Historically, the addition of polymers to turbulent flows of Newtonian fluids has been known to effectively reduce turbulent friction drag by up to 80 %. Conducted in the Hydrodynamics Laboratory in Virginia Tech, this research presents a comprehensive analysis into drag reducing effects through experimental, theoretical, and computational analyses. A major focus of this research was the evaluation of one of the newest viscoelastic Reynolds Averaged Navier-Stokes (RANS) turbulence models. Based on the k−ε−v 2−f framework, this model describes the viscoelastic effects of polymer additives using the Finitely Extensible Nonlinear Elastic-Peterlin (FENEP) constitutive model. To evaluate its accuracy, multiple simulation scenarios were benchmarked against Direct Numerical Simulation (DNS) data. Results indicated, that the viscoelastic RANS turbulence model shows a high accuracy against DNS percentages of drag reduced when dealing with higher solvent viscosity to polymer viscosity ratios, but revealed inconsistencies at lower ratios. Additionally, our theoretical and empirical flow rates from the inclined channel were closely aligned. The results of this study highlight the significant capacity of polymer additives to improve energy efficiency in industries that heavily rely on fluids / Master of Science / In fluid dynamics, understanding the behaviour of fluids under different conditions can unlock solutions to many engineering challenges. An area of much interest is the introduction of polymers to turbulent flows. The addition of polymers to turbulent flows can effectively dampen turbulence, leading to reduced drag. Our research, conducted at Virginia Tech's Hydrodynamics Laboratory, engaged in further study regarding this phenomena. We employed one of the latest viscoelastic computational models to predict drag reduction in polymer additive flows. This advanced model operates on the foundation of certain mathematical constructs, taking into account various parameters associated with polymeric solutions. By comparing our model's predictions with high-end direct numerical simulations (DNS), we found it to be highly accurate, especially when the base fluid had a much higher viscosity than the polymer additives. But, it's worth noting that the model showed some deviations in cases where this viscosity difference was less pronounced. Furthermore, our tests also showcased a close alignment between predicted and observed flow rates in an inclined channel setup. Our findings underscore the potential of polymers to revolutionize industries, enhancing energy efficiency in processes that involve fluid flows
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/116522 |
| Date | 18 October 2023 |
| Creators | Clares Pastrana, Jorge Arturo |
| Contributors | Aerospace and Ocean Engineering, Paterson, Eric G., Roy, Christopher J., Brizzolara, Stefano |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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