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Projeto de investigação
Rheokinematic formulation and process design of biomaterials for footwear
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Literature Review on Single and Twin-Screw Extruders Design for Polymerization Using CFD Simulation
Publication . Delvar, Elham; Oliveira, Inês; Brito, Margarida S. C. A.; Silva, Cláudia G.; Santamaria-Echart, Arantzazu; Barreiro, M.F.; Santos, Ricardo J.
This work presents a comprehensive review of the evolution in modeling reactive
extrusion (REx), tracing developments from early analytical models to advanced computational
fluid dynamics (CFD) simulations. Additionally, it highlights the key challenges
and future directions in this field. Analytical models to describe the velocity profiles were
proposed in the 1950s, involving certain geometrical simplifications. However, numerical
models of melt polymeric flow in extruders have proven to be crucial for optimizing screw
design and predicting process characteristics. The state-of-the-art CFD models for single
and twin-screw extruders design address the impact of geometry (type of mixing elements
and geometrical simplifications of CFD geometries), pressure and temperature gradients,
and quantification of mixing. Despite the extensive work conducted, modeling reactive
extrusion using CFD remains challenging due to the intricate interplay of mixing, heat
transfer, chemical reactions, and non-Newtonian fluid behavior under high shear and temperature
gradients. These challenges are further intensified by the presence of multiphase
flows and the complexity of extruder geometries. Future advancements should enhance
simulation accuracy, incorporate multiphase flow models, and utilize real-time sensor data
for adaptive modeling approaches.
Contributions to accelerating a numerical simulation of free flow parallel to a porous plane
Publication . Schepke, Claudio; Spigolon, Roberta A.; Rufino, José; Cristaldo, Cesar F. Da C.; Pizzolato, Glener L.
Flow models over flat p orous surfaces have applications in natural processes, such as material, food, chemical processing, or mountain mudflow simulations. The development
of simplified a nalytical or numerical models can predict characteristics such as velocity, pressure, deviation length, and even temperature of such flows for geophysical and engineering purposes. In this context, there is considerable interest in theoretical and experimental models. Mathematical models to represent such phenomena for fluid mechanics have continuously been developed and implemented. Given this, we propose a mathematical and simulation model to describe a free-flowing flow pa rallel toa
porous material and its transition zone. The objective of the application is to analyze the influence o f t he p orous matrix on the flow u nder d ifferent m atrix p roperties. W e i mplement a Computational Fluid Dynamics scheme using the Finite Volume Method to simulate and calculate the numerical solutions for case studies. However, computational applications of this type demand high performance, requiring parallel execution techniques. Due to this, it is necessary to modify the sequential version of the code. So, we propose a methodology describing the steps required to adapt and improve the code. This approach decreases 5.3% the execution time of the sequential version of the code. Next,
we adopt OpenMP for parallel versions and instantiate parallel code flows and executions on multi-core. We get a speedup of 10.4 by using 12 threads. The paper provides simulations that offer the correct understanding, modeling, and construction of abrupt transitions between free flow a nd porous media. The process presented here could expand to the simulations of other porous media problems. Furthermore, customized simulations require little processing time, thanks to parallel processing.
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Fundação para a Ciência e a Tecnologia
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Número da atribuição
2023.01245.BD