Because of the oscillatory nature of the void-fraction radial variation of packed beds, there are a number of locations close to the wall where the local void fraction is exactly equal to the asymptotic value. For the bed described in Example 4.1, calculate the distance from the wall to the first five such locations.

Data From Example 4.1:-

It is well known that the wall in a packed bed affects the packing density resulting in void fraction variations in the radial direction. Mueller (1992) developed the following equation to predict the radial void fraction distribution in a cylindrical tower packed with equal-sized spheres:

J₀ = Bessel function of the first kind of order zero r = radial distance measured from the wall Consider a cylindrical vessel with a diameter of 305 mm packed with solid spheres with a diameter of 20 mm. Plot the radial void fraction fluctuations near the walls for this packed bed.

Transcribed Image Text:

= + (1-6) (ar *) exp(-Br*) (4-1) where d D a 7.45 3.15 P for 2.02 13.0 D dp (4-2) d d, 0.315 0.725-P = 0.365+0.220- D D = r d. P D 0 < < 2d,