Influence of magnetic field location on the heat transfer and friction factor of CoFe2O4-BaTiO3/EG hybrid nanofluids in laminar flow: an experimental study

• Autor(a) principal: Sundar, L. Syam
• Data de Publicação: 2023
• Outros Autores: Ramana, E. Venkata
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/37904
• topic: Uniform magnetic field; Laminar flow; Magnetic nanofluid; Variable locations

This report describes the heat transfer and friction factor characteristics of CoFe2O4-BaTiO3/ethylene glycol hybrid nanofluids flow in a tube with and without a magnetic field. The CoFe2O4 and BaTiO3 nanoparticles were synthesized by the sol–gel method individually and then ball-milled to form 35:65% (in mol.) composite hybrid nanoparticles. Structure, morphology, and size were characterized by x-ray diffraction and transmission electron microscope. Temperature-dependent magnetization was studied by a vibrating sample magnetometer. The stable ethylene glycol-based hybrid nanofluids were prepared and the heat transfer and friction factor experiments were conducted in the following parameters: 248.03 < Re < 1995.43; 0 <ϕ < 1.0%; and 0 < Gauss < 4000, respectively. The magnetic field is applied at different places with x/d (distance/diameter) of 30, 60, and 90, respectively. It was found that the Nusselt number is raised by 22.19% at 1.0% vol. of nanofluid and at a Reynolds number of 1240.15, with a penalty in friction factor of 21.88%, against base fluid data without magnetic field. The Nusselt number is further raised by 68.95% and 72.33%, respectively, for 1.0% vol. of nanofluid with magnetic field ( B →) of 1600 G and 4000 G, compared to the base fluid. Under the magnetic field of 4000 G and for 1.0% vol. of nanofluid, the Nusselt number is improved by 41.03%, 35.14%, and 25.94% at different places of x/d of 30, 60, and 90, respectively, as compared to the absence of magnetic field. The results are further showed that at location of x/d of 30 under magnetic field of 4000 G, the greatest Nusselt number had been attained. With the magnetic field of 4000 G and at 1.0% vol. of nanofluid, the friction factor is further enhanced to 68.75%, compared to without magnetic field.