Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.104
L. C. Carvalho, A. G. Barbosa de Lima, V. D. de Miranda, J.M. Freitas de Oliveira, E. S. de Lima
The shape memory alloys have been used in the most different sectors such as aerospace, automotive and biomedical due to their ability to return to their original shape when subjected to high temperatures. Modeling and numerical simulation have become great allies in engineering due to the possibility of solving complex problems, especially in cases where experimental research is limited. In the present study, a two-dimensional mathematical model was developed to describe the solidification process of a Ni-Ti alloy in stainless steel metal mold sand confined. It was considered the flow of a refrigerant fluid (air) in the top of the mold. The energy conservation equation, including the phase change term, was discretized using finite volume method (FVM) and a fully implicit formulation. Results of the Ni-Ti alloy and mold temperature distributions over time are presented and analyzed. It was verified that results are independent of the mesh size and time step. The last point to be solidified is located at the top left corner of the study domain and the temperature distribution over time proved to be satisfactory for the absence of internal defects, such as voids, cracks, residual stresses and macro segregation.
{"title":"Solidification of Ni-Ti Shape Memory Alloy: Modeling and Simulation","authors":"L. C. Carvalho, A. G. Barbosa de Lima, V. D. de Miranda, J.M. Freitas de Oliveira, E. S. de Lima","doi":"10.4028/www.scientific.net/DF.24.104","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.104","url":null,"abstract":"The shape memory alloys have been used in the most different sectors such as aerospace, automotive and biomedical due to their ability to return to their original shape when subjected to high temperatures. Modeling and numerical simulation have become great allies in engineering due to the possibility of solving complex problems, especially in cases where experimental research is limited. In the present study, a two-dimensional mathematical model was developed to describe the solidification process of a Ni-Ti alloy in stainless steel metal mold sand confined. It was considered the flow of a refrigerant fluid (air) in the top of the mold. The energy conservation equation, including the phase change term, was discretized using finite volume method (FVM) and a fully implicit formulation. Results of the Ni-Ti alloy and mold temperature distributions over time are presented and analyzed. It was verified that results are independent of the mesh size and time step. The last point to be solidified is located at the top left corner of the study domain and the temperature distribution over time proved to be satisfactory for the absence of internal defects, such as voids, cracks, residual stresses and macro segregation.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125846901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.145
A. Azevedo, J. Delgado, A. S. Guimarães, I. Ribeiro
After intensifying the knowledge of hygric permeance (HP) in multi-layered test samples, which were subjected to the imbibition process, a significant set of HP values (with different interface types) was experimentally achieved. This was done in order to develop a new model which allows estimating more correctly the hygric permeance. The idea is predicts the HP with several scenarios, i.e., different interfaces (perfect contact, hydraulic contact and air space interface), interfaces heights and materials studied, in the attempt to estimate the HP without the need to resort to the measurement by the experimental route in the attempt to estimate the HP without the need to resort to the measurement by the experimental route and even with possible measurement, generator automatic calculation (without human opinion/criteria). In this paper, the Hygric Permeance will be calculated by two different methods, gravimetric and gamma ray methods, and a new methodology proposes. The maximum flows transmitted were determined by the slope of the mass variation per contact area in function of the time involved. When having interface, the calculations admit that the first layer is saturated and that all the increased weight stems becomes from the relative humidity that penetrates the interface. The new methodology proposed is analysis of the prevision mathematical model that describes the mass variation per contact area in function of the time, after the “knee point”. This work it is the first attempt to provide a set of values that refer from hygric permeance in masonry of building walls, these being random values experimentally determined.
