das india kulkarni etal presentation 2008&09

7/31/2019 Das India Kulkarni Etal Presentation 2008&09

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Dr. Debendra Kumar DasMr. Devdatta P. Kulkarni

Mr. Praveen K. NamburuMr. Ravikanth VajjhaMr. Bhaskar C. Sahoo

Mechanical Engineering DepartmentUniversity of Alaska Fairbanks

USA

Fluid Dynamics & Thermal Performance of Nanofluids



Topics of DiscussionIntroduction

Example of nano and micro scalesAdvantages of NanofluidRheology of Nanofluids

Copper oxide (CuO) in water (5 to 15% Volume)Copper oxide in propylene glycol/water (1 to 6% Volume)

Effect on the Prandtl NumberFigure of Merit: Mouromtseff NumberHeat Transfer and Fluid Dynamic Performance of SiO 2 ,CuO and Al 2O3 nanofluidCase I: Application of Nanofluid in Building HeatingCase II: Application of Nanofluid as Coolant in DieselElectric Generator (DEG)Acknowledgements 2



What is Nanofluid?• The concept was proposed by Choi, U.S., Argonne National Lab, 1999• Dispersion of metallic nanometer sized particles (<100nm) in liquid

Source: Boutin, C., 2001

Significance of Nanoparticles

•Microparticles settle at the bottom due togravity, leading to clogging and wear

•Nanoparticles are permanentlysuspended by Brownian motion and whenthere is no flow they are distributed in

balance between buoyant weight andthermal agitation.

3



Nanoscience - Scale

1 Micron=millionth of a m, Red Blood cell100 Micron=Human Hair1 Nanometer=millionth of a pinhead=10 H 2 Atoms = dia. of water molecule

= billionth of a meter (10 -9)

Miniaturization : Richard Feynman, 1959micromachine

Aids virus 100 nm

DNA dia <3 nm

3



Carbon Nanotube

Single wall 6-membered rings cylindrical tube of diameter 0.5 nm to100 nm. Thermal conductivity 3000 W/m.K, Copper (400 W/m.K).



Schematic diagram of a cooling arrangement forelectronic chips using nanofluids

Source: Incropera and Dewitt 24



Application in the Shell and TubeHeat Exchanger

This heat exchanger for the chemical industry contains over 17

kilometers of tubing. Nanofluids will reduce the size.



Application in Automobile Radiators



Advantages of Nanofluid

Source: Eastman, 2001

Dramatic Increase in thermalconductivity of base liquid

Material Thermalconductivity(W/mK)

Material ThermalConductivity(W/mK)

NonmetallicLiquidWaterEngine OilEthylene Glycol

0.6130.1450.253

MetallicSolidsSilverCopperAluminum

429401237

])()1(

)()1()1([

p f f p

p f f p f nf k k k nk

k k nk nk k k

Hamilton & Crosser’s Equation for ThermalConductivity of Nanofluid

Source: Hamilton &Crosser, 1962

4



Theory of Nanofluid

4.021 PrRe)0.1( 321

nf mnf

md

mnf Pecc Nu Nusselt Number

nf

pmd

d uPe

Particle Peclet Number

4.0333.0218.0754.0 PrRe)285.110.1(4328.0 nf nf d nf Pe Nu


Laminar Flow

Turbulent Flow

Dk Nuh nf nf nf / )(Heat Transfer Coefficient

Source: Li and Xuan,2002

5



Topic of Discussion

Rheology of NanofluidsCopper oxide (CuO) in water (5 to 15% Volume)

6



Rheology of Nanofluids

Einstein ’s Correlation: )5.21( f s

Batchelors ’s Correlation: )25.65.21( 2 f s

Brinkman ’s Correlation: 5.2)1(1

f s

= suspension viscosity, = viscosity of base fluid and

is volume fraction of nanoparticles

s f

White Correlation: 200

0

)()(lnT

T c

T

T ba f

7



Viscosity Measurement Setup

SampleChamber

Brookfield LVDV-II

Viscometer

JulaboTemperatureControl Bath

Spindle

8



Temperature Control for Nanofluids

9



Shear Rate Vs Shear Stress

0

2

4

68

10

12

14

16

18

20

0 10 20 30 40 50 60

Shear Rate (1/sec)

S h e a r

S t r e s s ( N / m 2 )

