مسعود مفرحی

The present research investigates the heat transfer enhancement by adding alumina nanoparticle to water,Ethylene glycol, and 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][EtSO4] ionic liquid (called ionic liquid-based nanofluid or INf in synonym) as a basefluid. A horizontal tube with constant heatflux was modeled intwo-dimensional geometry with a diameter and length of 4.0 mm and 6.0 m, respectively. Al2O3(20 nm indiameter) nanoparticles added to the basefluid in 0.5, 1.0 and 2.5 weight fraction percent. Various factors suchas Reynolds number, nanofluids concentration, type of basefluid, and especiallyfluid inlet temperature studiedin this research. Impressive results observed with variation influid temperature which for the temperature belowroom temperature (278.15 K) IL-based nanofluid shows greater heat transfer coefficient than water and Ethyleneglycol-based nanofluids because of its higher thermal conductivity and viscosity at a lower temperature. Andalso, by adding nanoparticles to the basefluids and increasing the concentration of nanofluids, the heat transfercoefficient increased. Both the maximum heat transfer coefficient and heat transfer enhancement observed forIL-based nanofluid at 2.5 wt% concentration of nanoparticle. Finally, a correlation proposed forNunumber thatsatisfies for all studied nanofluids with R2= 0.971 and AREP = 7.9%.