The Viscoelastic Swirled Flow in the Confusor
Aidar Kadyirov1, Rinat Zaripov1, Julia Karaeva1
1Institute of Power Engineering and Advanced Technologies, FRC Kazan Scientific Center, Russian Academy of Sciences, 420111 Kazan, Russia.
Polymers
|March 6, 2021
Summary
This study models viscoelastic fluid flow in a confusor, finding swirl intensity primarily affects circumferential velocity. Swirl intensity decreases exponentially along the flow path.
Area of Science:
- Fluid Dynamics
- Rheology
- Polymer Science
Background:
- Viscoelastic fluid behavior is complex and crucial in polymer processing.
- Confusor flows with swirl present unique challenges in modeling.
- The Giesekus model is a common approach for describing non-Newtonian fluid dynamics.
Purpose of the Study:
- To develop a 2D mathematical model for steady, swirled, viscoelastic laminar flow in a confusor.
- To analyze the impact of swirl intensity on velocity profiles and normal stress differences.
- To propose a method for determining nonlinear parameters of the Giesekus model.
Main Methods:
- Developed a two-dimensional mathematical model for viscoelastic flow.
- Employed a two-mode Giesekus model to describe low-density polyethylene.
- Validated the model against literature special cases.
- Proposed a system of equations for parameter estimation.
Main Results:
- Increased swirl intensity (Wi < 5.1) affects only circumferential velocity; axial and radial velocities remain constant.
- The first normal stress difference (N1) increases along the confusor, peaking at the exit.
- Swirl intensity exhibits an exponential decrease, quantified by dimensionless damping coefficients.
Conclusions:
- The developed model accurately captures viscoelastic flow behavior in a confusor under swirl.
- Swirl significantly influences velocity distribution and normal stress development.
- The proposed parameter estimation method aids in accurate constitutive model application.
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