期刊文献+
共找到233篇文章
< 1 2 12 >
每页显示 20 50 100
New approach for modeling flow stress of aluminum alloy 6A10 considering temperature variation
1
作者 李雪松 伍来智 +1 位作者 陈军 张鸿冰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第8期1482-1487,共6页
The flow stress behavior of aluminum alloy 6A10 was studied by the hot compression tests at temperatures from 350℃ to 550 ℃ and strain rates from 0.1 s^-1 to 10 s^-1 with Gleeble-1500 thermo-mechanical simulator. Th... The flow stress behavior of aluminum alloy 6A10 was studied by the hot compression tests at temperatures from 350℃ to 550 ℃ and strain rates from 0.1 s^-1 to 10 s^-1 with Gleeble-1500 thermo-mechanical simulator. The result demonstrates that the temperatures of specimen differ from initial ones affected by deformation conditions, and that the softening mechanism is dynamic recovery. A new approach was proposed to analyze the flow stress character directly from actual stress, strain, temperature and strain rate data, without performing any previous flow stress correction caused by temperature variation. Comparisons between the experimental and predicted results confirm that the established flow stress model can give reasonable estimation, indicating that the mentioned approach can be used in flow stress model analysis of the materials that undergo only dynamic recovery based on the data obtained under variable deformation temperature. 展开更多
关键词 aluminum alloy 6A10 flow stress model dynamic recovery
下载PDF
WT-FCTGN:A wavelet-enhanced fully connected time-gated neural network for complex noisy traffic flow modeling
2
作者 廖志芳 孙轲 +3 位作者 刘文龙 余志武 刘承光 宋禹成 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期652-664,共13页
Accurate forecasting of traffic flow provides a powerful traffic decision-making basis for an intelligent transportation system. However, the traffic data's complexity and fluctuation, as well as the noise produce... Accurate forecasting of traffic flow provides a powerful traffic decision-making basis for an intelligent transportation system. However, the traffic data's complexity and fluctuation, as well as the noise produced during collecting information and summarizing original data of traffic flow, cause large errors in the traffic flow forecasting results. This article suggests a solution to the above mentioned issues and proposes a fully connected time-gated neural network based on wavelet reconstruction(WT-FCTGN). To eliminate the potential noise and strengthen the potential traffic trend in the data, we adopt the methods of wavelet reconstruction and periodic data introduction to preprocess the data. The model introduces fully connected time-series blocks to model all the information including time sequence information and fluctuation information in the flow of traffic, and establishes the time gate block to comprehend the periodic characteristics of the flow of traffic and predict its flow. The performance of the WT-FCTGN model is validated on the public Pe MS data set. The experimental results show that the WT-FCTGN model has higher accuracy, and its mean absolute error(MAE), mean absolute percentage error(MAPE) and root mean square error(RMSE) are obviously lower than those of the other algorithms. The robust experimental results prove that the WT-FCTGN model has good anti-noise ability. 展开更多
关键词 traffic flow modeling time-series wavelet reconstruction
下载PDF
Algorithmic approach to discrete fracture network flow modeling in consideration of realistic connections in large-scale fracture networks
3
作者 Qihua Zhang Shan Dong +2 位作者 Yaoqi Liu Junjie Huang Feng Xiong 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第9期3798-3811,共14页
Analyzing rock mass seepage using the discrete fracture network(DFN)flow model poses challenges when dealing with complex fracture networks.This paper presents a novel DFN flow model that incorporates the actual conne... Analyzing rock mass seepage using the discrete fracture network(DFN)flow model poses challenges when dealing with complex fracture networks.This paper presents a novel DFN flow model that incorporates the actual connections of large-scale fractures.Notably,this model efficiently manages over 20,000 fractures without necessitating adjustments to the DFN geometry.All geometric analyses,such as identifying connected fractures,dividing the two-dimensional domain into closed loops,triangulating arbitrary loops,and refining triangular elements,are fully automated.The analysis processes are comprehensively introduced,and core algorithms,along with their pseudo-codes,are outlined and explained to assist readers in their programming endeavors.The accuracy of geometric analyses is validated through topological graphs representing the connection relationships between fractures.In practical application,the proposed model is employed to assess the water-sealing effectiveness of an underground storage cavern project.The analysis results indicate that the existing design scheme can effectively prevent the stored oil from leaking in the presence of both dense and sparse fractures.Furthermore,following extensive modification and optimization,the scale and precision of model computation suggest that the proposed model and developed codes can meet the requirements of engineering applications. 展开更多
