Synergistic Thermo-Hydrodynamic Enhancement in Ternary Hybrid Nanofluids (THN) Stabilized in Ethylene Glycol– Distilled Water Mixture (EG@DW 50:50)

Abstract The synthesis of homogeneous and well dispersed mixed metal oxide (MMO) in a mixture of Ethylene Glycol and Distilled Water (EG@DW, 50:50) mixture is established using 2-Step probe sonication, ZnO, Al 2 O 3 , and TiO2 as an MMO/EG@DW based ternary hybrid nanofluids (THN) were prepared to evaluate the thermophysical, hydrodynamic and convective heat transfer coefficient (CHTC) characteristics in a closed straight stainless steel based circular geometry heat exchanger subjected to a constant heat flux of 10092.41 W m-2. All the metal oxides with different sizes and morphologies were taken at an equal 33.3 % weight and dispersed in EG@DW base fluid at four varying concentrations: 0.025 wt.%, 0.05 wt.%, 0.075 wt.% and 0.1 wt.% to attain well-dispersed hybrid nanofluids. The FESEM, UV-vis, and wt.% absorbance characterizations were carried out to see the uniform dispersion of all particles. The dynamic/kinematic viscosities, density, and thermal conductivity were evaluated at varying temperatures from 20ºC to 45ºC and varying wt.% concentrations. A significant improvement in all parameters was noticed when all metal oxides were loaded together in the EG@DW base fluid. The photograph sedimentation test was employed to assess the longer-term stability and suspension of all particles, and the results revealed surprising stability up to 7 weeks after preparation. Following the confirmation of the experimental analytical correlation, different test runs for MMO/EG@DW-based THN were conducted through a circular geometry heat exchanger in turbulent regions. A prominent enhancement in CHTC and Nusselt numbers was recorded on average and locally against varying Reynolds (Re) numbers from 5849 to 24544. The 0.1 wt.% concentration contributed a higher enhancement of 3120 W m−2 K−1 in CHTC of the MMO/EG@DW based THN with a slight increase in applied pumping power, which is due to the use of EG with DW. Further, the study stated that all the positive parameters at all Reynolds ranges and wt.% concentrations of MMO/EG@DW based THN offered the possible use of mixed metal oxides hybrid/composite aqueous suspension, together as an alternative working liquid in varying thermal management systems.