278K

283K

288K

293K

298K

303K

308K313K

318K

323K

For 15% Vol. CuO in waternK

10n<1, Pseudoplastic and time independent



Viscosity Vs Particle Loading

0

50

100

150

200

250

300

350

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16

Volumetric Solids Loading

S u s p e n s

i o n

V i s c o s

i t y ( m

. P a . s 278K

283K

288 K

293K

298K

303K

308K

313K

318K

323K

12



Nanofluid Viscosity (Function of Temp & Concentration)

0

50

100

150

200

250

300

350

270 280 290 300 310 320 330

Temperature (K)

S u s p e n s

i o n

V i s c o s

i t y ( m

. P a . s

)5% EXPT5% Calc

8% Expt

8% Calc

10% Expt

10% Calc

13% Expt

13% Calc15% Expt

15% Calc

BT

As )1

(ln 3.10781585720587 2 A

8715.2548.5312.107 2 B

R2 = 0.99

R2 = 0.97

T is temperature in Kelvin and ranging from 0.05 to 0.15 13



Topic of Discussion

Rheology of NanofluidsCopper oxide in propylene glycol/water (1 to 6% Volume)

14



Rheology of CuO-PG/Water

y = 0.1063xR2 = 0.9998

0.0

5.0

10.0

15.020.0

25.0

30.0

0.0 50.0 100.0 150.0 200.0 250.0 300.0

Shear Rate (1/sec)

S h e a r

S t r e s s ( D

/ c m 2 ) 5.9% CuO Loading at 50 Deg C

0

100

200

300

400

500

600

700

-40 -20 0 20 40 60Temperature (Deg C)

V i s c o s

i t y ( c P )

ExperimetalASHRAE

.

Constitutive Equationof Newtonian Fluid

Benchmark TestCase

15



Viscosity Vs Temperature

1

10

100

1000

10000

-40 -20 0 20 40 60

Temperature (Deg C)

V i s c o s

i t y o

f N a n o

f l u i d ( c P

0% CuO

1% CuO

2% CuO

3% CuO

4%CuO

5% Cuo

5.9% CuO

16



Relative Viscosity of Nanofluid

0

1

2

3

4

5

6

-40 -20 0 20 40 60

Temperature (Deg C)

M u r

( M u s

/ M u f )

1% CuO2% CuO

3% CuO

4% Cuo5% CuO

5.9% Cuo

0

0.5

1

1.5

2

2.5

3

3.5

4

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

Volume Fraction

M u r

ExperimentalBatchelor Equation

Relative Viscosity as aFunction of Temperature

Comparison of Experiments with

Batchelor’s Equation

17



Viscosity of Nanofluid (CuO-PG/Water)

0

500

1000

1500

2000

2500

3000

3500

230 250 270 290 310 330

Temperature (Kelvin)

V i s c o s

i t y ( m

. P a

S )

E(0%)

C(0%)E(1%)

C(1%)

E(5.9%)C(5.9%)

E(4%)

C(4%)

Bs Ae T e A 0199.09.736)ln(

B = 44.794 - 0.0765 T with R2 = 0.98

with R2 = 0.99

T is temperature in Kelvin and ranging from 0 to 0.06 18



Conclusions: Rheology I

For CuO-WaterNanofluids with 5 to 15% vol. concentration behaved

as time-independent, shear thinning, pseudoplastic fluid.

The viscosity was found to be a strong function of temperature and the volumetric concentration.

A new correlation for viscosity of these nanofluids asa function of temperature and volumetric concentration

was developed.The curve fit correlation of viscosity verses

temperature agrees within 10% of the experimentalmeasurements.

19



Conclusions: Rheology IIFor CuO-PG/Water

Viscosity measurement for a 60:40 propylene glycol/water mixturewithout any nanoparticle suspension shows excellent agreement with theASHRAE data.

The viscosity of a CuO nanofluid in propylene glycol and water solution

is an exponential function of volume percentage and temperature. The behavior of this nanofluid up to a volume percentage of 5.9% is

Newtonian in nature.

The deviation from Batchelor’s classical equation is observed to be

substantial for nanofluids.Relative viscosity curves display higher slopes at low temperatures.

A new correlation has been developed for this type of nanofluid. Thedeviation between experimental data and values given by this correlation iswithin 10%.

