A study on the pressure loss,heat transfer enhancement and fouling control in a vertical particulate flow

In this study, the pressure loss, the heat transfer rate and the fouling characteristics of a particulate flow were investigated. Particles used were the glass beads of 3.0 mm diameter with 2.54 specific gravity. The particles augmented the heat transfer at the flow velocities lower than 1.0 m/s. In this range, the heat transfer coefficient slighly increased as the particle volume fraction increased, and was almost independent of the flow velocity. The particles also increased the pressure loss at the flow velocities lower than 1.0 m/s. Above 1.0 m/s, however, the heat transfer coefficient and the pressure loss were essentially the same as those of flow with pure water. Through the flow visualization study, the collision frequency on the wall by particles is shown to be closely related with the heat transfer enhancement. The particles effectively controlled fouling. Fouling tests using ferric oxide revealed that the particles effectively removed the pre-exsisting deposit as well as they prevented the deposit buildup.