Doctoral Dissertations

Keywords and Phrases

Dimensionless Groups Methodology; Fluidized Bed Reactor Scale-Up; Fluidized Beds Hydrodynamics; Gamma Ray Computed Tomography (CT); Radioactive Particle Tracking (RPT).; Scale-Up New Methodology


"This research focuses on validating our newly developed mechanistic scale-up methodology for hydrodynamics similarity of gas-solid fluidized bed reactors (FBRs) by implementing our advanced non-invasive measurement techniques which are gamma ray computed tomography (CT) and radioactive particle tracking (RPT) that measure local hydrodynamic parameters. Experiments were carried out in two fluidized beds of 14 cm and 44 cm in diameter using air as the gas phase and particles of different materials. Since in these reactors the gas dynamic dictates the bed hydrodynamics, the new mechanistic scale-up methodology is based on maintaining similar or closer time averaged radial profiles of gas holdups at a height within the bed in two different gas-solid fluidized beds in order to achieve local and global similarity of dimensionless hydrodynamic parameters. The findings validate the achievement of hydrodynamics similarity in local solids and gas holdups distribution obtained by CT technique and in three dimension local solids velocities, solids shear stresses, normal stresses, turbulent kinetic energy, and turbulent eddy diffusivities measured by RPT technique. Also in this work we found based on local hydrodynamic parameters obtained by using CT and RPT that the scale-up method of matching a set of dimensionless groups is invalid for hydrodynamics similarity and the proposed dimensionless groups are insufficient to capture the key phenomena in these reactors. In addition, we studied the effect of bed height and particles type, size, and density on gas holdup, particle velocity, and turbulent parameters measured by these advanced techniques"--Abstract, page iv.


Al-Dahhan, Muthanna H.

Committee Member(s)

Ludlow, Douglas K.
Park, Joontaek
Liang, Xinhua
Usman, Shoaib


Chemical and Biochemical Engineering

Degree Name

Ph. D. in Chemical Engineering


Missouri University of Science and Technology

Publication Date

Spring 2016

Journal article titles appearing in thesis/dissertation

  • Validation of new the scale-up methodology for gas-solid fluidized beds using advanced non-invasive measurement techniques (CT and RPT)
  • Assessment of scale-up dimensionless groups methodology of gas-solid fluidized beds using advanced non-invasive measurement techniques (CT and RPT)
  • Local time averaged gas holdup in gas-solid fluidized bed study by non-invasive measurement technique
  • Bed diameter effect on the hydrodynamics of gas-solid fluidized beds via radioactive particle tracking (RPT) technique


xxi, 262 pages

Note about bibliography

Includes bibliographic references.


© 2016 Abdelsalam Yahya Efhaima, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Subject Headings

Fluidized reactors -- Design
Gas-solid interfaces -- Computer simulation
Computational fluid dynamics
Gamma ray detectors
Two-phase flow -- Computer simulation

Thesis Number

T 10909

Electronic OCLC #