivity enhancementof suspension containing nanosized alumiua particlesrdquo Journalof Applied Physics vol 97 no 7 pp 4568ndash4572 2002

[20] Y Xuan and Q Li ldquoExperimental investigation on heat transferenhancement of nanofluidsrdquo in Proceedings of the InternationalSymposium on Nano-Materials and Technology Beijing China2001

[21] Q Li and Y Xuan ldquoConvective heat transfer performances ofnanofluidsrdquo in Proceedings of the 12th International Heat Trans-fer Conference Grenoble France August 2002

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


Pum

pVa

lve

Flow

met

erReservoir

tank

Reservoirtank

Thermocouple

Cooling tower

Heat exchanger

2

1

Power supply

Heater

Thermocouple Pressure meterPressure meter

Figure 1 Schematic diagram of experimental apparatus

copper tube we had designed the experimental system forexample the copper tube was heated by electric resistancewire but it could not heat uniformly and the data of exper-iment is not accurate

This paper aims to consider effects of nanofluid coolanton heat transfer by improved setup and get the more accuratedata So it is better to understand the heat transfer characteris-tics of nanofluid comparedwith glycol fluid Furthermore theresults from calculation of several Nusselt correlations werecompared with the measured data Because CuO nanofluidsnot only have high thermal conductivity but also make goodcompatibility with basic liquid the cost is not too high Sotaking the factors into consideration CuO nanofluids will beselected

Firstly the theory of experiment and data parameter isdiscussed in Section 2 Secondly Section 3 provides the detai-led theory of conducted heat Thirdly in Section 4 the rela-tionship between Reynolds number and heat transfer coef-ficient (including pressure and flow) would be introducedFinally some concluding remarks are made in Section 5

2 The Building of Experimental System

21 Schematic Diagram of Experimental Setup As is shown inFigure 1 the reservoir tank (about 5 liters) was made of poly-methylmethacrylate and intended to hold the preparationof nanofluid while being equipped with the thermocoupleof the accuracy of 01∘C and the pressure of intakeouttakewas measured by the pressure meter A flow meter recordedthe nanofluids quantity of flow the bypass line was used todischarge liquid The copper tube with an inner diameter of25mm and an external diameter of 30mm and a length of1000mm was used as the test section the copper tube casingwas full of ethylene glycol The tube surface was covered withheat preservation material of aluminum silicate and a fiberglass tape the tube was fixed by flange plates on both endsand gauze with asbestos was located in the middle which hasthe function of preserving heat

Therewere two pyroelectric sensors (one has the accuracyof 01∘C another has the accuracy of 1∘C) in the test sectionthey were used to measure the tube wall and fluid tempera-ture In order to control the fluid flow rate a valve was usedThe first circulatory systemwasmade up of the reservoir tankand the test section the system could measure the heat trans-fer coefficient of the nanofluid Secondly circulatory systemwas a heat exchanger and a cooling tank the function was topreserve constant temperature at the inlet of the test sectionThe third circulatory system was a heating device and a testsection the main function of that was to heat ethylene glycolwhich was located in the middle of the sleeve and the coppertube to preserve a constant temperature of the tube wall

22 The Experimental Step In this section the nanofluidwith 50sim60 nmCuO particles will be prepared different massfractions for the experiment and there are four steps that willbe followed before analyzing the test data

(1) Check out the air tightness of the test device

(2) By making nanofluid with ldquotwo stepsrdquo andmeasuringlittle nanoparticles and dispersant they were addedinto the glycol fluid andmixed in 120minutesmakinguse of ultrasonic shaking in 150minutes in order to getnanofluid suspension and we will use sodium dodec-yl-benzenesulfonate (SDBS) as a dispersant Further-more we observed the effect of nanofluid stabilitywith different volume fraction of SDBS In order toobtain stability nanofluid we used sodium dodecyl-benzenesulfonate (SDBS) as a dispersantThe volumeof SDBS has a great impact on the stability of CuO-glycol nanofluid By increasing the volume of SDBSthe stability of CuO-glycol is better

(3) Measured nanofluid was added into the system theexport and import of the test section and the tubewall temperature were constant until making use ofthe heat device heating copper tube equably







119862119901nf =

(1 minus 120593) 120588bf119862119901bf + 120593120588np119862119901np

120588nf (2)


120583nf = (1 + 25120593) 120583bf (3)



119896nf119896bf= 1 + 44119877

119890

04

np119875119903066

bf (119879

119879119891119903

)

10

(119896np

119896bf)

003

120593066

119875119903bf=120583bf119862119901bf

119896

(4)



Renp =120588bf119881119889np

120583bf=2120588bf120581119861119879

1205871205832bf119889np (5)





= 119902119862119901nfΔ119879

Δ119879 = 119879out minus 119879in

119902 = 119878 sdot V sdot 120588nf

119878 =120587119889ℎ

2

4

V =119902V

119904

(6)




