This is the second paper of a series where we introduce a control volume based finite element method （CVFEM） to simulate multiphase flow in porous media. This is a fully conservative method able to deal with unstruc...This is the second paper of a series where we introduce a control volume based finite element method （CVFEM） to simulate multiphase flow in porous media. This is a fully conservative method able to deal with unstructured grids which can be used for representing any complexity of reservoir geometry and its geological objects in an accurate and efficient manner. In order to deal with the inherent heterogeneity of the reservoirs, all operations related to discretization are performed at the element level in a manner similar to classical finite element method （FEM）. Moreover, the proposed method can effectively reduce the so-called grid orientation effects. In the first paper of this series, we presented this method and its application for incompressible and immiscible two-phase flow simulation in homogeneous and heterogeneous porous media. In this paper, we evaluate the capability of the method in the solution of highly nonlinear and coupled partial differential equations by simulating hydrocarbon reservoirs using the black-oil model. Furthermore, the effect of grid orientation is investigated by simulating a benchmark waterflooding problem. The numerical results show that the formulation presented here is efficient and accurate for solving the bubble point and three-phase coning problems.展开更多
This paper presents a new three-dimensional(3D) volume measurement approach of bubble in gas-liquid two-phase flow. According to the dual perspective imaging principle,bubble feature images can be captured from two di...This paper presents a new three-dimensional(3D) volume measurement approach of bubble in gas-liquid two-phase flow. According to the dual perspective imaging principle,bubble feature images can be captured from two different view angles. The least square ellipse fitting algorithm is used to figure out the feature parameters from the captured images. Then the 3D volume of bubble can be quantitatively measured. Compaerd with the traditional volume estimation methods based on single perspective imaging,it can effectively reduce the loss of bubble feature information. In the experiment,the 3D volume reconstruction of bubbles from dual perspective images is conducted,and the variation of bubble volume in the bubble rising process is studied. The results show that the measurement accuracy based on the proposed 3D method is higher than those based on traditional methods. The volume of rising bubble is periodically changed,which indicates that bubble achieves periodic rotation and deformation in the rising process.展开更多
Forced convection heat transfer of ethylene glycol based nanofluid with FeOinside a porous medium is studied using the electric field. The control volume based finite element method(CVFEM) is selected for numerical si...Forced convection heat transfer of ethylene glycol based nanofluid with FeOinside a porous medium is studied using the electric field. The control volume based finite element method(CVFEM) is selected for numerical simulation. The impact of the radiation parameter(R), the supplied voltage(?φ), the volume fraction of nanofluid(?), the Darcy number(Da), and the Reynolds number(Re) on nanofluid treatment is demonstrated. Results prove that thermal radiation increases the temperature gradient near the positive electrode. Distortion of isotherms increases with the enhance of the Darcy number and the Coulomb force.展开更多
In 2018,the Chinese government identified four municipalities and seven sub-provincial cities for the implementation of the National Drug Pooled Procurement(NDPP)pilot program(the“4+7”policy).In the present study,we...In 2018,the Chinese government identified four municipalities and seven sub-provincial cities for the implementation of the National Drug Pooled Procurement(NDPP)pilot program(the“4+7”policy).In the present study,we analyzed the effects of the“4+7”policy with data of 25 pilot drugs from the National Healthcare Security Administration(NHSA)from the aspects of drug price,volume,and expenditure.After the implementation of the policy,the average price of total and winning drugs was decreased by 54.47%and 73.82%,respectively,while the DDDc of non-winning drugs was decreased by only 1.54%,and the DDDc of uncertificated generic drugs was increased 83.18%.The DDDs indicating the volume of total and winning drugs was increased by 21.18%and 353.98%,respectively,and the DDDs of non-winning drugs was decreased by 61.35%.The costs of total and non-winning drugs were decreased by 44.83%and 61.94%,respectively,and the cost of winning drugs was increased by 18.87%.The“4+7”policy reduced the price and cost of pilot drugs and improved the affordability and accessibility of drugs.However,there were also problems with unexpected excessive price increases of uncertificated generic drugs and relatively high prices of non-winning products.Therefore,we highly suggested promoting the normalization and institutionalization of pooled drug procurement,enhancing the administrative capacity of local procurement platforms,and strengthening monitoring the price of non-winning,especially for the uncertificated generic drugs.展开更多
Wireless Communication is a system for communicating information from one point to other,without utilizing any connections like wire,cable,or other physical medium.Cognitive Radio(CR)based systems and networks are a r...Wireless Communication is a system for communicating information from one point to other,without utilizing any connections like wire,cable,or other physical medium.Cognitive Radio(CR)based systems and networks are a revolutionary new perception in wireless communications.Spectrum sensing is a vital task of CR to avert destructive intrusion with licensed primary or main users and discover the accessible spectrum for the efficient utilization of the spectrum.Centralized Cooperative Spectrum Sensing(CSS)is a kind of spectrum sensing.Most of the test metrics designed till now for sensing the spectrum is produced by using the Sample Covariance Matrix(SCM)of the received signal.Some of the methods that use the SCM for the process of detection are Pietra-Ricci Index Detector(PRIDe),Hadamard Ratio(HR)detector,Gini Index Detector(GID),etc.This paper presents the simulation and comparative perfor-mance analysis of PRIDe with various other detectors like GID,HR,Arithmetic to Geometric Mean(AGM),Volume-based Detector number 1(VD1),Maximum-to-Minimum Eigenvalue Detection(MMED),and Generalized Likelihood Ratio Test(GLRT)using the MATLAB software.The PRIDe provides better performance in the presence of variations in the power of the signal and the noise power with less computational complexity.展开更多
基金科技部"中国新加坡联合研究计划 (0 0 3/ 1 0 1 / 0 4 ) (NSTB- MOST Joint Research Program)"资助项目 (NSTB:National Science and Technology Bureau of SingaporeMOST:Ministry of Science and Technology of China.)
