Murray State University
Department of Physics and Engineering

Centrifugal Fluidized Bed Project

    Gas-solid fluidization is an important approach used for a variety of chemical and physical processes.  This technology has found several applications in space, ranging from the production of oxygen from lunar rock and soil to the processing of human waste.  Current space applications of  fluidization have made use of the vertical column fluidized bed, which represents a well-developed technology which is in use in a large variety of terrestrial applications.  In this investigation, an alternative arrangement for fluidization, the centrifugal fluidized bed, is considered.  Advantages of centrifugal fluidization over columnar beds include a larger gas flow rate with lower gas bypassing, independence from the local gravitational field, fluidization control via rotational speed control, and a smaller space requirement.  Previous investigations into centrifugal fluidized beds have considered the point of incipient fluidization by analyzing a thin disk fluidized bed of only a few centimeters thickness.  Fluidization characteristics which concern the formation and combination of bubbles and the transition to turbulent and fast fluidization regimes have not been fully considered.
    This investigation takes a broader view of centrifugal fluidization beyond understanding of minimum fluidization conditions.  Several comparisons are being made between centrifugal and constant gravity fluidization by first observing a column in centrifugal motion and then in a stationary vertical orientation.  Specifically this research project seeks to provide:
    1)  an improved understanding of the effects of a widely varying acceleration component along the length of a fluidized bed of substantial thickness
    2)  determination of the location of the points of incipient fluidization and bubbling, and comparison to existing models
    3)  an investigation of the effect of the decreasing flow area as gas flows inward into a cylindrical geometry
    4)  observation of fluidization from incipient fluidization to fast fluidization
    5)  evaluation of expressions for minimum fluidization velocity developed for constant cross-sectional area flow and for flow with decreasing cross-sectional area.
    In this investigation a plexi-glass column fluidized bed (see pictures below) are placed in a centrifuge and spun to create a gravity field that varies from approximately 16 g's at its base to 4 g's at its top.  Attached to the bed are pressure taps to measure differential pressures in the bed at five locations along the length of the bed.  Also attached to the centrifuge is a video camera and a mirror for visually recording the fluidization effects.  Comparisons to constant gravity fluidization are made by placing the columnar bed in a standard vertical arrangement.  A second bed is being constructed such that its cross sectional area will be inversely proportional to the radius at all locations.  This rotating cylindrical segment will simulate a standard cylindrical configuration to examine the effects of the increasing superficial velocity along the length of the bed.
OTHER RESEARCH PROJECTS
    Limestone Desulfurization Modeling
   Coal Fragmentation
    Naval Reserves Projects
    Other Research Interests/Opportunities
Contact Information
Address: Dept. of Physics & Engineering, 131 Blackburn Science Building,  Murray State University, Murray, KY 42071-0009
Office:  Blackburn Science Bldg., Room 171
Phone: (270) 762-4918 (Direct Line),  762- 2993 (Physics Office)
Fax:   (270) 762-6107
Email: ted.thiede@murraystate.edu


 | Return to Ted Thiede | Return To Physics and Engineering Physics Faculty |
| MSU Home |  Dept. of Physics and Engineering Physics | 
 'Murray State University is not responsible for the contents of these individual pages.
Comments on these pages should be directed to the page author.'
Direct comments and questions to ted.thiede@murraystate.edu
Last Modified February, 1999.