Aerodynamics of a jet in a fluidized bed

An engineering method of calculating a jet in a fluidized bed

“…This is confirmed by experiment [3,6], which shows that the frequency of jet disruption does not remain constant and is dependent on the flow conditions; this frequency fm may be 6-48 tiz or more in the jet condition, and the flow of the jet may be considered as quasistationary, with constant maximal parameters in the fluidized bed, which can be calculated via (1)-( 5), ( 7)- (9), and (17). The parametric criterion Xj/Hp [3] defines the existence of the jet condition and, as a special case, the condition for local existence of a fountain.…”

“…we obtain, after substitution of (13)-( 16) into (11) and certain transformations, the equation for the mean density in the boundary layer of the jet in the main section: If pg is much less than Pro, as follows from (1)-( 5), (9), and (17), it is inevitable that a discontinuity occurs in the jet [1,4]. This is confirmed by experiment [3,6], which shows that the frequency of jet disruption does not remain constant and is dependent on the flow conditions; this frequency fm may be 6-48 tiz or more in the jet condition, and the flow of the jet may be considered as quasistationary, with constant maximal parameters in the fluidized bed, which can be calculated via (1)-( 5), ( 7)- (9), and (17). The parametric criterion Xj/Hp [3] defines the existence of the jet condition and, as a special case, the condition for local existence of a fountain.…”

“…The U 0 and r 0 of (19) are known from conditions of the problem, while Xj is determined from experiment [3], and U b is calculated from (18) (for the given range in the Re b and Ar), or else it is determined by experiment. Equation {19) gives reliable C1, because the velocity profile derived from (7) agrees well with that over the full width of the boundary layer at various parts in the jet as calculated from {7); the spread in the experimental points does not exceed 7.7%.…”

“…We can use (1)-( 9) and (17) for kinematic calculation of a gas jet if we are given either C 1 or C2, as ' and U b. It has been found by experiment for local fountain conditions [3] in semiinfinite (horiwell as Pm zontal and vertical) gas jets that U b is constant along the jet and is independent of the velocity and direction of discharge, the nozzle diameter, and the fluidization number. To determine U b we can use a formula [8] as corrected via the factor 77 = 0.80, which has been derived by experiment for particles 1-5 mm in size: 0.80 Ar R% 18 ~-0.61 V Ar 480 ~< Reb ~< 2300; 19.8.10 ' < Ar ..< 313.104.…”

A new approach to jet phenomena gas entrainment and recirculation in a bidimensional spouted fluidized bed

“…Although many researchers (Shakhova and Minaev, 1970;Yang and Keairns, 1978;Gidaspow et al, 1983a;Rowe et al, 1979) describe the jet behaviour as being unsteady, all the above models consider the jet as being permanent. We propose here a new approach which accounts for the fluctuating nature of the jet.…”