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This paper aims to study the hybrid process of osmotic dehydration and convective air drying of foods. Emphasis has been put on cassava cubes (Manihot esculenta Crantz.). Convective drying kinetics of fresh and osmotically dehydrated cassava cubes was evaluated at the following hot air-drying conditions: temperature 50°C, velocity 1.35 m/s, and absolute humidity 0.060 dry water/g. Experimental results of the moisture loss, solids gain, and incorporation of sodium chloride are shown and analyzed. For estimation of the effective mass diffusion coefficient, experiment data of average moisture content of cassava cubes (fresh and osmotically dehydrated) was fitted to the simplified Fick model and a good agreement was obtained. The effective mass diffusivity of the osmotically dehydrated cassava cube was 2.75 x10-10 m2/s and to fresh cassava cubes 5.45x10-10 m2/s.

Environmental concern has encouraged development related to polluted water treatment. Produced water originated from oil exploration has been submitted to different separation processes such as settling tanks, floaters, two-phase and three-phase separators, hydrocyclones, and membranes. On the use of membranes, the goal is to separate soluble components from solutions based on the size, charge, shape, and molecular interactions between the solute and membrane surface. In the present work, a numerical study was developed on the oil-water mixture separation process using a porous ceramic membrane module. The mathematical model used in this research is composed of mass and momentum conservation equations coupled to Darcy ́s law and SST k-ω turbulence model. Simulations were carried out employing the Ansys CFX commercial software. Results of the pressure, velocity, oil concentration distribution inside the device and membrane are presented and discussed. The results showed that the geometric aspects of the proposed microfiltration module and the membrane distribution within the separation module had a significant influence on the hydrodynamic flow leading to polarized layer dispersion.

The objective of this work is to describe the fluid flow in porous media including the sorption term of the fluid by the fibers. The study has been applied to the manufacture of fiber-reinforced polymer composites by resin transfer molding, giving emphasis to radial resin infiltration in a one-dimensional approach. The mass conservation equation and Darcy’s law are presented and the solution of the governing equation is obtained. The advanced mathematical modeling includes the effect of fluid sorption by the porous media. Predicted flow front results and resin pressure fields within the mold during the injection process are presented, and the effects of the sorption term, injection pressure and fibrous medium permeability analyzed.

The study of heat transfer in fixed bed tubular reactors of heated or cooled walls has presented great interest by the academy and industry. The adequate and safe design of such equipment requires the use of reliable and realistic mathematical. Unfortunately several studies are restrict to homogeneous model applied to circular and elliptic cylindrical reactors. Then, the objective of this work was to predict heat transfer in packed-bed elliptic cylindrical reactor, by using a proposed heterogeneous model. The mathematical model is composed for one solid phase and another fluid phase, in which the balance equation for each constituent is applied separately. The finite volume method was utilized to solve the partial differential equations using the WUDS scheme for interpolation of the convective and diffusive terms, and the fully implicit formulation. Results of the temperature distribution of the fluid and solid phases along the reactor are presented and analyzed. It was verified that the highest temperature gradients of the phases are located close to the wall and inlet of the reactor.

This paper aims to study convective drying of industrial hollow bricks in a tunnel dryer. A transient mathematical model based on the heat and mass conservation equations applied to the air and brick was derived and the numerical solution (finite-volume method) of the governing equations is presented. Predicted and experimental data of the average moisture content and the temperature of the product during the drying process are compared and a good concordance was verified. Numerical results inside the bed confirm an almost null difference between the moisture content along the process. Similar behavior was verified to the product temperature. These results confirm an efficient drying process.

Drying is a complex process of coupledheat and mass transfer of wet porous material. Wet clay products when exposed to drying without control can suffer cracks and deformations, reducing its quality post-drying. Thus, this work aims to study the hollow ceramic materials drying with arbitrary shape using lumped models. Here, the exact solution of the governing equations were obtained using the method of separation of variables. Results of the average moisture constant and temperature of the material along the process are presented and analyzed. It was observed that the moisture loss process occurs at a lower speed than the heating of the ceramic material because its thermal diffusivity is greater than the mass diffusivity and that the area/volume relationship strongly affects the heat and mass transfer of the material.

This work presents a theoretical drying study of sisal fiber. Fibers with moisture content of around 11.2% were dried in an oven in the temperature 90°C. A transient and three-dimensional mathematical modeling to predict heat and mass transfer in a bed of fiber was proposed and numerically solved by using the finite-volume method. Results of the average moisture content and surface temperature were compared with experimental data to verify the consistence of the proposed model, and good agreement was verified.

