An experimental investigation of single-phase natural circulation behavior in a rectangular loop with Al2O3 nanofluids

In this paper, the natural circulation behavior in a rectangular loop was investigated experimentally with water and different concentration of Al2O3 nanofluids (0.3–2% by wt. and particle size 40–80 nm). It was demonstrated that, not only the flow instabilities are suppressed but also the natural circulation flow rates are enhanced with nanofluids. The enhancement in natural circulation flow rate and suppression of instabilities were found to be dependent on the concentration of nanoparticles in water.