A. Thomas, B. Abbès, Yu Ming Li, F. Abbès, J. Duval
Constant demands of light-weighting have forced many industries to resort to manufacturing practices that promise a component with a higher strength-to-weight ratio. Hot forging is one such method used to produce parts using difficult-to-form materials as well as to achieve complex geometries. Although numerical methods provide an efficient means to predict the material yield and the stress/strain states of the product at different stages of forming and classical methods are accurate enough to provide a suitable representation of the process, they tend to be computationally expensive. This limits their use in process optimization studies. The Pseudo Inverse Approach (PIA) developed in the context of 2D axisymmetric cold forming, provides a quick and fairly accurate estimate of the stress and strain fields in the final product for a given initial shape. In this work, the PIA is extended to include the thermal and viscoplastic effects associated with the hot forging process. The results are compared with commercially available software based on the classical approaches to show the efficiency and the limitations of PIA.
{"title":"Thermo-viscoplastic numerical modeling of metal forging process by Pseudo Inverse Approach","authors":"A. Thomas, B. Abbès, Yu Ming Li, F. Abbès, J. Duval","doi":"10.1051/meca/2020002","DOIUrl":"https://doi.org/10.1051/meca/2020002","url":null,"abstract":"Constant demands of light-weighting have forced many industries to resort to manufacturing practices that promise a component with a higher strength-to-weight ratio. Hot forging is one such method used to produce parts using difficult-to-form materials as well as to achieve complex geometries. Although numerical methods provide an efficient means to predict the material yield and the stress/strain states of the product at different stages of forming and classical methods are accurate enough to provide a suitable representation of the process, they tend to be computationally expensive. This limits their use in process optimization studies. The Pseudo Inverse Approach (PIA) developed in the context of 2D axisymmetric cold forming, provides a quick and fairly accurate estimate of the stress and strain fields in the final product for a given initial shape. In this work, the PIA is extended to include the thermal and viscoplastic effects associated with the hot forging process. The results are compared with commercially available software based on the classical approaches to show the efficiency and the limitations of PIA.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"530 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74217909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X. Xu, Hongwei Ge, Jijun Deng, Jibo Wang, Renxiang Chen
Herringbone planetary gear system (HPGS) has high power density and complex structure. The torsional flexibility of the left and right teeth of the sun gear is closely related to the dynamic characteristics of the HPGS. In this research, considering the coordination conditions of both sides torsional stiffness and axial slide of the sun gear, a new dynamic model of the HPGS considering the meshing phase difference between left and right teeth of the sun gear is developed based on the lumped-parameter method, and the influence mechanism of torsional stiffness and axial sliding is studied. Moreover, the dynamic parameters and dynamic characteristics of the HPGS are analyzed in the case of varying torsoinal stiffness and axial slide. The results show that the torsional stiffness of left and right teeth and the axial slide of sun gear have significant impacts on the dynamic parameters and dynamic mesh force response. With the increase of the torsional flexibility (the decrease the torsional stiffness), the sun gear and planet gear meshing stiffness and the maximum tooth surface load are both increased on the left side (input side) and decreased on the right side, but the main peak values and peak frequencies of dynamic response on both sides of the s-p meshing pairs decrease significantly. In addition, when the sun gear slides toward the output side axially, meshing stiffness and dynamic mesh force response main peak values decreased on the left side (input side) and increased on the right side, but the main resonance peaks frequencies keep the same.