Cashew is a fruit with high nutritional value and great economic importance in the Northeast region of Brazil, however, due to high moisture content, it is highly perishable. Freezing is one the most efficient methods for conservationof biological products, especially, fruits and vegetables. Then, the optimizationof the freezing process by numerical simulation is crucial. In this sense, the objective of this work was to investigate the influence of the moisture content on the cooling and freezing processes of cashew appleby using thecomputational fluid dynamics technique. Results of the cooling and freezing kinetics of the cashew apple and temperature distribution inside the fruitduring these processes are presented and analyzed. It was verified that the variation inthe initial moisture content had small effect in the total time of the process, however the samples with higher moisture content presented higher heat transfer rate during the cooling period and lesser during the freezing period.

This work presents a non-steady state and three-dimensional mathematical modeling to predict moisture transport (based on the Langmuir-Type Model) inside the vegetable fiber-reinforced composite materials. The numerical solutions of the governing equations have been obtain using the finite-volume method. The model was apply for vegetable fiber-reinforced polymer composites. Emphasis to the geometrical dimension effect of the composite in the water absorption process was given. Results of the average moisture content, free and entrapped water molecules concentration kinetics and free and entrapped water molecules concentration distributions inside the material along the process are shown and analyzed. In the distributions of the analyzed properties, it was observed that the geometric dimensions of the composite has influence in the water absorption process.

Rice (Oryza sativa L.) is one of the most produced and consumed cereals in the world, being characterized as the main food of more than half of the world population, since it is source of energy, protein, vitamins and minerals. Freshly harvested rice from the field generally has a high moisture content to be stored safely and, therefore, a suitable drying process needs to be conducted to decrease the physical-chemical activity of the product and inhibit the associated microbial activities. In this work, experiments were carried out on the intermittent drying of rice grains, in order to evaluate the effects of different drying air temperatures (40, 50, 60 and 70 °C) and tempering times (30, 60, 120, 180 and 240 min). Intermittent drying was simulated by means of a new liquid diffusion model based on a prolate spheroid geometry. To validate the model, the solution was fitted to the experimental data for the drying air temperatures of 40 and 70 °C and tempering periods ranging from 0 to 180 min. The results show that, for all experiments of intermittent drying of rough rice, the effective operating time decreased compared to the continuous drying. In addition, intermittent drying produces lower temperature on the grain surface, which minimizes the thermal damages caused to the product during the process. Numerical simulations provide information on moisture distribution inside the rice grain during the periods of interruption in hot air application. After 15 min of drying at temperatures of 40 and 70 °C, followed by a 60-min pause at room temperature, it is possible to respectively reduce about 72 and 68% of the moisture content gradients inside the rice grain. With tempering of 180 min, it is possible to eliminate almost all moisture content gradients for the drying at 70 °C.

This work aims to numerically study the moisture absorption in polymer composites reinforced with vegetal fiber, using the diffusive model of Langmuir, which considers the existence of water molecules inside the material free to diffuse and adsorb at the capillaries walls, in the solid. A three-dimensional and transient mathematical modelling to describe the water absorption process by the composite and its numerical solution via finite volume method are presented and discussed. Results of the free solute concentration, entrapped solute concentration, local moisture content and average moisture content obtained at different instants of the process are presented and analyzed. It was verified that the concentration gradients of the molecules (free and entrapped) are higher at the material surface. In addition, as the concentration of free water increases, there is also an increase in entrapped water concentration within the material at any time of the process.

Oil spill at sea by pipeline cracks can cause environmental damage. Knowledge of interfacial phenomena of immiscible liquids helps to study the dispersion of pollutants in oceans, favoring thus flow behavior of the forecast in the vicinity of the leak in submerged pipelines. This study aims to numerically study the leakage of behavior in a submerged pipeline carrying oil. It adopted a two-dimensional model based on mass conservation equations, linear momentum and the model k-ε standard turbulence. We used the Ansys CFX for meshing with 40,510 hexahedral elements. The results of pressure fields and volumetric fraction of oil are analyzed and discussed.

