Hedstrom number, Bingham plastic

Hedstrom number Nne t0D2 p /vHe — 2 Mx t0 = yield stress Pvc = limiting viscosity (Yield x inertia)/ viscous stresses Flow of Bingham plastics... 

The basic dimensionless variables for the Bingham plastic are the Reynolds number, the Hedstrom number, and the friction factor. Eliminating Dec from the Reynolds number and Eq. (7-25) (as above), the cost group is ... 

With regard to the drag on a sphere moving in a Bingham plastic medium, the drag coefficient (CD) must be a function of the Reynolds number as well as of either the Hedstrom number or the Bingham number (7V Si = /Vne//VRe = t0d/fi V). One approach is to reconsider the Reynolds number from the perspective of the ratio of inertial to viscous momentum flux. For a Newtonian fluid in a tube, this is equivalent to... 

Figure 3.10 shows a friction factor - Reynolds number chart for Bingham plastics at various values of the Hedstrom number. The turbulent flow line is that for Newtonian behaviour and is followed by some Bingham plastics with low values of the yield stress [Thomas (1962)]. 

Hedstrom number He LHyp Pi Bingham Reynolds number x Bingham number Flow of Bingham plastics... 

The parameter Ca is called the Casson number and is analogous to the Hedstrom number He for the Bingham plastic and Herschel-Bulkley models. 

This parameter is defined to accommodate Herschel-Bulkley model fluids. In the limit To = 0, it reduces to an equivalent power law particle Reynolds number. In the limit n = 1, it reduces to a compound parameter involving the Bingham plastic particle Reynolds number and particle Hedstrom number. In both limits it reduces to the Newtonian particle Reynolds number. This correlation permits... 

For a Bingham plastic slurry, the transition from laminar to turbulent flow depends on the Hedstrom number. The critical Reynolds number, which allows... 

Figure 4.6 Friction factor as a function of Reynolds number and Hedstrom number for slurries exhibiting Bingham plastic rheology...

Hedstrom [96] has proposed a simple criterion to distinguish between laminar and turbulent flow of Bingham plastic materials. The Reynolds number at which turbulence sets in is determined by the intersection of a parametric curve, defined by... 

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