Authors: MD Tanvir Khan, Sudipta Debnath, Zahir U. Ahmed
Volume 10, Issue 4, Paper No. 100401
Anticipating the swirl turbulent flow and heat transfer phenomena within a nozzle is tremendously challenging due to the complexities of measurement diagnostics. The amalgamation of nanoparticles with fluids often exacerbates this perplexity for the resurgence of effective fluid properties that ambiguously affect thermo-fluidic behaviors. This study numerically focuses on the low concentration (1%) nanoparticles to investigate the effect of swirl as well as nanofluids on the flow and thermal characteristics of incompressible turbulent liquid jets. Both the aqueous and non-aqueous nanofluids are taken into consideration in a variety of flow conditions. The aqueous nanofluid resembles the properties of water, while the thermofluidic behavior of the non-aqueous nanofluids differs significantly. The Reynolds number enhances the average Nusselt number as well as the pressure drop inside the nozzle, and the non-aqueous nanofluids exhibit a relatively higher average Nusselt number and pressure drop. The average Nusselt number increases up to 322% for Dowtherm + Al2O3, and 320% for Syltherm800 + Al2O3 compared to H2O. Aqueous nanofluid indicates a higher thermal performance factor than non-aqueous nanofluids. The skin friction coefficient decreases with the Reynolds number since the effective viscosity reduces. (CH2OH)2 + Al2O3 predicts the maximum heat transfer rate albeit with a penalty of high-pressure drop. Correlations are developed for the average Nusselt number and thermal performance factor to relate several control parameters.
Keywords: Swirl nozzle, Nanofluid, CFD, Heat transfer, Thermal performance factor