关键词 Discrete fracture network(DFN)flow model Geometric algorithm Fracture flow Water-sealing effect
下载PDF
Changes in filtration and capacitance properties of highly porous reservoir in underground gas storage:CT-based and geomechanical modeling
4
作者 Valerii Khimulia Vladimir Karev +1 位作者 Yury Kovalenko Svyatoslav Barkov 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期2982-2995,共14页
The paper presents the results of comprehensive studies of filtration and capacitance properties of highly porous reservoir rocks of the aquifer of an underground gas storage facility.The geomechanical part of the res... The paper presents the results of comprehensive studies of filtration and capacitance properties of highly porous reservoir rocks of the aquifer of an underground gas storage facility.The geomechanical part of the research included studying the dependence of rock permeability on the stress-strain state in the vicinity of the wells,and physical modeling of the implementation of the method of increasing the permeability of the wellbore zone-the method of directional unloading of the reservoir.The digital part of the research included computed tomography(CT)-based computer analysis of the internal structure,pore space characteristics,and filtration properties before and after the tests.According to the results of physical modeling of deformation and filtration processes,it is found that the permeability of rocks before fracture depends on the stress-strain state insignificantly,and this influence is reversible.However,when downhole pressure reaches 7-8 MPa,macrocracks in the rock begin to grow,accompanied by irreversible permeability increase.Porosity,geodesic tortuosity and permeability values were obtained based on digital studies and numerical modeling.A weak degree of transversal anisotropy of the filtration properties of rocks was detected.Based on the analysis of pore size distribution,pressure field and flow velocities,high homogeneity and connectivity of the rock pore space is shown.The absence of pronounced changes in pore space characteristics and pore permeability after non-uniform triaxial loading rocks was shown.On the basis of geometrical analysis of pore space,the reasons for weak permeability anisotropy were identified.The filtration-capacitance properties obtained from the digital analysis showed very good agreement with the results of field and laboratory measurements.The physical modeling has confirmed the efficiency of application of the directional unloading method for the reservoir under study.The necessary parameters of its application were calculated:bottomhole geometry,stage of operation,stresses and pressure drawdown value. 展开更多
关键词 Permeability anisotropy Reservoir porosity Rocks computed tomography(CT) Digital core analysis Filtration flow numerical modeling
下载PDF
FLOW STRESS MODELING FOR AERONAUTICAL ALUMINUM ALLOY 7050-T7451 IN HIGH-SPEED CUTTING 被引量:15
5
作者 付秀丽 艾兴 +1 位作者 万熠 张松 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2007年第2期139-144,共6页
The high temperature split Hopkinson pressure bar (SHPB) compression experiment is conducted to obtain the data relationship among strain, strain rate and flow stress from room temperature to 550 C for aeronautical ... The high temperature split Hopkinson pressure bar (SHPB) compression experiment is conducted to obtain the data relationship among strain, strain rate and flow stress from room temperature to 550 C for aeronautical aluminum alloy 7050-T7451. Combined high-speed orthogonal cutting experiments with the cutting process simulations, the data relationship of high temperature, high strain rate and large strain in high-speed cutting is modified. The Johnson-Cook empirical model considering the effects of strain hardening, strain rate hardening and thermal softening is selected to describe the data relationship in high-speed cutting, and the material constants of flow stress constitutive model for aluminum alloy 7050-T7451 are determined. Finally, the constitutive model of aluminum alloy 7050-T7451 is established through experiment and simulation verification in high-speed cutting. The model is proved to be reasonable by matching the measured values of the cutting force with the estimated results from FEM simulations. 展开更多
关键词 high-speed cutting flow stress models SHPB compression experiment FEM simulation
下载PDF
Design and Implementation of Visualized Workflow Modeling System Based on B/S Structure 被引量:2
6
作者 王坚 李巍丽 《Journal of Donghua University(English Edition)》 EI CAS 2007年第1期75-78,共4页
According to the necessity of flexible workflow management system, the solution to set up the visualized workflow modelling system based on B/S structure is put forward, which conforms to the relevant specifications o... According to the necessity of flexible workflow management system, the solution to set up the visualized workflow modelling system based on B/S structure is put forward, which conforms to the relevant specifications of WfMC and the workflow process definition meta-model. The design for system structure is presented in detail, and the key technologies for system implementation are also introduced. Additionally, an example is illustrated to demonstrate the validity of system. 展开更多
关键词 work flow work flow modeling system XPDL parsing.
