A Theory for Heterogeneous Flow of Solids in Pipes

A theory for the flow of heterogeneous mixtures (particulate solids which settle in the fluid carrier) is derived assuming that the existence of bed deposits is the principal cause of the observed differences in the flow characteristics between heterogeneous-mixture flow and single-phase fluid flow. The theoretical solution is in qualitative agreement with observed flow characteristics. The theory is indicative that head loss varies nonlinearly with concentration and substantiates the plausibility that (a) higher head losses with heterogeneous mixtures than with single-phase fluid flow are the result of bed deposits and (b) the minimum head loss on a constant-concentration curve is the result of a finite bed deposit rather than the common assumption of incipient deposition.