Effect of the magnetic field direction on forced convection heat transfer enhancements in ferrofluids

• Published in: European physical journal. Applied physics Vol. 71; no. 1; pp. 10901 - 10910
• Main Authors: Razek, Adel, Cherief, Wahid, Avenas, Yvan, Ferrouillat, Sébastien, Kedous-Lebouc, Afef, Jossic, Laurent, Berard, Jean, Petit, Mickael
• Format: Journal Article
• Language: English
• Published: Les Ulis EDP Sciences 01.07.2015
• Subjects: Convective heat transfer; Electromagnetism; Engineering Sciences; Ferrofluids; Fluids mechanics; Forced convection; Heat flux; Heat transfer; Heat transfer coefficients; Laminar flow; Magnetic fields; Mechanics; Micro and nanotechnologies; Microelectronics; Pressure drop; Temperature; Thermal conductivity; Thermics
• ISSN: 1286-0042; 1286-0050
• DOI: 10.1051/epjap/2015150059

Applying a magnetic field on a ferrofluid flow induces a large increase of the convective heat transfer coefficient. In this paper, the thermal-hydraulic behaviors of two commercial ferrofluids are compared. The variations of both the pressure drop and the heat transfer coefficient due to the magnetic field are measured in the following conditions: square duct, laminar flow and uniform wall heat flux. The square section with two insulated walls allows for the characterization of the effect of the magnetic field direction. The experimental results show that the heat transfer is better enhanced when the magnetic field is perpendicular to the heat flux. In the best case, the local heat transfer coefficient increase is about 75%. On the contrary, another experimental setup shows no enhancement of thermal conductivity when the magnetic field is perpendicular to the heat flux.