Analysis of turbulent heat transfer characteristics of nanofluids in the Lightnin static mixer

The static mixer is a kind of highly efficient and online heat and mass transfer enhanced equipment and has excellent characteristics in the chemical process intensification. The lack of research about the effects of physical properties of nanofluids on the heat transfer characteristics in the Lightnin static mixer (LSM) restricts a further industrial application of LSM in the field of enhancing heat transfer. The effects of volume fraction, particle type and size of nanoparticles on the heat transfer in LSM were numerically evaluated under the conditions of Re=8000—28000 and constant heat flux using the SST k-ω turbulence model and multiphase mixture model. With the increasing of volume fraction of Cu-H2 O nanofluids, the comprehensive heat transfer performance (PEC) and synergy between velocity field and temperature field of nanofluids are gradually enhanced while the total entropy production rate and Be gradually decrease. The PEC values of Cu-H2 O nanofluids with volume fractions from 0.5% to 2.0% could be obtained up to 2.16—2.25, 3.16—3.25, 3.94—4.15 and 4.64—5.16 at Re=8000—28000, respectively. The enhanced heat transfer performance of Cu-H2 O nanofluids is much better than that in the Al2 O3-H2 O and CuO-H2 O nanofluids. The average PEC of Al2 O3-H2 O and CuO-H2 O are 0.47 and 0.46 times of Cu-H2 O nanofluids, respectively. With the increasing particle size of Cu-H2 O nanofluid, the comprehensive heat transfer performance and synergistic performance of the nanofluids are gradually weakened while the total entropy production rate and Be gradually increase. © 2021, Chemical Industry Press Co., Ltd.. All rights reserved.