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Experimental investigation on oil-gas separator of air-conditioning systems

Dianbo XIN,Shuliang HUANG,Song YIN,Yuping DENG,Wenqiang ZHANG

《能源前沿（英文）》 2019年 第13卷 第2期   页码 411-416 doi: 10.1007/s11708-017-0447-9

摘要： The oil-return system plays an important role in the variable refrigerant flow (VRF) systems because it ensures the reliable operation of the VRF systems. The oil-gas separator is the most essential component of the oil-return system, and the separation efficiency of the separator directly influences the performance of the VRF systems. Therefore, in this paper, a test rig was built to measure the oil discharge ratio of the compressor and the separation efficiency of the oil-gas separator. A sound velocity transducer was used to measure the oil mass concentration instantaneously, because the sound velocity was changed with the mass ratio of oil to refrigerant. The separation efficiency of the separator could be obtained by comparing the mass fraction of oil to refrigerant before and after the separator was connected to the system.

关键词： variable refrigerant flow system     oil-gas separator     separation efficiency    

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Simulation on refrigerant flow in adiabatic capillary tube

WANG Meixia, LIU Cunfang, ZHOU Qiangtai

《机械工程前沿（英文）》 2008年 第3卷 第3期   页码 332-336 doi: 10.1007/s11465-008-0054-x

摘要： This paper proposes a new mathematical model to calculate flow characteristics of the adiabatic capillary tube, which is aimed at solving problems existing in some earlier models. The Stocker’s model was modified with consideration of various effects due to sub-cooling, area concentration, and rolling diameter. The new model can be used not only for R22, but also for its substitutes such as R410A and R407C. A comparison of simulation results of the modified model with those in literature showed that the errors are within 10%. The flow characteristics are finally analyzed.

关键词： mathematical     diameter     literature     sub-cooling     adiabatic capillary    

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New refrigeration system using CO vapor-solid as refrigerant

HUANG Dongping, DING Guoliang, QUACK Hans

《能源前沿（英文）》 2008年 第2卷 第4期   页码 494-498 doi: 10.1007/s11708-008-0070-x

摘要： A refrigerant must be in the vapor-liquid phase in a vapor-compression refrigeration system, therefore, CO cannot be used as a refrigerant for temperatures lower than -56°C because solid CO will form under the triple point temperature of -56°C. A refrigeration system with CO vapor-solid particles as refrigerant is put forward, by which a temperature lower than the triple point is achieved. An adjustable nozzle, a sublimator, a high-pressure regulating valve and a low-pressure regulating valve are used to replace the conventional evaporator. Theoretical cycle analysis of the refrigeration system shows that its COP can be 50% higher than that of the conventional one.

关键词： refrigerant     adjustable     temperature     vapor-compression refrigeration     sublimator    

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Mechanical design and analysis of a novel variable stiffness actuator with symmetrical pivot adjustment

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 711-725 doi: 10.1007/s11465-021-0647-1

摘要： The safety of human–robot interaction is an essential requirement for designing collaborative robotics. Thus, this paper aims to design a novel variable stiffness actuator (VSA) that can provide safer physical human–robot interaction for collaborative robotics. VSA follows the idea of modular design, mainly including a variable stiffness module and a drive module. The variable stiffness module transmits the motion from the drive module in a roundabout manner, making the modularization of VSA possible. As the key component of the variable stiffness module, a stiffness adjustment mechanism with a symmetrical structure is applied to change the positions of a pair of pivots in two levers linearly and simultaneously, which can eliminate the additional bending moment caused by the asymmetric structure. The design of the double-deck grooves in the lever allows the pivot to move freely in the groove, avoiding the geometric constraint between the parts. Consequently, the VSA stiffness can change from zero to infinity as the pivot moves from one end of the groove to the other. To facilitate building a manipulator in the future, an expandable electrical system with a distributed structure is also proposed. Stiffness calibration and control experiments are performed to evaluate the physical performance of the designed VSA. Experiment results show that the VSA stiffness is close to the theoretical design stiffness. Furthermore, the VSA with a proportional–derivative feedback plus feedforward controller exhibits a fast response for stiffness regulation and a good performance for position tracking.

关键词： variable stiffness actuator     variable stiffness module     drive module     symmetrical structure     double-deck grooves     expandable electrical system    

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Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

《能源前沿（英文）》 2012年 第6卷 第2期   页码 184-192 doi: 10.1007/s11708-012-0185-y

摘要： Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator (DFIG)-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control.

