6.6 Correlations for packed and fluidized bed
6.6.1 Packed bed
The heat transfer correlation for gas flow through a packed bed is given as,
|
(6.17) |
Conditions to use eq.6.12 are,
where,
is the Stanton number.
is the particle Reynolds number
dp = Diameter or the effective diameter of a particle
v0 = Superficial fluid velocity. It is the velocity based on the cross-section of the bed).
∈ : Bed porosity or void fraction
∈ : 0.3 → 0.5
| Theoretically: | ∈ | = 0.69 for uniform shape |
= 0.71 bed of cubes |
||
= 0.79 bed of cylinder  |
Colburn factor
6.6.2 Fluidized bed
The heat transfer coefficient to or from particles in a fluidized bed can be estimated with the help of following correlation,
|
(6.18) |
where, v0 is the superficial velocity.