The Archimedes number is generally used in design of tubular
chemical process reactors. The following are non-exhaustive examples of using the Archimedes number in reactor design.
Packed-bed fluidization design The Archimedes number is applied often in the engineering of
packed beds, which are very common in the chemical processing industry. A packed bed reactor, which is similar to the ideal
plug flow reactor model, involves packing a tubular
reactor with a
solid catalyst, then passing
incompressible or
compressible fluids through the solid bed. :u_{mf}=\frac{\mu}{\rho_ld_v}\left((33.7^2+0.0408\text{Ar})^\frac{1}{2}-33.7\right) where: • d_v is the diameter of sphere with the same volume as the solid particle and can often be estimated as d_v\approx 1.13d_p, where d_p is the diameter of the particle. :\varepsilon_g=b_1\left[\text{Eo}^{b2}\text{Ar}^{b3}\text{Fr}^{b4}\left(\frac{d_r}{D}\right)^{b5}\right]^{b6} where: • \varepsilon_g is the gas holdup fraction • \text{Eo} is the
Eötvos number • \text{Fr} is the
Froude number • d_r is the diameter of holes in the column's
spargers (holed discs that emit bubbles) • D is the column diameter • Parameters b1 to b6 are found empirically
Spouted-bed minimum spouting velocity design A
spouted bed is used in drying and coating. It involves spraying a liquid into a bed packed with the solid to be coated. A fluidizing gas fed from the bottom of the bed causes a spout, which causes the solids to circle linearly around the liquid. Work has been undertaken to model the minimum velocity of gas required for spouting in a spouted bed, including the use of
artificial neural networks. Testing with such models found that Archimedes number is a parameter that has a very large effect on the minimum spouting velocity. ==See also==