The oil industry has sought to minimize the environmental impact from mining activities and oil transportation. Oil transportation by pipelines is subject to failures and leaks which cause financial losses and environmental damage, often irreparable. Currently, the study of leaks in pipelines has attracted the attention of many researchers. The aim of this study is to evaluate the influence of the curved curvature radius connection in pipeline leakage. We used a mathematical model of multiphase flow to describe the two-phase flow, based on the particle model. Oil is the continuous phase while water a dispersed phase. To model this effect we used the turbulence model SST. All simulations were carried out using the Ansys CFX ® commercial code. Results of the total pressure and pressure drop are presented and discussed. The results confirm the influence of the bending radius of curved connection on the behavior of the total pressure and the total pressure drop in two-phase flow in pipelines with and without leakage.

Oil transport is used mainly by pipeline networks to transport oil from refineries and distributions points to the consumers. This is the main way to transport oils especially in areas of difficult access, ensuring efficiency, lowest cost and safety. In the chemical and petroleum industry it is possible to observe the presence of leak in the pipes, which has stimulated the development of reliable techniques for the rapid and accurate detection of leaks along the pipe in order to eliminate or minimize loss and environmental damage. In this context, this study aims to evaluate the effect of the numerical presence of leakage of two-phase flow (oil-water) pipe connections using the commercial software ANSYS CFX. The results from the fields of pressure, velocity and volume fraction are presented and assessed for illustrating the effect of the presence of the leak in the dynamic flow in the pipe with a curved connection.

The growing global demand for energy has led researchers to seek the improvement of technology in order to maximize the generation of electricity by different ways. Among the different methods of production is the energy produced by thermal power plants, which account for more than 60% of the energy produced in the world. This energy is generated through combustion of fuels such as coal, diesel oil, natural gas and others. The main problem caused by the production of thermal energy is the emission of gaseous pollutants into the atmosphere, such as carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides (NOx), and also particulate matter which causes environmental problems such as acid rain, greenhouse effect, and health problems, especially respiratory diseases. Computational fluid dynamics (CFD) is presented as an important tool in solving problems involving the dispersion of chemicals into the atmosphere. In this sense, this study aims to evaluate the thermofluid dynamics of pollutants’ dispersion emitted from the chimney of a thermal power plant, based on numerical simulations using the Ansys CFX 12.0 commercial code. Fields of velocity and mass concentration of the component involved in the process are presented and analyzed.

The growing demand for oil brings the need for discovery of deeper reservoirs, especially of ultra-deepwater reservoirs. Thus, production in marine systems using components such as risers (flexible or rigid pipes) has been the focus of many studies in different areas. These ducts are used in the transportation of multiphase fluids (oil, water and gas) produced from the oil well located on the seabed to the platform surface. Due to the extreme conditions present in the offshore fields of production, the equipments that transport produced fluids operate close to their limits. So eventually, the flexible pipes may have structural integrity faults like leaks, which can cause production losses, accidents with victims and environmental disasters. The leak depends of a number of properties or parameters measured at the site of the leak, for example, integrity of the pipe material, release of fluids and noise emission characteristics or manifestation of some other type of signal behavior, variation of pressure drops close to the leak, among others. There are a variety of techniques available for detecting leaks, among which there is the mathematical modeling approach using computational techniques. In this context, this paper aims to study the fluid dynamics of a transient multiphase flow in a catenary riser in the presence of leakage. Herein a 3D Eulerian-Eulerian model was applied, including the turbulent model (RNG k-ε), using the commercial package ANSYS CFX® 15 to perform all simulations. The numerical results of velocity, volume fraction and pressure of the involved phases are presented and discussed.

The onshore and offshore production of oil and natural gas is characterized by the multiphase flow in ducts and pipes, which are interconnected by various equipments such as wellhead, pumps, compressors, processing platforms, among others. The transport of oil and oil products is essential to the viability of the sector, but is susceptible to failures, that can cause great environmental damage. Considering this necessity of the transportation sector of oil and derivatives, leakage in pipelines with curved connections, are the object of study for various researchers. In this sense, this work contributes to the study of three-phase flow (oil-water-gas) in a curved pipe (90°) using Computational Fluid Dynamics. The physical domain is constituted by two tubes of 4 meters trenched by a 90° curve, with the poring whole in the curvated accessory. The mathematical model is based on a particle model, where the oil is considered as a continuous phase and the water and gas as a particulate phase. The SST (Shear Stress Transport) turbulence model was adopted. All simulations were carried out using the Ansys CFX® 12.1 commercial code. Results of the pressure, velocity and volumetric fraction of the phases are presented and discussed.

