Formulation of multiphase mixture models for fragmenting flows

•Formulation of multiphase mixture models of fragmentation is discussed.•Consequences of specific constitutive choices are determined.•Independence of large and small scale effects is investigated.•Plug flow fragmentor closed form solutions are presented.

The formulation of multiphase mixture models of fragmentation is discussed. It is demonstrated that choices of constitutive equations play a critical role in creating the independence of large and small scale effects exhibited by some models appearing in the literature. A model of this kind is used to make closed form plug flow fragmentor predictions which could be useful in the investigation of size class convergence.