Heat transfer performance of Al2O3 − ([C4mim][NT f2]) nano-suspension in a 2 − D channel for application in a flat plate solar collector

Abstract

IoNanofluids are a recent class of nanotechnology based heat transfer fluids synthesized by suspending nanoparticles in ionic liquids. These IoNanofluids are superior to conventional nanofluids due to their higher thermal stability and are more suitable for high temperature applications. In this study, a numerical analysis of laminar forced convection in a 2-D channel using Al2O3 in ([C4mim][NT f2]) IoNanofluids has been presented. Flow Reynolds number (Re) is varied from 250 to 1000, particle volume fraction ranges from 0 % to 2.5 % and three inlet temperatures of 293 K, 313 K and 333 K have been taken into account. A uniform heat flux of 1000 W m−2 is applied on the top wall to resemble the scenario in a flat plate solar collector. Governing equations of flow and heat transfer has been solved using a Finite Volume Method based commercial software ANSY S F luent 15.0. Furthermore, unique feature of this study is that the thermo-physical properties of IoNanofluids are considered to be temperature dependent. Results indicate that IoNanofluids provide better cooling than conventional water based coolants. The top surface of the channel experiences a decrease of upto 4 K at an inlet temperature of 333 K. Mean Nusselt number and heat transfer coefficients increase by the addition of nanoparticles to the ionic basefluid. IoNanofluids show better heat transfer enhancement than conventional water based nanofluids at higher temperatures. Hence, it can be concluded that IoNanofluids have a higher potential to be employed in high temperature applications.