Stochastic analysis of a three-phase fluidized bed; Fractal approach

Journal Article · Mon Oct 01 00:00:00 EDT 1990 · A.I.Ch.E. Journal (American Institute of Chemical Engineers); (United States)

DOI:https://doi.org/10.1002/aic.690361008· OSTI ID:5725925

Fan, L T; Neogi, D; Yashima, M; Nassar, R ^[1]

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1. Dept. of Statistics, Kansas State Univ., Manhattan, KS (US)

This paper reports on three-phase fluidized beds that have played important roles in various areas of chemical and biochemical processing. The characteristics of such beds are highly stochastic due to the influence of a variety of phenomena, including the jetting and bubbling of the fluidizing medium and the motion of the fluidized particles. A novel approach based on the concept of fractals, has been adopted to analyze these complicated and stochastic characteristics. Specifically, pressure fluctuations in a gas-liquid-solid fluidized bed under different batch operating conditions have been analyzed in terms of Hurst's rescaled range (R/S) analysis, thus yielding the estimates for the so-called Hurst exponent, H. The time series of the pressure fluctuations has a local fractal dimension of d{sub FL} = 2 {minus} H. An H value of 1/2 signifies that the time series follows Brownian motion; otherwise, it follows fractional Brownian motion (FBM), which has been found to be the case for the three-phase fluidized bed investigated.

• OSTI ID: 5725925
• Journal Information: A.I.Ch.E. Journal (American Institute of Chemical Engineers); (United States), Journal Name: A.I.Ch.E. Journal (American Institute of Chemical Engineers); (United States) Vol. 36:10; ISSN AICEA; ISSN 0001-1541
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400105 -- Separation Procedures
400201 -- Chemical & Physicochemical Properties
42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
BROWNIAN MOVEMENT
BUBBLES
FLUID FLOW
FLUIDIZED BED REACTORS
FLUIDIZED BEDS
FLUIDS
FRACTALS
FUEL DISPERSION REACTORS
GASES
HOMOGENEOUS REACTORS
LIQUIDS
MATHEMATICS
PHASE STUDIES
PRESSURE GRADIENTS
REACTORS
SOLIDS
STOCHASTIC PROCESSES
TIME-SERIES ANALYSIS