Table 3

Convective heat transfer coefficient and frictional effects

Sl. no.

Reference

Nanoparticle

Base fluid

Flow regime

Wall boumdary condition

Concentration

Enhancement in heat transfer coefficient

Pressure drop/friction factor

1

Hwang et al. [23]

Al₂O₃ (30 ± 5 nm)

Water

Fully developed laminar flow with

Constant heat flux

0.01-0.3 vol.%

@ Re = 700 for 0.3%, heat transfer coeff., h increases by 8%

Friction factor follows f = 64/Re_D

2

Heris et al. [24]

Al₂O₃

Water

Laminar, Re:700-2050

Constant wall temp.

0.2, 0.5, 1.0, 1.5, 2.0, 2.5% volume

@ Peclet no., Pe = 6000 for 2.5%, h increases by 41%

ΔP = 200 Pa/m @ Re = 700

ΔP = 700 Pa/m @ Re = 2000

3

Anoop et al. [25]

Al₂O₃ (45 and 150 nm)

Water

Laminar thermally developing flow

Constant heat flux

1, 2, 4, and 6 wt%

@ x/D = 147, Re = 1550 and 4%, for 45 nm h increases by 25% and for 150 nm h increases by 11%

-

4

Lee et al. [26]

Al₂O₃ (36 nm)

Water

Laminar flow in microchannels, Re_Dh = 140-941

Constant heat flux

1, 2% by volume

@ Q = 300 W, Re = 800 for 2%, h increases by 17%

@ Re = 800

ΔP = 21000 Pa for 2 vol.%

ΔP = 15000 Pa for water.

5

Gherasim et al. [27]

Al₂O₃ (47 nm)

Water

Laminar radial flow

Constant heat flux

2, 4, and 6% by volume

@q" = 3900 W/m², disk spacing of 2 mm and Re = 500 for 4%, heat transfer is doubled

-

6

Kim et al. [28]

Al₂O₃ (20-50 nm), amorphous carbonic nanofluids (20 nm)

Water

Laminar and turbulent flows

Constant heat flux

Amorphous carbonic nanofluids @3.5 vol.%, Al₂O₃ nanofluids @3 vol.%.

@x/D = 50, Re = 1460 for 3% Al₂O₃, h increases by 25%

@x/D = 50, Re = 6020 for 3% Al₂O₃, h increases by 15%

-

7

Heris et al. [29]

CuO (50-60 nm), Al₂O₃ (20 nm)

Water

Laminar flows

Constant wall temp.

0.2-3 vol.%

@Pe = 6500 for 3% Al₂O₃ Nu = 8.5

@Pe = 6500 for 3% CuO Nu = 8

-

8

Jung et al. [30]

Al₂O₃ (170 nm)

Water, Water-Ethylene glycol 50:50

Laminar flow in rectangular microchannel

Constant heat flux

0.6, 1.2, 1.8% by volume

@x/D = 0, Re = 284 for 1.8% in water, h increases by 40%.

@x/D = 0, Re = 32 for 1.8% in water-EG, h increases by 14%.

Friction factors comparable with that of water

9

Ding et al. [31]

Titanate (20 nm), CNT, titanate nanotubes (d = 10 nm and l = 100 nm), nano diamond (2-50 nm)

Water

Thermally developing laminar and turbulent flow

Constant heat flux

0-4 vol.%

Heat transfer deteriorates for ethylene glycol-based titania and aqueous-based nano-diamond nanofluids. Water-CNT nanofluids give max enhancement

10

Sharma et al. [32]

Al₂O₃ (47 nm)

Water

Hydrodynamically and thermally developed Transition flow.

Constant heat flux

0.02, 0.1% by volume

For 0.1% in the range of Re = 3500-8000 heat transfer enhanced by 14-24%

-

11

Duangthongsuk et al. [33]

TiO₂ (21 nm)

Water

Turbulent flow, Re-4000-17000

Double pipe counter flow heat exchanger

0.2 vol.%

h increases by 6-11% for the flow range of Re = 4000-17000

Pressure drop and friction factor of the nanofluid are close to those of water

12

Ding et al. [34]

MWCNT

Water

Laminar flow

Cosntant heat flux

0.1, 0.25, and 0.5% by volume

@x/D = 150, Re = 1200 for 0.1% h increases by 150%

-

13

Yu et al. [35]

SiC (170 nm)

Water

Re = 3300-13000

Constant heat flux

3.7 vol.%

@Re = 10000 h is enhanced by 60%

The pumping power penalty for SiC-water is lesser than for Al₂O₃-water

Comparison of enhancement of heat transfer coefficient and frictional effects in various nanofluids.

Thomas and Balakrishna Panicker Sobhan Nanoscale Research Letters 2011 6:377   doi:10.1186/1556-276X-6-377