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Dynamic simulation based optimized design method of concrete production system for RCC dam

ZHAO Chunju, ZHOU Yihong

《结构与土木工程前沿(英文)》 2007年 第1卷 第4期   页码 405-410 doi: 10.1007/s11709-007-0055-6

摘要: The construction system of roller compacted concrete (RCC) dam is running according to a series of connected procedures which are highly impacted and interacted consisting with the resource level. Therefore, a dynamic simulation mode

关键词: interacted     dynamic simulation     construction     resource     RCC    

Dynamic simulation of urban water metabolism under water environmental carrying capacity restrictions

Weihua ZENG,Bo WU,Ying CHAI

《环境科学与工程前沿(英文)》 2016年 第10卷 第1期   页码 114-128 doi: 10.1007/s11783-014-0669-6

摘要: A revised concept for urban water metabolism (UWM) is presented in this study to address the inadequacies in current research on UWM and the problems associated with the traditional urban water metabolic process. Feedback loops can be analyzed to increase the water environmental carrying capacity (WECC) of the new urban water metabolism system (UWMS) over that of a traditional UWMS. An analysis of the feedback loops of an UWMS was used to construct a system dynamics (SD) model for the system under a WECC restriction. Water metabolic processes were simulated for different scenarios using the Tongzhou District in Beijing as an example. The results for the newly developed UWM case showed that a water environment of Tongzhou District could support a population of 1.1926 × 10 , an irrigation area of 375.521 km , a livestock of 0.7732 × 10 , and an industrial value added of ¥193.14 × 10 (i.e. about US$28.285× 10 ) in 2020. A sensitivity analysis showed that the WECC could be improved to some extent by constructing new sewage treatment facilities or by expanding the current sewage treatment facilities, using reclaimed water and improving the water circulation system.

关键词: urban water metabolism system (UWMS)     system dynamic simulation     water environmental carrying capacity (WECC)     feedback loops     bilateral control    

Dynamic simulation of a space gas-cooled reactor power system with a closed Brayton cycle

《能源前沿(英文)》 2021年 第15卷 第4期   页码 916-929 doi: 10.1007/s11708-021-0757-9

摘要: Space nuclear reactor power (SNRP) using a gas-cooled reactor (GCR) and a closed Brayton cycle (CBC) is the ideal choice for future high-power space missions. To investigate the safety characteristics and develop the control strategies for gas-cooled SNRP, transient models for GCR, energy conversion unit, pipes, heat exchangers, pump and heat pipe radiator are established and a system analysis code is developed in this paper. Then, analyses of several operation conditions are performed using this code. In full-power steady-state operation, the core hot spot of 1293 K occurs near the upper part of the core. If 0.4 $ reactivity is introduced into the core, the maximum temperature that the fuel can reach is 2059 K, which is 914 K lower than the fuel melting point. The system finally has the ability to achieve a new steady-state with a higher reactor power. When the GCR is shut down in an emergency, the residual heat of the reactor can be removed through the conduction of the core and radiation heat transfer. The results indicate that the designed GCR is inherently safe owing to its negative reactivity feedback and passive decay heat removal. This paper may provide valuable references for safety design and analysis of the gas-cooled SNRP coupled with CBC.

关键词: gas-cooled space nuclear reactor power     closed Brayton cycle     system startup and shutdown     positive reactivity insertion accident    

基于GIS的地震火灾动态蔓延模拟

谢旭阳,任爱珠

《中国工程科学》 2007年 第9卷 第8期   页码 82-87

摘要:

用惠更斯原理对震后火灾的动态蔓延过程进行了模拟,并开发了基于GIS的城市地震次生火灾动态蔓延模拟系统,该系统可以模拟单个 或者多个起火点的动态蔓延过程。研究结果可以定量地估计地震次生火灾对城市的危害,从而在最短时间内给救灾应急提供决策依据。

关键词: 地震次生火灾     GIS     火灾动态蔓延     模拟系统    

Analysis of dispatching rules in a stochastic dynamic job shop manufacturing system with sequence-dependent

Pankaj SHARMA,Ajai JAIN

《机械工程前沿(英文)》 2014年 第9卷 第4期   页码 380-389 doi: 10.1007/s11465-014-0315-9

摘要:

Stochastic dynamic job shop scheduling problem with consideration of sequence-dependent setup times are among the most difficult classes of scheduling problems. This paper assesses the performance of nine dispatching rules in such shop from makespan, mean flow time, maximum flow time, mean tardiness, maximum tardiness, number of tardy jobs, total setups and mean setup time performance measures viewpoint. A discrete event simulation model of a stochastic dynamic job shop manufacturing system is developed for investigation purpose. Nine dispatching rules identified from literature are incorporated in the simulation model. The simulation experiments are conducted under due date tightness factor of 3, shop utilization percentage of 90 % and setup times less than processing times. Results indicate that shortest setup time (SIMSET) rule provides the best performance for mean flow time and number of tardy jobs measures. The job with similar setup and modified earliest due date (JMEDD) rule provides the best performance for makespan, maximum flow time, mean tardiness, maximum tardiness, total setups and mean setup time measures.