{"title":"An investigation on dynamic characteristics of herringbone planetary gear system with torsional flexibility between the left and right teeth of the sun gear","authors":"X. Xu, Hongwei Ge, Jijun Deng, Jibo Wang, Renxiang Chen","doi":"10.1051/meca/2020074","DOIUrl":"https://doi.org/10.1051/meca/2020074","url":null,"abstract":"Herringbone planetary gear system (HPGS) has high power density and complex structure. The torsional flexibility of the left and right teeth of the sun gear is closely related to the dynamic characteristics of the HPGS. In this research, considering the coordination conditions of both sides torsional stiffness and axial slide of the sun gear, a new dynamic model of the HPGS considering the meshing phase difference between left and right teeth of the sun gear is developed based on the lumped-parameter method, and the influence mechanism of torsional stiffness and axial sliding is studied. Moreover, the dynamic parameters and dynamic characteristics of the HPGS are analyzed in the case of varying torsoinal stiffness and axial slide. The results show that the torsional stiffness of left and right teeth and the axial slide of sun gear have significant impacts on the dynamic parameters and dynamic mesh force response. With the increase of the torsional flexibility (the decrease the torsional stiffness), the sun gear and planet gear meshing stiffness and the maximum tooth surface load are both increased on the left side (input side) and decreased on the right side, but the main peak values and peak frequencies of dynamic response on both sides of the s-p meshing pairs decrease significantly. In addition, when the sun gear slides toward the output side axially, meshing stiffness and dynamic mesh force response main peak values decreased on the left side (input side) and increased on the right side, but the main resonance peaks frequencies keep the same.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"18 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72971279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this publication is to show how to integrate the designing process of straight bevel gears into a computer software so it can be further used for making the three-dimensional (CAD) model of the gear pair. During meshing the driven and the driving gears engage gradually so contact points can be mathematically determined between the element pairs according to the developed coordinate system's arrangement. With my-developed computer software, I designed a certain bevel gear pair having straight teeth. Naturally, many different types of this pair could be designed. After that Loaded Tooth Contact Analysis (LTCA) have been done − by normal stress, normal deformation and normal elastic strain parameters. The aim of the LTCA is the analysis of the connection tooth zone in mechanical aspects by different loads. If the received parameters are not appropriate, you can return to the mechanical designing process where the starting parameters of the gear could be modified. Different load torques were used to determine the established mechanical parameters of the elements.
{"title":"Computer-aided design and loaded tooth contact analyses of bevel gear pair having straight teeth by different loaded torques","authors":"Sándor Bodzás","doi":"10.1051/meca/2019076","DOIUrl":"https://doi.org/10.1051/meca/2019076","url":null,"abstract":"The aim of this publication is to show how to integrate the designing process of straight bevel gears into a computer software so it can be further used for making the three-dimensional (CAD) model of the gear pair. During meshing the driven and the driving gears engage gradually so contact points can be mathematically determined between the element pairs according to the developed coordinate system's arrangement. With my-developed computer software, I designed a certain bevel gear pair having straight teeth. Naturally, many different types of this pair could be designed. After that Loaded Tooth Contact Analysis (LTCA) have been done − by normal stress, normal deformation and normal elastic strain parameters. The aim of the LTCA is the analysis of the connection tooth zone in mechanical aspects by different loads. If the received parameters are not appropriate, you can return to the mechanical designing process where the starting parameters of the gear could be modified. Different load torques were used to determine the established mechanical parameters of the elements.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"54 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82242058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Effective thermal conductivity (ETC) is a considerable thermo-physical property in design, manufacturing, and usage of multifunctional equipment that benefit cellular structures such as open-cell metal foams. An accurate understanding of key parameters effecting on ETC is classified by: Analytical, Numerical and Experimental approaches. In this study, a comprehensive investigation based on mentioned approaches is presented and a comparison between various factors affecting ETC including porosity, pore size, temperature, pressure and shape factor is made. Porosity and pore size, as main morphological features of open-cell metal foams, indicate structural characterization of them. Increase of porosity and pore size resulted decrease of ETC. The temperature effects on ETC in case of temperatures lower than 250 °C is ignorable although for temperature higher than 500 °C with change of heat transfer mechanism temperature plays a primary role in determining ETC. Few studies have been made on pressure parameter that illustrated its effect on ETC is insignificant. Multiple manufacturing methods produce different topological structures so; the influence of shape factor on ETC requires more efforts to reach a better understanding. Finally, applicable techniques for measuring ETC are briefly discussed.
