Effect of Powder Head and Fluidizing Velocity to Fluidized Powder Conveying in a Horizontal Rectangular Channel

Abstract

This study has experimentally investigated fluidized powder conveying in a horizontal rectangular channel when the powder head at the powder discharge vessel and fluidizing velocity at the bottom of the discharge vessel and the horizontal channel were varied. The powder used was glass beads of the Geldart B particle, with mean particle diameter of 118m, the particle density of 2623kg/m 3 and the minimum fluidizing velocity of 12.3mm/s. As the result, steady powder conveying achieved in case of the reduced powder head in the powder discharge vessel. It is also necessary to supply the air at the bottom of the powder discharge vessel, and to give to greater than the minimum fluidizing velocity at the bottom of a horizontal channel. The profile of mass flow rate and solid loading ratio against fluidizing velocity to the bottom of the powder discharge vessel and a horizontal channel revealed the similar tendency when the powder head was changed. It was clarified that when the powder head was lowered, the total pressure drop decreased, the mass flow rate and the solid loading ratio also decreased, and then the performance of the pneumatic conveying equipment was greatly affected. In addition, it was confirmed that high dense pneumatic conveying could be realized even if the powder head was changed within the range of the present experiment. Moreover, the flow pattern in the horizontal channel during steady conveying showed the ripple flow, and the bubble flow was generated into the powder layer as the fluidizing velocity at the bottom of the channel increased. It is also inferred that the part of the pressure energy of the powder bed in the powder discharge vessel became the driving force for the horizontal conveying of the powder.