Polydisperse coal slurry rheology. Quarterly report
The dimensionless groups defined (Peclet number, shear attraction number and the shear repulsion number) can be used to characterize the essential features of suspension rheology. Examination of these groups makes the importance of characteristic particle size clear. The shear-repulsion number increases as the square of the particle size, while both the Peclet number and the shear-attraction number increases as the cube. This means that these parameters increase rapidly with increasing particle size, implying a rapid increase in the relative importance of shear forces with increasing particle size. For colloidal particles, for which the average particle size is about 1 micron, the dimensionless parameters tend to small values and non-Newtonian effects become important. For large particles with an average size larger than 50 microns, on the other hand, these parameters become much larger than unity and hydrodynamic forces dominate so that any non-Newtonian behavior should vanish. This is exactly what is required by the spatially periodic suspension model. The geometric variables of the spatially periodic model were adjusted to yield the same maximum packing fraction as that given by the truly bimodal suspension results. We then followed an inverse procedure, as previously, and determined the coarse and colloidal volume fractions of the six slurries that would yield the experimental low shear extrapolated viscosities. The reason why the extrapolated results were used is because the Farris data is applicable in the low shear limit only.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge (USA)
- DOE Contract Number:
- FG22-84PC70061
- OSTI ID:
- 5967158
- Report Number(s):
- DOE/PC/70061-7; ON: DE86009841
- Country of Publication:
- United States
- Language:
- English
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FUEL SLURRIES
RHEOLOGY
VISCOSITY
COAL
MATHEMATICAL MODELS
MIXTURES
PARTICLE SIZE
RESEARCH PROGRAMS
SHEAR
WATER
CARBONACEOUS MATERIALS
DISPERSIONS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
MATERIALS
OXYGEN COMPOUNDS
SIZE
SLURRIES
SUSPENSIONS
010600* - Coal
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013000 - Coal
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Handling
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