CAPACITIVE SYSTEM FOR 3-DIMENSIONAL IMAGING OF FLUIDIZED-BED DENSITY

The U.S. Department of Energy's Morgantown Energy Technology Center ha s been developing a capacitance imaging system (CIS) to support its fl uidized-bed research programs. A second-generation system for capaciti vely imaging a cold, laboratory-scale, 15.24-cm diameter fluidized bed is described. The CIS acquires interelectrode, bed-crossing displacem ent current data to provide 193-pixel density values at four 2.54-cm v ertically spaced levels and presents a three-dimensional density displ ay at a rate of 30 maps per second in real time. The CIS also stores d isplacement current data at a rate of 60 density maps per level per se cond for post-run analysis. Different means of data processing are des cribed that produce one method for real-time display and two methods f or post-run analysis of data. The results of calibration and fluidizat ion tests are presented, together with the errors associated with each of the methods for the known pixel densities in the calibration tests . Improvement in the calibration procedure to reduce these errors is p roposed. Test results indicate the CIS would be a useful tool for rese arch and monitoring operations in two-phase systems.