Table 3 Convective heat transfer coefficient and frictional effects
From: A review of experimental investigations on thermal phenomena in nanofluids
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/ReD |
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, ReDh = 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 |