METHOD OF DETERMINING RHEOLOGICAL CHARACTERISTICS OF NON-NEWTONIAN LIQUIDS Russian patent published in 2011 - IPC G01N11/08 

FIELD: physics.

SUBSTANCE: method of determining rheological properties of non-Newtonian liquids involves passing a liquid through a capillary. The liquid is passed at different velocities through the capillary which is in form of an annular channel. Pressure fall at the ends of the capillary ΔP and volume-flow rate of the liquid Q are determined using the formula: where V is the volume of lubricant passing through the capillary in time (t) of one cycle of the experiment; d is the plunger diameter; S is the plunger displacement. Further, the dependency of tangential stress on the velocity gradient is calculated using the following formulas: where is the velocity gradient; τ_ω is tangential stress; h is the thickness of the annular gap; R is the radius of the capillary; L is the length of the capillary, and the obtained data are used to plot a curve of the flow of the non-Newtonian liquid under analysis.

EFFECT: high accuracy of determining rheological properties of non-Newtonian liquids.

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