关键词: scheduling     stochastic dynamic job shop     sequence-dependent setup times     dispatching rule     simulation    

Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

《能源前沿(英文)》 2019年 第13卷 第1期   页码 185-192 doi: 10.1007/s11708-017-0452-z

摘要: Solar absorption-subcooled compression hybrid refrigeration system is a new type of efficient and economical solar refrigeration device which always meets the demand of cooling load with the change of solar irradiance. The performance of the hybrid system is higher due to the improvement of evaporator temperature of absorption subsystem. But simultaneously, the variation of working process as well as performance is complicated since the absorption and compression subsystems are coupled strongly. Based on the measured meteorological data of Guangzhou, a subtropical city in south China, a corresponding parametric model has been developed for the hybrid refrigeration system, and a program written by Fortran has been used to analyze the performance of the hybrid system under different external conditions. As the condensation temperature ranges from 38°C to 50°C, the working time fraction of the absorption subsystem increases from 75% to 85%. Besides, the energy saving fraction also increases from 5.31% to 6.02%. The average COP of the absorption subsystem is improved from 0.366 to 0.407. However, when the temperature of the absorption increases from 36°C to 48°C, the average COP of hybrid system decreases from 2.703 to 2.312. Moreover, the working time fraction of the absorption subsystem decreases from 80% to 71.7%. The energy saving fraction falls from 5.67% to 5.08%. In addition, when the evaporate temperature increases from 4°C to 14°C, the average COP of the absorption subsystem decreases from 0.384 to 0.365. The work of the compressor decreases from 48.2 kW to 32.8 kW and the corresponding average COP of the absorption subsystem is improved from 2.591 to 3.082.

关键词: solar     absorption-subcooled     compression hybrid     dynamic simulation     performance analysis    

Molecular dynamic simulation on the conformation of mouse muscle type nAChR

Shengai SUN, Rilei YU, Yanhui ZHANG, Yanni LI,

《化学科学与工程前沿(英文)》 2010年 第4卷 第3期   页码 348-352 doi: 10.1007/s11705-009-0284-4

摘要: A mouse muscle type nAChR model ((α1)βδγ) was built based on the cryoelectron microscopic structure of intact nAChR and the high resolution crystal structure of nAChR-α1 subunit. The conformation of the pentameric nAChR model was investigated by molecular dynamic simulation. The function of water molecule in the hydrophilic interior was clarified. The reason for Tyr127 showing two alternative conformations was discussed in detail.

关键词: pentameric     hydrophilic     Tyr127     cryoelectron microscopic     conformation    

Dynamic simulation of gas turbines via feature similarity-based transfer learning

Dengji ZHOU, Jiarui HAO, Dawen HUANG, Xingyun JIA, Huisheng ZHANG

《能源前沿(英文)》 2020年 第14卷 第4期   页码 817-835 doi: 10.1007/s11708-020-0709-9

摘要: Since gas turbine plays a key role in electricity power generating, the requirements on the safety and reliability of this classical thermal system are becoming gradually strict. With a large amount of renewable energy being integrated into the power grid, the request of deep peak load regulation for satisfying the varying demand of users and maintaining the stability of the whole power grid leads to more unstable working conditions of gas turbines. The startup, shutdown, and load fluctuation are dominating the operating condition of gas turbines. Hence simulating and analyzing the dynamic behavior of the engines under such instable working conditions are important in improving their design, operation, and maintenance. However, conventional dynamic simulation methods based on the physic differential equations is unable to tackle the uncertainty and noise when faced with variant real-world operations. Although data-driven simulating methods, to some extent, can mitigate the problem, it is impossible to perform simulations with insufficient data. To tackle the issue, a novel transfer learning framework is proposed to transfer the knowledge from the physics equation domain to the real-world application domain to compensate for the lack of data. A strong dynamic operating data set with steep slope signals is created based on physics equations and then a feature similarity-based learning model with an encoder and a decoder is built and trained to achieve feature adaptive knowledge transferring. The simulation accuracy is significantly increased by 24.6% and the predicting error reduced by 63.6% compared with the baseline model. Moreover, compared with the other classical transfer learning modes, the method proposed has the best simulating performance on field testing data set. Furthermore, the effect study on the hyper parameters indicates that the method proposed is able to adaptively balance the weight of learning knowledge from the physical theory domain or from the real-world operation domain.

