The effect of fiber length distribution on suspension crowding.

Expressions are developed to extend the concept of fiber crowding, developed by Kerekes et al., to account for the distribution of fiber lengths which are often lognormal. The theory shows that the mean crowding no. for fibers with a distribution of lengths is higher than that for fibers of uniform length equal to the mean by a factor dependent only on the coeff. of variation of fiber length. For a lognormal distribution of fiber lengths, the distribution of crowding nos., itself, resembles a lognormal distribution and this is consistent with measurements of floc size in the literature. The theory allows also detn. of the fraction of fibers in suspension with a crowding no. greater or less than a given value and provides a new basis for detn. of the crit. concn. of a given fiber type. The results are of use in studies of flocculation and paper forming dynamics. [on SciFinder (R)]