Study on an N-Parallel FENE-P Constitutive Model Based on Multiple Relaxation Times for Viscoelastic Fluid

Abstract

Abstract. An N-parallel FENE-P constitutive model based on multiple relaxation times is proposed in this paper, which aims at accurately describing the apparent viscosity of viscoelastic fluid. The establishment of N-parallel FENE-P constitutive model and the numerical approach to calculate the apparent viscosity are presented in detail, respectively. To validate the performance of the proposed constitutive model, it is compared with the conventional FENE-P constitutive model (It only has single relaxation time) in estimating the apparent viscosity of two common viscoelastic fluids: polymer and surfactant solutions. The comparative results indicate the N-parallel FENE-P constitutive model can represent the apparent viscosity of polymer solutions more accurate than the traditional model in the whole range of shear rate (0.1s -1~1 000s -1 ), and the advantage is more noteworthy especially when the shear rate is higher (10s -1~1 000s -1 ). Despite both the proposed model and the traditional model can't capture the interesting shear thickening behavior of surfactant solutions, the proposed constitutive model still possesses advantage over the traditional one in depicting the apparent viscosity and first normal stress difference. In addition, the N-parallel FENE-P constitutive model demonstrates a better applicability and favorable adjustability of the model parameters.

Experimental and modeling study of hydrophobic associative polyacrylamide for enhanced oil recovery in carbonate reservoir

“…Since polymer molecules are more sensitive to enforced shear rates, which also reduce a degree of entanglements, minor viscosity with rising flow rates is the result [47]. The shear viscosity of a polymer increases as its molecular weight or concentration increases [48]. The viscosity of HAPAM, however, decreases with increasing concentration.…”

“…Shear viscosity and flow curve was studied under shear rate between (5-45) s -1 . The samples were allowed to rest for (48) hours to examine their shear resistance qualities, viscosity was measure under 25 °C and shear rate 7.2 s -1 . HAPAM solutions were aged chemically by being placed in an oven at 25, 50, and 65 °C for intervals of 2, 4, 10, 20, and 30 hours, respectively, while being sheared at a rate of 7.2 s -1 .…”

LES Study on High Reynolds Turbulent Drag-Reducing Flow of Viscoelastic Fluids Based on Multiple Relaxation Times Constitutive Model and Mixed Subgrid-Scale Model

“…To improve the computational accuracy of constitutive model needed for LES of viscoelastic turbulent flows, an N-parallel FENE-P model based on multiple relaxation times was proposed in our recent work [8]. As shown in Fig.…”

“…However, it is reported in some studies that the apparent viscosity calculated with Giesekus model and FENE-P model still deviated from experimental data to some extent, indicating an unsatisfactory accuracy [7]. Inspired by the fact that constitutive model with multiple relaxation times can better describe the relaxation-deformation of microstructures formed in viscoelastic fluid, an N-parallel FENE-P model based on multiple relaxation times was proposed in our recent work [8]. The comparison with experimental data shows the N-parallel FENE-P model can further improve the computational accuracy of rheological characteristics, such as apparent viscosity and first normal stress difference.…”