Investigation on the thermal conductivity and convective heat transfer enhancement in helical coiled heat exchanger using ultrasonically prepared rGO–TiO₂ nanocomposite-based nanofluids

ABSTRACT

This work deals with sonochemical synthesis of finely dispersed reduced graphene oxide–TiO₂ (rGO/TiO₂) nanocomposites with successful immobilisation of TiO₂ nanoparticles on rGO. Structural and morphological analysis of prepared rGO/TiO₂ nanocomposite was done with the use of UV/VIS, TEM, XRD and FTIR analysis that confirms the formation of finely dispersed rGO/TiO₂ nanocomposite. A helical coiled heat exchanger was used for examining convective heat transfer enhancement exhibited by the prepared rGO/TiO₂ nanocomposite-based nanofluid. Thermal conductivity enhancement of rGO/TiO₂ nanocomposite-based nanofluids with the nanocomposite loading of 0.1–0.5 volume % in water was investigated. An investigation on improvement in the heat transfer coefficient was carried out at different loading of rGO/TiO₂ nanocomposite in base fluid at various Reynolds number values. Percentage enhancement in the heat transfer coefficient was around 35.7% for 0.25 volume % concentration of rGO/TiO₂ nanocomposite in base fluid.

KEYWORDS:

• rGO/TiO₂ nanocomposite-based nanofluids
• ultrasound
• helical coiled heat exchanger
• thermal conductivity
• heat transfer coefficient

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Department of Science and Technology (Government of India), Science and Engineering Research Board (SERB) [Start Up Research Grant (Young Scientists), Sanction order no. YSS/2014/000889, 2015]