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Improvement of part-load performance of gas turbine by adjusting compressor inlet air temperature and

《能源前沿（英文）》 2022年 第16卷 第6期   页码 1000-1016 doi: 10.1007/s11708-021-0746-z

摘要： A novel adjusting method for improving gas turbine (GT) efficiency and surge margin (SM) under part-load conditions is proposed. This method adopts the inlet air heating technology, which uses the waste heat of low-grade heat source and the inlet guide vane (IGV) opening adjustment. Moreover, the regulation rules of the compressor inlet air temperature and the IGV opening are studied comprehensively to optimize GT performance. A model and calculation method for an equilibrium running line is adopted based on the characteristic curves of the compressor and turbine. The equilibrium running lines calculated through the calculation method involve three part-load conditions and three IGV openings with different inlet air temperatures. The results show that there is an optimal matching relationship between IGV opening and inlet air temperature. For the best GT performance of a given load, the IGV could be adjusted according to inlet air temperature. In addition, inlet air heating has a considerable potential for the improvement of part-load performance of GT due to the increase in compressor efficiency, combustion efficiency, and turbine efficiency as well as turbine inlet temperature, when inlet air temperature is lower than the optimal value with different IGV openings. Further, when the IGV is in a full opening state and an optimal inlet air temperature is achieved by using the inlet air heating technology, GT efficiency and SM can be obviously higher than other IGV openings. The IGV can be left unadjusted, even when the load is as low as 50%. These findings indicate that inlet air heating has a great potential to replace the IGV to regulate load because GT efficiency and SM can be remarkably improved, which is different from the traditional viewpoints.

关键词： inlet air temperature     inlet guide vane (IGV) opening     part-load     equilibrium running line     gas turbine (GT) efficiency     surge margin (SM)    

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Part-load, startup, and shutdown strategies of a solid oxide fuel cell-gas turbine hybrid system

Yang LI, Yiwu WENG, Shilie WENG

《能源前沿（英文）》 2011年 第5卷 第2期   页码 181-194 doi: 10.1007/s11708-011-0149-7

摘要： Current work on the performance of a solid oxide fuel cell (SOFC) and gas turbine hybrid system is presented. Each component model developed and applied is mathematically defined. The electrochemical performance of single SOFC with different fuels is tested. Experimental results are used to validate the SOFC mathematical model. Based on the simulation model, a safe operation regime of the hybrid system is accurately plotted first. Three different part-load strategies are introduced and used to analyze the part-load performance of the hybrid system using the safe regime. Another major objective of this paper is to introduce a suitable startup and shutdown strategy for the hybrid system. The sequences for the startup and shutdown are proposed in detail, and the system responses are acquired with the simulation model. Hydrogen is used instead of methane during the startup and shutdown process. Thus, the supply of externally generated steam is not needed for the reforming reaction. The gas turbine is driven by complementary fuel and supplies compressed air to heat up or cool down the SOFC stack operating temperature. The dynamic simulation results show that smooth cooling and heating of the cell stack can be accomplished without external electrical power.

关键词： solid oxide fuel cell (SOFC)     hybrid system     part-load strategy     startup     shutdown    

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Heating energy performance and part load ratio characteristics of boiler staging in an office building

Da Young LEE, Byeong Mo SEO, Yeo Beom YOON, Sung Hyup HONG, Jong Min CHOI, Kwang Ho LEE

《能源前沿（英文）》 2019年 第13卷 第2期   页码 339-353 doi: 10.1007/s11708-018-0596-5

摘要： Commercial buildings account for significant portions of the total building energy in South Korea and thus a variety of research on the boiler operation related to heating energy in office buildings has been carried out thus far. However, most of the researches have been conducted on the boiler itself, i.e., the part load ratio characteristics and the corresponding gas energy consumption patterns are not analyzed in the existing studies. In this study, the part load ratio and the operating characteristics of gas boiler have been analyzed within an office building equipped with the conventional variable air volume system. In addition, the gas consumption among different boiler staging schemes has been comparatively analyzed. As a result, significant portions of total operating hours, heating load and energy consumption has been found to be in a part load ratio range of 0 through 40% and thus energy consumption is significantly affected by boiler efficiency at low part load conditions. This suggests that boiler operation at the part load is an important factor in commercial buildings. In addition, utilizing sequential boiler staging scheme can save a gas usage of about 7%. For annual heating energy saving, applying the sequential control boiler with a 3:7 proportion staging is considered to be the optimal control algorithm for maximum efficiency of boilers.