下载PDF
Continuum modeling for two-lane traffic flow with consideration of the traffic interruption probability 被引量:2
7
作者 田川 孙棣华 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第12期51-59,共9页
Considering the effects that the probability of traffic interruption and the friction between two lanes have on the car-following behaviour, this paper establishes a new two-lane microscopic car-following model. Based... Considering the effects that the probability of traffic interruption and the friction between two lanes have on the car-following behaviour, this paper establishes a new two-lane microscopic car-following model. Based on this microscopic model, a new macroscopic model was deduced by the relevance relation of microscopic and macroscopic scale parameters for the two-lane traffic flow. Terms related to lane change are added into the continuity equations and velocity dynamic equations to investigate the lane change rate. Numerical results verify that the proposed model can be efficiently used to reflect the effect of the probability of traffic interruption on the shock, rarefaction wave and lane change behaviour on two-lane freeways. The model has also been applied in reproducing some complex traffic phenomena caused by traffic accident interruption. 展开更多
关键词 two lanes traffic interruption probability traffic flow dynamics model numerical simulation
下载PDF
Modeling on Residence Time Distribution in Subsurface Flow Constructed Wetlands by Multi Flow Dispersion Model 被引量:2
8
作者 ZHANG Tao SONG Xinshan +1 位作者 LU Shoubo YAN Denghua 《湿地科学》 CSCD 2010年第3期233-239,共7页
As an important design factor for constructed wetlands,hydraulic retention time and its distribution will affect the treatment performance.Instantaneously injected sodium chloride tracers were used to obtain residence... As an important design factor for constructed wetlands,hydraulic retention time and its distribution will affect the treatment performance.Instantaneously injected sodium chloride tracers were used to obtain residence time distributions of the lab scale subsurface flow constructed wetland.Considering the presence of trailing and multiple peaks of the tracer breakthrough curve,the multi flow dispersion model(MFDM)was used to fit the experimental tracer breakthrough curves.According to the residual sum of squares and comparison between the experimental values and simulated values of the tracer concentration,MFDM could fit the residence time distribution(RTD)curve satisfactorily,the results of which also reflected the layered structure of wetland cells,thus to give reference for application of MFDM to the same kind of subsurface flow constructed wetlands. 展开更多
关键词 subsurface flow constructed wetlands tracer test residence time distribution multi flow dispersion model
下载PDF
Modeling study on the flow patterns of gas–liquid flow for fast decarburization during the RH process 被引量:2
9
作者 Yi-hong Li Yan-ping Bao +2 位作者 Rui Wang Li-feng Ma Jian-sheng Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2018年第2期153-163,共11页
A water model and a high-speed video camera were utilized in the 300-t RH equipment to study the effect of steel flow patterns in a vacuum chamber on fast decarburization and a superior flow-pattern map was obtained d... A water model and a high-speed video camera were utilized in the 300-t RH equipment to study the effect of steel flow patterns in a vacuum chamber on fast decarburization and a superior flow-pattern map was obtained during the practical RH process. There are three flow patterns with different bubbling characteristics and steel surface states in the vacuum chamber: boiling pattern(BP), transition pattern(TP), and wave pattern(WP). The effect of the liquid-steel level and the residence time of the steel in the chamber on flow patterns and decarburization reaction were investigated, respectively. The liquid-steel level significantly affected the flow-pattern transition from BP to WP, and the residence time and reaction area were crucial to evaluate the whole decarburization process rather than the circulation flow rate and mixing time. A superior flow-pattern map during the practical RH process showed that the steel flow pattern changed from BP to TP quickly, and then remained as TP until the end of decarburization. 展开更多
关键词 modeling study flow pattern vacuum chamber residence time decarburization RH process
下载PDF
Time lag characteristics of sap flow in seed-maize and their implications for modeling transpiration in an arid region of Northwest China 被引量:5
10
作者 BO Xiaodong DU Taisheng +1 位作者 DING Risheng Louise COMAS 《Journal of Arid Land》 SCIE CSCD 2017年第4期515-529,共15页
