Effect of Magnetic Field on Heat Transfer Enhancement and Pressure Drop of Fluid Flow with Magnetic Particle Suspension in a Curled Pipe

The characteristics of heat transfer enhancement and pressure drop in the curled pipe under the effect of a magnetic field are presented in this paper. The suspensions, which are composed of g-Fe2O3 (gamma-phase iron oxide) magnetic particles with a median diameter of 15–20 nm dispersed in plain water have been used. The magnetic particles at different concentrations by volume of 0.50%, 0.75% and 1.00% were used in the pipe flow experiments. The suspension enters the curled pipe at the innermost turn, flows under a uniform surface heat flux, and exits at the outermost turn. To increase the rate of heat transfer, three different strengths of an external magnetic field of 600 Gauss (G), 1,200 G, and 1,800 G were utilized by the electromagnets mounted on plates located at the top and bottom of the curled pipe. The effects of magnetic field strength, concentration by volume of magnetic particles, and curve ratios on the heat transfer enhancement and pressure drop are shown. The results show that the Nusselt number increases with increasing magnetic field strength, particle volume concentration, and curve ratio. The Nusselt number increased by up to 14.34%, 19.19%, and 26.26% for magnetic field strengths of 600 G, 1,200 G, and 1,800 G, respectively.