关键词： EnergyPlus     boiler     part load ratio     gas consumption     office building     boiler staging    

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Heat prices for public buildings in Tianjin

Boyuan HAO,Zhe TIAN,Yan DING,Peng PENG

《能源前沿（英文）》 2016年 第10卷 第3期   页码 249-259 doi: 10.1007/s11708-016-0412-z

摘要： Energy-saving awareness of heat users and heating enterprises can be stimulated by implementing heat metering for public buildings and by establishing scientific and reasonable policies for heat prices in China. In this paper, a two-part heat price for public buildings in Tianjin is introduced, which divides the heat price into a basic part and a metering part. According to the statistical analysis of information collected from two pilot heating enterprises, the specific heat load for public buildings in Tianjin is calculated, and three candidate schemes of heat price are proposed. A simulation of heat cost is also conducted, and the benefits for both heat users and heating enterprises are balanced. Finally, the two-part heat price for public buildings in Tianjin is determined: the basic heat price is recommended to be 20 CNY/m , and the metering heat price is recommended to be 76.10 CNY/GJ. Such a price could be implemented in the initial stage of heat metering for public buildings in Tianjin.

关键词： heat metering     public buildings     two-part heat price     specific heat load    

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Residual stresses in coating-based systems, part I: Mechanisms and analytical modeling

ZHANG Xiancheng, WU Yixiong, XU Binshi, WANG Haidou

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 1-12 doi: 10.1007/s11465-007-0001-2

摘要： Thin films and multi-layered coatings comprised of different classes of materials are often used for various functional devices. The thermo-mechanical integrity of these systems is becoming a major concern and is strongly related to the residual stresses because of the fabrication processes. In this paper, the sources of the residual stresses in the coating-based systems and the concept of misfit strain were briefly reviewed. Analytical models were developed to predict the residual stresses in multi-layered film structures or coating-based systems using the force and moment balances. In addition, the residual stress distributions in the func tionally and compositionally graded coatings were also analyzed.

关键词： briefly     different     thermo-mechanical integrity     addition     residual    

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Process development for green part printing using binder jetting additive manufacturing

Hadi MIYANAJI, Morgan ORTH, Junaid Muhammad AKBAR, Li YANG

《机械工程前沿（英文）》 2018年 第13卷 第4期   页码 504-512 doi: 10.1007/s11465-018-0508-8

摘要：

Originally developed decades ago, the binder jetting additive manufacturing (BJ-AM) process possesses various advantages compared to other additive manufacturing (AM) technologies such as broad material compatibility and technological expandability. However, the adoption of BJ-AM has been limited by the lack of knowledge with the fundamental understanding of the process principles and characteristics, as well as the relatively few systematic design guideline that are available. In this work, the process design considerations for BJ-AM in green part fabrication were discussed in detail in order to provide a comprehensive perspective of the design for additive manufacturing for the process. Various process factors, including binder saturation, in-process drying, powder spreading, powder feedstock characteristics, binder characteristics and post-process curing, could significantly affect the printing quality of the green parts such as geometrical accuracy and part integrity. For powder feedstock with low flowability, even though process parameters could be optimized to partially offset the printing feasibility issue, the qualities of the green parts will be intrinsically limited due to the existence of large internal voids that are inaccessible to the binder. In addition, during the process development, the balanced combination between the saturation level and in-process drying is of critical importance in the quality control of the green parts.

关键词： binder jetting     additive manufacturing     green part     process optimization     process development    

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以东为鉴 秀丽晚成——西部风景园林开发浅议

孟兆祯

《中国工程科学》 2000年 第2卷 第10期   页码 56-58

摘要：

首先我们要站在人类社会生产与自然环境协调的可持续发展的高度着手综合的国土规划，建立从总体到单体的规划设计科学序列。现阶段城市的本质应为人类聚居并藉以生存的生活环境。城市化进程与自然环境间并非针锋相对的破坏关系。城市形象不仅仅是建筑加道路的形象，而是以人工美入自然，将城市和建筑融汇到自然环境中的形象。我们美好的前景是将城市和建筑建在绿色环境中。风景名胜区和城市园林的建设当前仍须将保护自然资源放在首位。要创造特色，从各市的自然环境和人文脉络中捕捉城市风景园林的特色，不要盲目跟风。秀丽山川，大器晚成。扎实积累，功到必成。

关键词： 城市化进程     风景名胜区     城市园林    

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Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid

Nitin Kumar SAXENA,Ashwani Kumar SHARMA

《能源前沿（英文）》 2015年 第9卷 第4期   页码 472-485 doi: 10.1007/s11708-015-0373-7

摘要： It is well recognized that the voltage stability of a power system is affected by the load model and hence, to effectively analyze the reactive power compensation of an isolated hybrid wind-diesel based power system, the loads need to be considered along with the generators in a transient analysis. This paper gives a detailed mathematical modeling to compute the reactive power response with small voltage perturbation for composite load. The composite load is a combination of the static and dynamic load model. To develop this composite load model, the exponential load is used as a static load model and induction motors (IMs) are used as a dynamic load model. To analyze the dynamics of IM load, the fifth, third and first order model of IM are formulated and compared using differential equations solver in Matlab coding. Since the decentralized areas have many small consumers which may consist large numbers of IMs of small rating, it is not realistic to model either a single large rating unit or all small rating IMs together that are placed in the system. In place of using a single large rating IM, a group of motors are considered and then the aggregate model of IM is developed using the law of energy conservation. This aggregate model is used as a dynamic load model. For different simulation studies, especially in the area of voltage stability with reactive power compensation of an isolated hybrid power system, the transfer function of the composite load is required. The transfer function of the composite load is derived in this paper by successive derivation for the exponential model of static load and for the fifth and third order IM dynamic load model using state space model.