{"title":"Effective factors on thermal conductivity of stochastic structures open cell metal foams","authors":"M. Saljooghi, A. Raisi, Amir Farahbakhsh","doi":"10.1051/meca/2020028","DOIUrl":"https://doi.org/10.1051/meca/2020028","url":null,"abstract":"Effective thermal conductivity (ETC) is a considerable thermo-physical property in design, manufacturing, and usage of multifunctional equipment that benefit cellular structures such as open-cell metal foams. An accurate understanding of key parameters effecting on ETC is classified by: Analytical, Numerical and Experimental approaches. In this study, a comprehensive investigation based on mentioned approaches is presented and a comparison between various factors affecting ETC including porosity, pore size, temperature, pressure and shape factor is made. Porosity and pore size, as main morphological features of open-cell metal foams, indicate structural characterization of them. Increase of porosity and pore size resulted decrease of ETC. The temperature effects on ETC in case of temperatures lower than 250 °C is ignorable although for temperature higher than 500 °C with change of heat transfer mechanism temperature plays a primary role in determining ETC. Few studies have been made on pressure parameter that illustrated its effect on ETC is insignificant. Multiple manufacturing methods produce different topological structures so; the influence of shape factor on ETC requires more efforts to reach a better understanding. Finally, applicable techniques for measuring ETC are briefly discussed.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"28 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84421100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Permanent Magnetic Coupling (PMC) is used in underwater vehicle to transmit torque from the motor to propeller without leakage and friction. Output rotational speed stability of PMC is an important index indicating the PMC output makes smaller vibration. To improve the stability of the output rotational speed, PMC dynamic characteristic was analyzed based on Lagrange equation in this paper. The dynamic characteristic was indicated by the angular phase generated by the master rotor and the slave rotor. The angular phase varied with the damping coefficient, torsional rigidity and rotational inertia of PMC. These parameters' influence on the angular phase was analyzed and the results revealed the rules between these parameters and the angular phase. Based on the rules, a variable damping method was proposed to control the angular phase. The angular phase changed smoothly with this method that was used to design a variable damping controller based on electromagnetic damping effect principle. This method was verified by theoretical calculation and finite element analysis (FEA). Finally, a novel variable damping PMC was designed to improve the output rotational speed stability of PMC.
{"title":"Rotational speed control of magnetic coupling with variable damping method","authors":"Z. Jian, L. Kun","doi":"10.1051/meca/2020027","DOIUrl":"https://doi.org/10.1051/meca/2020027","url":null,"abstract":"Permanent Magnetic Coupling (PMC) is used in underwater vehicle to transmit torque from the motor to propeller without leakage and friction. Output rotational speed stability of PMC is an important index indicating the PMC output makes smaller vibration. To improve the stability of the output rotational speed, PMC dynamic characteristic was analyzed based on Lagrange equation in this paper. The dynamic characteristic was indicated by the angular phase generated by the master rotor and the slave rotor. The angular phase varied with the damping coefficient, torsional rigidity and rotational inertia of PMC. These parameters' influence on the angular phase was analyzed and the results revealed the rules between these parameters and the angular phase. Based on the rules, a variable damping method was proposed to control the angular phase. The angular phase changed smoothly with this method that was used to design a variable damping controller based on electromagnetic damping effect principle. This method was verified by theoretical calculation and finite element analysis (FEA). Finally, a novel variable damping PMC was designed to improve the output rotational speed stability of PMC.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"4 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74540073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the most severe cases of longitudinal bone fractures such as femur, tibias, humerus etc., the bone can be completely separated into two fragments. In order to guarantee the re-ossification of the bone, it is required to reposition the bone fragments together. This process requires a delicate surgery called “bone reduction surgery”. The most advanced technique relies on the use of a robotic manipulator to reposition the bone fragments with higher precision and stability than manual surgeries. The present work introduces the kinematic design of a new hybrid mechanical architecture to perform this task. It is composed of a 3-PRP planar mechanism attached with a 3-RPS tripod mechanism. The kinematic analysis of this mechanism is provided while taking account the tripod parasitic motion. Kinematic simulations using Matlab and Adams are performed to validate the kinematic and velocity models and the parasitic motion compensation provided by the planar mechanism. The workspace of this hybrid mechanism is then compared to the standard hexapod mechanism that is widely used in bone reduction surgery. It reveals that the proposed mechanism can generate a larger workspace with the same linkage dimensions.
