Fountain Geometry in Shallow Spouted Beds

Abstract

The effect of the operating conditions (base angle, air inlet diameter, stagnant bed height, particle diameter, and air velocity) on the fountain geometry (height and amplitude) has been studied. Likewise, particle ascending and descending zones in the fountain have been delimited. These studies have been carried out by means of an optical fiber and by an image treatment system. An equation has been proposed for the calculation of the fountain height from the vertical component of the particle velocity in the axis at the base of the fountain. The contactor base angle has a major incidence on the fountain geometry. The external diameter of the fountain and that of the core are conditioned by the diameter of the spout at the base of the fountain. The diameter of the core (or ascending zone) decreases with the fountain level for all experimental conditions.

Solid Trajectories and Cycle Times in Spouted Beds

“…The initial data of the program are the experimental results obtained in previous papers and those that have been calculated by means of correlations. Thus, the input data are the geometry and characteristics of the contactor−particle system, the spout shape, the fountain geometry, and the experimental results of the vertical component of the velocity in the annular zone and at the axis . The calculation steps are as follows:…”

“…Kutluoglu et al studied the role of the fountain in the distribution of particles on the upper surface of the annulus, and they remark the importance of this distribution in the trajectories of the particles in the whole bed and in the segregation when particles of different size are handled. 25 Two zones are distinguished in the fountain: 26 the core, where particles from the spout ascend, and the periphery, where the particles descend and fall onto the upper surface of the annular zone. The trajectories in the fountain have been calculated by solving eqs 1 and 2 together with the corresponding boundary conditions, which are as follows: eq 3 on the surface of the fountain (H < z < H + H f , r ) r f ), at the axis (H < z < H + H f , r ) 0), and on the surface of the annular zone (z ) H, r s < r < r w ); eq 4 at the core-periphery interface in the fountain (H < z < H + H f , r ) r n ).…”

Influence of Bed Geometry on the Drying of Skimmed Milk in a Spouted Bed

“…From that, it was obtained the design parameters for the stable operation in a spouted bed. Olazar et al [3] investigated the effect of the operating conditions (base angle, air inlet diameter, stagnant bed height, particle diameter and air velocity) on the fountain geometry. It was seen that the contactor base angle had a major incidence on the fountain geometry.…”

Fountain Geometry of Beds Consisting of Plastic Wastes in Shallow Spouted Beds

“…The knowledge of the fountain height, the maximum height value at the axis, is important in the design of spouted beds, to establish the total height of the contactor. The fountain height has been determined experimentally by several authors, in conventional spouted beds [3][4][5][6][7][8][9][10][11][12][13] and in conical spouted beds. 14,15 Furthermore, correlations have been proposed in the literature for its calculation from the geometric factors of the contactorparticle system.…”

“…The development of the correlations has been addressed through, on the one hand, theoretical bases such as force balances 16,17 and, on the other hand, empirical correlations based on particular design factors determined from experimental studies. [18][19][20] In previous papers, the fountain geometry has been studied in cylindrical spouted beds with uniform beds consisting of glass spheres of different particle size 11 and in conical spouted beds with uniform beds consisting of materials of different density. 15 In this paper, the geometry of the fountain (height, H f , and amplitude, A f ) and the delimitation of the interface between its core and periphery in uniform beds consisting of materials of different density and sphericity have been studied.…”