Effects of functionalized graphene nanofluids on the performance of A compact heat exchanger

Abstract

The need for more powerful automobiles (conventional / electric vehicles) leads to the newlinegeneration of excessive heat, necessitating enhanced cooling requirements. This will newlineincrease the size of the compact heat exchanger (radiator) used in the automobile, if a newlineconventional coolant is used. With the advancement of nanotechnology, a new generation newlineof heat transfer fluids can now be formulated to improve the conductive properties of these newlinecoolants for such cooling needs while retaining the basic flow properties of these advanced newlinecoolants. newlineNano-coolants are engineered colloidal suspensions of nanoparticles in the conventional newlinecoolant (water-ethylene glycol). Typical nanoparticles used include metals such as copper, newlinesilver, gold, aluminium, etc.; metallic oxides such as Al2O3, CuO, TiO2 etc; carbon-based newlinenanoparticles such as single-walled-carbon-nano-tubes (SWCNT), multi-walled-carbonnano- newlinetubes (MWCNT), graphene, functionalized graphene, C60 Fullerene etc. newlineAccurate prediction of heat transfer characteristics of coolants used in thermal management newlineof energy systems such as heat exchangers, power electronics and HVAC, is indispensable newlinein maintaining its operating conditions within safety limits. Apart from safety, factors such newlineas power consumption and operating cost are important constraints to be considered in newlinedesigning an energy-efficient and cost-effective cooling solution. newlineIn the present work, an attempt is made to study the effect of - adding carboxyl graphene newline(CG), graphene oxide (GO), reduced graphene oxide (RGO) and novel hybrid nanoparticles newlineto a conventional hot fluid - 50:50 ethylene-glycol and water, at ultra-low volume newlineconcentrations - on the performance of a compact heat exchanger (liquid-air, automotive newlineradiator). The research work focuses on the effect of nanoparticle concentration, Reynolds newlinenumber of hot fluid (80 170) and Reynolds number of air (210 270) at a constant inlet newlinetemperature of the hot fluid of 40 ºC. newlineThe effect of these parameters on the radiator performance is measured in terms of nin