With the aim of visualizing the real-time simulation calculation of water delivery system (WDS), a structural drawing-oriented (SDO) simulation technique was presented, and applied to Zhangjiuhe Diversion Project, whi...With the aim of visualizing the real-time simulation calculation of water delivery system (WDS), a structural drawing-oriented (SDO) simulation technique was presented, and applied to Zhangjiuhe Diversion Project, which is a long-distance water delivery system constructed for draw- ing water from the Zhangjiuhe River to Kunming city. Taking SIMULINK software as simulating plat-form, the technique established a visual dynamic simulation model for the system. The simulation procedure of the system was simplified,and the efficiency of modeling was also enhanced according to the modularization and reutilization of the simulation program. Furthermore, a self-optimization model was presented. Based on the digital simulation models, the on line controlled optimization link was added, and the input data can be continually optimized according to the feedback information of simulating output. The system was thus optimized automatically. Built upon MATLAB software, simulation optimization of the Zhangjiuhe Diversion Project was achieved, which provides a new way for the research of optimal operation of WDS.展开更多
In this paper, a bidirectional partial generalized （lag, complete, and anticipated） synchronization of a class of continuous-time systems is defined. Then based on the active control idea, a new systematic and concr...In this paper, a bidirectional partial generalized （lag, complete, and anticipated） synchronization of a class of continuous-time systems is defined. Then based on the active control idea, a new systematic and concrete scheme is developed to achieve bidirectional partial generalized （lag, complete, and anticipated） synchronization between two chaotic systems or between chaotic and hyperchaotic systems. With the help of symbolic-numerical computation, we choose the modified Chua system, Lorenz system, and the hyperchaotic Tamasevicius Namajunas-Cenys system to illustrate the proposed scheme. Numerical simulations are used to verify the effectiveness of the proposed scheme. It is interesting that partial chaos synchronization not only can take place between two chaotic systems, but also can take place between chaotic and hyperchaotic systems. The proposed scheme can also be extended to research bidirectional partial generalized （lag, complete, and anticipated） synchronization between other dynamical systems.展开更多
A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method whi...A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method which combines sedimentation simulation and simulated annealing （SA） method to generate 3-D digital cores based on 2-D images of rocks. The method starts with the sedimentation simulation to build a 3-D digital core, which is the initial configuration for the SA method. We update the initial digital core using the SA method to match the auto-correlation function of the 2-D rock image and eventually build the final 3-D digital core. Compared with the typical SA method, the hybrid method has significantly reduced the computation time. Local porosity theory is applied to quantitatively compare the reconstructed 3-D digital cores with the X-ray micro CT 3-D images. The results indicate that the 3-D digital cores reconstructed by the hybrid method have homogeneity and geometric connectivity similar to those of the X-ray micro CT image. The formation factors and permeabilities of the reconstructed 3-D digital cores are estimated using the finite element method （FEM） and lattice Boltzmann method （LBM）, respectively. The simulated results are in good agreement with the experimental measurements. Comparison of the simulation results suggests that the digital cores reconstructed by the hybrid method more closely reflect the true transport properties than the typical SA method alone.展开更多
The variations of ocean environmental parameters invariably result in variations of local modal wave numbers of a sound pressure field. The asymptotic Hankel transform with a short sliding window is applied to the com...The variations of ocean environmental parameters invariably result in variations of local modal wave numbers of a sound pressure field. The asymptotic Hankel transform with a short sliding window is applied to the complex sound pressure field in the water containing a mesoscale eddy to examine the variation of local modal wave numbers in such a range-dependent environment. The numerical simulation results show that modal wave number spectra obtained by this method can reflect the location and strength of a mesoscale eddy, therefore it can be used to monitor the strength and spatial scale of ocean mesoscale eddies.展开更多
One of the significant differences between the digital system and the analog system is software. The software takes charge of the functions and the management of the digital system. Nowadays railway equipment has begu...One of the significant differences between the digital system and the analog system is software. The software takes charge of the functions and the management of the digital system. Nowadays railway equipment has begun to be designed and implemented based on digital technology with online and real time performance to achieve high speed and high density operation. The software is designed, coded and implemented into the system, and controls hardware components in order to satisfy the functional requirements of the system. As the functions that are implemented by software are increased, it becomes very difficult to predict the soil-ware failures because of its complexity. Therefore, it has become one of the key issues how to assure that the sottware is reliable, safe and secure. In this paper, the safety criteria are suggested to secure the software safety for the field of railway system. Characteristic of railway software and review safety related standards are analyzed. The authors also suggest development methodology and certification procedure for the developer and assessor to easily make safety critical railway software with following the safety criteria.展开更多
The paper deals with development and application the numerical model for solution of processes at combustion chamber of the thermal power plant boiler. Mathematical simulation is based on solution of physical and chem...The paper deals with development and application the numerical model for solution of processes at combustion chamber of the thermal power plant boiler. Mathematical simulation is based on solution of physical and chemical processes occuring at burning pulverized coal in the furnace model. Three-dimensional flows, heat and mass transfer, chemical kinetics of the processes, effects of thermal radiation are considered. Obtained results give quantitative information on velocity distributions, temperature and concentration profiles of the components, the amount of combustion products including harmful substances. The numerical model becomes a tool for investigation and design of combustion chambers with high-efficiency and reliable operation of boiler at thermal power plants.展开更多
This study presents the concept of a cyclone furnace for coal dust oxy-fuel combustion and gasification. The results of numerical calculations for the combustion and gasification processes were also presented.
