Enhancement and control of local heat transfer coefficients in a gas flow containing soft magnetic particles

A novel technique of enhancing and controlling the local heat transfer coefficients from the hot watt to cooling gas flow has been proposed using soft magnetic solid particles in order to reduce die disadvantage of inefficient gas-solid two-phase flow. The characteristics of the flow and local heat transfer were examined in a vertical rectangular channel flow involving fertile particles 145 pm in diameter. The Reynolds number of the channel flow was set on the order of 10⁴, and the particle mass loading ratio was varied up to 1.6. The result indicated 60% enhancement of heat transfer downstream from the location of the magnet at a mass loading ratio of about 1.6. A farther enhancement in heat transfer is provided by increasing the particle mass loading ratio and the magnetic field intensity. The mechanism of heat transfer enhancement can be clarified by considering the increase in the local heat capacity near the heat plate.