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Indian Journal of Chemical Technology (IJCT) >
IJCT Vol.12 [2005] >
IJCT Vol.12(2) [March 2005] >
| Title: | Chaotic analysis of pressure fluctuations in a gas-solid fluidized bed |
| Authors: | Ahuja, Pradeep
Agrawal, Harshit
Sethi, Anadi Kishore
Raj, Utpal |
| Keywords: | Chaotic analysis
pressure fluctuations
gas-solid fluidized bed
Lyapunov exponent
Hurst exponent |
| Issue Date: | Mar-2005 |
| Publisher: | CSIR |
| IPC Code: | F23C10/00; F23C101/00 |
| Abstract: |
The aim of the
present work is to determine the superficial gas velocity range for which chaos
occurs in a gas-solid fluidized bed for various static-bed-height to bed diameter
ratios and sand/plastic-bead mixtures and to observe the change in
deterministic chaos parameters. Four piezo-resistive pressure transducer along
the height of fluidized bed have been used to record pressure fluctuations at
600 Hz. Amplitude Adjusted Fourier Transform (AAFT) technique has been used for
generating surrogate data. Data have been analyzed for the superficial gas
velocity range of 0 to 16 times the minimum fluidization velocity. For the
various static bed heights and sand plastic-bead mixtures it is seen that chaos
is observed in the superficial gas velocity range of 8 to 12 times the minimum
fluidization velocity. The Hurst
exponent rises with superficial gas velocity and then falls after a maximum.
The change in the fractal dimension between surrogate and original time series
also follows the same trend. The superficial velocity range for which chaos
occurs is confirmed when there is change in fractal dimension between original
and surrogate series greater than 0.55, Hurst
exponent is above 0.5 and Lyapunov exponent is positive.
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| Page(s): | 212-219 |
| ISSN: | 0975-0991 (Online); 0971-457X (Print) |
| Source: | IJCT Vol.12(2) [March 2005]
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