Study of a Port Design for Silo Blenders

Abstract

Experimental results are reported on two silo-blenders equipped with a new design of ports in their downcomers. None of the mixing streams was falling freely. The mixing of pellets within the ports is determined as a function of the port geometric characteristics such as awning angle, height of port, width of awning and width of the downcomer, and of the particle properties such as the angle of repose. It was observed that two dimensionless quantities are sufficient to describe the mixing fraction at the port. Visual observations on the flow near the port were made and the port’s mixing response surface was estimated. When the new port design was fitted in a cylindrical blender the active channel of the port was recorded as well as the average velocity distribution in the channel.