关键词： doubly fed induction generator (DFIG)     load frequency control     inertial control     wind energy conversion system (WECS)    

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变频驱动并联水泵变压变流量运行优化调度

李洪斌,张承慧,宋军

《中国工程科学》 2001年 第3卷 第9期   页码 52-57

摘要：

分析了变频驱动并联水泵变压变流量运行优化调度问题的常用建模方法，并比较了各种方法的优劣。 常用的方法是以水泵轴功率作为目标函数，以供水指标和高效区为约束条件。另一种方法是以满足扬程指标时 的实际流量与所需流量之差的二次方作为目标函数，以水泵的高效区作为约束条件。提出了一种新的建模方法， 模型物理意义与实际工况严格相符，具有较高的精度，满足了工程中对水泵切换频率尽量小的要求。仿真结果 表明该方法是有效的。

关键词： 优化调度     有约束非线性规划     水泵调速    

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Applications of thermostatically controlled loads for demand response with the proliferation of variable

Meng SONG, Wei SUN

《能源前沿（英文）》 2022年 第16卷 第1期   页码 64-73 doi: 10.1007/s11708-021-0732-5

摘要： More flexibility is desirable with the proliferation of variable renewable resources for balancing supply and demand in power systems. Thermostatically controlled loads (TCLs) attract tremendous attentions because of their specific thermal inertia capability in demand response (DR) programs. To effectively manage numerous and distributed TCLs, intermediate coordinators, e.g., aggregators, as a bridge between end users and dispatch operators are required to model and control TCLs for serving the grid. Specifically, intermediate coordinators get the access to fundamental models and response modes of TCLs, make control strategies, and distribute control signals to TCLs according the requirements of dispatch operators. On the other hand, intermediate coordinators also provide dispatch models that characterize the external characteristics of TCLs to dispatch operators for scheduling different resources. In this paper, the bottom-up key technologies of TCLs in DR programs based on the current research have been reviewed and compared, including fundamental models, response modes, control strategies, dispatch models and dispatch strategies of TCLs, as well as challenges and opportunities in future work.

关键词： thermostatically controlled load     demand response     renewable energy     power system operation    

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Sustainable design of sanitation system based on material and value flow analysis for urban slum in Indonesia

Ken USHIJIMA, Mitsuteru IRIE, Neni SINTAWARDANI, Jovita TRIASTUTI, Umi HAMIDAH, Tadaharu ISHIKAWA, Naoyuki FUNAMIZU

《环境科学与工程前沿（英文）》 2013年 第7卷 第1期   页码 120-126 doi: 10.1007/s11783-012-0460-5

摘要： Material flow analysis (MFA) and value flow analysis (VFA) were applied to the sanitation system in an urban slum in Indonesia. Based on the results of the MFA and VFA, garbage and excreta disposal costs were evaluated to be 0.7% and 1.1%, respectively, of per capita income. Such value flows seem reasonable in light of the recognized affordability to pay (ATP) standard. However, current excreta disposal methods create negative impacts on downstream populations. Because such disadvantages do not go back to disposers, but passed to downstream, the current value flow structure does not motivate individual toilet users to install treatment facility. Based on current material and value flow structures, a resource recycling sanitation system scenario was examined. Based on VFA, an affordable initial cost for such a system was calculated; this was found to be comparable in price to a cheaper composting toilet that is currently available in the market.

关键词： material flow     value flow     resource recycling system     sustainable design     initial cost     urban slum    

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Boiling heat transfer correlations for refrigerant mixtures flowing inside micro-fin tubes

ZHANG Xiaoyan, ZHANG Xingqun, CHEN Yunguang, YUAN Xiuling

《能源前沿（英文）》 2008年 第2卷 第4期   页码 489-493 doi: 10.1007/s11708-008-0110-6

摘要： Based on experimental results of ternary non-azeotropic refrigerant mixture R417A flowing and boiling in one smooth and two internally grooved horizontal tubes with different geometrical parameters, a boiling heat transfer correlations was developed for refrigerant mixtures flowing inside micro-fin tubes by applying the enhancement factor in the present modified-Kattan model which was modified by the experimental data of R417A in a smooth tube. The comparison between the calculation and the experimental results indicates that the prediction by the present correlations is in good agreement with the experiment of refrigerant mixtures inside different micro-fin tubes with a standard deviation of ± 30% for vapor qualities below 80%.

