CFD study on heat transfer and pressure drop of nanofluids (SiO2/H2O, Al2O3/H2O, CNTs/H2O) in a concentric tube heat exchanger

Abstract

In this work, a computational fluid dynamics (CFD) analysis has been carried out over a concentric tube heat exchanger for analysing the overall heat transfer coefficient, heat transfer rate and pressure loss of SiO2/water, Al2O3/water and CNTs/water nanofluids at different volume concentrations (1 %, 2% and 3%) under turbulent flow condition (Reynolds number range 2000–10000). Analysis resulted in 23.6%, 26.83% and 37.25% enhancement of the overall heat transfer coefficient and 20.71%, 23.72% and 32.65% enhancement in the heat transfer rate with 3% volume concentration of SiO2/water nanofluid, Al2O3/water nanofluid and CNTs/water nanofluid when compared with base fluid, respectively. Despite all these enhancements, a little increment in pressure loss is also observed. It has been concluded that the overall heat transfer coefficient and heat transfer rate increases with the increase in the Reynolds number as well as volume concentration of nanofluids.