{"title":"Hygric Permeance - New Calculation Methodology","authors":"A. Azevedo, J. Delgado, A. S. Guimarães, I. Ribeiro","doi":"10.4028/www.scientific.net/DF.24.145","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.145","url":null,"abstract":"After intensifying the knowledge of hygric permeance (HP) in multi-layered test samples, which were subjected to the imbibition process, a significant set of HP values (with different interface types) was experimentally achieved. This was done in order to develop a new model which allows estimating more correctly the hygric permeance. The idea is predicts the HP with several scenarios, i.e., different interfaces (perfect contact, hydraulic contact and air space interface), interfaces heights and materials studied, in the attempt to estimate the HP without the need to resort to the measurement by the experimental route in the attempt to estimate the HP without the need to resort to the measurement by the experimental route and even with possible measurement, generator automatic calculation (without human opinion/criteria). In this paper, the Hygric Permeance will be calculated by two different methods, gravimetric and gamma ray methods, and a new methodology proposes. The maximum flows transmitted were determined by the slope of the mass variation per contact area in function of the time involved. When having interface, the calculations admit that the first layer is saturated and that all the increased weight stems becomes from the relative humidity that penetrates the interface. The new methodology proposed is analysis of the prevision mathematical model that describes the mass variation per contact area in function of the time, after the “knee point”. This work it is the first attempt to provide a set of values that refer from hygric permeance in masonry of building walls, these being random values experimentally determined.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123566946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.61
J. L. de Oliveira, A. G. Barbosa de Lima, R. Pereira Ramos, H. L. Fernandes Magalhães, W. R. Gomes dos Santos, S. R. de Farias Neto
In the oil industry, pipelines (circular ducts) are widely used for the transportation of oil and yours derived. Because of their advantages, such as low operating cost and increased safety during transportation, pipelines have become indispensable for transporting oil in large quantities and for long distances. As an alternative to this problem, the transport of oil and water can be accomplished using ducts with an elliptical cross-section. Thus, this work has the objective of studying the flow of oil and water in cylindrical ducts with an elliptical cross-section by using the Ansys CFX software. Results of the velocity, pressure and volumetric fraction distributions of the oil and water phases are presented and analyzed. By applying the same inlet velocity to oil and water, revealed that the elliptical duct, with aspect ratio equal to 5.0, has a pressure drop less (84.2%) than the pressure drop obtained for one duct of circular cross-section (aspect ratio equal to 1.0).
{"title":"Two-Phase Flow (Oil and Water) in Ducts with the Elliptical Cross-Section: Modeling and Simulation","authors":"J. L. de Oliveira, A. G. Barbosa de Lima, R. Pereira Ramos, H. L. Fernandes Magalhães, W. R. Gomes dos Santos, S. R. de Farias Neto","doi":"10.4028/www.scientific.net/DF.24.61","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.61","url":null,"abstract":"In the oil industry, pipelines (circular ducts) are widely used for the transportation of oil and yours derived. Because of their advantages, such as low operating cost and increased safety during transportation, pipelines have become indispensable for transporting oil in large quantities and for long distances. As an alternative to this problem, the transport of oil and water can be accomplished using ducts with an elliptical cross-section. Thus, this work has the objective of studying the flow of oil and water in cylindrical ducts with an elliptical cross-section by using the Ansys CFX software. Results of the velocity, pressure and volumetric fraction distributions of the oil and water phases are presented and analyzed. By applying the same inlet velocity to oil and water, revealed that the elliptical duct, with aspect ratio equal to 5.0, has a pressure drop less (84.2%) than the pressure drop obtained for one duct of circular cross-section (aspect ratio equal to 1.0).","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127840891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.121
R. M. da Silva, A. S. Pereira, V. D. de Miranda, J.M. Freitas de Oliveira, A. G. Barbosa de Lima
In this work a transient three-dimensional mathematical model was developed using cylindrical-elliptic coordinate system and thermo-physical properties as functions of the position or temperature. The aim is to predict heat transfer in an elliptic-cylindrical fixed bed reactor subjected to a chemical reaction of first order whose heat of reaction is given by the power law. The governing equation of the phenomenon is solved using the finite volume method, and the WUDS interpolation scheme, and the fully implicit method. Results are presented and discussed by varying reagent concentration, Arrhenius pre-exponential factor and reagent temperature at the reactor inlet. It was found that: first-order reactions at low molar concentrations have few effect in the temperature distribution and high molar concentrations, from 0.8 kmol/m3, increase the radial temperature gradients; an increase in the inlet temperature of reactor favours the increase in the heating zone in the centre of the equipment, but does not significantly alter the radial temperature gradients; the Arrehnius pre-exponential factor varying in the same order of magnitude as the concentration of reagents practically produces the same field of temperature in the reactor,
