Modeling Asymmetric Flow of Viscoelastic Fluid in Symmetric Planar Sudden Expansion Geometry Based on User-Defined Function in FLUENT CFD Package

Abstract

Through embedding an in-house subroutine into FLUENT code by utilizing the functionalization of user-defined function provided by the software, a new numerical simulation methodology on viscoelastic fluid flows has been established. In order to benchmark this methodology, numerical simulations under different viscoelastic fluid solution concentrations (with solvent viscosity ratio varied from 0.2 to 0.9), extensibility parameters (100 ≤ 2 ≤ 500), Reynolds numbers (0.1 ≤ Re ≤ 100), and Weissenberg numbers (0 ≤ Wi ≤ 20) are conducted on unsteady laminar flows through a symmetric planar sudden expansion with expansion ratio of 1 : 3 for viscoelastic fluid flows. The constitutive model used to describe the viscoelastic effect of viscoelastic fluid flow is FENE-P (finitely extensive nonlinear elastic-Peterlin) model. The numerical simulation results show that the influences of elasticity, inertia, and concentration on the flow bifurcation characteristics are more significant than those of extensibility. The present simulation results including the critical Reynolds number for which the flow becomes asymmetric, vortex size, bifurcation diagram, velocity distribution, streamline, and pressure loss show good agreements with some published results. That means the newly established method based on FLUENT software platform for simulating peculiar flow behaviors of viscoelastic fluid is credible and suitable for the study of viscoelastic fluid flows.

A Fully Implicit Log-Conformation Tensor Coupled Algorithm for the Solution of Incompressible Non-Isothermal Viscoelastic Flows

“…Numerical simulations can describe these complex flow mechanisms and help to gain a better understanding of, and improvements in, the processes where they occur. For that purpose, Computational Fluid Dynamics (CFD) are used to guide the theoretical researchers and practitioner engineers, through the use of both open-source [ 3 , 4 , 5 , 7 , 19 ] and proprietary software [ 20 ]. In the last decade, a significant effort has been made in research on the non-isothermal flows of viscoelastic fluids.…”

Numerical study on the characteristics of natural supercavitation by planar symmetric wedge-shaped cavitators for rotational supercavitating evaporator

“…Preliminary numerical researches based on ANSYS FLUENT computational fluid dynamics (CFD) software have been conducted on the viscoelastic fluid flows [31,32]. For the absence of the constitutive model of viscoelastic fluid in ANSYS FLUENT code, FENE-P (finitely extensive nonlinear elastic-Peterlin) constitutive model was firstly embedded into ANSYS FLUENT by utilizing the functionalization of user-defined function (UDF) to describe the viscoelastic effect in the laminar flow of viscoelastic fluid [31].…”

“…For the absence of the constitutive model of viscoelastic fluid in ANSYS FLUENT code, FENE-P (finitely extensive nonlinear elastic-Peterlin) constitutive model was firstly embedded into ANSYS FLUENT by utilizing the functionalization of user-defined function (UDF) to describe the viscoelastic effect in the laminar flow of viscoelastic fluid [31]. And then…”

Conjugate Heat Transfer from Sudden Expansion Using Nanofluid

“…0), Moffatt eddies appear and gradually increase in size with increasing n and asymptotically reach a constant value above n % 3. Newtonian fluid as well as viscoelastic fluids is tested in sudden expansion using commercial software by integrating user defined function by Zheng et al [32]. In their study, they got good agreement with Newtonian fluid for wide range of Reynolds number; however, their FENE-P model results minor discrepancy with benchmark results.…”