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This paper presents a numerical investigation on heat transfer and flow behavior for non-Newtonian nanofluids with different nanoparticles (Al2O3 and CuO) and carboxymethyl cellulose (CMC) with water as a base fluid. The analysis has been carried out in an elliptical tube. Power law model is adopted to depict the non-Newtonian nature of nanofluid. The present study has been done with a range of nano sized particles 0-4% by volume and the variation of Reynolds number is kept under the laminar condition. The physical model covers two concentric tubes used to create an annular space. The effects of volume fraction, particle type and base fluids have been investigated at different Reynolds number numerically. Also, the effect of pressure and heat transfer coefficient on the flow behavior of non-Newtonian nanofluids are analyzed. The results concluded that Al2O3 particles showed 219 % and CuO particles give 195 % higher heat transfer coefficient as compare with pure water.

In this study a numerical investigation is carried out for heat transfer and fluid flow analysis using ethylene glycol-based TiO 2 -SiO 2 non-Newtonian hybrid nanofluid over a range of volume fractions from 0 to 5% inside a helically corrugated tube under turbulent flow conditions. The analysis is performed with different mixing ratios of TiO 2 and SiO 2 at different corrugation-height ratios (e/D h = 0.05, 0.07, 0.09) and pitch ratios (p/D h = 0.25, 0.30, 0.35). Numerical simulations have been conducted using ANSYS FLUENT 19.0 with a constant heat flux of 25 kW/m 2 maintained at the wall surface for a range of Reynolds numbers from 5000 to 30,000. The thermal-hydraulic performance factor exceeds unity in almost every tested combination. It increases by increasing the values of e/D h and p/D h and decreasing the concentration of TiO 2 in the hybrid-nanoparticle mixing ratio. Thus employing hybrid nanofluids inside corrugated tubes is a worthwhile arrangement at a proper mixing ratio of TiO 2 and SiO 2 .

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