{"title":"Heat Transfer in a Fixed Bed Elliptic-Cylindrical Reactor: A Pseudo-Homogeneous Model with First-Order Chemical Reaction Term","authors":"R. M. da Silva, A. S. Pereira, V. D. de Miranda, J.M. Freitas de Oliveira, A. G. Barbosa de Lima","doi":"10.4028/www.scientific.net/DF.24.121","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.121","url":null,"abstract":"In this work a transient three-dimensional mathematical model was developed using cylindrical-elliptic coordinate system and thermo-physical properties as functions of the position or temperature. The aim is to predict heat transfer in an elliptic-cylindrical fixed bed reactor subjected to a chemical reaction of first order whose heat of reaction is given by the power law. The governing equation of the phenomenon is solved using the finite volume method, and the WUDS interpolation scheme, and the fully implicit method. Results are presented and discussed by varying reagent concentration, Arrhenius pre-exponential factor and reagent temperature at the reactor inlet. It was found that: first-order reactions at low molar concentrations have few effect in the temperature distribution and high molar concentrations, from 0.8 kmol/m3, increase the radial temperature gradients; an increase in the inlet temperature of reactor favours the increase in the heating zone in the centre of the equipment, but does not significantly alter the radial temperature gradients; the Arrehnius pre-exponential factor varying in the same order of magnitude as the concentration of reagents practically produces the same field of temperature in the reactor,","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130519881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.37
H. L. Fernandes Magalhães, G. Moreira, B. R. de Brito Correia, R. Soares Gomez, A. G. Barbosa de Lima, S. R. de Farias Neto
One of the main challenges related to the oil industry is the conscious disposal of effluents from the stages of oil exploration and production. The treatment of the water produced originated these processes has become a challenge for the sector. The membrane filtration technique emerges as an important tool in the treatment of these oily waters, due to their good characteristics, such as uniformity in permeate quality and long shelf life. In this work, a 2D mathematical model was developed, using computational fluid dynamics (CFD) as tool for the evaluation of the water-oil separation process in a tubular ceramic membrane. Linear momentum, energy, and mass conservation equations were used, which were solved using the commercial package ANSYS CFX® 15. The results obtained demonstrate that the developed model was able to predict the behavior of the water/oil separation process through the membrane, evidencing the influence of the oil particle size under the formation of the polarization layer by concentration, as well as, allowed to verify the importance of the temperature and the retention index of the solute under the permeation velocity and system performance.
{"title":"Thermo-Fluid Dynamics Analysis of the Oil-Water Separation Using Ceramic Membrane","authors":"H. L. Fernandes Magalhães, G. Moreira, B. R. de Brito Correia, R. Soares Gomez, A. G. Barbosa de Lima, S. R. de Farias Neto","doi":"10.4028/www.scientific.net/DF.24.37","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.37","url":null,"abstract":"One of the main challenges related to the oil industry is the conscious disposal of effluents from the stages of oil exploration and production. The treatment of the water produced originated these processes has become a challenge for the sector. The membrane filtration technique emerges as an important tool in the treatment of these oily waters, due to their good characteristics, such as uniformity in permeate quality and long shelf life. In this work, a 2D mathematical model was developed, using computational fluid dynamics (CFD) as tool for the evaluation of the water-oil separation process in a tubular ceramic membrane. Linear momentum, energy, and mass conservation equations were used, which were solved using the commercial package ANSYS CFX® 15. The results obtained demonstrate that the developed model was able to predict the behavior of the water/oil separation process through the membrane, evidencing the influence of the oil particle size under the formation of the polarization layer by concentration, as well as, allowed to verify the importance of the temperature and the retention index of the solute under the permeation velocity and system performance.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126872097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.25
H. L. Fernandes Magalhães, E. M. Cabral, T.E. da Silva Freitas, V. A. A. Brandão, A. G. Barbosa de Lima, S. R. de Farias Neto
Hydrocyclones are equipment that offer various advantages and have been the subject of studying for many researches related to separation processes of gas-solid, solid-liquid, and liquid-liquid mixtures. The purpose of this work is to study the oil-water separation process in a hydrocyclone by Computational Fluid Dynamics (CFD). Results of the pressure, velocity and volume fraction fields inside the device are presented and analyzed. It was possible to conclude that the proposed mathematical model was able to predict separation performance and the three-dimensional behavior of the phases flow analyzed (water/oil) in the hydrocyclone.