Based on the basic idea of zone modeling method, a two-layer zone model is developed and programmed to calculate the fire growth and smoke spread in a multi-room building subjected to a fire.The related predictiVe equ...Based on the basic idea of zone modeling method, a two-layer zone model is developed and programmed to calculate the fire growth and smoke spread in a multi-room building subjected to a fire.The related predictiVe equations, numerical simulation method and sub-models implemented in this model are concisely described. A set of experimental data from Cooper’s work at NIST for a two-room compatment fire are chosen for comparison with the model and program, and the numerical results fundamentally agree well with the experimental data. Then, an example of numerical calculation of a two-story building fire is presented, and the relevant output results are given and analyzed.展开更多
A mathematical model for atmospheric staged circulating fluidized bed combustion, which takes fluiddynamics, combustion, heat transfer, pollutants formation and retention, into account was developedin the Institute of...A mathematical model for atmospheric staged circulating fluidized bed combustion, which takes fluiddynamics, combustion, heat transfer, pollutants formation and retention, into account was developedin the Institute of Engineering Thermophysics (IET) recently. The model of gas solid flow at the bot-tom of the combustor was treated by the tworphase theory of fluidized bed and in the upper regionas a core-sannulus flow structure. The chemical species CO, CO2, H2, H2O, CH4, O2 and N2 wereconsidered in the reaction process. The mathematical model consisted of sub-models of fluid namics,coal heterogeneous and gas homogeneous chemical reactions, heat transfer, particle fragmentation andattrition, mass and energy balance etc. The developed code was applied to simulate an operating stagedcirculating fluidized bed combustion boiler of early design and the results were in good agreement withthe operating data. The main submodels and simulation results are given in this paper.展开更多
基金National Natural Science Foundation of China(No.50179032)Natural Science Foundation of Tianjin(No.000345)
文摘With the aim of visualizing the real-time simulation calculation of water delivery system (WDS), a structural drawing-oriented (SDO) simulation technique was presented, and applied to Zhangjiuhe Diversion Project, which is a long-distance water delivery system constructed for draw- ing water from the Zhangjiuhe River to Kunming city. Taking SIMULINK software as simulating plat-form, the technique established a visual dynamic simulation model for the system. The simulation procedure of the system was simplified,and the efficiency of modeling was also enhanced according to the modularization and reutilization of the simulation program. Furthermore, a self-optimization model was presented. Based on the digital simulation models, the on line controlled optimization link was added, and the input data can be continually optimized according to the feedback information of simulating output. The system was thus optimized automatically. Built upon MATLAB software, simulation optimization of the Zhangjiuhe Diversion Project was achieved, which provides a new way for the research of optimal operation of WDS.
基金The author thanks the referees for their valuable suggestions and is very grateful to Dr. Yan Zhen-Ya for his enthusiastic guidance and help.
文摘In this paper, a bidirectional partial generalized （lag, complete, and anticipated） synchronization of a class of continuous-time systems is defined. Then based on the active control idea, a new systematic and concrete scheme is developed to achieve bidirectional partial generalized （lag, complete, and anticipated） synchronization between two chaotic systems or between chaotic and hyperchaotic systems. With the help of symbolic-numerical computation, we choose the modified Chua system, Lorenz system, and the hyperchaotic Tamasevicius Namajunas-Cenys system to illustrate the proposed scheme. Numerical simulations are used to verify the effectiveness of the proposed scheme. It is interesting that partial chaos synchronization not only can take place between two chaotic systems, but also can take place between chaotic and hyperchaotic systems. The proposed scheme can also be extended to research bidirectional partial generalized （lag, complete, and anticipated） synchronization between other dynamical systems.
