Pendular bonds

Fig. 5. Reduced pendular bonding force-reduced separation distance curves. [From Rumpf (R5).]...

The flatness of the computed curves in Fig. 6 shows that in the case of spheres in contact F is insensitive to rather large changes in V (or / ). Mason and Clark (M3) have measured the pendular bonding force as a function of the separation distance and bridge volume. Considering the experimental uncertainty involved, their results follow the expected trend quite satisfactorily. 

Fig. 6. Reduced pendular bonding force-reduced bridge volume curves when spheres are in contact.

H, Bonding force of pendular bond solid bond... 

At low liquid levels, it is assumed that the liquid will distribute itself evenly through the bed, forming discrete liquid bridges at points of contact between particles (Figure 11.20). This is known as the pendular state. The strength of an individual pendular bond, spherical particles can be calculated ... 

As the liquid content is increased, the pendular state will remain until the pendular bonds start to coalesce and liquid bridges form between non-touching points. This is known as the funicular state (Figure 11.20). The state depends on the degree of liquid saturation or voidage saturation, which is defined as the ratio of the liquid volume to the total volume of pores in the powder bed. Typically, a powder bed will remain in the pendular state until the liquid saturation reaches around 25 percent, and in the funicular state between 25 and 80 percent. 

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