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Residence Time Distribution of Particles in a Screw Feeder: Experimental and Modelling Study
Author(s) -
Huo Chaofei,
Fan Chuigang,
Feng Ping,
Lin Weigang,
Song Wenli
Publication year - 2015
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.22240
Subject(s) - markov chain , mechanics , rotation (mathematics) , residence time distribution , mathematics , materials science , physics , geometry , statistics , flow (mathematics)
Experiments were conducted to investigate the effects of screw speed and screw feeder inclination on the residence time distribution (RTD) of particles in a screw feeder via a pulse stimulus response technique. Two models based on Markov chains were developed to simulate particle flows within and between pitches. In upward and horizontal screw feeder inclination cases, a three‐parameter two‐dimensional Markov chain model consisting of parallel active and stagnant zones fitted well with the experimental RTD data, with correlation coefficients (R 2 ) higher than 0.98, and gave a clear physical meaning for the parameters introduced. In these cases, a high screw speed or a horizontal inclination induced a high probability of forward movement from a pitch to the next pitch ( f ) during each rotation period of the screw, and a low ratio of stagnant zone to active zone ( r ) in a pitch. The upward screw feeder inclination yielded a higher diffusion probability from stagnant zone to active zone ( d ). In the downward screw feeder inclination case, a one‐dimensional Markov chain model without a stagnant zone was in agreement with the corresponding experimental data. The analysis showed that during each rotation period of the screw, the particles in a pitch could be transferred not only to the next pitch but also to the following two pitches.