This work presents an experimental study on the behavior of clays during the drying process. Experimental tests were carried out with clay material for the production of red ceramics and white ceramic (ball clay). Different dimensions and the material initial moisture content plus temperature and relative air-drying humidity were taken into account. Drying kinetics and volume changes of parallelepiped-shaped samples were shown and analyzed. It has been verified that air-drying temperatures and body shape have an enormous influence on the drying rate process. The drying process occurs during the falling drying period and the volume changes display two linear periods.

This work aims to investigate the infiltration of a CaCO3filled resin in fibrous porous media (resin transfer molding process) using the PAM-RTM software. A preform of glass fiber mat (fraction 30%), with dimensions 320 x 150 x 3.6 mm, has been used in rectilinear injection experiments conducted at room temperature and injection pressure 0.25, 0.50 and 0.75 bar. The polyester resin contain 0% and 40% CaCO3. The numerical results were evaluated by direct comparison with experimental data. The flat flow-front profile of the rectilinear flow was reached approximately half length of the mold. It was observed, that the both velocity infiltration and permeability have decreased with increasing the CaCO3content, thus, increasing the time to processing of the composite material.

This paper aims to present an experimental study of rough rice (BRSMG CONAI cultivar) drying by using a stationary method. The grain was dried in an oven with air mechanical movement under controlled conditions of velocity, temperature and relative humidity. In order to obtain balanced moisture content, the samples studied were kept at 40 and 70°C. Results of the drying and heating kinetics of the grain during the process are shown and analyzed. It was found that higher drying rate and lower time for drying as higher air temperature (70°C) is used. It can be concluded that the reduction of the moisture content of the grain, is considered very complex and, depending on the method and drying conditions, can substantially provokes breaking and cracks, which reduces final product quality.

This work aims to study convective drying of ellipsoidal solids. Aplication has been done to drying of wheat Kernel. Diffusion equation in cylindrical coordinates has been solved via Galerkin-based integral method considering convective boundary conditions and constant thermo-physical properties. Results of the temperature and moisture content are presented and compared with wheat experimental drying data at relative humidity 33.8 % and temperature 47.0°C. It was verified that heat transfer in the drying process occurs much faster than the mass transfer, thus providing a rapid heating of the product, which reduces grain quality.

This paper aims to present a mathematical model, based on the thermodynamics of irreversible processes to describe both the heat and mass transfer (liquid and vapor) during the drying of bodies with oblate spheroidal shape. The model was applied to describe drying of lentil grain, considering variables transport coefficients and convective boundary conditions at the surface of the solid. All equations were presented in oblate spheroidal coordinates and numerically solved by using the finite-volume method. Results of the average moisture content, average temperature, liquid flux, vapor flux, and moisture content and temperature distributions inside a lentil kernel during drying process (T=40 oC, RH=50% and v=0.3 m/s) were presented and analyzed.

The aim of this research is to study the pollutant emissions of the commercial diesel engine, operating with B5 (commercial diesel), B70, B80, B90 and natural gas. The fuel used in the engine consists of a mixture of 15% diesel and biodiesel (liquid fuel) and 85% natural gas. Experiments were made using 40, 60 and 80 kW load. The engine was instrumented to obtain the temperature, air, gas and diesel (plus biodiesel) flow rates, the air pressure at the entrance of the engine, the lubricant oil temperature, and the concentration of exhaust gases during each experimental test. It was verified that the emission of NOx, NO and CO2 had decreased while the emissions of CO and SO2 had increased, when compared to the conditions using standard diesel (B5) alone.

The purpose of this paper is to present an experimental study of clay brick drying. For the drying experiments, industrial holed bricks were dried in an oven under controlled conditions of velocity, temperature (constant and variable) and relative humidity of air. The continuous drying experiments ended when the mass reached constant weight. Experimental tests were performed under atmospheric pressure. Results of the drying and heating kinetics and volume variations during the process are shown and analyzed. It was verified that the drying process happens in the falling drying rate period, and air temperature has large influence in the drying rate during process. It was verified that the largest temperature, moisture content and stress gradients are located in the vertexes of the brick.

