Figure 16 Variation of property enhancement ratio with temperature for the turbulent flow condition

Conclusions:

In summary, factors that aid in discerning the stability of nanofluids include the zeta potential, electrical conductivity, and the pH value. Even if higher values are obtained for the parameter of thermal conductivity, they are not adequate to enhance the state of heat transfer; findings that have been documented by most of the previous literature focusing on CuO, SiO2 and Al2O3 nanofluids. Rather, additional parameters such as the temperature of nanofluids, the diameter of nano particles, and the volume fraction determine the capacity of the nanofluids to enhance the heat transfer aspect; with the factor of the ratio of heat transfer between the nanofluids and the nano particles unexceptional. In the regression equation, the oxide nanofluids’ thermal conductivity is seen to be predicted by the heat capacity term; outcomes that concur with some of the previous studies. Also, the change in the density of the particles relative to the nano particles’ specific heat and their size is seen to affect the nanofluids’ thermal conductivity. The latter trend aids in inferring the value deviations that have been reported by different scholarly researchers. Overall, this study established that higher values of thermal conductivity were associated with 40EGW-based nanofluids.
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