Paper Number
SE1                         My Program 

Session
Rheology and Sustainability for Energy and Production

Title
Coating and extrusion models for viscoelastic fluids

Presentation Date and Time
October 22, 2025 (Wednesday) 3:45

Track / Room
Track 2 / Sweeney Ballroom B

Authors (Click on name to view author profile)

  1. Ortiz, Weston (University of New Mexico)
  2. Rao, Rekha R. (Sandia National Laboratories)

Author and Affiliation Lines (in printed abstract book)
Weston Ortiz1 and Rekha R. Rao2
1University of New Mexico, Albuquerque, NM 87111; 2Sandia National Laboratories, Albuquerque, NM 87123

Speaker / Presenter 
Ortiz, Weston

Keywords
computational methods; flow-induced instabilities; industrial applications; non-Newtonian fluids; polymer melts

Text of Abstract
Viscoelastic materials are often found in many industrial coating processes from electrode inks to polymer melts and solutions. For these processes, a material is extruded from a die and subsequently deposited on a substrate. The material can often experience high shear-rates and stresses during deposition, which can result in unstable flow leading to defect formation. Computation fluid dynamics (CFD) models can be used to help inform process choices and find stable flows, such as determining the low flow limit for coating flows. CFD of viscoelastic flows can often be difficult due to both the increased computational costs and numerical issues like the high Weissenberg number problem (HWNP), where we see loss of convergence as the amount of elasticity in the fluid is increased. The simulations utilize a DEVSS/SUPG stabilized finite element formulation using a symmetric square root conformation tensor transformation for the viscoelastic constitutive equation, which can alleviate the HWNP and handle constitutive equations with multiple modes. An arbitrary-Lagrangian-Eulerian (ALE) approach is used for interface tracking of the evolving geometry. In this paper, we investigate several viscoelastic flows free surface flows relating to industrial processes, including die swell from fiber spinning, blade coating, film casting, and slide coating. When available, comparison to experimental results are shown.