Plant capacity for water storage leads to time lags between basal stem sap flow and transpiration in various woody plants. Internal water storage depends on the sizes of woody plants. However, the changes and its infl... Plant capacity for water storage leads to time lags between basal stem sap flow and transpiration in various woody plants. Internal water storage depends on the sizes of woody plants. However, the changes and its influencing factors in time lags of basal stem flow during the development of herbaceous plants including crops remain unclear. A field experiment was conducted in an arid region of Northwest China to examine the time lag characteristics of sap flow in seed-maize and to calibrate the transpiration modeling. Cross-correlation analysis was used to estimate the time lags between stem sap flow and meteorological driving factors including solar radiation(R_s) and vapor pressure deficit of the air(VPD_(air)). Results indicate that the changes in seed-maize stem sap flow consistently lagged behind the changes in R_s and preceded the changes in VPD_(air) both on hourly and daily scales, suggesting that light-mediated stomatal closures drove sap flow responses. The time lag in the maize's sap flow differed significantly during different growth stages and the difference was potentially due to developmental changes in capacitance tissue and/or xylem during ontogenesis. The time lags between stem sap flow and R_s in both female plants and male plants corresponded to plant use of stored water and were independent of total plant water use. Time lags of sap flow were always longer in male plants than in female plants. Theoretically, dry soil may decrease the speed by which sap flow adjusts ahead of shifts in VPD_(air) in comparison with wet soil and also increase the speed by which sap flow adjusts to R_s. However, sap flow lags that were associated with R_s before irrigation and after irrigation in female plants did not shift. Time series analysis method provided better results for simulating seed-maize sap flow with advantages of allowing for fewer variables to be included. This approach would be helpful in improving the accuracy of estimation for canopy transpiration and conductance using meteorological measurements. 展开更多
关键词 seed-maize sap flow capacitance transfer function model time lag stored water use
下载PDF
The Design of a Three-Dimensional Physical Modeling System for Real-Time Groundwater Flows 被引量:1
11
作者 SHI Feng ZHANG Fawang +5 位作者 CHEN Li HAN Zhantao YAO Hongchao QIAN Long CHEN Liang JIANG Chengchao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第6期2103-2103,共1页
In the past decades,physical modeling has been widely used in hydrogeology for teaching,studying and exhibition purposes.Most of these models are used to illustrate hydrogeological profiles,but few can depict three-di... In the past decades,physical modeling has been widely used in hydrogeology for teaching,studying and exhibition purposes.Most of these models are used to illustrate hydrogeological profiles,but few can depict three-dimensional groundwater flows,making it impossible to validate groundwater flows simulated by numerical methods with physical modeling. 展开更多
关键词 The Design of a Three-Dimensional Physical modeling System for Real-Time Groundwater flows
下载PDF
Groundwater flow through fractured rocks and seepage control in geotechnical engineering: Theories and practices 被引量:2
12
作者 Chuang-Bing Zhou Yi-Feng Chen +1 位作者 Ran Hu Zhibing Yang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第1期1-36,共36页
Groundwater flow through fractured rocks has been recognized as an important issue in many geotechnical engineering practices.Several key aspects of fundamental mechanisms,numerical modeling and engineering applicatio... Groundwater flow through fractured rocks has been recognized as an important issue in many geotechnical engineering practices.Several key aspects of fundamental mechanisms,numerical modeling and engineering applications of flow in fractured rocks are discussed.First,the microscopic mechanisms of fluid flow in fractured rocks,especially under the complex conditions of non-Darcian flow,multiphase flow,rock dissolution,and particle transport,have been revealed through a com-bined effort of visualized experiments and theoretical analysis.Then,laboratory and field methods of characterizing hydraulic properties(e.g.intrinsic permeability,inertial permeability,and unsaturated flow parameters)of fractured rocks in different flow regimes have been proposed.Subsequently,high-performance numerical simulation approaches for large-scale modeling of groundwater flow in frac-tured rocks and aquifers have been developed.Numerical procedures for optimization design of seepage control systems in various settings have also been proposed.Mechanisms of coupled hydro-mechanical processes and control of flow-induced deformation have been discussed.Finally,three case studies are presented to illustrate the applications of the improved theoretical understanding,characterization methods,modeling approaches,and seepage and deformation control strategies to geotechnical engi-neering projects. 展开更多
