Hydrodynamic modeling of vertical accelerating gas-solids flow

The one-dimensional model of accelerating turbulent gas-solids dilute phase flow of coarse particles is formulated and experimentally verified by measuring the pressure distribution along the transport tube. The theoretical basis of the model is the continuity and momentum equations for the fluid and particle phases of Nakamura and Capes (Can. J. Chem. Eng., 51 (1973) 39) and the authors' variational model for calculating fluid-particle interphase drag coefficient (Grbavcic et al., Powder Technol., 68 (1991) 199). The main model assumptions are that the constituted relations for fluid-particle interphase drag coefficient, fluid-wall friction coefficient and particle-wall friction coefficient remain the same regardless of the acceleration of the fluid and particle phases. In addition, the transport line inlet voidage required for closure has been derived for the cases where top-closed spouted or spout-fluid beds were used as a feeding device to the transport tube. Experiments were performed by transporting spherical glass particles 1.94 mm in diameter in a 30 mm i.d. glass tube. Reynolds number for the particles, based on slip velocity, ranged from 1524 to 2562 and loading ratio was varied between 4.8 and 26.4. Model predictions for the pressure distribution along the transport tube are in good agreement with experimental measurements.

[1]  S. Stemerding,et al.  The pneumatic transport of cracking catalyst in vertical risers , 1962 .

[2]  M. H. Morgan,et al.  Spout voidage distribution, stability and particle circulation rates in spouted beds of coarse particles—I. Theory , 1985 .

[3]  L. Fan,et al.  Pressure fluctuations and choking criterion for vertical pneumatic conveying of fine particles , 1985 .

[4]  Variational model for prediction of the fluid-particle interphase drag coefficient and particulate expansion of fluidized and sedimenting beds , 1991 .

[5]  John D. Paccione,et al.  Modeling and measurement of the effective drag coefficient in decelerating and non-accelerating turbulent gas—solids dilute phase flow of large parti , 1993 .

[6]  S. Ergun.  Fluid flow through packed columns , 1952 .

[7]  K. Nakamura,et al.  Vertical pneumatic conveying: A theoretical study of uniform and annular particle flow models , 1973 .

[8]  Shigeru Matsumoto,et al.  Solid particle velocity in vertical gaseous suspension flows , 1986 .

[9]  K. B. Mathur,et al.  An analysis of air and solid flow in a spouted wheat bed , 1959 .

[10]  Shozaburo Saito,et al.  PNEUMATIC CONVEYING OF SOLIDS THROUGH STRAIGHT PIPES , 1969 .

[11]  Hydrodynamic modeling of vertical liquid-solids flow , 1992 .

[12]  O. Levenspiel,et al.  Fluidization engineering, 2nd edition , 1991 .

[13]  O. Levenspiel,et al.  A short note on the drag correlation for spheres , 1986 .

[14]  Wen-Ching Yang,et al.  A correlation for solid friction factor in vertical pneumatic conveying lines , 1978 .

[15]  M. H. Morgan,et al.  Measurements of spout voidage distributions, particle velocities and particle circulation rates in spouted beds of coarse particles—II. Experimental verification , 1987 .

[16]  Andrzej Kmiec,et al.  Acceleration of the solid phase during pneumatic conveying in vertical pipes , 1987 .

[17]  W. Gauvin,et al.  The drag coefficients of single spheres moving in steady and accelerated motion in a turbulent fluid , 1961 .

[18]  Dimitri Gidaspow,et al.  Vertical Pneumatic Conveying Using Four Hydrodynamic Models , 1979 .

[19]  K. Nakamura,et al.  Vertical pneumatic conveying: An experimental study with particles in the intermediate and turbulent flow regimes , 1973 .

[20]  L. S. Leung.  The Ups and Downs of Gas-Solid Flow - A Review , 1980 .