Annulus leakage and distribution of the fluid flow in a liquid spout-fluid bed with a draft tube

Erbil A.

CHEMICAL ENGINEERING SCIENCE, vol.58, no.20, pp.4739-4745, 2003 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 58 Issue: 20
  • Publication Date: 2003
  • Doi Number: 10.1016/j.ces.2003.05.005
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.4739-4745
  • Istanbul Technical University Affiliated: No


The distribution of flow between the annulus and the draft tube sections in a liquid phase spout-fluid bed with a draft tube was studied in a flat-based semi-circular column of 80 mm diameter equipped with a semi-circular draft tube of 20 turn diameter at superficial fluid velocities well above the minimum fluidization velocity. The particles used were glass spheres of 3 mm diameter, and the spouting medium was tap water. A sodium chloride solution was injected into the reactor and the response recorded to determine the flow distribution between the draft tube and the annulus sections. The responses of the tracer injections prove that part of the flow originating from the annulus inlet leaks into the draft tube when any amount of annulus inlet flow is present. This finding makes a significant contribution to the understanding of the entrance region below a draft tube which has been modeled as a spout-fluid bed where fluid enters the annulus region based on the pressure distribution at the spout-annulus interface while the flow is in the radial direction from the spout into the annulus. This work shows that there is cross flow in the entrance region resulting in fluid exchange between the streams originating from the spouting inlet nozzle and the annulus inlet flow.