关键词 Fractured rock Groundwater flow flow visualization Hydraulic property Hydromechanical coupling Groundwater flow modeling Seepage control
下载PDF
Modeling and simulation of non-isothermal three-phase flow for accurate prediction in underbalanced drilling
13
作者 FALAVAND-JOZAEI A HAJIDAVALLOO E +1 位作者 SHEKARI Y GHOBADPOURI S 《Petroleum Exploration and Development》 CSCD 2022年第2期406-414,共9页
The present study aims at investigating the effect of temperature variation due to heat transfer between the formation and drilling fluids considering influx from the reservoir in the underbalanced drilling condition.... The present study aims at investigating the effect of temperature variation due to heat transfer between the formation and drilling fluids considering influx from the reservoir in the underbalanced drilling condition. Gas-liquid-solid three-phase flow model considering transient thermal interaction with the formation was applied to simulate wellbore fluid to calculate the wellbore temperature and pressure and analyze the influence of different parameters on fluid pressure and temperature distribution in annulus. The results show that the non-isothermal three-phase flow model with thermal consideration gives more accurate prediction of bottom-hole pressure(BHP) compared to other models considering geothermal temperature. Viscous dissipation, the heat produced by friction between the rotating drilling-string and well wall and drill bit drilling, and influx of oil and gas from reservoir have significant impact on the distribution of fluid temperature in the wellbore, which in turn affects the BHP. Bottom-hole fluid temperature decreases with increasing liquid flow rate, circulation time, and specific heat of liquid and gas but it increases with increasing in gas flow rate. It was found that BHP is strongly depended on the gas and liquid flow rates but it has weak dependence on the circulation time and specific heat of liquid and gas. BHP increase with increasing liquid flow rate and decreases with increasing gas flow rate. 展开更多
关键词 under-balanced drilling bottom-hole pressure fluid temperature CUTTINGS three-phase flow model temperature profile wellbore heat transfer
下载PDF
Two-Phase Flow Modeling in a Single Closed Loop Pulsating Heat Pipes
14
作者 杨洪海 Sameer Khandekar +1 位作者 Sanka V. V.S. N.S. Manyam Manfred Groll 《Journal of Donghua University(English Edition)》 EI CAS 2007年第4期439-444,共6页
Mathematical modeling of pulsating heat pipes through ‘first’ principles is a contemporary problem which remains quite elusive. Simplifications and assumptions made in all the modeling approaches developed so far re... Mathematical modeling of pulsating heat pipes through ‘first’ principles is a contemporary problem which remains quite elusive. Simplifications and assumptions made in all the modeling approaches developed so far render them unsuitable for engineering design. In this paper, a more realistic modeling scheme is presented which provides considerable try for thought toward the next progressive step. At high enough heat flux level, closed loop pulsating heat pipes experience a bulk internal unidirectional fluid circulation. Under such a condition, conventional two-phase flow modeling in capillary tubes may be applied. This has been attempted for single-loop PHPs. A homogeneous model and a separated two-fluid flow model based on simultaneous conservation of mass, momentum and energy, have been developed for an equivalent ‘open flow’ system. The model allows prediction of two-phase flow parameters in each sub-section of the device thereby providing important insights into its operation. The concept of ‘void fraction constraint’ in pulsating heat pipe operation is introduced and its relevance to future modeling attempts is outlined. 展开更多
关键词 Closed loop pulsating heat pipe flow modeling parametric influences
下载PDF
A Review of the Dynamic Modeling Approaches for Characterizing Fluid Flow in Naturally Fractured Reservoirs
15
作者 M.N.Tarhuni W.R.Sulaiman +2 位作者 M.Z.Jaafar M.Milad A.M.Alghol 《Energy Engineering》 EI 2021年第4期761-795,共35页
