Experimental estimation of elongational stresses of dilute polymer solutions and a related examination of some constitutive equations

doi:10.1016/0377-0257(88)85010-9

Journal of Non-Newtonian Fluid Mechanics

Volume 27, Issue 2, 1988, Pages 133-151

https://doi.org/10.1016/0377-0257(88)85010-9 Get rights and content

Abstract

Elongational stresses of dilute polymer solutions have been estimated by utilizing the flow through small orifices under the condition of no vortex upstream of the orifice plane. The flow was approximated with a linearly converging flow towards an apex of a cone, its validity being partially confirmed by the measured center velocities, and the elongational stresses are determined from the measured thrusts of dilute polymer solutions. On the other hand, elongational stresses were theoretically obtained with the modified Maxwell model and the second order fluid. A comparison was made between the experimental and the theoretical results and the following points were clarified; below an elongational rate of 2 × 10⁴ s⁻¹ the modified Maxwell model gives elongational stresses close to the experimentally determined ones, but above that elongational rate it deviates from the experimental results. The second order fluid is not sufficient to describe the stresses in this kind of elongational flow and an acceleration term such as δ²e^ij/δt² may be necessary in this case.

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Experimental estimation of elongational stresses of dilute polymer solutions and a related examination of some constitutive equations

Abstract

Chem. Eng. J.

J. Non-Newtonian Fluid Mech.

J. Non-Newtonian Fluid Mech.

J. non-Newtonian Fluid Mech.

Computers & Fluids

J. Non-Newtonian Fluid Mech.

J. non-Newtonian Fluid Mech.

J. Fluid Mech.