ℎ =11990210158401015840

119879w minus 119879f

11990210158401015840=

Nu = ℎ119897119896nf

(7)


119879w =3

sum

119894=1

119879119894

3

119879f =(119879out + 119879in)

2

(8)


ℎ (119909) =11990210158401015840

119879w (119909) minus 119879f (119909) (9)


119879f (119909) = 119879in +11990210158401015840

120588nf119862119901nfV119878119897 (10)


120575119877 =

119873

sum

119894=1

(120597119877

120597119909119894

120575119909119894)

2

12

(11)















500 1000 1500 2000

400

800

1200

1600


Re



h(W

m2

K)



119891 =2Δ119875119889h119897120588nfV

(12)






1600

1400

1200

1000

800

60002 06 1 14

Distance (m)

h(x)

(Wm

2K)

The h(x) veracity




65

55

45

35

Tem

pera

ture

(∘C)

500 1000 1500 2000 2500

Re



120

100

80

60

400 04 08 12

Distance X (m)

Nu



Re = 2600




6000

5000

4000

3000

2000

1000

00 500 1000 1500 2000

Re

Pres

sure

dro

p (p

a)

Pressure variation



5 Conclusions







Nomenclature







Acknowledgments



References






















2O3-water




2and water-MWCNT
















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials









119862119901nf =

(1 minus 120593) 120588bf119862119901bf + 120593120588np119862119901np

120588nf (2)


120583nf = (1 + 25120593) 120583bf (3)



119896nf119896bf= 1 + 44119877

119890

04

np119875119903066

bf (119879

119879119891119903

)

10

(119896np

119896bf)

003

120593066

119875119903bf=120583bf119862119901bf

119896

(4)



Renp =120588bf119881119889np

120583bf=2120588bf120581119861119879

1205871205832bf119889np (5)





= 119902119862119901nfΔ119879

Δ119879 = 119879out minus 119879in

119902 = 119878 sdot V sdot 120588nf

119878 =120587119889ℎ

2

4

V =119902V

119904

(6)




ℎ =11990210158401015840

119879w minus 119879f

11990210158401015840=

Nu = ℎ119897119896nf

(7)


119879w =3

sum

119894=1

119879119894

3

119879f =(119879out + 119879in)

2

(8)


ℎ (119909) =11990210158401015840

119879w (119909) minus 119879f (119909) (9)


119879f (119909) = 119879in +11990210158401015840

120588nf119862119901nfV119878119897 (10)


120575119877 =

119873

sum

119894=1

(120597119877

120597119909119894

120575119909119894)

2

12

(11)















500 1000 1500 2000

400

800

1200

1600


Re



h(W

m2

K)



119891 =2Δ119875119889h119897120588nfV

(12)






1600

1400

1200

1000

800

60002 06 1 14

Distance (m)

h(x)

(Wm

2K)

The h(x) veracity




65

55

45

35

Tem

pera

ture

(∘C)

500 1000 1500 2000 2500

Re



120

100

80

60

400 04 08 12

Distance X (m)

Nu



Re = 2600




6000

5000

4000

3000

2000

1000

00 500 1000 1500 2000

Re

Pres

sure

dro

p (p

a)

Pressure variation



5 Conclusions







Nomenclature







Acknowledgments



References






















2O3-water




2and water-MWCNT
















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials














500 1000 1500 2000

400

800

1200

1600


Re



h(W

m2

K)



119891 =2Δ119875119889h119897120588nfV

(12)






1600

1400

1200

1000

800

60002 06 1 14

Distance (m)

h(x)

(Wm

2K)

The h(x) veracity




65

55

45

35

Tem

pera

ture

(∘C)

500 1000 1500 2000 2500

Re



120

100

80

60

400 04 08 12

Distance X (m)

Nu



Re = 2600




6000

5000

4000

3000

2000

1000

00 500 1000 1500 2000

Re

Pres

sure

dro

p (p

a)

Pressure variation



5 Conclusions







Nomenclature







Acknowledgments



References






















2O3-water




2and water-MWCNT
















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






1600

1400

1200

1000

800

60002 06 1 14

Distance (m)

h(x)

(Wm

2K)

The h(x) veracity




65

55

45

35

Tem

pera

ture

(∘C)

500 1000 1500 2000 2500

Re



120

100

80

60

400 04 08 12

Distance X (m)

Nu



Re = 2600




6000

5000

4000

3000

2000

1000

00 500 1000 1500 2000

Re

Pres

sure

dro

p (p

a)

Pressure variation



5 Conclusions







Nomenclature







Acknowledgments



References






















2O3-water




2and water-MWCNT
















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials








Nomenclature







Acknowledgments



References






















2O3-water




2and water-MWCNT
















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





2and water-MWCNT
















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



Research Article Experimental Research on Heat Transfer...

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