Project/scholarship details
- Project/scholarship ID
113988
- Reference
PTDC/EME-MFE/113988/2009
- FundRef URI
- Funder
FCT - Fundação para a Ciência e a Tecnologia, I.P.
- Funder's country
Portugal
- Funding program
5876-PPCDTI
- Funding amount
81,000.00 €
- Start date
2011-03-01
- End date
2014-10-31
Documents
Implementation of slip boundary conditions in the finite volume method : new te...
Ferrás, Luís Jorge Lima; Nóbrega, J. M.; Pinho, F. T.Two different techniques for the implementation of the linear and nonlinear slip boundary conditions into a finite volume method based numerical code are presented. For the linear Navier slip boundary condition, an implicit implementation in the system of equations is carried out for which there is no need for any relaxation, especially when handling high slip coefficients. For three different nonlinear slip bo...
Effect of polymer melt wall slip on the flow balance of profile extrusion dies
Carneiro, O. S.; Ferrás, Luís Jorge Lima; Pinho, Fernando T.; Nóbrega, J. M.This work describes the implementation of the wall slip boundary condition in an in-house developed 3D numerical code based on the Finite Volume Method. For this purpose, several phenomenological models relating the velocity and the shear stress at the wall were implemented. This new feature is verified using a simple case study, by comparing the numerical results with those obtained through the corresponding a...
Analytical and numerical study of the electro-osmotic annular flow of viscoelas...
Ferrás, Luís Jorge Lima; Afonso, A. M.; Alves, M. A.; Nóbrega, J. M.; Pinho, F. T.In this work we present semi-analytical solutions for the electro-osmotic annular flow of viscoelastic fluids modeled by the Linear and Exponential PTT models. The viscoelastic fluid flows in the axial direction between two concentric cylinders under the combined influences of electrokinetic and pressure forcings. The analysis invokes the Debye-Hückel approximation and includes the limit case of pure electro-os...
Comparison of different numerical methods for the solution of the time-fraction...
Morgado, M.L.; Ferrás, Luís Jorge Lima; Rebelo, M.In this work we perform a comparison of two different numerical schemes for the solution of the time-fractional diffusion equation with variable diffusion coefficient and a nonlinear source term. The two methods are the implicit numerical scheme presented in [M.L. Morgado, M. Rebelo, Numerical approximation of distributed order reaction- diffusion equations, Journal of Computational and Applied Mathematics 275 ...
Design and optimization of an extrusion die for the production of wood–plastic ...
Gonçalves, Nelson Daniel Ferreira; Teixeira, P.; Ferrás, Luís Jorge Lima; Afonso, A. M.; Nóbrega, J. M.; Carneiro, O. S.In this work, the optimization of an extrusion die designed for the production of a wood–plastic composite (WPC) decking profile is investigated. The optimization was performed with the help of numerical tools, more precisely, by solving the continuity and momentum conservation equations that govern such flow, and aiming to balance properly the flow distribution at the extrusion die flow channel outlet. To capt...
Fractional bioheat equation
Ferrás, Luís Jorge Lima; Ford, N. J.; Morgado, M. L.; Nóbrega, J. M.; Rebelo, M.In this work we develop a new mathematical model for the Pennes’ bioheat equation assuming a fractional time derivative of single order. A numerical method for the solu- tion of such equations is proposed, and, the suitability of the new model for modelling real physical problems is studied and discussed; COMPETE, FEDER and Fundação para a Ciência e a Tecnologia (the Portuguese Foundation for Science and Techno...
Development of a new 3D OpenFOAM® solver to model the cooling stage in profile ...
Fernandes, C. S.; Habla, F.; Carneiro, O. S.; Hinrichsen, O.; Nóbrega, J. M.[Excerpt] The advantages resulting from the use of numerical modelling tools to support the design of processing equipment are almost consensual. The design of calibration systems in profile extrusion is not an exception . H owever , the complex geome tries and heat exchange phenomena involved in this process require the use of numerical solvers able to model the heat exchange in more than one domain ( calibrat...
Development of a new 3D openFOAM (R) solver to model the cooling stage in profi...
Fernandes, Célio Bruno Pinto; Habla, F.; Carneiro, O. S.; Hinrichsen, O.; Nóbrega, J. M.; Rhee, BIn this work a new solver is developed in OpenFOAM computational library, to model the cooling state in profile extrusion. The solver is able to calculate the temperature distribution in a two domain system, comprising the profile and calibrator, considering the temperature discontinuity at the interface. The derivation of the model is based on the local instantaneous energy conservation equation, in conjunctio...
Prototype system to study the effect of weld lines on the performance of extrud...
Carneiro, O. S.; Mota, A. R.; Sitotaw, Y.; Nóbrega, J. M.In several thermoplastic extrusion based processes the melt flow has to be divided into independent streams that are merged before the flow channel outlet. This promotes the formation of weld lines, usually related to mechanical weak zones and aesthetic imperfections. There is a large amount of scientific publications related to weld lines formed in other processing techniques, e.g. injection molding. However, ...
A numerical and theoretical study on viscoelastic fluid slip flows
Ferrás, Luís Jorge Lima; Afonso, A. M.; Nóbrega, J. M.; Pinho, F. T.This work describes a theoretical and numerical investigation of viscoelastic fluid flows, considering slip boundary conditions. The viscoelastic fluid is described by the simplified Phan-Thien-Tanner model, and the governing equations with slip boundary conditions are solved by a finite volume method using (1) a recently proposed methodology to control the growth of the slip velocity along the iterative proces...
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