| Autor: |
Cherpakova, Nadezhda A., Pyshnograi, G. V., Pyshnograi, I. G. |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2020, Vol. 2216 Issue 1, p050001-1-050001-6, 6p, 5 Graphs |
| Abstrakt: |
Many liquid systems, including polymeric and biopolymer materials, often exhibit a slip anomaly near a solid surface. Such effect leads to a violation of the hypothesis of sticking on the wall and the need to indicate the corresponding boundary conditions. This anomalous behavior of materials in a viscous state (suspensions, solutions and melts) on solid surfaces requires a comprehensive study of both the rheological properties and the calculation of flow parameters and characteristics in the nodes of the process equipment. First, there are quite complex problems in determining the rheological characteristics of a material in accordance with viscometric studies. The next stage is associated with specific problems on the motion of a fluid, which exhibits slippage on solid surfaces and in the direct use of the slip velocity as boundary conditions. This work is to determine the slip velocity on the wall, which is usually a function of the wall stress, geometrical dimensions and temperature. The dependence of the sliding velocity on the wall on these factors can be found from viscometric measurements. Further, the case of a plane Poiseuille flow was considered, taking into account polymer slippage at the boundary. The system of equations of the modified Vinogradov and Pokrovskii model describes a non-parabolic velocity profile in the interspace between parallel plates, which is confirmed by experimental data. The dependences obtained can be used to study more complex flows. This is illustrated by the example of the calculation of the three-dimensional velocity profile of a nonlinear viscoelastic fluid in a channel with a square cross section. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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