Table 3 Summary of experimental forced convection studies under constant wall temperature boundary conditions for various nanofluids
Researcher | Nanofluid | Method of nanofluid preparation | Particle size (nm) | Particle volume concentration | Flow regime (Range of Reynolds number) | Heat transfer enhancement mechanisms |
|---|---|---|---|---|---|---|
Fotukian and Esfahany (2010a) | γ-Al2O3/water | Ultrasonic cleaning and mechanical mixing | 20 | 0-0.2 | Turbulent (5000–35000) | Dispersion of suspended nanoparticles |
Heyat et al. (Heyhat et al. 2012) | Al2O3/water | Two-step | 40 | 0.1-2 | Turbulent (2500–17000) | Increasing the particle volume concentrations |
Fotukian andEsfahany (2010b) | CuO/water | Ultrasonic mixing | 30-50 | 0-0.3 % | Turbulent (5000–35000) | In presence of nanoparticles flowing in the tube, enhanced thermal energy transfer from the wall to the nanofluid |
Akbaridoust et al. (2013) | CuO/ water | *EEW | 68 | 0.1, 0.2 vol. % | Laminar (140–1000) | Higher values of particle volume fraction, greater curvature ratio (helical tube) |
Ferrouillat et al. (2011) | SiO2/water | Prepared from a commercial solution | 22 | 5–34 (wt.%) | Laminar and turbulent (200–10,000) | Increase of particle volume concentration |
Anoop et al. (2012) | SiO2/water | Top-down approach | 20 | 0.2, 0.5 and 1 (wt.%) | Laminar (2–23) | Applications of nanofluids have been explored in the literature for cooling of micro devices due to the anomalous enhancements in their thermo-physical properties as well as due to their lower susceptibility to clogging |
Ashtiani et al. (2012) | *MWCNT/heat transfer oil | Electrical mixing and then ultrasonic cleaning | 10-30 | 0, 0.1, 0.2 and 0.4 (wt. %) | Laminar hydrodynamically fully developed regime (lower than 1500) | Flattening tube at a constant nanoparticle weight fraction, particle volume fraction and increasing volumetric flow rate |
Pakdaman et al. (2013) | *MWCNT-heat transfer oil | Ultrasonic processing | - | 0, 0.1, 0.2 and 0.4 (wt. %) | Laminar flow in the thermal entrance region (0–2000) | Suspending nanoparticles in the base fluid enhances thermophysical properties |
Heris et al. (2006) | CuO/water Al2O3/water | Ultrasonic vibration | 50-60 20 | 0.2 – 3 | Laminar (650–2050) | For low concentrations, heat transfer coefficient ratios for nanofluid to homogeneous model are close to each other but by enhancing the volume concentration, more heat transfer enhancement for Al2O3/water can be detected |
Hojjat et al. (2011) | *γ- Al2O3/ CMC TiO2/CMC CuO/CMC | Ultrasonic vibration | 25 10 30-50 | 0.1-1.5 | Turbulent (8000–33000) | Peclet number and the nanoparticle concentration |
Meriläinen et al. (2013) | Al2O3/water SiO2/ water MgO/water | Ultrasound processing | 41-53 15–47 28-110 | 0.5- 4 0.5 -4 0.5-2 | Turbulent (3000–10000) | Use of small sized, spherical shape and smooth particles (less than 10 nm in size) |