Effect of various surfactants on stability and thermophysical properties of nanofluids
Jin Wang, Guolong Li, Tan Li, Min Zeng, Bengt Sundén
Abstract
Abstract The effect of Fe 3 O 4 nanoparticles and carbon nanotubes (CNTs) on the viscosity of a nanofluid is experimentally investigated from 278 to 313 K by changing the nanoparticle volume fraction. These nanoparticles were put into distilled water with various surfactants, i.e., Colace (docusate sodium), trisodium citrate dihydrate (TSC), polyvinyl pyrrolidone, cetyl trimethylammonium bromide, tetramethylammonium hydroxide (TMAH), acacia senegal (GA), sodium dodecyl benzene sulfonate, sodium dodecyl sulfate (SDS), and sodium laurylsulfonate (SLS). Based on the present measurements, new empirical formulas are proposed for Fe 3 O 4 –water, CNT–water and Fe 3 O 4 –CNT–water nanofluids to provide accurate predictions for the nanofluid viscosity. Based on the viscosity testing, stabilities and thermal conductivities of Fe 3 O 4 –TMAH, Fe 3 O 4 –Colace, Fe 3 O 4 –TSC, CNT–SDS, CNT–GA, Fe 3 O 4 –CNT–SLS, and Fe 3 O 4 –CNT–TSC nanofluids with a volume concentration of 0.5% are investigated in the present research. Results indicate that better stability, smaller viscosity, and higher thermal conductivity are obtained, when the surfactants TMAH, SDS, and SLS are added into the Fe 3 O 4 –water, CNT–water, and the Fe 3 O 4 –CNT–water nanofluid, respectively. The CNT–water and Fe 3 O 4 –CNT–water nanofluids exhibit a shear-thinning behavior, whereas a linear rheological behavior can be observed by water-based Colace–Fe 3 O 4 , TMAH–Fe 3 O 4 , and TSC–Fe 3 O 4 nanofluids.