20



Topic of Discussion

Effect on the Prandtl Number

21



Effect on Prandtl Number (In EG/Water)

Pr)(Re, f Nu



(For laminar flow)

(For turbulent flow)

(Source: Li & Xuan, 2002)

k

c p Pr

Nusselt Number

Prandtl Number

])()1(

)()1()1([

p f f p


k k nk nk k k

ThermalConductivity

n is a function of shape; for spherical particles n is 3

22



Density and Specific Heat of Nanofluid

p f nf )1(Density of Nanofluid

Source: Pak & Cho, 1998

1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

0 2 4 6 8 10 12Volumetric Nanoparticle Concentration (%)

D e n s

i t y ( k g

/ m ^ 3 )

SiO2Al2O3CuO

2300

2400

2500

2600

2700

2800

2900

3000

3100

3200

3300

0 2 4 6 8 10 12Particle Volume Concentration (%)

S p e c

i f i c H e a

t o

f N a n o

f l u i d ( J / k g - K

) SiO2Al2O3CuO

Specific Heat of Nanofluid

nf

pf f pss pnf

C C C

)1(

Source:Buongiorno, 2006

23



Viscosity and Thermal Conductivity

0.39

0.41

0.43

0.45

0.47

0.49

0.51

0.53

0.55

0 2 4 6 8 10 12

Nanoparticle Volume Concentration (%)

T h e r m a l

C o n

d u c t i v i t y

( W / m K )

SiO2Al2O3CuO

24

0

20

40

60

80

100

120

140160

180

200

-40 -30 -20 -10 0 10 20 30 40 50 60

Tempearture (C)

V i s c o s

i t y ( c P )

SiO2 (10%)SiO2 (8%)SiO2 (6%)

SiO2 (4%)SiO2 (2%)EG/Water



Prandtl Number Vs Particle Loading

20

30

40

50

60

70

80

90

100

0 2 4 6 8 10 12

Volume Percentage (%)

P r a n

d t l N u m

b e r

( P r )

SiO2Al2O3CuO

25



Particle Size Effect on Prandtl Number

35

37

39

41

43

45

4749

51

53

0 2 4 6 8 10 12Particle Volume Percentage (%)

P r a n

d t l N u m

b e r

( P r )

SiO2 20 nm

SiO2 50 nmSiO2 100 nm

0

2

4

6

8

10

12

0 2 4 6 8 10 12

Volume Concentration (%)

V i s c o s i t y o

f N a n o

f l u i d ( c P )

20 nm SiO250 nm SiO2100 nm SiO2

27



Conclusions: Prandtl Number

Nanofluid density increases as volume concentration increases. It increasesrapidly for higher density particles.

Adding nanoparticles to a base fluid reduces the specific heat of thenanofluid.

Viscosity is a strong function of volume concentration, temperature andparticle diameter of nanoparticles.

Prandtl number increases rapidly as particle volume concentration increases.Among the three fluids analyzed, it is highest for copper oxide nanofluidsand lowest for silicon dioxide nanofluids.

The Prandtl number also changes with particle diameter. The smaller thediameter, the higher is the Prandtl number.

The Prandtl number increases exponentially as the nanofluid is cooled belowsub zero temperatures.

28



Topic of Discussion

Figure of Merit: Mouromtseff Number

29



Comparison of Heat Transfer Rates of Nanofluids

Comparison on the basis of Mouromtseff number (Mo)

The Mouromtseff number is a Figure of Merit (FOM) for heattransfer fluids.

e

d p

ba C k Mo

Mouromtseff

Number

k , , C p and µ are thermal conductivity,density, specific heat and dynamic

viscosity of the fluid respectively

The exponents a, b, d, and e take on values appropriate to the heat transfer mode of interest and the corresponding heat transfer correlation

])()1(

)()1()1([

p f f p


k k nk nk k k

s f nf )1(

BT

As )1

(ln nf

pf f pss pnf

C C C

)1(

Thermal Conductivity Density

ViscositySpecific Heat

30



Derivation of Mo Number



(For laminar flow)


(Source: Li & Xuan, 2002) Dk Nuh nf nf nf / )(

07.0

6.04.0333.0

218.0754.0 )])(285.11(1[nf

nf pnf nf

nf

p k C d Mo

5238.0

6.04.09238.0001.06886.0 )])(6286.7(1[

nf

nf pnf nf

nf

p k C d Mo

(For laminar flow)