RTM process is widely used for the production of high quality fiber reinforced composites parts. Computer simulations can play an important role in optimization of RTM processes by reducing risks and costs. In this paper, we present a two dimensional mathematical modelling for the mold filling stage in RTM process. It was used a two phase model (air-resin) which neglects the capillary and gravitational effects and considers all phases incompressible. The set of partial differential equations, expressed in boundary-fitted coordinates, are discretized by using the finite volume method and solved using a fully implicit methodology and the Newton's method. To validate the methodology, numerical and experimental data of the filling time and flow front position along the process are compared and good agreement was obtained.

Studies in polymer composites reinforced with vegetable fiber show that they are enough sensitive to influences from environmental agents such as water and temperature. The moisture causes degradation of the mechanical properties of natural fiber reinforced composites to a large extent when compared to synthetic fiber reinforced composites. This is a consequence of the higher moisture absorption, and the hydrofilic nature of the natural fiber. In this sense, the purpose of this work is to study theoretically the water absorption in unsaturated polyester composites reinforced with caroá natural fiber (Neoglazioviavariegata) at the temperature 50°C. The composite had a weight composition of 30% caroá and 70% unsaturated polyester resin and dimensions of 20× 20× 3 mm3. Results of the average moisture content and moisture content distribution during the absorption process are presented and analyzed. Comparison between numerical and experimental data of the average moisture content presented good agreement. We conclude that the water absorption rate is faster in the vertex region of the composites.

This work aims to investigate the infiltration of a CaCO3filled resin using experiments and the PAM-RTM software. A preform of glass fiber mat, with dimensions 320 x 150 x 3.6 mm, has been used for experiments conducted at room temperature, with injection pressure of 0.25bar. The resin contained 10 and 40% CaCO3content with particle size 38μm. The numerical results were evaluated by direct comparison with experimental data. The flat flow-front profile of the rectilinear flow was reached approximately halfway the length of the mold. It was observed, that the speed of the filling decreases with increasing CaCO3content and,the higher the amount of CaCO3in the resin, the lower the permeability of the reinforcement that is found. The reduction in permeability is due to the presence of calcium carbonate particles between the fibers, hindering the resin flow in the fibrous media. The computational fluid flow analysis with the PAM-RTM proved to be an accurate tool study for the processing of composite materials.

Resin Transfer Molding (RTM) is one of the most widely known composite manufacturing techniques of the liquid molding family, being extensively studied and used to obtain advanced composite materials comprised of fibers embedded in a thermoset polymer matrix. Nowadays, RTM is used by many industrial sectors such as automotive, aerospace, civil and sporting equipment. Therefore, the objective of this study is to verify the effect of calcium carbonate mixed in resin in the RTM process. Several rectilinear infiltration experiments were conducted using glass fiber mat molded in a RTM system with cavity dimensions of 320 x 150 x 3.6 mm, room temperature, maximum injection pressure 0.202 bar and different content of CaCO3 (10 and 40%) with particle size of 75μm. The results show that the use of filled resin with CaCO3 influences the preform impregnation during the RTM molding, changing the filling time and flow from position, however it is possible to make the composite with a good quality and low cost.

The transport of oil and its derivates is mainly done through pipelines linking the oil fields, refineries and distribution networks to consumers. They are considered the best, safe and economical way to fluids transportation over long distances. Despite significant advances in the development of lighter and stronger materials for the construction of pipelines and the growing number of gas and oil pipelines, many problems of leaks have been observed, which has encouraged the development of reliable techniques to inspect and detect quickly and accurately possible leaks along these pipelines. The goal is to eliminate or minimize damage to the oil industry and mainly to the environment. In this context, this paper aims to study the thermo-fluid dynamics of a transient three-phase flow (oil, water and gas) in a horizontal pipe in the presence of a leakage at different positions. Herein it was applied a 3D Eulerian-Eulerian model, including the transient turbulent model (RNGk-ε), using the ANSYS CFX®12.1 commercial package to perform all simulations. Numerical results of velocity, pressure and volume fraction fields of the involved phases are presented and discussed.

The oil industry has sought to minimize the environmental impact from mining activities and oil transportation. The oil transportation by pipeline is subject to failures and leaks that cause financial losses and environmental damage, often irreparable. In this sense, the aim of this study is to evaluate the influence of the leak diameter in the behavior of the two-phase flow (oil and water) in a pipe. A transient and incompressible multiphase flow mathematical model based on the particle model was used here. Oil is the dispersed phase while water is the continuous phase. To model the turbulence effect it was used the standard k-ε model. All simulations were carried out using the Ansys CFX® commercial code. Results of the pressure, velocity and volumetric fraction of the phases are presented and discussed. The results confirm the difficulty to detect leakage with small diameters.

