Hydrodynamic drag reduction based on drop impact images

• Grant number: 05/00873-8
• Support Opportunities: Regular Research Grants
• Start date: January 01, 2006
• End date: March 31, 2008
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Edvaldo Sabadini
• Grantee: Edvaldo Sabadini
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• City of the host institution: Campinas

Abstract

The presence of very small amounts (ppm) of high-MW polymers in a solution produces high levels of drag reduction in a turbulent flow. This phenomenon, often termed as the Toms Effect, is highly dependent not only on MW, but also on the flexibility of the macromolecular chain. Several experimental techniques are usually used to quantify the levels of drag reduction, and to correlate with the molecular models. However , both, the experimental results and the theoretic models are still limited. Recently we have proposed a new experimental approach of the phenomenon, based on the evolution of the structures after a collision of a drop against a shallow liquid surface, both containing a drag reducing agent. In milliseconds after the drop impact, a crown and a cavity is impinged in the liquid surface, and the collapse of these structures produces a jet named as Rayleigh jet. We have demonstrated that the jet is highly sensitive to the elongational effects due to the presence of the polymer in the solution. The stretching-contraction dynamic of the polymer chain absorbs the dissipate energies of the small vortices created in within the flow, resulting in the drag reduction. The macroscopic effect can be visualised in the high amplitude of the Rayleigh jet. The main contribution of this new technique is the correlation between the rates of the fluid deformation and the macromolecular motion.In this project we intent to study this phenomenon with more details using a very fast CCD camera. The dynamic of the liquid deformation captured from the evolution of the splash will allow us to correlate different drag reducing agents (flexible and rigid particles) with the Elastic Theory to drag reduction. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

RODRIGUES, ROBERTA K.; FOLSTA, MAURICIO G.; MARTINS, ANDRE L.; SABADINI, EDVALDO. Tailoring of wormlike micelles as hydrodynamic drag reducers for gravel-pack in oil field operations. JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING, v. 146, p. 142-148, OCT 2016. (05/00873-8)

Filed patent(s) as a result of this research project