{"title":"Hydrodynamic Study of the Water/Oil Separation Process in a Hydrocyclone: Modeling and Simulation","authors":"H. L. Fernandes Magalhães, E. M. Cabral, T.E. da Silva Freitas, V. A. A. Brandão, A. G. Barbosa de Lima, S. R. de Farias Neto","doi":"10.4028/www.scientific.net/DF.24.25","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.25","url":null,"abstract":"Hydrocyclones are equipment that offer various advantages and have been the subject of studying for many researches related to separation processes of gas-solid, solid-liquid, and liquid-liquid mixtures. The purpose of this work is to study the oil-water separation process in a hydrocyclone by Computational Fluid Dynamics (CFD). Results of the pressure, velocity and volume fraction fields inside the device are presented and analyzed. It was possible to conclude that the proposed mathematical model was able to predict separation performance and the three-dimensional behavior of the phases flow analyzed (water/oil) in the hydrocyclone.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132517505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.11
B. R. de Brito Correia, G. Moreira, H. L. Fernandes Magalhães, M.K. Teixeira de Brito, A. G. Barbosa de Lima
Oil reservoirs are porous and permeable rocks that allow the hydrocarbon accumulation. Reservoir simulations are necessary to obtain the best fluid flow conditions in the porous medium and increase oil recovery capacity. The aim of this paper was to study the influence of the absolute rock permeability on the oil recovery of a complex geometry oil reservoir, using water injection with the black oil model. Numerical simulations in boundary-fitted coordinates were performed in a two-dimensional and irregularly shaped reservoir. Finite volume method was used to solve the governing equations and two inverted five-spot meshes were set in parallel for a total injection time of 30 years. Results of injected porous volume per recovered oil volume, the water cut charts and the water saturations maps showed that the lower porous medium permeability increased the oil recovery, once the permeability intensified fingers and early breakthrough, which leads to high water production rates and consequent reduction of the waterflooding efficiency.
