SIMPLIFIED SCALING RELATIONSHIPS

In later sections, the use of the scaling relationships to design small scale models will be illustrated. For scaling to hold, all of the dimensionless parameters given in Eqs. (36), (37) or (39) must be identical in the scale model and the commercial bed under study. If the small scale model is fluidized with air at ambient conditions, then the fluid density and viscosity are fixed and it will be shown there is only one unique modeling condition which will allow complete similarity. In some cases this requires a model which is too large and unwieldy to simulate a large commercial bed. 

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This will be referred to as the simplified scaling relationship. At low Reynolds numbers, this still includes the gas-to-particle density ratio. 

Figure 24. Error in drag coefficient for simplified scaling relationships, ua/umj = 10. (From Glicksman et al., 1993b.)...

The simplified scaling relationships, Eq. (53), offer some flexibility in the model design since fewer parameters must be matched than with the full set of scaling relationships. When the fluidizing gas, the pressure and temperature of the scale model are chosen, the gas density and viscosity for the scale model are set. The model must still be geometrically similar to the commercial bed. There is still one free parameter. Generally this will be the linear scale of the model. For the simplified scaling relationships, the gas-to-solid density ratio must be maintained constant... 

Since the gas-to-solid density ratio of the model and the commercial beds must be the same to satisfy the simplified scaling relationships, Eq. (87) combined with Eqs. (81) and (78) becomes,... 

Table 4. Scale Models of Atmospheric Commercial Hot Bed Using the Simplified Scaling Relationship...

Glicksman, L. R., Hyre, M. R., and Woloshun, K., Simplified Scaling Relationships for Fluidized Beds, Powder Technol.,11 All (1993b)... 

Table 5 Scale models of atmospheric commercial hot bed using the simplified scaling relationship... 

Glicksman LR, Hyre MR, Woloshun K. Simplified scaling relationships for fluidized beds. Powder Technol 77 177, 1993b. 

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