Numerical study of the flow of R1270-based nanorefrigerants in a circular tube subject to uniform heat flux

In this work, turbulent convective heat transfer of propylene (R1270)-based nanorefrigerant in a circular tube with a uniform heat flux of 20 kW/m(2) is numerically investigated using different types of nanoparticles namely Al2O3, CuO, SiO2 and ZnO with a volume concentration ranging from 0 to 5%. Computations have been carried out using the commercial CFD code Fluent for Reynolds number ranging from 20,000 to 100,000 and a nanoparticle diameter of 30 nm. Results in terms of the average convective heat transfer coefficients of both pure R1270 and R1270-based nanorefrigerants have been compared successfully to values obtained using correlations from the literature. It is found that among nanorefrigerants studied, R1270/CuO performs the best, followed in order by R1270/Al2O3, R1270/ZnO and R1270/SiO2. It is also shown that the convective heat transfer coefficient is enhanced by increasing the Reynolds number and the nanoparticles volume concentration.