Fluid flow in fractured media has been studied for decades and received considerable attention in the oil and gas industry because of the high productivity of naturally fractured reservoirs.Due to formation complexity... Fluid flow in fractured media has been studied for decades and received considerable attention in the oil and gas industry because of the high productivity of naturally fractured reservoirs.Due to formation complexity and reservoir heterogeneity,characterizing fluid flow with an appropriate reservoir model presents a challenging task that differs relatively from homogeneous conventional reservoirs in many aspects of view,including geological,petrophysical,production,and economics.In most fractured reservoirs,fracture networks create complex pathways that affect hydrocarbon flow,well performance,hence reservoir characterization.A better and comprehensive understanding of the available reservoir modeling approaches is much needed to accurately characterize fluid flow behavior in NFRs.Therefore,in this paper,a perspective review of the available modeling approaches was presented for fluid flow characterization in naturally fractured medium.Modeling methods were evaluated in terms of their description,application,advantages,and disadvantages.This study has also included the applications of these reservoir models in fluid flow characterizing studies and governing equations for fluid flow.Dual continuum models were proved to be better than single continuum models in the presence of large scale fractures.In comparison,discrete models were more appropriate for reservoirs that contain a smaller number of fractures.However,hybrid modeling was the best method to provide accurate and scalable fluid flow modeling.It is our understanding that this paper will bridge the gap between the fundamental understanding and application of NFRs modeling approaches and serve as a useful reference for engineers and researchers for present and future applications. 展开更多
关键词 Naturally fractured reservoirs simulation techniques fluid flow modeling HETEROGENEITY dual continuum modeling discrete fracture network modeling
下载PDF
NUMERICAL MODELING OF TURBULENTEVAPORATING GAS-DROPLET TWO-PHASE FLOWS IN AN AFTERBURNER DIFFUSOR OF TURBO-FAN JET ENGINES
16
作者 Zhou Lixing and Zhang JianTsinghua University 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 1990年第4期258-265,共8页
The two-dimensional turbulent evaporating gas-droplet two-phase flows in an afterburner diffusor of turbo-fan jet engines are simulated by the k-ε turbulence model and the particle trajectory model. Comparison of pre... The two-dimensional turbulent evaporating gas-droplet two-phase flows in an afterburner diffusor of turbo-fan jet engines are simulated by the k-ε turbulence model and the particle trajectory model. Comparison of predicted gas velocity and temperature distributions with experimental results for the cases without liquid spray shows pretty good agreement. Gas-droplet two-phase flow predictions give plausible droplet trajectories, fuel-vapor concentration distribution, gas-phase velocity and temperature field in presence of liquid droplets. One run of computation with this method is made for a particular afterburner. The results indicate that the location of the atomizers is not favorable to flame stabilization and combustion efficiency. The proposed numerical modeling can also be adopted for optimization design and performance evaluation of afterburner combustors of turbo-fan jet engines. 展开更多
关键词 NUMERICAL modeling OF TURBULENTEVAPORATING GAS-DROPLET TWO-PHASE flowS IN AN AFTERBURNER DIFFUSOR OF TURBO-FAN JET ENGINES JET GAS
下载PDF
Simulation Analysis of New Energy Vehicle Engine Cooling System Based on K-E Turbulent Flow Mathematical Model
17
作者 Hongyu Mu Yinyan Wang +7 位作者 Chuanlei Yang Hong Teng Xingtian Zhao Hongquan Lu Dechun Wang Shiyang Hao Xiaolong Zhang Yan Jin 《Energy Engineering》 EI 2023年第10期2325-2342,共18页
New energy vehicles have better clean and environmental protection characteristics than traditional fuel vehicles.The new energy engine cooling technology is critical in the design of new energy vehicles.This paper us... New energy vehicles have better clean and environmental protection characteristics than traditional fuel vehicles.The new energy engine cooling technology is critical in the design of new energy vehicles.This paper used oneand three-way joint simulation methods to simulate the refrigeration system of new energy vehicles.Firstly,a k-εturbulent flow model for the cooling pump flow field is established based on the principle of computational fluid dynamics.Then,the CFD commercial fluid analysis software FLUENT is used to simulate the flow field of the cooling pump under different inlet flow conditions.This paper proposes an optimization scheme for new energy vehicle engines’“boiling”phenomenon under high temperatures and long-time climbing conditions.The simulation results show that changing the radiator’s structure and adjusting the thermostat’s parameters can solve the problem of a“boiling pot.”The optimized new energy vehicle engine can maintain a better operating temperature range.The algorithm model can reference each cryogenic system component hardware selection and control strategy in the new energy vehicle’s engine. 展开更多
