Study on Evaluation of Cohesive Powder Flow Using Test of Powder Discharge by Air Flow

Abstract

We investigated to the evaluation of flowability of cohesive powder using the test of powder discharge from an orifice by air flow. In this study, we used three kinds of Calcium hydroxide which changed the particle diameter. The mean particle diameter of an original powder, Ca(OH)₂ A, is 13.1μm. Other particle diameters, i.e. Ca(OH)₂ B and Ca(OH)₂ C, are 14.1μm and 2.5μm respectively. As The experimental conditions, the initial void fraction and the interstitial air pressure have been changed. The result was obtained that the flowability of Ca(OH)₂ B was the highest flow which was judged from the relation of the mass flow rate and the average interstitial air pressure. Furthermore, the influence of cohesiveness between particles was examined from the relationship between the ration of separation force to gravity force and the initial void fraction. The result indicated that the cohesiveness of Ca(OH)₂ C which has the smallest particle diameter was the strongest.