{"title":"Kinematic design of a hybrid planar-tripod mechanism for bone reduction surgery","authors":"T. Essomba, Sinh Nguyen Phu","doi":"10.1051/meca/2020030","DOIUrl":"https://doi.org/10.1051/meca/2020030","url":null,"abstract":"In the most severe cases of longitudinal bone fractures such as femur, tibias, humerus etc., the bone can be completely separated into two fragments. In order to guarantee the re-ossification of the bone, it is required to reposition the bone fragments together. This process requires a delicate surgery called “bone reduction surgery”. The most advanced technique relies on the use of a robotic manipulator to reposition the bone fragments with higher precision and stability than manual surgeries. The present work introduces the kinematic design of a new hybrid mechanical architecture to perform this task. It is composed of a 3-PRP planar mechanism attached with a 3-RPS tripod mechanism. The kinematic analysis of this mechanism is provided while taking account the tripod parasitic motion. Kinematic simulations using Matlab and Adams are performed to validate the kinematic and velocity models and the parasitic motion compensation provided by the planar mechanism. The workspace of this hybrid mechanism is then compared to the standard hexapod mechanism that is widely used in bone reduction surgery. It reveals that the proposed mechanism can generate a larger workspace with the same linkage dimensions.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77972270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Johnson-Cook constitutive equation was utilized to model the 10100 copper and AA 1100 aluminum wires at the cold wire drawing process. Initial Johnson cook parameters were determined through quasi-static tensile tests at different strain rates. Analytical and finite element with VUHARD subroutine solutions were implemented to calculate the drawing forces using the Johnson cook parameters. Wire drawing experiments were carried out at different drawing conditions with two areal reductions and four drawing speeds with the strain rate ranged from 37 s−1 to 115 s−1 and wire drawing forces were measured using a load cell connected to the drawing die. Results showed that the Johnson cook model with parameters determined from a quasi-static condition was not able to predict the material behavior at the wire drawing process with a moderate strain rate. In order to modify the initial JC parameters an inverse analysis approach was adopted. An objective function was defined based on analytical and experimental drawing forces differences with respect to JC parameters. Using the Newton–Raphson method, new JC parameters were identified by minimizing the objective function. Updated Johnson cook parameters showed much more correlation with experimental results.
{"title":"An inverse analysis to identify the Johnson-Cook constitutive model parameters for cold wire drawing process","authors":"A. Aghdami, B. Davoodi","doi":"10.1051/meca/2020070","DOIUrl":"https://doi.org/10.1051/meca/2020070","url":null,"abstract":"Johnson-Cook constitutive equation was utilized to model the 10100 copper and AA 1100 aluminum wires at the cold wire drawing process. Initial Johnson cook parameters were determined through quasi-static tensile tests at different strain rates. Analytical and finite element with VUHARD subroutine solutions were implemented to calculate the drawing forces using the Johnson cook parameters. Wire drawing experiments were carried out at different drawing conditions with two areal reductions and four drawing speeds with the strain rate ranged from 37 s−1 to 115 s−1 and wire drawing forces were measured using a load cell connected to the drawing die. Results showed that the Johnson cook model with parameters determined from a quasi-static condition was not able to predict the material behavior at the wire drawing process with a moderate strain rate. In order to modify the initial JC parameters an inverse analysis approach was adopted. An objective function was defined based on analytical and experimental drawing forces differences with respect to JC parameters. Using the Newton–Raphson method, new JC parameters were identified by minimizing the objective function. Updated Johnson cook parameters showed much more correlation with experimental results.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"126 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76838617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ouardia Ait Oucheggou, V. Pointeau, G. Ricciardi, É. Guazzelli, L. Bergougnoux
Particle trapping and deposition around an obstacle occur in many natural and industrial situations and in particular in the nuclear industry. In the steam generator of a nuclear power plant, the progressive obstruction of the flow due to particle deposition reduces the efficiency and can induce tube cracking leading to breaking and damage. The steam generator then loses its role as a safety barrier of the nuclear power plant. From a fundamental standpoint, dilute and concentrated particulate flows have received a growing attention in the last decade. In this study, we investigate the transport of solid particles around obstacles in a confined flow. Experiments were performed in a simplified configuration by considering a laminar flow in a vertical tube. An obstacle was inserted at the middle height of the tube and neutrally-buoyant particles were injected at different locations along the tube. We have investigated first the trajectories of individual particles using particle tracking (PT). Then, the particle trajectories were modeled by using the Boussinesq-Basset-Oseen equation with a flow velocity field either measured using particle image velocimetry (PIV) or calculated by the Code_Saturne software in order to account for the three-dimensional (3D) character of the obstacle wake. This paper presents a comparison between the experimental observations and the predictions of the modeling for an obstacle consisting of a rectangular step at a Reynolds number of ≈100 and evidences the importance of accounting for the 3D complex nature of the flow.
