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Statistical models for surface renewal in heat and mass transfer. Part III: Residence times and age distributions at wall surface of a fluidized bed, application of spectral density
Author(s) -
Koppel L. B.,
Patel R. D.,
Holmes J. T.
Publication year - 1970
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690160324
Subject(s) - dimensionless quantity , residence time (fluid dynamics) , mass transfer , mechanics , autocorrelation , fluidized bed , surface (topology) , work (physics) , heat transfer , residence time distribution , chemistry , thermodynamics , materials science , statistics , mathematics , geometry , flow (mathematics) , physics , geology , geotechnical engineering
A method was developed for estimating the age density of transporting elements at a transport surface by using the spectral density of the total element counts. Only total counts, and not individual element histories, need be observed. The method was compared with autocorrelation methods used in an earlier work. Residence times were measured for several sizes of particles at a paticular wall surface of a stirred fluidized bed and at various gas velocities using both spectral density and autocorrelation methods. A dimensionless plot brought all data points near a single curve, valid only for this surface in this bed. Checks of these residence times against values obtained by direct observation of individual particles confirmed the methods.