In recent years, attention has been given to the processes controlling the emission of oily effluents and their environmental impact. Many industrial processes generate large volumes of water contaminated with oil, called oily waters. The oily water must be treated before its discard in order to meet the criteria established by environmental agencies (for example in Brazil, 20 mg/L). In present days, the process of separating oil/water with ceramic membranes has attracted the attention of many researchers [1,2]. In this sense, the aim of this study is to evaluate the influence of the tangential inlet shape in the oil/water separation via ceramic membranes. We use a mathematical multiphase flow model to describe the oil-water separation, based on the particle model. Here oil is the dispersed phase while water the continuous phase. To model the turbulence effect we use the RNGk-εmodel. All simulations were carried out using the Ansys CFX ® commercial code. Results of streamlines and velocity, pressure and volume fraction of phase fields are present and analyzed. The numerical results indicate that no significant difference when using a circular or rectangular pipe with the same cross-sectional area.

Multiphase flows commonly occur in the production and transportation of oil, natural gas and water. In this type of flow, the phases can flow in different spatial configurations disposed inside the pipe, so called multiphase flow patterns. The identification of flow patterns and the determination of the pressure drop along the pipe lines for different volumetric flows are important parameters for management and control of production. In this sense, this work proposes to numerically investigate the non-isothermal multiphase flow of a stream of ultraviscous heavy oils containing water and natural gas in submerged risers (catenary) via numerical simulation (ANSYS CFX 11.0). Results of the pressure, volumetric fractions and temperature distributions are presented and analyzed. Numerical results show that the heat transfer was more pronounced when using the largest volume fraction of gas phases.

The study of heat transfer phenomenon in porous media by fluids percolated in the axial direction has been of interest to many researchers in various branches of science and technology. Applications are directed to different process such as filtration, distillation, absorption and adsorption in columns, drying and catalytic reactions in fixed beds. The literature has presented several solutions of the heat diffusion / convection equation in fixed bed reactors, but these studies are limited to a cylindrical geometry. In this sense, this work aim to present a pseudo-homogeneous three-dimensional model to describe the steady-state heat transfer within a fixed bed reactor with elliptic cylindrical geometry by considering variable porosity. The energy equation written in elliptical cylindrical coordinates and applied to the porous medium (particulate system) is discretized numerically using the finite volume method. Results of the temperature distribution within the bed are presented analyzed. It was verified that with increased porosity heat transfer inside the reactor tends to be more intense and thus, lower temperature gradients are found in all cross section of the reactor.

Drying can be defined as a simultaneous heat and mass transfer process between product and air drying. These phenomena have occurred due to thermal and moisture gradients and they are affected by different parameters. The inadequate management of this process can cause severe damage to the product such as cracking, loss of nutritional properties and even loss of the product quality. Thus, this paper proposes a numerical study of heat and mass transfer that occurs during the rough rice drying process, using the commercial software ANSYS CFX®. Herein the grain was considered as ellipsoid of revolution.

In this work, a numerical solution for the diffusion equation applied to solids with arbitrary shape considering convective boundary condition is presented. To this end, the diffusion equation, written in generalized coordinates, was discretized by the finite-volume method with a fully implicit formulation. The transport parameters and the dimensions of the solids are considered constant during all process. For each time step, the system of equations obtained for a given non-orthogonal structured mesh was solved by the Gauss-Seidel method. One computational code was developed in FORTRAN, using the CFV 6.6.0 Studio, in a Windows platform. The proposed solution was validated using analytical and numerical solutions of the diffusion equation for different geometries (parallelepiped and finite cylinder). The analysis and comparison of the results showed that the proposed solution provides correct results for the cases investigated. In order to verify the potential of the proposed numerical solution, we used experimental data of the drying of ceramic roof tiles for the following temperature: T = 55.6 °C. The analysis of the results and the statistical indicators enables to affirm that the developed numerical solution satisfactorily describes the drying processes in this temperature for the convective boundary condition.