{"title":"Particle-laden flow around an obstacle in a square pipe: experiments and modeling","authors":"Ouardia Ait Oucheggou, V. Pointeau, G. Ricciardi, É. Guazzelli, L. Bergougnoux","doi":"10.1051/meca/2020063","DOIUrl":"https://doi.org/10.1051/meca/2020063","url":null,"abstract":"Particle trapping and deposition around an obstacle occur in many natural and industrial situations and in particular in the nuclear industry. In the steam generator of a nuclear power plant, the progressive obstruction of the flow due to particle deposition reduces the efficiency and can induce tube cracking leading to breaking and damage. The steam generator then loses its role as a safety barrier of the nuclear power plant. From a fundamental standpoint, dilute and concentrated particulate flows have received a growing attention in the last decade. In this study, we investigate the transport of solid particles around obstacles in a confined flow. Experiments were performed in a simplified configuration by considering a laminar flow in a vertical tube. An obstacle was inserted at the middle height of the tube and neutrally-buoyant particles were injected at different locations along the tube. We have investigated first the trajectories of individual particles using particle tracking (PT). Then, the particle trajectories were modeled by using the Boussinesq-Basset-Oseen equation with a flow velocity field either measured using particle image velocimetry (PIV) or calculated by the Code_Saturne software in order to account for the three-dimensional (3D) character of the obstacle wake. This paper presents a comparison between the experimental observations and the predictions of the modeling for an obstacle consisting of a rectangular step at a Reynolds number of ≈100 and evidences the importance of accounting for the 3D complex nature of the flow.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"146 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79953484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study describes experimental research on two-phase flow displacement using Magnetic Resonance Imaging (MRI) techniques. The overall purpose of this investigation is to determine kinetics process of phase trapping during (water-oil) two-phase flow, the front deformation and the phases saturation propagation along a vertical model. In these water flooding experiments, the porous medium model consists of packed beads of polystyrene (0.4 mm < dp < 0.6 mm) or sand grains (0.02 mm < dp < 0.50 mm). In order to conduct high accuracy experiments, a Nuclear Magnetic Resonance (NMR) spectrometer operating at 14 T (corresponding to a 600 MHz 1H resonance) equipped with an imaging device was used. With this equipment we can measure and visualize the two-phase flow in a vertical model of porous medium under ambient conditions. The obtained results have shown that the oil saturation profile is strongly influenced by the material properties such as the phase wetting, the sample porosity and permeability as well as the injection rate. The influence of flow velocity on the residual oil saturation was also studied. The experimental results allow an essential understanding of immiscible fluid displacement in two different types of porous medium that differ from each other mainly by the effects of wettability.