关键词: gas turbine     dynamic simulation     data-driven     transfer learning     feature similarity    

Decision support for the development, simulation and optimization of dynamic process models

Norbert Asprion, Roger Böttcher, Jan Schwientek, Johannes Höller, Patrick Schwartz, Charlie Vanaret, Michael Bortz

《化学科学与工程前沿(英文)》 2022年 第16卷 第2期   页码 210-220 doi: 10.1007/s11705-021-2046-x

摘要: Simulation is besides experimentation the major method for designing, analyzing and optimizing chemical processes. The ability of simulations to reflect real process behavior strongly depends on model quality. Validation and adaption of process models are usually based on available plant data. Using such a model in various simulation and optimization studies can support the process designer in his task. Beneath steady state models there is also a growing demand for dynamic models either to adapt faster to changing conditions or to reflect batch operation. In this contribution challenges of extending an existing decision support framework for steady state models to dynamic models will be discussed and the resulting opportunities will be demonstrated for distillation and reactor examples.

关键词: decision support     multicriteria optimization     model validation     dynamic model     sensitivity analysis    

of carbon dioxide photoreduction process in a laboratory-scale photoreactor by computational fluid dynamic

《化学科学与工程前沿(英文)》 2022年 第16卷 第7期   页码 1149-1163 doi: 10.1007/s11705-021-2096-0

摘要: The production of solar fuels via the photoreduction of carbon dioxide to methane by titanium oxide is a promising process to control greenhouse gas emissions and provide alternative renewable fuels. Although several reaction mechanisms have been proposed, the detailed steps are still ambiguous, and the limiting factors are not well defined. To improve our understanding of the mechanisms of carbon dioxide photoreduction, a multiphysics model was developed using COMSOL. The novelty of this work is the computational fluid dynamic model combined with the novel carbon dioxide photoreduction intrinsic reaction kinetic model, which was built based on three-steps, namely gas adsorption, surface reactions and desorption, while the ultraviolet light intensity distribution was simulated by the Gaussian distribution model and Beer-Lambert model. The carbon dioxide photoreduction process conducted in a laboratory-scale reactor under different carbon dioxide and water moisture partial pressures was then modeled based on the intrinsic kinetic model. It was found that the simulation results for methane, carbon monoxide and hydrogen yield match the experiments in the concentration range of 10−4 mol·m–3 at the low carbon dioxide and water moisture partial pressure. Finally, the factors of adsorption site concentration, adsorption equilibrium constant, ultraviolet light intensity and temperature were evaluated.

关键词: carbon dioxide photoreduction     computational fluid dynamic simulation     kinetic model     Langmuir adsorption    

Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

Wenpo REN, Honggang CHEN, Chaohe YANG, Honghong SHAN,

《化学科学与工程前沿(英文)》 2010年 第4卷 第3期   页码 250-256 doi: 10.1007/s11705-009-0281-7

摘要: Two kinds of heavy oils were fractionated into eight fractions by Liquid-Solid Adsorption Chromatography, respectively, and samples were collected to measure properties. According to the elemental analysis, molecular weight and H-NMR data, average molecular structures of polycyclic aromatic and heavy resin were constructed with improved Brown-Ladner (B-L) method and several corrections. And then, the most stable conformations of polycyclic aromatic and heavy resin in vacuum and toluene solution were obtained by molecular dynamic simulation, and the molecular size was gotten via the radius of gyration analysis. The results showed that the radius of gyration of polycyclic aromatic and heavy resin was 0.55–0.70 nm in vacuum and 0.60–0.90 nm in toluene solution. With molecular weight increasing, the molecular size in vacuum and toluene solution also increased. Due to the swelling behavior of solvent, the alkyl side chains of heavy oil molecule in solution were more stretched. Thus, the molecular size in toluene solution was larger than that in vacuum.

关键词: dynamic simulation     molecular dynamic     behavior     molecule     Adsorption Chromatography    

基于虚拟现实的截流施工动态可视化仿真研究

佟大威

《中国工程科学》 2011年 第13卷 第12期   页码 80-83

摘要:

利用虚拟现实和3dsmax技术进行了截流施工场景三维仿真建模,并在此基础上,结合龙口水力指标的动态计算,提出了基于虚拟现实的截流施工三维动态可视化仿真技术,实现了截流过程的逼真预演和多方案的比较分析,从而为截流组织设计与决策提供了强有力的可视化分析手段。

关键词: 虚拟现实     截流     三维动态     可视化仿真    

Model reduction of contact dynamics simulation using a modified Lyapunov balancing method

Jianxun LIANG, Ou MA, Caishan LIU

《机械工程前沿(英文)》 2011年 第6卷 第4期   页码 383-391 doi: 10.1007/s11465-011-0244-9

摘要:

Finite element models are often used to simulate impact and contact dynamics responses of multibody dynamical systems. However, such a simulation remains very inefficient because very small integration time step must be used when solving the involved differential equations, especially when the involved contact stiffness is high. Although many model reduction techniques have been available to improve the efficiency of finite element based simulations, these techniques cannot be readily applied to contact dynamics simulations due to the high nonlinearity of the contact dynamics models. This paper presents a model reduction approach for finite-element based multibody contact dynamics simulation, based on a modified Lyapunov balanced truncation method. An example is presented to demonstrate that, by applying the model reduction the simulation process is significantly speeded up and the resulting error is bounded within an acceptable level. The performance of the method with respect to some influential factors such as element size, shape and contact stiffness is also investigated.