This article proposes a numerical solution for the diffusion equation applied to solids with arbitrary geometry using non-orthogonal structured grids for the boundary condition of the first kind. A transient three-dimensional mathematical formulation written in boundary fitted coordinates and numerical formalism to discretize the diffusion equation by using the finite volume method, including numerical analysis of the computational solution are presented. To validate the proposed solution, the results obtained in this work were compared with well-known numerical solution available in literature and good agreement was observed. In order to verify the potential of the proposed numerical solution, it was applied to describe mass transfer inside ceramic roof tiles during drying. For that, it was used experimental data of the drying kinetics at the following temperatures: 55.6; 69.7; 82.7 and 98.6 °C. An optimization technique using experimental dataset has been presented to estimation of transport properties. The obtained statistical indicators enable to conclude that the numerical solution satisfactorily describes the drying processes.

This research is to obtain nanocomposites of HDPE/bentonite clay. Inorganic polymers reinforced with materials are of great interest due to their applications in automotive, and electrical and electronic industries. The nanocomposites were produced by melt intercalation with different percentages of clay and compared with pure HDPE. Clay was used as modified and unmodified and it was characterized by X-ray diffraction (XRD) and X-ray fluorescence (XRF). The obtained nanocomposites were characterized through thermogravimetry (TG). It was verified by XRF that clay performed compositions of bentonites characteristics. By XRD, it was observed increases basal spacing for organoclay. By TG, in general, it was verified that the nanocomposites presented greater thermal stability in relation to HDPE.

This paper presents a theoretical investigation of the mass transfer during the drying of solids of revolution with arbitrary shape. A two-dimensional mathematical model by assuming the liquid diffusion to be the sole mechanism of moisture transport, constant thermophysical properties and convective boundary condition at the surface of the solid is presented. The resulting equation is solved analytically by using the Galerkin-based integral method. Results of the mean moisture content and moisture content distribution within the porous solid are present and analyzed during the process, for different Biot number and aspect ratio. We conclude that solid drying rate is affected by Biot number and area/volume relationships, and which drying process is faster in sharp areas and closed to surface of the solid.

The purpose of this paper is to present an experimental study of brick drying. For the drying experiments, industrial brick (clay) was dried in an oven under controlled conditions of air velocity, air temperature and air relative humidity. The continuous drying experiments ended when the mass reached constant weight. In order, to obtain the balanced moisture content, each sample was kept under the same drying air temperature for 48 hours inside the oven. The tests were performed under atmospheric pressure. Results of the drying and heating kinetics and volume variations during the process are shown and analyzed. It was verified that air temperature has big influence in the drying rate during process. It was verified that the largest temperature, moisture content and stress gradients are located in the vertexes of the brick. The drying process happens in the falling drying rate period.

The aim of this work is to study theoretically the effect of porosity of an oil reservoir with arbitrary geometry on the oil recovery factor. A two-dimensional mathematical modeling (Black-oil model) and numerical solution applied to two-phase flow (water-oil) into the reservoir with irregular geometry including water injection is presented. The conservation equations written in generalized coordinates are solved using the finite volume method, with a fully implicit technique. Results of the pressure and saturation distributions and oil recovery factor over time are presented and evaluated for different values of porosity of the reservoir.

This work presents a three-dimensional numerical solution for the diffusion equation in transient state, in an arbitrary domain. For this end, the diffusion equation was discretized using the finite volume method with a fully implicit formulation and generalized coordinates, for the equilibrium boundary condition. For each time step, the system of equations obtained for a given structured mesh was solved by the Gauss-Seidel method. The computational code was developed in FORTRAN, using the CFV 6.6.0 Studio, in a Windows platform. The proposed solution was validated using analytical and numerical solutions of the diffusion equation for different geometries (orthogonal and non-orthogonal meshes). The analysis and comparison of the results showed that the proposed solution provides correct results for the cases investigated. The developed computational code was applied in the simulation of the drying of ceramic roof tiles for the following temperature: 55.6 °C. The analysis of the results makes it possible to affirm that the developed numerical solution satisfactorily describes the drying processes in this temperature.

Resin Transfer Moulding (RTM) as it is most known process in the Resin Injections family, is an extensively studied and used processing method. This process is used to manufacture advanced composite materials made of fibres embedded in a thermoset polymer matrix. Fibre reinforcement in RTM processing of polymer composites is considered as a fibrous porous medium regarding its infiltration by the polymer resin. In this sense, the present work aims the computational analysis of a fluid in a porous media for a RTM composite moulding by using the ANSYS CFX® commercial software. In order to validate the numerical study of the fluid flow in a known RTM system, experiments was carried out in laboratory to characterize the fluid (vegetal oil) flowing into the porous media (0/90 glass fibre woven), were pressure and fibre volume fraction have been fixed. The numerical simulation provides information about volume fraction, pressure and velocity distribution of the phases (resin and air) inside the porous media. The predicted results were compared with the experimental data and its has shown a solid relationship between them.