(Source: Kulkarni et al., 2007)

31



Mo Number for Water

0

1

2

3

4

5

6

7

8

water 5 8 10 13 15

% of CuO Particles in Water

R e

l a t i v e

H e a

t T r a n s

f e r r a

t eLaminar

Turbulent

32



Mo Number forLaminar Flow

Laminar

0

0.5

1

1.5

2

2.5

60:40 EG/Water + CuONanoparticles

60:40 PG/water + CuONanoparticles

R e

l a t i v e

H e a t

T r a n s

f e r Water

0%

1%

2%

3%

4%

5%

6%

Turbulent

0

0.2

0.4

0.6

0.8

1

1.2

60:40 EG/Water + CuONanoparticles

60:40 PG/water + CuONanoparticles

R e

l a t i v e

H e a

t T r a n s

f eWater

0%

1%

2%3%

4%

5%

6%

Mo Number forTurbulent Flow

33



Conclusions: Mo Number

For internal laminar flow, the FOM of copperoxide nanofluids is much superior to pure basefluids (water, EG/water, PG/water).

For the CuO nanofluids, the optimal volumepercentage appears to be 5% in internal turbulentflows.

Ethylene glycol based nanofluids have better

FOM than propylene glycol based nanofluids.

34



Topic of Discussion

Heat Transfer and Fluid Dynamic Performance of SiO 2 ,CuO and Al 2O3 nanofluid

35



Heat Transfer and Fluid DynamicPerformance of SiO 2 Nanofluids

Rheology of SiO 2-EG/Water

0

10

20

30

40

50

60

70

80

90

100

230 240 250 260 270 280 290 300 310 320 330Temperature (K)

V i s c o s i t y ( c P )

ExperimentASHRAE

50nm

0

20

40

60

80

100

120

140

160

180

200

-40 -30 -20 -10 0 10 20 30 40 50 60

Temperature (C)

v i s c o s i t y ( c P )

sio2(10%)sio2(8%)sio2(6%)sio2(4%)sio2(2%)

Benchmark Test Case

Viscosity Vs Temperature forVarious Concentrations of SiO 2

BT nf Ae)log(

06.1551232.78943.32339.0 23 A

0192.00004.0067 2 E B

36



Experimental Setup

37



Determination of Heat Transfer Coefficient

f wnf T T

qh "

f p T C mq.

4.08.0

PrRe023.0 Nu

1

10

100

100 1000 10000 100000

Reynolds Number

N u

/ P r ^ 0 .

4

ExperimentDittus Boelter for EG/WaterBenchmark Case

Dittus Boelter Equationfor EG/water

Heat gained by fluid

Heat transfer coefficientof nanofluid

38



Heat Transfer Coefficient Vs Reynolds Number

5000

7000

9000

11000

13000

15000

17000

19000

3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000

Reynolds Number (Red)

H e a t

T r a n s f e r

C o e f f i c i e n

t , h ( W / m 2 K )

10% SiO28% SiO2

6% SiO2

4% SiO2

2% SiO2

Ethylene Glycol/Water

39



Effect of Particle Size on Heat Transfer Coefficient

6% SiO2 NF

6000

8000

10000

12000

14000

16000

18000

20000

22000

3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000

Reynolds Number (Re)

H e a t

T r a n s f e r

C o e f f i c i e n

t h ( W / m 2 K )

20 nm50 nm100 nm

4% SiO2

5000

7000

9000

11000

13000

15000

17000

19000

21000

3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000


H e a t

T r a n s

f e r C o e f f i c i e n

t h ( W / m 2 K )

20 nm50 nm100 nm

Heat Transfer CoefficientFor 6% SiO 2 nanofluid

Heat Transfer CoefficientFor 4% SiO 2 nanofluid

40



Pressure Loss Measurement

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0 5000 10000 15000 20000 25000 30000

Reynolds Number (Red)

D a r c y

F r i c

t i o n

F a c

t o r

( f )

BlasiusExperimental

)Re0791.0(44 41

f C f Darcy Friction Factorby Blasius Equation

Benchmark Test Case

41



Friction Factor with Varying Concentration

0

0.01

0.02

0.03

0.04

0.05

0.06

0 2000 4000 6000 8000 10000 12000 14000

Reynolds Number

D a r c y

F r i c

t i o n

F a c

t o r

( f )

2%

4%

6%

Blasius

0%

2

)2( LV

d P f

Friction Factor

43



Effect of Particle Size on Pressure Loss

0

100

200

300

400

500

600

700

800

900

0 1 2 3 4 5 6 7 8 9

Velocity (m/s)

P r e s s u r e

L o s s

( k P a

)

20 nm B 20 nm E

50 nm B 50 nm E

100 nm B 100 nm E

0% B 0% E

44

l



ConclusionsViscosity of a nanofluid is a function of nanoparticle

concentration, increasing as the concentration increases.