关键词: contact dynamics     dynamic simulation     model reduction     finite element method    

Dynamic modelling and simulation of a post-combustion CO capture process for coal-fired power plants

《化学科学与工程前沿(英文)》 2022年 第16卷 第2期   页码 198-209 doi: 10.1007/s11705-021-2057-7

摘要: Solvent-based post-combustion capture technologies have great potential for CO2 mitigation in traditional coal-fired power plants. Modelling and simulation provide a low-cost opportunity to evaluate performances and guide flexible operation. Composed by a series of partial differential equations, first-principle post-combustion capture models are computationally expensive, which limits their use in real time process simulation and control. In this study, we propose a first-principle approach to develop the basic structure of a reduced-order model and then the dominant factor is used to fit properties and simplify the chemical and physical process, based on which a universal and hybrid post-combustion capture model is established. Model output at steady state and trend at dynamic state are validated using experimental data obtained from the literature. Then, impacts of liquid-to-gas ratio, reboiler power, desorber pressure, tower height and their combination on the absorption and desorption effects are analyzed. Results indicate that tower height should be designed in conjunction with the flue gas flow, and the gas-liquid ratio can be optimized to reduce the reboiler power under a certain capture target.

关键词: CO2 capture     post-combustion capture     simulation     dominant factor    

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 28-36 doi: 10.1007/s11465-008-0007-4

摘要: This research focuses on the characteristics of how a ball-screw changes its temperature corresponding to the periodic change of the end-most heat source. Based on the theory of heat transfer, this paper supplies a numerical solution to the non-homogeneous equation of heat transfer through the group explicit (GE) finite difference approach. The temperature distribution for the ball-screw at different times and directions is shown. By simulating and modeling the temperature field and thermal deformation of the ball-screw under periodically varying heat sources, this paper describes the thermal dynamic characteristics of the ball-screw under such conditions. By testing the thermal dynamic characteristics of the ball-screw, the numerical solution is validated.

关键词: numerical solution     temperature corresponding     temperature distribution     end-most     ball-screw    

标题 作者 时间 类型 操作

Dynamic simulation based optimized design method of concrete production system for RCC dam

ZHAO Chunju, ZHOU Yihong

期刊论文

Dynamic simulation of urban water metabolism under water environmental carrying capacity restrictions

Weihua ZENG,Bo WU,Ying CHAI

期刊论文

Dynamic simulation of a space gas-cooled reactor power system with a closed Brayton cycle

期刊论文

基于GIS的地震火灾动态蔓延模拟

谢旭阳,任爱珠

期刊论文

Analysis of dispatching rules in a stochastic dynamic job shop manufacturing system with sequence-dependent

Pankaj SHARMA,Ajai JAIN

期刊论文

Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

期刊论文

Molecular dynamic simulation on the conformation of mouse muscle type nAChR

Shengai SUN, Rilei YU, Yanhui ZHANG, Yanni LI,

期刊论文

Dynamic simulation of gas turbines via feature similarity-based transfer learning

Dengji ZHOU, Jiarui HAO, Dawen HUANG, Xingyun JIA, Huisheng ZHANG

期刊论文

Decision support for the development, simulation and optimization of dynamic process models

Norbert Asprion, Roger Böttcher, Jan Schwientek, Johannes Höller, Patrick Schwartz, Charlie Vanaret, Michael Bortz

期刊论文

of carbon dioxide photoreduction process in a laboratory-scale photoreactor by computational fluid dynamic

期刊论文

Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

Wenpo REN, Honggang CHEN, Chaohe YANG, Honghong SHAN,

期刊论文

基于虚拟现实的截流施工动态可视化仿真研究

佟大威

期刊论文

Model reduction of contact dynamics simulation using a modified Lyapunov balancing method

Jianxun LIANG, Ou MA, Caishan LIU

期刊论文

Dynamic modelling and simulation of a post-combustion CO capture process for coal-fired power plants

期刊论文

Numerical solution, simulation and testing of the thermal dynamic characteristics of ball-screws

XIA Junyong, HU Youmin, WU Bo, SHI Tielin

期刊论文