Visualization in the Reh Diagram

In Equation (3.89), the Archimedes number is calculated as shown in Equation (3.81). 3.12.4.6 Visualization in the Reh Diagram 

Reh [138-140] established a diagram to illustrate the states of gas-particle interactions on one glance. This is very useful in understanding the operation ranges of gasification systems especially if particle segregation (e.g., agglomeration) effects occur. 

The basic idea is the concept of load multiples iri) relating the drag force f d to the gravimetric force Fg which is corrected using the buoyancy force as shown in Equation (3.90). 

The same relation is expressed in Equations (3.91) using the dimensionless Reynolds (Re) and Archimedes (Ar) numbers, see Equations (3.87) and (3.81), where is the drag function of a particle or bed depending on the Reynolds number Re and the bed voidage e. For fluid-particle interaction the following states can be distinguished  

Reh [138] suggested the coordinates (3/4) (R fAr) = f(Re) because a single spherical particle has the drag function (Re) = (3/4)Co. Consequently, the ordinate expresses the reciprocal value of the drag coefficient Co, hence 

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