文摘介绍一种用于液体特性研究的新型仪器——光纤、电容液滴分析仪 (FCDA:Fiber- Capacitive Drop Analyzer)。该仪器利用光纤液滴分析技术和电容液滴分析技术制成特殊的液滴传感器 ,获取经过液滴的光强信号随液滴生长变化的规律 ,得到反映液体综合特性的“液滴指纹图”。通过对部分样品进行测试实验 ,证明液滴指纹图可以作为鉴别液体的依据 ,同时具有测量液体物理。
基金Iranian Offshore OilCompany (IOOC) for financial support of this work
文摘This is the second paper of a series where we introduce a control volume based finite element method （CVFEM） to simulate multiphase flow in porous media. This is a fully conservative method able to deal with unstructured grids which can be used for representing any complexity of reservoir geometry and its geological objects in an accurate and efficient manner. In order to deal with the inherent heterogeneity of the reservoirs, all operations related to discretization are performed at the element level in a manner similar to classical finite element method （FEM）. Moreover, the proposed method can effectively reduce the so-called grid orientation effects. In the first paper of this series, we presented this method and its application for incompressible and immiscible two-phase flow simulation in homogeneous and heterogeneous porous media. In this paper, we evaluate the capability of the method in the solution of highly nonlinear and coupled partial differential equations by simulating hydrocarbon reservoirs using the black-oil model. Furthermore, the effect of grid orientation is investigated by simulating a benchmark waterflooding problem. The numerical results show that the formulation presented here is efficient and accurate for solving the bubble point and three-phase coning problems.
基金supported by the National Natural Science Foundation of China(Nos.61372143 and 61671321)
文摘This paper presents a new three-dimensional(3D) volume measurement approach of bubble in gas-liquid two-phase flow. According to the dual perspective imaging principle,bubble feature images can be captured from two different view angles. The least square ellipse fitting algorithm is used to figure out the feature parameters from the captured images. Then the 3D volume of bubble can be quantitatively measured. Compaerd with the traditional volume estimation methods based on single perspective imaging,it can effectively reduce the loss of bubble feature information. In the experiment,the 3D volume reconstruction of bubbles from dual perspective images is conducted,and the variation of bubble volume in the bubble rising process is studied. The results show that the measurement accuracy based on the proposed 3D method is higher than those based on traditional methods. The volume of rising bubble is periodically changed,which indicates that bubble achieves periodic rotation and deformation in the rising process.
文摘Forced convection heat transfer of ethylene glycol based nanofluid with FeOinside a porous medium is studied using the electric field. The control volume based finite element method(CVFEM) is selected for numerical simulation. The impact of the radiation parameter(R), the supplied voltage(?φ), the volume fraction of nanofluid(?), the Darcy number(Da), and the Reynolds number(Re) on nanofluid treatment is demonstrated. Results prove that thermal radiation increases the temperature gradient near the positive electrode. Distortion of isotherms increases with the enhance of the Darcy number and the Coulomb force.
文摘In 2018,the Chinese government identified four municipalities and seven sub-provincial cities for the implementation of the National Drug Pooled Procurement(NDPP)pilot program(the“4+7”policy).In the present study,we analyzed the effects of the“4+7”policy with data of 25 pilot drugs from the National Healthcare Security Administration(NHSA)from the aspects of drug price,volume,and expenditure.After the implementation of the policy,the average price of total and winning drugs was decreased by 54.47%and 73.82%,respectively,while the DDDc of non-winning drugs was decreased by only 1.54%,and the DDDc of uncertificated generic drugs was increased 83.18%.The DDDs indicating the volume of total and winning drugs was increased by 21.18%and 353.98%,respectively,and the DDDs of non-winning drugs was decreased by 61.35%.The costs of total and non-winning drugs were decreased by 44.83%and 61.94%,respectively,and the cost of winning drugs was increased by 18.87%.The“4+7”policy reduced the price and cost of pilot drugs and improved the affordability and accessibility of drugs.However,there were also problems with unexpected excessive price increases of uncertificated generic drugs and relatively high prices of non-winning products.Therefore,we highly suggested promoting the normalization and institutionalization of pooled drug procurement,enhancing the administrative capacity of local procurement platforms,and strengthening monitoring the price of non-winning,especially for the uncertificated generic drugs.
文摘Wireless Communication is a system for communicating information from one point to other,without utilizing any connections like wire,cable,or other physical medium.Cognitive Radio(CR)based systems and networks are a revolutionary new perception in wireless communications.Spectrum sensing is a vital task of CR to avert destructive intrusion with licensed primary or main users and discover the accessible spectrum for the efficient utilization of the spectrum.Centralized Cooperative Spectrum Sensing(CSS)is a kind of spectrum sensing.Most of the test metrics designed till now for sensing the spectrum is produced by using the Sample Covariance Matrix(SCM)of the received signal.Some of the methods that use the SCM for the process of detection are Pietra-Ricci Index Detector(PRIDe),Hadamard Ratio(HR)detector,Gini Index Detector(GID),etc.This paper presents the simulation and comparative perfor-mance analysis of PRIDe with various other detectors like GID,HR,Arithmetic to Geometric Mean(AGM),Volume-based Detector number 1(VD1),Maximum-to-Minimum Eigenvalue Detection(MMED),and Generalized Likelihood Ratio Test(GLRT)using the MATLAB software.The PRIDe provides better performance in the presence of variations in the power of the signal and the noise power with less computational complexity.