本文介绍了利用磁共振成像技术对两相流驱替进行的实验研究。本研究的总体目的是确定(水-油)两相流动中相捕获的动力学过程、前缘变形和相饱和度沿垂直模型的扩展。在这些水驱实验中，多孔介质模型由聚苯乙烯填充珠(0.4 mm < dp < 0.6 mm)或砂粒(0.02 mm < dp < 0.50 mm)组成。为了进行高精度实验，使用了一台工作在14 T(对应600 MHz 1H共振)的核磁共振(NMR)光谱仪，并配备了成像装置。利用该装置，我们可以测量和可视化环境条件下多孔介质垂直模型中的两相流。结果表明，相润湿性、样品孔隙度和渗透率以及注入速率等材料性质对含油饱和度剖面有较大影响。研究了流速对剩余油饱和度的影响。实验结果使人们对两种不同类型的多孔介质中的非混相流体驱替有了基本的了解，这两种介质的主要区别在于润湿性的影响。
{"title":"Studying of parameters of two-phase displacement in porous media with MRI technique","authors":"J. Fannir, I. Panfilova, S. Leclerc, D. Stemmelen","doi":"10.1051/meca/2020058","DOIUrl":"https://doi.org/10.1051/meca/2020058","url":null,"abstract":"This study describes experimental research on two-phase flow displacement using Magnetic Resonance Imaging (MRI) techniques. The overall purpose of this investigation is to determine kinetics process of phase trapping during (water-oil) two-phase flow, the front deformation and the phases saturation propagation along a vertical model. In these water flooding experiments, the porous medium model consists of packed beads of polystyrene (0.4 mm < dp < 0.6 mm) or sand grains (0.02 mm < dp < 0.50 mm). In order to conduct high accuracy experiments, a Nuclear Magnetic Resonance (NMR) spectrometer operating at 14 T (corresponding to a 600 MHz 1H resonance) equipped with an imaging device was used. With this equipment we can measure and visualize the two-phase flow in a vertical model of porous medium under ambient conditions. The obtained results have shown that the oil saturation profile is strongly influenced by the material properties such as the phase wetting, the sample porosity and permeability as well as the injection rate. The influence of flow velocity on the residual oil saturation was also studied. The experimental results allow an essential understanding of immiscible fluid displacement in two different types of porous medium that differ from each other mainly by the effects of wettability.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"10 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89838710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaoliang Cheng, Chunyang Zhao, Hailong Wang, Yang Wang, Zhenlong Wang
Microwave cutting glass and ceramics based on thermal controlled fracture method has gained much attention recently for its advantages in lower energy-consumption and higher efficiency than conventional processing method. However, the irregular crack-propagation is problematic in this procedure, which hinders the industrial application of this advanced technology. In this study, the irregular crack-propagation is summarized as the unstable propagation in the initial stage, the deviated propagation in the middle stage, and the non-penetrating propagation in the end segment based on experimental work. Method for predicting the unstable propagation in the initial stage has been developed by combining analytical models with thermal-fracture simulation. Experimental results show good agreement with the prediction results, and the relative deviation between them can be <5% in cutting of some ceramics. The mechanism of deviated propagation and the non-penetrating propagation have been revealed by simulation and theoretical analysis. Since this study provides effective methods to predict unstable crack-propagation in the initial stage and understand the irregular propagation mechanism in the whole crack-propagation stage in microwave cutting ceramics, it is of great significance to the industrial application of thermal controlled fracture method for cutting ceramic materials using microwave.
{"title":"Mechanism of irregular crack-propagation in thermal controlled fracture of ceramics induced by microwave","authors":"Xiaoliang Cheng, Chunyang Zhao, Hailong Wang, Yang Wang, Zhenlong Wang","doi":"10.1051/meca/2020077","DOIUrl":"https://doi.org/10.1051/meca/2020077","url":null,"abstract":"Microwave cutting glass and ceramics based on thermal controlled fracture method has gained much attention recently for its advantages in lower energy-consumption and higher efficiency than conventional processing method. However, the irregular crack-propagation is problematic in this procedure, which hinders the industrial application of this advanced technology. In this study, the irregular crack-propagation is summarized as the unstable propagation in the initial stage, the deviated propagation in the middle stage, and the non-penetrating propagation in the end segment based on experimental work. Method for predicting the unstable propagation in the initial stage has been developed by combining analytical models with thermal-fracture simulation. Experimental results show good agreement with the prediction results, and the relative deviation between them can be <5% in cutting of some ceramics. The mechanism of deviated propagation and the non-penetrating propagation have been revealed by simulation and theoretical analysis. Since this study provides effective methods to predict unstable crack-propagation in the initial stage and understand the irregular propagation mechanism in the whole crack-propagation stage in microwave cutting ceramics, it is of great significance to the industrial application of thermal controlled fracture method for cutting ceramic materials using microwave.","PeriodicalId":49018,"journal":{"name":"Mechanics & Industry","volume":"77 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86184734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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