Heat transfer performance of TiO2-SiO2 nanofluids in a tube with wire coil inserts

• Main Authors: K., Abdul Hamid, Azmi, W. H., R., Mamat, Sharma, K. V.
• Format: Article
• Language: English
• Published: Elsevier Ltd 2019
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://umpir.ump.edu.my/id/eprint/24393/1/Heat%20transfer%20performance.pdf; http://umpir.ump.edu.my/id/eprint/24393/; https://doi.org/10.1016/j.applthermaleng.2019.02.083; https://doi.org/10.1016/j.applthermaleng.2019.02.083

The compound technique that combines nanofluids with wire coil inserts has proven itself in achieving double augmentation in heat transfer. This paper presents the thermal hydraulic performance of TiO2-SiO2 nanofluids with wire coil inserts. The experiments were conducted for Reynolds number from 2300 to 12,000 to determine the heat transfer performance and friction factor of TiO2-SiO2nanofluids with wire coil inserts. The TiO2-SiO2 nanofluids were prepared by using the two-step method for volume concentrations of 0.5–3.0%. The wire coil inserts are designed at various ratios of pitch over diameter (P/D) in the range of 0.83–4.17. The heat transfer performance of nanofluids was enhanced for a maximum of 254.4%, while the friction factor was obtained in the range of 1.76–6.38 times higher than water/EG in a plain tube. The thermal performance factor (TPF), η for the nanofluids with wire coil inserts at all volume concentrations was observed greater than 1.0. The optimum performance of TiO2-SiO2 nanofluids with wire coil occurred at 2.5% volume concentration and 1.50 pitch ratio. At this condition, the TiO2-SiO2 nanofluids with wire coil inserts provide the highest TPF and represent the best condition for cooling system applications.