关键词： comparison     micro-fin     calculation     transfer     prediction    

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Evaluation of measurement uncertainty of the high-speed variable-slit system based on the Monte Carlo

Yin ZHANG, Jianwei WU, Kunpeng XING, Zhongpu WEN, Jiubin TAN

《机械工程前沿（英文）》 2020年 第15卷 第4期   页码 517-537 doi: 10.1007/s11465-020-0589-z

摘要： This paper presents a dynamic and static error transfer model and uncertainty evaluation method for a high-speed variable-slit system based on a two-dimensional orthogonal double-layer air-floating guide rail structure. The motion accuracy of the scanning blade is affected by both the moving component it is attached to and the moving component of the following blade during high-speed motion. First, an error transfer model of the high-speed variable-slit system is established, and the influence coefficients are calculated for each source of error associated with the accuracy of the blade motion. Then, the maximum range of each error source is determined by simulation and experiment. Finally, the uncertainty of the blade displacement measurement is evaluated using the Monte Carlo method. The proposed model can evaluate the performance of the complex mechanical system and be used to guide the design.

关键词： air-floating guide rail     error transfer model     driving and following structure     dynamic error     uncertainty evaluation     Monte Carlo method    

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Substance flow analysis for an urban drainage system of a representative hypothetical city in China

Hua BAI, Siyu ZENG, Xin DONG, Jining CHEN

《环境科学与工程前沿（英文）》 2013年 第7卷 第5期   页码 746-755 doi: 10.1007/s11783-013-0551-y

摘要： This paper discusses the use of substance flow analysis (SFA) as a tool to support quantified research on urban drainage systems. Based on the principle of mass balance, a static substance flow model is established to describe and examine the routes and intensities of water, chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) for a representative hypothetical city (RH city) in China, which is a devised and scaled city using statistical characteristics of urban circumstances at the national level. It is estimated that the annual flux of water, COD, TN and TP through the urban drainage system in 2010 was 55.1 million m , 16037.3 t, 1649.5 t and 209.7 t, respectively. The effluent of wastewater treatment plant (WWTP) was identified as the most important pathway for pollutant emissions, which contributed approximately 60% of COD, 65% of TN and 50% of TP to receiving water. During the wastewater treatment process, 1.0 million m , 7042.5 t, 584.2 t and 161.4 t of the four studied substances had been transmitted into sludge, meanwhile 3813.0 t of COD and 394.0 t of TN were converted and emitted to the atmosphere. Compared with the representative hypothetical city of 2000, urban population and the area of urban built districts had expanded by approximately 90% and 80% respectively during the decade, resulting in a more than threefold increase in the input of substances into the urban drainage system. Thanks to the development of urban drainage systems, the total loads of the city were maintained at a similar level.

关键词： substance flow analysis (SFA)     urban drainage system     representative hypothetical city (RH city)     water pollution control    

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The Building of Papermaking Enterprise’s Recycling Economy Evaluation Index System Based on Value Flow

Zhi-fang Zhou,Jing Ou,Sha-sha Wang,Xiao-hong Chen

《工程管理前沿（英文）》 2016年 第3卷 第1期   页码 9-17 doi: 10.15302/J-FEM-2016009

摘要： At present, the research on circular economy has made a lot of substantive results both at home and abroad. But for the papermaking enterprise, which is the representative of the light industry, few studies have analyzed the evaluation index system of circular economy. Since the current material flow analyses have limitations that the researchers cannot calculate materials with different units. The authors take advantage of the intrinsic correlation between the basic principle of value flow analysis and circular economy, and then analyze the dynamic changes of material flow and value flow through enterprises internal production process. Considering the resource output, the authors set up the layered structure of the evaluation index system, and then preliminarily determine the index form. Next, the authors use the frequency statistics analysis method to adjust indicators, forming a preliminary index system. After that, the principal component analysis and independent analysis are applied for screening. Finally, the authors build a circular economy evaluation index system for papermaking enterprise to provide scientific guidance for the process of circular economy.

关键词： circular economy     the papermaking enterprise     material flow analysis     value flow analysis     evaluation index system    

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基于知识的多变量非线性系统变结构解耦控制

涂承媛,曾衍钧

《中国工程科学》 2001年 第3卷 第10期   页码 48-52

摘要：

文章提出了一种基于知识的变结构解耦控制策略，并用于多变量非线性系统的控制，避免了传统解耦控制所必须的建模过程，特别是避免了相应的大量复杂的矩阵运算。阐述了其控制知识库中的一些模块，给出了其算法要点。提出的策略成功地用于一个3×3强耦合系统一三绕组加热标准温度源的恒温控制，得到了温 度稳定性和温度均匀性都优于1℃的效果，这是传统方法用于该系统所无法实现的。

关键词： 多变量非线性系统     解耦控制     基于知识的变结构解耦    

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Variable identification and automatic tuning of the main module of a servo system of parallel mechanism

YANG Zhiyong, XU Meng, HUANG Tian, NI Yanbing

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 82-88 doi: 10.1007/s11465-007-0014-x