基金sponsored by NSFC(Grant No.40574030)CNPC Research Project(Grant No.06A30102)
文摘A 3-D digital core describes the pore space microstructure of rocks. An X-ray micro CT scan is the most accurate and direct but costly method to obtain a 3-D digital core. In this study, we propose a hybrid method which combines sedimentation simulation and simulated annealing （SA） method to generate 3-D digital cores based on 2-D images of rocks. The method starts with the sedimentation simulation to build a 3-D digital core, which is the initial configuration for the SA method. We update the initial digital core using the SA method to match the auto-correlation function of the 2-D rock image and eventually build the final 3-D digital core. Compared with the typical SA method, the hybrid method has significantly reduced the computation time. Local porosity theory is applied to quantitatively compare the reconstructed 3-D digital cores with the X-ray micro CT 3-D images. The results indicate that the 3-D digital cores reconstructed by the hybrid method have homogeneity and geometric connectivity similar to those of the X-ray micro CT image. The formation factors and permeabilities of the reconstructed 3-D digital cores are estimated using the finite element method （FEM） and lattice Boltzmann method （LBM）, respectively. The simulated results are in good agreement with the experimental measurements. Comparison of the simulation results suggests that the digital cores reconstructed by the hybrid method more closely reflect the true transport properties than the typical SA method alone.
文摘The variations of ocean environmental parameters invariably result in variations of local modal wave numbers of a sound pressure field. The asymptotic Hankel transform with a short sliding window is applied to the complex sound pressure field in the water containing a mesoscale eddy to examine the variation of local modal wave numbers in such a range-dependent environment. The numerical simulation results show that modal wave number spectra obtained by this method can reflect the location and strength of a mesoscale eddy, therefore it can be used to monitor the strength and spatial scale of ocean mesoscale eddies.
文摘One of the significant differences between the digital system and the analog system is software. The software takes charge of the functions and the management of the digital system. Nowadays railway equipment has begun to be designed and implemented based on digital technology with online and real time performance to achieve high speed and high density operation. The software is designed, coded and implemented into the system, and controls hardware components in order to satisfy the functional requirements of the system. As the functions that are implemented by software are increased, it becomes very difficult to predict the soil-ware failures because of its complexity. Therefore, it has become one of the key issues how to assure that the sottware is reliable, safe and secure. In this paper, the safety criteria are suggested to secure the software safety for the field of railway system. Characteristic of railway software and review safety related standards are analyzed. The authors also suggest development methodology and certification procedure for the developer and assessor to easily make safety critical railway software with following the safety criteria.
基金funded by the Ministry of Education and Science of Kazakhstan Republic,№0112РК01095support from the Technology Agency of the Czech Republic in the frame of the Competence Centre Advanced Technology of Heat and Electricity Output,No.TE01020036
文摘The paper deals with development and application the numerical model for solution of processes at combustion chamber of the thermal power plant boiler. Mathematical simulation is based on solution of physical and chemical processes occuring at burning pulverized coal in the furnace model. Three-dimensional flows, heat and mass transfer, chemical kinetics of the processes, effects of thermal radiation are considered. Obtained results give quantitative information on velocity distributions, temperature and concentration profiles of the components, the amount of combustion products including harmful substances. The numerical model becomes a tool for investigation and design of combustion chambers with high-efficiency and reliable operation of boiler at thermal power plants.
文摘This study presents the concept of a cyclone furnace for coal dust oxy-fuel combustion and gasification. The results of numerical calculations for the combustion and gasification processes were also presented.
文摘Based on the basic idea of zone modeling method, a two-layer zone model is developed and programmed to calculate the fire growth and smoke spread in a multi-room building subjected to a fire.The related predictiVe equations, numerical simulation method and sub-models implemented in this model are concisely described. A set of experimental data from Cooper’s work at NIST for a two-room compatment fire are chosen for comparison with the model and program, and the numerical results fundamentally agree well with the experimental data. Then, an example of numerical calculation of a two-story building fire is presented, and the relevant output results are given and analyzed.
文摘A mathematical model for atmospheric staged circulating fluidized bed combustion, which takes fluiddynamics, combustion, heat transfer, pollutants formation and retention, into account was developedin the Institute of Engineering Thermophysics (IET) recently. The model of gas solid flow at the bot-tom of the combustor was treated by the tworphase theory of fluidized bed and in the upper regionas a core-sannulus flow structure. The chemical species CO, CO2, H2, H2O, CH4, O2 and N2 wereconsidered in the reaction process. The mathematical model consisted of sub-models of fluid namics,coal heterogeneous and gas homogeneous chemical reactions, heat transfer, particle fragmentation andattrition, mass and energy balance etc. The developed code was applied to simulate an operating stagedcirculating fluidized bed combustion boiler of early design and the results were in good agreement withthe operating data. The main submodels and simulation results are given in this paper.
