Comparing Heat Transfer Rates of Water Based Nanofluids Using a Figure of Merit

In order to improve the safety of nuclear power plants, the use of nanofluids as a heat carrier in heat exchangers for scheduled and emergency cooling of the NPP power unit is proposed. The intensity of heat exchange depends on the thermophysical properties of heat carriers, and these properties depend on the nature of the heat carrier. The addition of nanoparticles to the base coolant significantly increases its viscosity, which is accompanied by an increase in hydraulic resistance and an increase in pumping power. In this work, the influence of the nature of water-based nano-heat carriers and the content of nanoparticles in the heat carrier on some figure of merit (FOM) is studied. The analysis of the numerical values of FOM makes it possible to evaluate the efficiency of the use of coolants. The paper analyses the quantitative assessment of the heat transfer efficiency of water-based of nanoparticles of metal oxides (Al
2
O
3
; TiO
2
; SiO
2
; ZnO; CuO). The results showed that the coolant with CuO nanoparticles has a higher Mouromtseff number (Mo), that is, it has good thermophysical parameters for heat exchange intensification. Also, the coolant with CuO nanoparticles is characterized by the best efficiency and economy indicators, because it has the lowest value of FOM
pumping
. A heat carrier with AhO
3
nanoparticles requires a smaller layer of thermal insulation to reduce heat losses, as it has the lowest value of FOM
heat losses
. The results of the theoretical research can be used to intensify the heat exchange of power systems that use coolants with an average temperature of 75 m°C.