As particle size increases, the viscosity of nanofluids decreases.

Heat transfer coefficients of nanofluids increase with volumeconcentration. A typical enhancement of heat transfer coefficient is

about 16% at a concentration of 10% with 20 nm particle diameterat Re = 10,000.

Particle size influences the heat transfer coefficient. The largerthe diameter, the higher the heat transfer coefficient.

Pressure loss is a function of the concentration, increasing withincreasing concentration. This is because the viscosity increaseswith concentration.

No appreciable change in pressure loss was observed withdifferent particle diameters. 45



A li i f N fl id i H i B ildi



Application of Nanofluids in Heating Buildings

Three nanofluids were considered.

1) SiO 2 in EG/water, 2) Al 2O3 in EG/water, 3) CuO in EG/water

Objectives of Study:

Determine the rheology and heat transfer coefficient of various nanofluids

Effect of nanofluids on volumetric flow rate, mass flow rate and pumpingpower for same thermal performance compared to base fluid

Effect on size of heat exchanger required

pump

nf PV W

.

.

v AV iPnf

,

.

Volumetric flow rate of nanofluid

Pumping power required for nanofluid

47

Vi i f V i N fl id



Viscosity of Various Nanofluids

0

50

100

150

200

250

300

350

400

450

-40 -30 -20 -10 0 10 20 30 40 50 60

Temperature (Deg C)

V i s c o s i t y o

f N a n o

f l u i d ( m P a .

S )

EG/Water

6% Cuo

6% Al2O3

6% SiO2

48



Heat Transfer Enhancement of Nanofluids

0

5000

10000

15000

20000

25000

0 2000 4000 6000 8000 10000 12000

Reynolds Number, Re

H e a t

T r a n s f e r

C o e

f f i c i e n t , h ( W / m 2 K )

6% CuO

6% Al2O36% SiO2

EG/Water

49



Pressure Loss of Various Nanofluids

0

200

400

600

800

1000

1200

3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 13000


P r e s s u r e

L o s s

( k P a

)

EG/Water6% CuO6% Al2O36% SiO2

50



N fl id i Ai H t E h g



Nanofluids in Air Heat Exchanger

moo t AU Q.

)( ,,

.

iP f iPi t t AhQ

P

oPiPmPP

x

t t Ak Q

)( ,,,.

))(( ,,,

.t t A AhQ oPF oPoc

ocF oPocPmP

Po

iiP

oo

h A Ahk A

x A

h A

AU

,,,,,

1

) / (

11

Heat transfer rate from a heating coil circulatingnanofluid to air

Rate of heat transfer from the nanofluid to the pipe

Rate of heat transfer through the pipe wall

Rate of heat transfer from the pipe and fin to the air

Overall heat transfer coefficient

Typical Data for Heat Exchanger:

iP A ,

oP A ,

mP A ,

F A

o A

och ,

= 0.03536 m 2

= 0.03658 m 2

= 0. 0.0375 m 2

= 0.948 m 2

= 0.09845 m 2

= 57 W/m 2K

= 0.75

52

R d ti i S f A ith N fl id



Reduction in Surface Area with Nanofluids

53



Topic of Discussion



Topic of Discussion

Case II: Application of Nanofluid as Coolant in DieselElectric Generator (DEG)

55

Application of Nanofl ids in Diesel Electric Generator



Application of Nanofluids in Diesel Electric Generator

56

Cogeneration Efficiency




cogen = ( Electrical Power + Rate of Heat Recovered)/ FuelConsumption energy rate

CogenerationEfficiency

V f H H V Q..

Heat rate from diesel fuel

H

JW el

cogen

Q

QW .

..

JW nf JW V m..