{"title":"Waterflooding Process in an Irregularly Shaped Oil Reservoir: A Finite-Volume Approach","authors":"B. R. de Brito Correia, G. Moreira, H. L. Fernandes Magalhães, M.K. Teixeira de Brito, A. G. Barbosa de Lima","doi":"10.4028/www.scientific.net/DF.24.11","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.11","url":null,"abstract":"Oil reservoirs are porous and permeable rocks that allow the hydrocarbon accumulation. Reservoir simulations are necessary to obtain the best fluid flow conditions in the porous medium and increase oil recovery capacity. The aim of this paper was to study the influence of the absolute rock permeability on the oil recovery of a complex geometry oil reservoir, using water injection with the black oil model. Numerical simulations in boundary-fitted coordinates were performed in a two-dimensional and irregularly shaped reservoir. Finite volume method was used to solve the governing equations and two inverted five-spot meshes were set in parallel for a total injection time of 30 years. Results of injected porous volume per recovered oil volume, the water cut charts and the water saturations maps showed that the lower porous medium permeability increased the oil recovery, once the permeability intensified fingers and early breakthrough, which leads to high water production rates and consequent reduction of the waterflooding efficiency.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123323759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.76
B. Lopes, V. D. de Miranda, J.M. Freitas de Oliveira, A. G. Barbosa de Lima, S. J. dos Santos Filho, F. Farias
Mining is a relevant economic activity in many countries. In the treatment of ores, water is an indispensable input. For classification of minerals, the mineral industry uses the hydrocyclone process, where water is used as the medium for transporting dispersed ore particles, that are separated from the liquid by centrifugal force inside anequipmentnamed hydrocyclone.The constant advance of computers processing power, the evolution in the techniques and numerical methods, allow to simulate with great precision complex physical problems of fluid dynamics such as flow in hydrocyclones.In this sense, this work aims to analyze the performance of a concentrating hydrocyclone in the separation of ore and water by CFD. In the fluid dynamics simulation, the Eulerian-Lagrangian approach and the Ansys Fluent software were used. Results of pressure, velocity, and volumetric fraction fields of theinvolved phases are presented and evaluated. From the analysis of the results, it was observed that increasing the flow mixture velocity at the entrance of the equipment tends to increase the separation performance of the hydrocyclone.
{"title":"Solid - Liquid Separation Process in Hydrocyclone by CFD","authors":"B. Lopes, V. D. de Miranda, J.M. Freitas de Oliveira, A. G. Barbosa de Lima, S. J. dos Santos Filho, F. Farias","doi":"10.4028/www.scientific.net/DF.24.76","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.76","url":null,"abstract":"Mining is a relevant economic activity in many countries. In the treatment of ores, water is an indispensable input. For classification of minerals, the mineral industry uses the hydrocyclone process, where water is used as the medium for transporting dispersed ore particles, that are separated from the liquid by centrifugal force inside anequipmentnamed hydrocyclone.The constant advance of computers processing power, the evolution in the techniques and numerical methods, allow to simulate with great precision complex physical problems of fluid dynamics such as flow in hydrocyclones.In this sense, this work aims to analyze the performance of a concentrating hydrocyclone in the separation of ore and water by CFD. In the fluid dynamics simulation, the Eulerian-Lagrangian approach and the Ansys Fluent software were used. Results of pressure, velocity, and volumetric fraction fields of theinvolved phases are presented and evaluated. From the analysis of the results, it was observed that increasing the flow mixture velocity at the entrance of the equipment tends to increase the separation performance of the hydrocyclone.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131496911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.131
T. N. Porto, A. G. Barbosa de Lima, R. Soares Gomez, T. de Andrade, G. Santos de Lima, N. Lima Tresena, W. B. D. de Lima
The development of materials with specific properties is a relevant engineering topic. The composite materials, hybrid of metal structures embedded in polymer matrices, are intensively used in mechanical systems in order to obtain materials with high resistance associated to low weight. To fabricate these materials, it is necessary to inject the polymeric resin in a liquid state in mold cavity, which characterizes a multiphase flow as the air present in the mold is repelled by strategically projected outlets. In this sense, a correct knowledge of the flow mechanisms existing in the molding process is necessary to guide the parts manufacture. Through the Ansys FLUENT® software, this work performs a mathematical modeling of the resin transient flow inside a mold where metal wires are located and presents a numerical solution that describes, through calculations of volumetric fractions, velocity and pressure fields, and the fluid dynamic aspects that characterize the liquid molding process. It has been observed that the pressure required to maintain the constant flow at the mold inlet is increased until 80s of the process, when the steady state condition is achieved, that there is a greater resistance to mold filling in the side regions close to the mold wall due to the metal wires arrangement and that the air removal velocity that occurs due to resin injection becomes very low from the moment that resin reaches the mold outlets.
