Experimental investigation of heat transfer performance of novel bio-extract doped mono and hybrid nanofluids in a radiator

The paper investigates the heat transfer performance of distilled water (DW) and ethylene glycol-DW mixture (EG-DW) based aluminum and magnesium sulfate nanofluids and their hybrid nanofluids in a radiator.Mono and hybrid nanofluids at 0.05% and 1% volume fractions with Malay Apple (Syzygium Malaccense) extract were formulated and run in the experimental set up at 0.4 kg/s.The heat transfer performances of DW, EG-DW, mono, and hybrid nanofluids were determined using Nusselt number (Nu), heat transfer rate ( Q) and coefficient (h), effectiveness (ε), heat transfer (Q), Prandtl number (Pr).An increment in the volume fraction was found to enhance Q, h, Nu, Q, Pr, and ε.The maximum heat transfer performance was obtained using mono (Mg/ DW (Q = 2.26 kW and Nu = 175), Al/EG-DW (Q = 6.57kW and Nu = 462)) and hybrid (Mg-Al/ DW (Q = 10.06 kW and Nu = 348)) nanofluids.In comparison with the corresponding base fluid, maximum heat transfer enhancements of 13.9%, 306.7%, and 493.9% were obtained for Mg/DW, Mg-Al/DW, and Al/EG-DW nanofluids, respectively.This remarkable heat transfer enhancement obtained can be related to the presence of the Malay Apple (Syzygium Malaccense) extract.These novel nanofluids appeared to be suitable candidates for radiator cooling.