Saturated Pool Boiling Heat Transfer of Toluene-Solvent Magnetic Fluid on a Vertical Cylindrical Surface. Effects of Field Gradient and Concentration of Particles.

Abstract

Saturated pool boiling heat transfer of toluene-solvent magnetic fluid with magnetite particles was investigated on a vertical cylindrical surface in the vertical magnetic field and gradient. The gradients of the boiling curves of pure toluene and magnetic fluid are much smaller than the previous results for a horizontal heater. The heat transfer of magnetic fluid is enhanced first in both the absence and presence of a magnetic field. However, with increase in heat flux it is reduced suddenly at a certain transition heat flux. The transition heat flux is higher with higher magnetic field gradient and lower magnetite concentration. The magnetic field gradient has no influence on the boiling heat transfer, and there is a hysteresis in the transition, which are much different results from the previous results for horizontal heater.