The main objective of this article is to describe the drying process of ceramic roof tiles, shaped from red clay, using diffusion models. Samples of the product with initial moisture content of 0.24 (db) were placed inside an oven in the temperatures of 55.6, 69.7, 82.7 and 98.6°C; and the data of the drying kinetics were obtained. The analytical solutions of the diffusion equation for the parallelepiped with boundary conditions of the first and third kinds were used to describe the drying processes. The process parameters were determined using an optimization algorithm based on inverse method coupled to the analytical solutions. The analysis of the results makes it possible to affirm that the boundary condition of the third kind satisfactorily describes the drying processes. The values obtained for the convective mass transfer coefficient were between 8.25 × 10−7 and 1.64 × 10−6 m s−1, and for the effective water diffusivity were between 9.21 × 10−9 and 1.80 × 10−8 m2 s−1.

In this paper, the influence of the geometric representation of samples of a composite material on the description of its water absorption is studied. It is supposed that diffusion models with boundary condition of the first kind satisfactorily describe the absorption, and that the volume and effective mass diffusivity are constant during the process. The geometries used to represent the samples are: infinite slab, rectangular plate and parallelepiped. The effective mass diffusivity is determined by coupling of the analytical solution corresponding to the model to an optimizer based on the inverse method. For the dimensions of the samples, based on statistical indicators obtained in the simulation of each model, it can be concluded that the best geometric representation is the parallelepiped. However, if there is no interest about the moisture distribution within the sample and the only objective of the research is to describe the water absorption kinetics, the infinite slab can also be used.

The world has been witnessing a growing interest in heavy oil fields as a result of a reduction in conventional oil reserves. In this sense, this work aims to study numerically the process of heavy oil recovering in oil reservoir via water injection. Transient three-dimensional numerical simulations, considering isothermal and non-isothermal processes, were performed using the ANSYS CFX 11 commercial code, and its effects upon the oil recovery factor evaluated. The numerical results indicated an increase of 29% (non-isothermal case) and 18% (isothermal case) in the recovery factor when water was injected on the reservoir surface as compared to the water internal injection in the reservoir.

The Aim of this Work Is to Present a Three-Dimensional Mathematical Modelling to Predict Heat and Mass Transport inside the Industrial Brick with Rectangular Holes during the Drying Including Shrinkage and Hygrothermalelastic Stress Analysis. the Numerical Solution of the Diffusion Equation, Being Used the Finite-Volume Method, Considering Constant Thermo-Physical Properties and Convective Boundary Conditions at the Surface of the Solid, it Is Presented and Analyzed. Results of the Temperature, Moisture Content and Stress Distributions, and Drying and Heating Kinetics Are Shown and Analyzed. Results of the Average Moisture Content and Surface Temperature of the Brick along the Drying Process Are Compared with Experimental Data (T = 80.0oC and RH = 4.6 %) and Good Agreement Was Obtained. it Was Verified that the Largest Temperature, Moisture Content and Stress Gradients Are Located in the Intern and External Vertexes of the Brick.

The hydrocyclone is an alternative for produced water treatment in the petroleum industries, especially at offshore fields. Many parameters, such as oil droplet diameter affect the separation performance of the hydrocyclone. In this sense, the purpose of this work is study the effect of oil droplet diameter and inlet fluid on the separation efficiency of a hydrocyclone to remove dispersed heavy-oil from a water continuous stream. Results of the streamline, pressure drop, volume fraction and efficiency of separation as a function of oil droplet diameter and feed velocity are presented and analyzed.

This paper proposes a numerical solution for the diffusion equation with convective boundary condition applied to solids obtained through the revolution of arbitrary bi-dimensional geometries, using generalized coordinates. The diffusion equation was discretized using the finite volume method, with a fully implicit formulation. The solution exploits symmetry conditions and that decreases the computational effort demanded, in comparison to the traditional use of three-dimensional grids. The proposed solution was used to describe diffusion processes which have a well-known solution. There was a good agreement among the results obtained through the proposed solution and the correspondent analytical solutions, as well as the experimental data.