M. F. Tomé -murilo@lcad.icmc.sc.usp.br
N. Mangiavacchi - norberto@lcad.icmc.sc.usp.br
A. Castelo - castelo@icmc.sc.usp.br
J. A. Cuminato - jacumina@lcad.icmc.sc.usp.br
A. Fortuna - fortuna@lcad.icmc.sc.usp.br
L. G. Nonato - nonato@lcad.icmc.sc.usp.br
L. Grossi - luciane@lcad.icmc.sc.usp.br
V. G. Ferreira - pvgf@lcad.icmc.sc.usp.br
Universidade de S˜ ao Paulo, Departamento de Ciencias de Computacao e Estatistica
Cx.P. 668 - 13560-161 - S˜ ao Carlos, SP, Brasil

Sean McKee - caas29@maths.strath.ac.uk
University of Strathclyde, Department of Mathematics
Glasgow, Scotland

This work presents a numerical technique for solving three-dimensional non-Newtonian free surface flows. It is an extension of the technique introduced by Tom´ e, McKee and Duffy (1996) to three dimensions. The governing equations are solved by the finite difference method on a staggered grid. It uses marker particles to describe the fluid which provides the location and visualization of the free surface. As currently implemented, the present method can simulate the flow of Cross and Power-law modelled fluids. Results demonstrating the capability of this technique for solving industrial problems are presented. In particular, results which simulate the flow of a non-Newtonian fluid jet impinging onto a flat surface are given.

Keywords: Free surface flows, Cross model, finite difference, non-Newtonian fluid
 
 

Oldrich Joel Romero - oldrich@mec.puc-rio.br
Márcio da Silveira Carvalho - msc@mec.puc-rio.br
Department of Mechanical Engineering; Pontifícia Universidade Católica do Rio de Janeiro.
Rua Marquês de São Vicente, 225. Gávea. Rio de Janeiro, RJ, 22453-900, Brazil.

Free surface flows on non Newtonian liquids occur in different industrial processes, such as coating, polymer extrusion, and many others. The complete understanding of the liquid flow is vital to the optimization of these important manufacturing processes. The use of appropriate constitutive models to describe the mechanical behavior of the liquid and the presence of the free surface make the problem highly complex. In this work, the performance of an algebraic viscoelastic model that is still able to predict elastic phenomenona, such as normal stress difference and variable extensional and shear viscosity in the flow exiting a slot is analyzed. It is well known that viscoelastic liquids present an exaggerated "swelling" as it exits the slot, phenomenon known as extrudate swell. The differential equations that describe the problem, i.e. the momentum, continuity and mesh generation equations for the unknown physical domain, were solved by the Galerkin's / finite element method. The resulting non-linear algebraic system was solved by Newton's method. The results show that the use of the appropriate algebraic model can capture the main features of the well studied elastic phenomenon at a much smaller computational cost.

Keywords: Viscoelastic liquids, extrudate swell, finite element method.
 
 

Cleber C. Costa - misticus@yahoo.com
Roberto G. Pereira - temrobe@vm.uff.br
Universidade Federal Fluminense, Departamento de Engenharia Mecânica
Rua Passos da Pátria, 156 - São Domingos - CEP: 24210-240 - Niterói, RJ, Brasil.

Mary R. Muniz - coapirio@uol.com.br
Cooperativa Apícola do Rio de Janeiro
Rua Presidente Castelo Branco, S/N o - Centro - CEP: 24030-260 - Niterói, RJ, Brasil.

In the apiculture are used two differents kinds of centrifuges that can be used to centrifugation of honey. The difference between these centrifuges is related with the arrangement of the honeycomb into the centrifuge. One of the centrifuges is named radial centrifuge, in this case the honeycombs are placed parallel to the centrifuge force axis. In the other models, the honeycombs are placed perpendicular to the centrifuge force axis. Some differences were observed between the honey centrifuged at both types. This work has as the main objective to determine the physical, chemistry and rheological variations to the some honey when centrifuged at both centrifuges. In the tests performed in this work was possible to observe a significant variation in the viscosity of honeys that was centrifuged at both centrifuges. Besides of the rheological tests, some other tests were investigated such  is: the honey moisture determination, an important parameter factor that it has an influence about the quality of honey, and the honey HMF determination. With this test one can know if the honey was warmed above 40 o C, that is the limit temperature to the honey not lost yours natural characteristics.