{"title":"Resin-Air Two-Phase Flow in Injection Molding Processes: An Application to Polymeric Composite Containing Embedded Metal Wires","authors":"T. N. Porto, A. G. Barbosa de Lima, R. Soares Gomez, T. de Andrade, G. Santos de Lima, N. Lima Tresena, W. B. D. de Lima","doi":"10.4028/www.scientific.net/DF.24.131","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.131","url":null,"abstract":"The development of materials with specific properties is a relevant engineering topic. The composite materials, hybrid of metal structures embedded in polymer matrices, are intensively used in mechanical systems in order to obtain materials with high resistance associated to low weight. To fabricate these materials, it is necessary to inject the polymeric resin in a liquid state in mold cavity, which characterizes a multiphase flow as the air present in the mold is repelled by strategically projected outlets. In this sense, a correct knowledge of the flow mechanisms existing in the molding process is necessary to guide the parts manufacture. Through the Ansys FLUENT® software, this work performs a mathematical modeling of the resin transient flow inside a mold where metal wires are located and presents a numerical solution that describes, through calculations of volumetric fractions, velocity and pressure fields, and the fluid dynamic aspects that characterize the liquid molding process. It has been observed that the pressure required to maintain the constant flow at the mold inlet is increased until 80s of the process, when the steady state condition is achieved, that there is a greater resistance to mold filling in the side regions close to the mold wall due to the metal wires arrangement and that the air removal velocity that occurs due to resin injection becomes very low from the moment that resin reaches the mold outlets.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133422282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.4028/www.scientific.net/DF.24.1
A. Azevedo, A. J. Costa e Silva, J. Delgado, F.M. Vieira, M. Souza
Mortar bond covering systems are multilayered and applied to a base, composed of render mortars (stucco, plaster) followed by some decorative element for a finishing touches (paint, ceramic plate, ornamental stones, etc.). In order to homogenize the characteristics of the base material and to increase the bond with the render mortar, it is a common practice to apply some type of preparation, either an even, smooth solution such as wetting the walls, or roughened solution utilizing roughcast. Studies have shown that the presence of calcium ions in ceramic bases results in the formation of a more dense crystalline structure at the interface, which culminates with higher mechanical bond strength. In this light, the present study presents an experimental investigation, the purpose of which is to evaluate, in a comparative way, the direct tensile strength of bond of a mortar coating applied to the same base, preceded in its application by five different preparation techniques. It can be concluded from this study that the preparation of the mortar base is of fundamental importance for bonding strength and, therefore, the addition of a lime solution to the roughcast is economically feasible and a satisfactory alternative in order to obtain positive results in environments where bond strength is critical.
{"title":"Influence of Lime Solution on the Bonding Strength of a Mortar Coating Base","authors":"A. Azevedo, A. J. Costa e Silva, J. Delgado, F.M. Vieira, M. Souza","doi":"10.4028/www.scientific.net/DF.24.1","DOIUrl":"https://doi.org/10.4028/www.scientific.net/DF.24.1","url":null,"abstract":"Mortar bond covering systems are multilayered and applied to a base, composed of render mortars (stucco, plaster) followed by some decorative element for a finishing touches (paint, ceramic plate, ornamental stones, etc.). In order to homogenize the characteristics of the base material and to increase the bond with the render mortar, it is a common practice to apply some type of preparation, either an even, smooth solution such as wetting the walls, or roughened solution utilizing roughcast. Studies have shown that the presence of calcium ions in ceramic bases results in the formation of a more dense crystalline structure at the interface, which culminates with higher mechanical bond strength. In this light, the present study presents an experimental investigation, the purpose of which is to evaluate, in a comparative way, the direct tensile strength of bond of a mortar coating applied to the same base, preceded in its application by five different preparation techniques. It can be concluded from this study that the preparation of the mortar base is of fundamental importance for bonding strength and, therefore, the addition of a lime solution to the roughcast is economically feasible and a satisfactory alternative in order to obtain positive results in environments where bond strength is critical.","PeriodicalId":311581,"journal":{"name":"Diffusion Foundations","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129362169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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