摘要： The variables of the main module of a servo system for miniature reconfigurable parallel mechanism were identified and automatically tuned. With the reverse solution module of the translation, the module with the exerted translation joint was obtained, which included the location, velocity and acceleration of the parallelogram carriage-branch. The rigid dynamic reverse model was set as the virtual work principle. To identify the variables of the servo system, the triangle-shaped input signal with variable frequency was adopted to overcome the disadvantages of the pseudo-random number sequence, i.e., making the change of the vibration amplitude of the motor dramatically, easily impact the servo motor and make the velocity loop open and so on. Moreover, all the variables including the rotary inertia of the servo system were identified by the additive mass. The overshoot and rise time were the optimum goals, the limited changing load with the attitude was considered, and the range of the controller variables in the servo system was identified. The results of the experiments prove that the method is accurate.

关键词： acceleration     reconfigurable parallel     additive     sequence     parallel mechanism    

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Mechanical design, modeling, and identification for a novel antagonistic variable stiffness dexterous

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0691-5

摘要： This study traces the development of dexterous hand research and proposes a novel antagonistic variable stiffness dexterous finger mechanism to improve the safety of dexterous hand in unpredictable environments, such as unstructured or man-made operational errors through comprehensive consideration of cost, accuracy, manufacturing, and application. Based on the concept of mechanical passive compliance, which is widely implemented in robots for interactions, a finger is dedicated to improving mechanical robustness. The finger mechanism not only achieves passive compliance against physical impacts, but also implements the variable stiffness actuator principle in a compact finger without adding supererogatory actuators. It achieves finger stiffness adjustability according to the biologically inspired stiffness variation principle of discarding some mobilities to adjust stiffness. The mechanical design of the finger and its stiffness adjusting methods are elaborated. The stiffness characteristics of the finger joint and the actuation unit are analyzed. Experimental results of the finger joint stiffness identification and finger impact tests under different finger stiffness presets are provided to verify the validity of the model. Fingers have been experimentally proven to be robust against physical impacts. Moreover, the experimental part verifies that fingers have good power, grasping, and manipulation performance.

关键词： multifingered hand     mechanism design     robot safety     variable stiffness actuator    

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标题 作者 时间 类型 操作

Experimental investigation on oil-gas separator of air-conditioning systems

Dianbo XIN,Shuliang HUANG,Song YIN,Yuping DENG,Wenqiang ZHANG

期刊论文

Simulation on refrigerant flow in adiabatic capillary tube

WANG Meixia, LIU Cunfang, ZHOU Qiangtai

期刊论文

New refrigeration system using CO vapor-solid as refrigerant

HUANG Dongping, DING Guoliang, QUACK Hans

期刊论文

Mechanical design and analysis of a novel variable stiffness actuator with symmetrical pivot adjustment

期刊论文

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

期刊论文

变频驱动并联水泵变压变流量运行优化调度

李洪斌,张承慧,宋军

期刊论文

Applications of thermostatically controlled loads for demand response with the proliferation of variable

Meng SONG, Wei SUN

期刊论文

Sustainable design of sanitation system based on material and value flow analysis for urban slum in Indonesia

Ken USHIJIMA, Mitsuteru IRIE, Neni SINTAWARDANI, Jovita TRIASTUTI, Umi HAMIDAH, Tadaharu ISHIKAWA, Naoyuki FUNAMIZU

期刊论文

Boiling heat transfer correlations for refrigerant mixtures flowing inside micro-fin tubes

ZHANG Xiaoyan, ZHANG Xingqun, CHEN Yunguang, YUAN Xiuling

期刊论文

Evaluation of measurement uncertainty of the high-speed variable-slit system based on the Monte Carlo

Yin ZHANG, Jianwei WU, Kunpeng XING, Zhongpu WEN, Jiubin TAN

期刊论文

Substance flow analysis for an urban drainage system of a representative hypothetical city in China

Hua BAI, Siyu ZENG, Xin DONG, Jining CHEN

期刊论文

The Building of Papermaking Enterprise’s Recycling Economy Evaluation Index System Based on Value Flow

Zhi-fang Zhou,Jing Ou,Sha-sha Wang,Xiao-hong Chen

期刊论文

基于知识的多变量非线性系统变结构解耦控制

涂承媛,曾衍钧

期刊论文

Variable identification and automatic tuning of the main module of a servo system of parallel mechanism

YANG Zhiyong, XU Meng, HUANG Tian, NI Yanbing

期刊论文

Mechanical design, modeling, and identification for a novel antagonistic variable stiffness dexterous

期刊论文