Keywords: Rheology, Foods, Honey, HMF, Moisture.
 
 

Roberto Carlos Gonçalves de Oliveira - rcgo@cenpes.petrobras.com.br
Carlos Henrique Monteiro de Carvalho - chmc@cenpes.petrobras.com.br
Marcia Cristina Khalil de Oliveira - macris@cenpes.petrobras.com.br
PETROBRAS/CENPES/DIPLOT
Quadra 7, CEP 21949-900, Ilha do Fundão, Rio de Janeiro, RJ, Brasil.

Flow problems associated to increased of the crude oil viscosity are well known by the oil companies. Part of these problems are related to the pour point; while others have to do with the presence of water in oil emulsions. In some cases these problems may also be associated with organic deposition in the transfer lines. Identifying the problem is therefore the key to find a solution for the problem. This paper describes a practical case where proper identification of the problem led to its solution means of adding chemical additives. The problem in question consisted of the need to increase the capacity to transfer crude oil from a certain export pipeline located on the Brazilian continental platform. Increasing the transferring capacity of this pipeline was complicated by construction limitations and the rheological characteristics of the fluid to be transferred. The experimental philosophy adopted in this paper can be put to use in other scenarios. It can be useful in many production systems specially in those which operate in high bathymetric levels.

Keywords: Crude oil emulsion, Emulsion properties, Emulsion rheology
 
 

João B. V. S. Ramalho - jramalho@cenpes.petrobras.com.br
PETROBRAS/CENPES/SEPROT - Prédio 20, sala 2014, Quadra 7, Cidade Universitária,
Ilha do Fundão - CEP: 21 949-900 - Rio de Janeiro, RJ, Brasil

During the process of crude oil production, it is common for emulsions to appear formed of drops of water dispersed in crude oil and stabilized by the presence of natural emulsifiers on the interface region. These emulsions present viscosity rates higher than the dehydrated crude oil and bear influence on the sizing of equipment used in the production, processing and transfer. As these emulsions grow older, the emulsifier adsorption on the surface increase, and consequently the emulsion gets more stable. The results of laboratory tests are presented, the emulsion being synthesized with 50% water content in volume, and the dynamic viscosity and efficiency of water-oil gravitational separation is evaluated on the first day the emulsion was prepared, and then after 15, 30, 45 and 60 days. An increase in viscosity and stability was observed as a result of the aging process.

Keywords: Aging, Emulsion, Viscosity, Stability
 
 

Carlos Henrique Monteiro de Carvalho - chmc@cenpes.petrobras.com.br
Roberto Carlos Gonçalves de Oliveira - rcgo@cenpes.petrobras.com.br
Petróleo Brasileiro, Centro de Pesquisa e Desenvolvimento Leopoldo A. Miquez de Mello
Quadra 7, Ilha do Fundão - 91494-900, Rio de Janeiro, RJ, Brasil

During the last decades, giant offshore crude oil reserves were discovered around the world. Most of them comprise heavy and high viscosity crude oils. During oil production, it is common to have co-production of emulsified water. The water may originate from the producing formation itself or be a consequence of recovery processes. The formation of water in oil emulsions (W/O) during production is highly undesirable due to the increase of the oil viscosity. Several studies have been carried out to prevent the formation of this type of emulsion or even to promote phase inversion production, creating oil in water emulsions (O/W) of low viscosity. In the present work experimental results are presented that show the influence of emulsion type on flow parameters. The flow parameters were evaluated from a flow simulator especially designed for this purpose.

Keyword: Emulsion, Viscosity emulsion, Flow emulsion, Type of emulsion, Heavy crude oil.
 
