The slope of this linearly increasing effect is larger for the water-based nanofluid as compared with the EG-based nanofluid. Figure 3d shows that the skin friction see more coefficients for the EG-based nanofluid is much larger than those for water-based nanofluid, and this resisted the motion of fluid, which is the selleck products reason why the Nusselt numbers for EG-based nanofluids are lesser than those of the water-based
nanofluids. Temperature dependence of heat transfer enhancement and determination of optimal particle concentration in Al2O3 + water nanofluid To find the effect of concentration of nanoparticles in the base fluid, calculations have been done, and the results are shown in Figures 4, 5, 6, and 7 and given in Tables 5, 6, 7, and 8. In Figure 4, the insets show the zoomed view at steady state. Figure 4 Average Nusselt numbers
for Al 2 O 3 + H 2 O nanofluid at (a, b, c, d) different wall temperatures. Figure 5 Effective Prandtl number (a) and modified Rayleigh number (b) of Al 2 O 3 + H 2 O nanofluid with concentration. KPT-8602 Figure 6 Local Nusselt numbers for Al 2 O 3 + H 2 O nanofluid at (a, b, c, d) different wall temperatures. Figure 7 Local skin friction coefficient for Al 2 O 3 + H 2 O nanofluid at (a, b, c, d) different wall temperatures. Table 5 Variation in average Nusselt number and average skin friction coefficient with concentration at 303 K Φ Nuavg Percentage increase in Nuavgat steady state Cfavg (103) Percentage increase in Cfavgat steady state 0 7.3157 – 1.7009 – 0.01 7.5058 2.60 1.7150 0.36 0.02 7.5363 3.02 1.7154 0.38 0.025 7.5313 2.95 1.7150 0.36 0.04 7.4612 1.99 1.7130 0.24 ε = 0.72, diameter of Cu powder = 470 μm, length of plate = 0.04 m, permeability = 7 × 10−9, T (plate) = 303 K, d p = 10 nm (Al2O3 + H2O). Table 6 Variation in average Nusselt number and average skin friction coefficient with concentration at 310 K Φ Nuavg Percentage increase in Nuavgat steady state Cfavg (103) Percentage increase in Cfavgat steady state 0 9.1505 – 2.7202 – 0.02 9.5864 4.76 2.7592 1.43 0.03 9.5875 4.78 2.7686 2.09 0.04 9.5262 4.11 2.7767 2.08 0.06 9.2465
1.05 2.7916 2.62 ε = 0.72, diameter of Cu powder = 470 μm, length of plate = 0.04 m, permeability = 7 × 10−9, T (plate) = 310 K, d check p = 11 nm (Al2O3 + H2O). Table 7 Variation in average Nusselt number and average skin friction coefficient with concentration at 317 K Φ Nuavg Percentage increase in Nuavgat steady state Cfavg (103) Percentage increase in Cfavgat steady state 0 10.5850 – 3.6357 – 0.01 11.1776 5.60 3.6945 1.62 0.02 11.3780 7.49 3.7244 2.44 0.03 11.4590 8.26 3.7483 3.10 0.035 11.4674 8.34 3.7589 3.39 0.04 11.4576 8.24 3.7690 3.67 0.06 11.2646 6.42 3.8052 4.66 0.09 10.6124 0.26 3.8493 5.88 ε = 0.72, diameter of Cu powder = 470 μm, length of plate = 0.04 m, permeability = 7 × 10−9, T (plate) = 317 K, d p = 11 nm (Al2O3 + H2O).