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Flow field in the freeboard of vortexing fluidized bed
Author(s) -
Chyang ChienSong,
Wan HouPeng,
Chen ChihChuan
Publication year - 1997
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.5450750601
Subject(s) - freeboard , pitot tube , nozzle , mechanics , vortex , tube (container) , flow (mathematics) , secondary flow , vortex tube , fluidization , airflow , materials science , meteorology , fluidized bed , physics , thermodynamics , turbulence , composite material
A systematic investigation on the flow field in a vortexing fluidized bed cold model was reported. The gas velocity profiles within the freeboard with diameters of 0.19 m and 0.29 m were measured by using a five‐hole pitot tube. A new parameter, called vortex number, V or defined as the ratio of tangential velocity to axial velocity of the swirling gas stream, was proposed for representing the swirl intensity. V or is found to be increased with secondary air velocity, and decreased with primary air velocity and diameter of secondary air nozzles. It is also found that the profile of swirl flow is significantly affected by the arrangement of the secondary air nozzles. The effects of inserted length of secondary air nozzles and geometric structure of expansion section on the swirl flow are also studied. Based on the experimental data, a correlation is presented to estimate the vortex number. Vortex number is found to be a function of the geometric structure of exhaust tube, diameter of secondary air nozzle and tangential air flow rate.