)(..

out JW in JW pJW JW JW T T C mQ

)(..

inSW out SW pSW SW SW T T C mQ

s f nf )1(

Mass flow rate of jacket water

Density of jacket water/nanofluid

Heat transfer from jacket water

Heat transfer from shop water

57

Measurement of Specific Heat of Nanofluids



Measurement of Specific Heat of Nanofluids

Benchmark Test for Water

Schematic of Experimental Setup

T MC Q Pnf s

58

Heating Time for Nanofluids



Heating Time for Nanofluids

Heat Input = 35.5 W59

Specific Heat of Nanofluids



Specific Heat of Nanofluids

0

1000

2000

3000

4000

5000

6000

7000

0 10 20 30 40 50 60 70 80

Tempearture of Nanofluid [Deg C]

S p e c i f i c

H e a t o f

N a n o f l u i d

[ J / k g - K

]

2000

2200

2400

2600

2800

3000

3200

3400

0 1 2 3 4 5 6 7Aluminum Oxide Nanoparticle Concentration

S p e c i f i c

H e a t o f N a n o

f l u i d ( J / k g . K )

Buongiorno EqnPak & Cho EqnExperiment

Specific Heat Variation withTemperature

Specific Heat Variation withVolume Concentration

60

El t i l L d DEG



Electrical Load on DEG

2% Al2O3 Electrical Load [kW] vs Time [sec]

0.000

5.000

10.000

15.000

20.000

25.000

30.000

35.000

0 500 1000 1500 2000 2500 3000 3500

Time [sec]

E l e c t r i c a l O u t p u

t [ k W ]

61

Jacket and Shop Water Flow Rate



Jacket and Shop Water Flow Rate

Jacket and Shop WaterFlow Rate

Jacket WaterTemperature

62



Fuel Flow Measurement

6% Al2O3 Fuel Volume [gal] vs. Time [sec]

y = -6.369409E-04x + 8.848424E+00R2 = 9.988593E-01

6.5

6.7

6.9

7.1

7.3

7.5

7.7

7.9

8.1

8.3

8.5

1000 1500 2000 2500 3000 3500 4000

Time [sec]

V o

l u m e

F u e l R e m a i n

i n g

[ g a l l o n s ]

63




Cogeneration EfficiencyCogeneration Efficiencies vs Fluid )

50-50 2% Al2O3

4% Al2O3

6% Al2O3

74.50%

75.00%

75.50%

76.00%

76.50%

77.00%

77.50%

78.00%

78.50%

79.00%

79.50%

1Type of Nanofluid

C o g e n e r a t i o n

E f f i c i e n c y

50-502% Al2O34% Al2O3

6% Al2O3

Cogenration Efficiency Considering Shop Water Heat

65.65

65.7

65.75

65.8

65.85

65.9

65.95

66

66.05

66.1

66.15

1Type of Fluid

C o g e n r a t i o n E

f f i c i e n c y

[ % ]

50/50 EG/Water2%Al2O34% Al2O36% Al2O3

Using Shop Water HeatRecovery

Using Jacket WaterHeat Recovery

64



Heat Exchanger Efficiency in DEG

76.5

77

77.5

78

78.5

79

79.5

80

80.5

81

81.5

1Type of Nanofluid

H e a t

E x c a h n g e r

E f f i c i e n c y

[ % ]

50/50-EG/Water2%Al2O34% Al2O36% Al2O3

65

Conclusions



The specific heat of nanofluids decreases as nanoparticleconcentration increases. The specific heat of nanofluids

increases with temperature.

The heating time for nanofluids decreases as nanoparticlesconcentration in the base fluid increases. However, when theheat rate is quite large, the time difference for heating is veryminimal.

The cogeneration efficiency of diesel generator decreases asnanoparticle concentration increases because the specific

heat decreases as particle concentration increases.

Heat exchanger efficiency increases as particleconcentration increases because of the higher heat transfer

coefficients of nanofluids. 66

Acknowledgements



Acknowledgements

Sarah Hall, Sandra Boatwright, Kala Hansen, Eric JohansenNed Manning, Tom McCarty & Gary Porter

Financial Support: Arctic Region Supercomputing Center, UAF

Graduate School, University of Alaska Fairbanks

Department of Mechanical Engineering, UAF

Center for Nanosensor Technology (DMEA), UAF

Petroleum Development Lab, UAF

Family & Friends

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das india kulkarni etal presentation 2008&09

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