电液比例变量泵控定量马达调速特性研究

以电液比例变量泵-定量马达恒速控制系统为研究对象,详细阐述了变量泵电液比例变量机构的控制原理,分析了变量泵的斜盘机构受力情况,推导了变量机构和泵控马达系统的数学模型.分别在仿真软件MATLAB/Simulink和AMESim上建立变量机构和变量泵控马达系统的仿真模型,对变量机构响应时间和马达输出转速响应进行了仿真研究和试验对比.利用发电机为恒转速负载,进行了实车试验.在突加/突减16 kW负载的试验中,马达转速在3 s内恢复到设定值,稳态的波动率为0.29%,瞬态调整率为6.0%.分析结果表明,电液比例变量泵控马达系统作为柴油机和恒转速负载之间的调速机构和动力传递纽带是可行的.     

采暖系统使用水银温度计室温测试误差及校正

通过建立室温测试动态模型及仿真，得出必要的测试时间。模拟了外温、测试室温、窗墙比和真实室温之间关系并给出修正图。为提高测试精度，提出和模拟降低误差方法。     

Plant refurbishment in historical buildings turned into museum

Suitable conditioning plant design is only one aspect of a wide problem that concerns thermo-physical building performance and then building envelope characteristics quality. This is really very important when a building is a museum and work of art at the same time, like the Hall of the Five Hundred that is the object of our study. Its need for conditioning is due to its prestige utilization for public meetings; but it must be seen as connected to different interventions for energy saving and rational energy use. Because of the architectural structure of the Hall and lack of space for plant allocation, the solution proposed in this paper is based on the minimum impact and reversibility concept. A movable platform on the existing floor that can hold all plants was proposed. This thin radiant panel solution was studied by a CFD simulation based on the finite volume method in transient conditions. In order to obtain reliable information concerning the fluid dynamic and thermal fields, the simulations were performed by using experimental data carried out by the Opificio delle Pietre Dure as comparison.     

数值模拟在外延阶梯型中庭空调设计中的应用

本文采用CFD软件对外延阶梯型中庭室内热环境进行数值模拟,不仅预测和验证了热环境的舒适性,而且根据模拟结果得出该建筑的空调负荷。为该类中庭的建筑形式设计、室内舒适性和节能设计提供了参考依据。     

Transition to a sustainable urban energy system from a long-term perspective: Case study in a Japanese business district

This paper investigates alternative prospects for an urban energy system from a long-term perspective in order to achieve a reduction in CO₂ emission by more than 50% of the current emission in the Japanese commercial sector. This will assist in making strategic choices with regard to the implementation of available technologies in order to create a substantial change. A simulation model based on the bottom-up approach – a fundamental part of the evaluation framework of technology implementation scenarios – provides insights into the changes required in all the components of urban energy systems from the equipment level to the entire building and systems level and finally to the neighborhood and city levels. This model is applied to the Yodoyabashi district, a central business district in Osaka, Japan, in order to predict the end-use energy consumption and CO₂ emission under various scenarios. This is based on different concepts of community energy management. The results of this case study suggest that we can achieve a reduction of 60–90% of the current CO₂ emission by the middle of the 21st century.     

Planning gang formwork operations for building construction using simulations

Concrete formwork is a labor-intensive and time-consuming operation. Many modular formwork systems have been developed to automate the process. Such systems improve the productivity as well as the cost-effectiveness of the operation. However, proper planning for the form reuse schemes in the design as well as the construction phases of a building, including resource allocations (modular form sets, cranes, workers, etc.), and the construction sequence, is vital for ensuring a successful use of modular formwork systems. Computer process simulation techniques are employed in this research for the study of different form reuse schemes to use gang forming systems in building construction. Five form reuse schemes are identified. The CYCLONE modeling methodology is employed to develop computer models for each of them. MicroCYCLONE simulations and sensitivity analyses of the schemes, using different numbers of form sets, cranes, and labor crews, are then conducted for a real case to assess their impact on the productivity as well as the cost-effectiveness of the operation. The objective is to better understand the characteristics of different form reuse schemes and, in turn, to produce better plans for gang forming construction. Thus, the application of modular formwork systems in building construction can be facilitated.     

A novel application of TPAD-MBR system to the pilot treatment of chemical synthesis-based pharmaceutical wastewater

A pilot-scale test was conducted with a two-phase anaerobic digestion (TPAD) system and a subsequential membrane bioreactor (MBR) treating chemical synthesis-based pharmaceutical wastewater. The TPAD system comprised a continuous stirred tank reactor (CSTR) and an upflow anaerobic sludge blanket-anaerobic filter (UASBAF), working as the acidogenic and methanogenic phases, respectively. The wastewater was high in COD, varying daily between 5789 and 58,792 mg L(-1), with a wide range of pH from 4.3 to 7.2. The wastewater was pumped at a fixed flow rate of 1m(3)h(-1) through the CSTR, the UASBAF and the MBR in series, resulting in respective HRTs of 12, 55 and 5h. Almost all the COD was removed by the TPAD-MBR system, leaving a COD of around 40 mg L(-1) in the MBR effluent. The pH of the MBR effluent was found in a narrow range of 6.8-7.6, indicating that the MBR effluent can be directly discharged into natural waters. A model, built on the back propagation neural network (BPNN) theory and linear regression techniques, was developed for the simulation of TPAD-MBR system performance in the biodegradation of chemical synthesis-based pharmaceutical wastewater. The model well fitted the laboratory data, and was able to simulate the removal of COD.     

地基反力的数值模拟和基础结构的内力响应

从地基与基础互相作用的概念出发 ,提出一种数值模拟地基反力分布函数的构造方法和具体形式 ,并应用这种地基反力的数值模拟形式 ,通过典型基础结构的内力分析 ,与应用现有的地基模型的结构计算相对比 ,表明它与有限压缩层地基模型的计算结果十分接近 ,但应用在基础结构计算分析上却简便易行 ,可以供工程设计计算和进行地基基础共同作用分析研究参考     

Structural reliability software at the University of California, Berkeley

The paper provides an overview of three software for structural reliability analysis developed at the University of California, Berkeley. These are CalREL, which is a general-purpose structural reliability code written in FORTRAN; FERUM, which is a collection of Matlab^® files that can be used for structural reliability analysis in conjunction with simple finite element models; and OpenSees, which is an object-oriented code for nonlinear structural response simulation with reliability capabilities. Reliability analysis methods featured by these software include FORM, SORM, Monte Carlo simulation, and various importance sampling methods. In addition, variable importance and sensitivity measures are provided.     

FSAE赛车双横臂前悬架运动学仿真及优化

应用机械系统动力学分析软件ADAMS,建立方程式赛车双横臂独立前悬架模型.在ADAMS/Car中,对其进行了运动学仿真分析,得到了车轮跳动时各项参数的变化规律.利用ADAMS/Insight对悬架的某些硬点位置进行了优化.结果表明,悬架系统的运动学特性得到改善.