 

André L. Martins - aleibsohn@cenpes.petrobras.com.br
Carlos H. M. de Sá - chsa@cenpes.petrobras.com.br
Affonso M. F. Lourenço - affonso-lourenco@utulsa.edu
Valter S. Junior - vsj@cenpes.petrobras.com.br
PETROBRAS/CENPES/DIPLOT
Ilha do Fundão - Av. 1 - Q. 07 - Cidade Universitária - Rio de Janeiro - RJ - Brasil - 21949-900

O presente artigo descreve um esforço experimental extenso em analisar a estabilidade de espumas e suas propriedades reológicas para aplicações como fluido de perfuração leve. Os pontos principais do estudo foram: 1) a influência do tipo de espumante e concentração na reologia da espuma; 2) a influência da fração volumétrica de gás sobre as propriedades reológicas da espuma. Então, correlações simples foram propostas para quantificar o comportamento experimental. Além disso, testes de campo foram realizados para avaliar um dos agentes espumantes investigados em laboratório, utilizando-se 16 (dezesseis) combinações de vazões gás-líquido.

Palavras-chave: Reologia, Espuma, Perfuração, Poços de Petróleo
 
 

Mˆonica F. Naccache - naccache@mec.puc-rio.br
Paulo R. Souza Mendes - pmendes@mec.puc-rio.br
Department of Mechanical Engineering
Pontif´ýcia Universidade Cat´ olica-Rio de Janeiro, RJ 22453-900

A numerical simulation of heat transfer during the laminar °ow of viscoplastic materials through annular eccentric spaces was performed. This geometry is found in the drilling process of petroleum wells. The inner cylinder is adiabatic and rotates with a constant angular velocity|in order to account for rotation of the column|while at the outer wall a uniform heat °ux is imposed. The conservation equations together with the Generalized Newtonian Liquid (GNL) model are solved numerically via a ¯nite volume method, using FLUENT. In order to handle the numerical di±culties related to the Herschel-Bulkley viscosity function, the bi-viscosity model was used. The e(r)ects of angular velocity and eccentricity on the °ow pattern and heat transfer coe±cient are investigated.

Keywords: Viscoplastic muds, Heat transfer, Annular °ows
 
 

Marcelo Vaqueiro de Souza e Silva - mvaqueiro@bol.com.br
Universidade Federal Fluminense, Departamento de Engenharia Mecânica
Rua Passos da Pátria, n o 156 - São Domingos - Niterói - RJ - Brasil - CEP:24210-240
Telefone: (0xx21) 620-7070 - Ramal: 303

Roberto Guimarães Pereira - temrobe@vm.uff.br
Universidade Federal Fluminense, Departamento de Engenharia Mecânica
Rua Passos da Pátria, n o 156 - São Domingos - Niterói - RJ - Brasil - CEP:24210-240
Telefone: (0xx21) 620-7070 - Ramal: 359
 

In the present work it was investigated the rheological behaviour of a dental cream and a dental gel. The basic components of these two types of dentrificies are: abrasives, moisturiser agents, binding agents, surfactants, thickeners, sparkling, sweeteners, preservatives, artificial colouring, flavours and special active ingredients. The rheological proprieties of dentrifices has been obtained using a rotational rheometer HAAKE RS-50, being realised tests of controlled shear rate, stress sweep and frequency sweep. This kind of analysis allows the development of new formulations and allows the evaluation of products which already exists in the market.

Keywords: Rheology, Dentrificies and Formulations.
 
 

NON NEWTONIAN PROPERTIES OF EMULSIONS

Francisco Ricardo Cunha{ frc@orion.enm.unb.br
Aldo Joao de Sousa aldo@orion.enm.unb.br
Universidade de BrasiIia, Departamento de Engenharia Mecanica-FT
Campus Universitario, 70910-900 - Brasilia, DF, Brasil

Jerzy Blawzdziewicz { jerzy@taylor.enc.yale.edu
Michael Loewenberg { michael@taylor.eng.yale.edu
Yale University, Department of Chemical Engineering
New Haven, CT, 06520-8286, USA

In this paper, three-dimensional boundary integral computer simulations of emulsions in oscillatory shear ow will be described. We obtain results for ordered BCC emulsions with dispersed-phase volume fractions below the critical concentration °c = 68% (maximum packing for BCC). Complex rheological features including: shear-thinning viscosities, normal stress diferences, and a nonlinear frequency response are explored. We have derived analytical results for slightly deformed drops in diluted emulsions at arbitrary shear-rates, which is particularly relevant to drops with viscosity ratios beyond the critical value for breakup in shear. Using our analysis and numerical simulations, we also explore the limiting high shear-rate rheology of diluted emulsions with high viscosity drops.