Heat transfer enhancement of the f-MWCNT- Fe2O3/Water hybrid nanofluid with the combined effect of wire coil with twisted tape and perforated twisted tape

Abstract

The impact of various variables on thermal conductivity and rheological behavior, such as nano particle weight concentration and temperature, and also the cumulative effects of coil ratio (CR = 3, 4) of wire coil insert and twist ratio (TR = 3, 4 and 5) of twisted tape (TT) and perforated twisted tape (PTT) on heat transfer coefficient and friction factor characteristics is explored. Nanofluids containing particles with weight percentages of 0.01%, 0.02%, and 0.03% were produced by dispersing functionalized multi-walled carbon nanotubes (f-MWCNTs) 60% by weight and Fe2O3 nanoparticles 40% by weight in distilled water and stabilizing them with an ultrasonic probe. The KD-2 Pro thermal analyzer and Rheometer are used to measure the thermal conductivity and viscosity of the hybrid nanofluids. The impact of various factors on the heat transfer and pressure drop is investigated, including Reynolds number, nanoparticle concentration, TR and CR of TT, PTT and WC. The findings clearly show that higher content of nanoparticles increases heat transfer as well as pressure drop. In contrast to the base coolant, the enhancement in heat transfer and friction factor is 21.66%–31.66% and 1.14 times, respectively. In comparison to a plain tube passing through 0.03 wt % hybrid nanofluid, the enhancements in heat transfer and friction are 32.31%–94.03%, 43.94%–141.07%, and 1.09 times, 1.13 times for the combined effect of TT and PTT having wire insert at ratio's of twist and coil are 3, respectively. Furthermore, UV–vis spectroscopy is being used to assess the stability of the prepared nanofluids, which is found to be acceptable. FESEM is used to determine the detailed surface properties.