关键词 New energy vehicle new energy vehicle engine k-ε turbulent flow mathematical model cooling system PID control
下载PDF
Viscoelastic modeling of the diffusion of polymeric pollutants injected into a pipe flow
18
作者 T.Chinyoka O.D. Makinde 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第2期166-178,共13页
This study focuses on the transient analysis of nonlinear dispersion of a polymeric pollutant ejected by an external source into a laminar pipe flow of a Newtonian liquid under axi-symmetric conditions.The influence o... This study focuses on the transient analysis of nonlinear dispersion of a polymeric pollutant ejected by an external source into a laminar pipe flow of a Newtonian liquid under axi-symmetric conditions.The influence of density variation with pollutant concentration is approximated according to the Boussinesq approximation and the nonlinear governing equations of momentum,pollutant concentration are obtained together with and Oldroyd-B constitutive model for the polymer stress.The problem is solved numerically using a semi-implicit finite difference method.Solutions are presented in graphical form for various parameter values and given in terms of fluid velocity,pollutant concentration,polymer stress components,skin friction and wall mass transfer rate.The model can be a useful tool in understanding the dynamics of industrial pollution situations arising from improper discharge of hydrocarbon pollutants into,say,water bodies.The model can also be quite useful for available necessary early warning methods for detecting or predicting the scale of pollution and hence help mitigate related damage downstream by earlier instituting relevant decontamination measures. 展开更多
关键词 Axi-symmetric flow·Polymeric pollutant dispersion·Oldroyd-B model Buoyancy forces·Semi-implicit finite difference method
下载PDF
Gray domain modeling of regional Karst groundwater flow system——a case study on the Karst system in a hydropower station area
19
《Global Geology》 1998年第1期74-74,共1页
关键词 a case study on the Karst system in a hydropower station area flow Gray domain modeling of regional Karst groundwater flow system CASE
下载PDF
Numerical Simulation of Diffusion Type Traffic Flow Model Using Second-Order Lax-Wendroff Scheme Based on Exponential Velocity Density Function
20
作者 Mojammel Haque Mariam Sultana Laek Sazzad Andallah 《American Journal of Computational Mathematics》 2023年第3期398-411,共14页
In order to control traffic congestion, many mathematical models have been used for several decades. In this paper, we study diffusion-type traffic flow model based on exponential velocity density relation, which prov... In order to control traffic congestion, many mathematical models have been used for several decades. In this paper, we study diffusion-type traffic flow model based on exponential velocity density relation, which provides a non-linear second-order parabolic partial differential equation. The analytical solution of the diffusion-type traffic flow model is very complicated to approximate the initial density of the Cauchy problem as a function of x from given data and it may cause a huge error. For the complexity of the analytical solution, the numerical solution is performed by implementing an explicit upwind, explicitly centered, and second-order Lax-Wendroff scheme for the numerical solution. From the comparison of relative error among these three schemes, it is observed that Lax-Wendroff scheme gives less error than the explicit upwind and explicit centered difference scheme. The numerical, analytical analysis and comparative result discussion bring out the fact that the Lax-Wendroff scheme with exponential velocity-density relation of diffusion type traffic flow model is suitable for the congested area and shows a better fit in traffic-congested regions. 展开更多
关键词 Traffic Congestion Diffusion Type Traffic flow Model Analytical Solution Numerical Solution Lax-Wendroff Scheme
下载PDF
上一页 1 2 12 下一页 到第
使用帮助 返回顶部