Viscometer using drag force measurements

Benoît Semin (1) , Marie-Hélène Noel (1) , Jean-Pierre Hulin (1) , Harold Auradou (1)

1 FAST - Fluides, automatique, systèmes thermiques

A robust and precise viscometer using the forces exerted by a laminar flow inside a small duct is presented: the force is measured on a long cylindrical sensor dipped into the flow. Two devices of respective volumes $1.4$ and $0.031\, \mathrm{ml}$ have been realized, demonstrating that the technique is usable with small fluid volumes. Several Newtonian and non-Newtonian fluids have been tested at shear rates ranging from $0.3$ up to $10\,\mathrm{s^{-1}}$ for the first device and from $85$ up to $2550\, \mathrm{s^{-1}}$ for the second one. For Newtonian fluids, of viscosities ranging from $10^{-3}$ to $0.1\, \mathrm{Pa.s}$, the linear response of the device has been verified and a $90\%$ agreement with the values provided by commercial rheometers is obtained. For non-Newtonian polymer solutions, the variation of the force with the flow velocity allows one to determine the dependence of the viscosity on the shear rate. Two shear thinning polymer solutions with a power law behaviour at intermediate shear rates have been investigated and their rheological parameters have been determined.

Mots clés: Viscometer; force; non-Newtonian; laminar

Domaines: Dynamique des Fluides [physics.flu-dyn]

Benoît Semin, Marie-Hélène Noel, Jean-Pierre Hulin, Harold Auradou. Viscometer using drag force measurements. Review of Scientific Instruments, 2011, pp.00. ⟨10.1063/1.3556445⟩. ⟨hal-00568712⟩