关键词： isolated hybrid power system (IHPS)     composite load model     static load     dynamic load     induction motor load model     aggregate load    

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Residual stresses in coating-based systems, part II: Optimal designing methodologies

ZHANG Xiancheng, WU Yixiong, XU Binshi, WANG Haidou

《机械工程前沿（英文）》 2007年 第2卷 第2期   页码 125-136 doi: 10.1007/s11465-007-0022-x

摘要： In this part of the work, different cases are studied to illustrate the implementation of the analytical models that have been developed in Part I [Front. Mech. Eng. China, 2007, 2(1): 1 12]. Different topics are involved in the optimal design of coating-based systems. Some essential relations among material properties and dimensions of the coating and substrate and the residual stress variations are reflected. For the multilayered coating-based systems, some optimal design methodologies are proposed, such as the decrease in stress discontinuity at the interface between the adjacent layers, the curvature as a function of the coating thickness, the effect of the interlayer on the residual stress redistribution, and so on. For the single-layered coating-based systems, some typical approximations that are often used to predict the residual stresses in the coating-based system or bilayer structure are corrected. A simplified model for predicting the quenching stress in a coating is also developed.

关键词： function     different     substrate     interlayer     implementation    

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Current progress on internal medicine in China—2006 Part II

YAO Dingkang, ZHU Liang, YU Renqian, MEI Changlin

《医学前沿（英文）》 2007年 第1卷 第4期   页码 343-351 doi: 10.1007/s11684-007-0066-7

摘要： A lot of progress has been made on internal medicine in the past year. Here a great deal of data were collected about internal medicine in China by searching for some most important medicine magazines published in China in 2006. Because there are so many articles on internal medicine, some representative reports were selected and further reviewed. In the part II, a summary of advances made in four branches includes nephrology, hematology, endocrinology and metabolism, rheumatology.

关键词： endocrinology     rheumatology     hematology     nephrology     representative    

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Current progress on internal medicine in China—2006 Part I

YAO Dingkang, ZHU Liang, ZHAO Xue, MEI Changlin

《医学前沿（英文）》 2007年 第1卷 第3期   页码 235-247 doi: 10.1007/s11684-007-0046-y

摘要： The growing interest has been placed in the current state of Chinaºs internal medicine from all over the world. Many data of internal medicine in China were collected by searching through some of the most prominent medical magazines published in China in 2006. Because there are many researches on the field of internal medicine, just some representative reports focusing on this topic were selected in this paper. In part I of this study, a summary of the advances made in cardiology, respiration diseases, and gastroenterology was presented.

关键词： internal medicine     Chinaºs internal     respiration     gastroenterology     cardiology    

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Reliability-based robust design optimization of vehicle components, Part I: Theory

Yimin ZHANG

《机械工程前沿（英文）》 2015年 第10卷 第2期   页码 138-144 doi: 10.1007/s11465-015-0333-2

摘要：

The reliability-based design optimization, the reliability sensitivity analysis and robust design method are employed to present a practical and effective approach for reliability-based robust design optimization of vehicle components. A procedure for reliability-based robust design optimization of vehicle components is proposed. Application of the method is illustrated by reliability-based robust design optimization of axle and spring. Numerical results have shown that the proposed method can be trusted to perform reliability-based robust design optimization of vehicle components.

关键词： vehicle components     reliability-based design optimization     reliability-based sensitivity analysis     multi-objective optimization     robust design    

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Reliability-based robust design optimization of vehicle components, Part II: Case studies

Yimin ZHANG

《机械工程前沿（英文）》 2015年 第10卷 第2期   页码 145-153 doi: 10.1007/s11465-015-0334-1

摘要：

The reliability-based optimization, the reliability-based sensitivity analysis and robust design method are employed to propose an effective approach for reliability-based robust design optimization of vehicle components in Part I. Applications of the method are further discussed for reliability-based robust optimization of vehicle components in this paper. Examples of axles,torsion bar, coil and composite springs are illustrated for numerical investigations. Results have shown the proposed method is an efficient method for reliability-based robust design optimization of vehicle components.

关键词： vehicle axles and springs     reliability-based design optimization     reliability-based sensitivity analysis     multi-objective optimization     robust design    

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Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

《机械工程前沿（英文）》 2011年 第6卷 第2期   页码 241-248 doi: 10.1007/s11465-011-0219-x

摘要：

This paper presents a new calculation method that can calculate the load distribution on pipe threaded connections under tension load. On the basis of elastic mechanics, the new method was developed by analyzing each thread tooth, and a new deformation and covariant equation by making a mechanics analysis on each thread tooth was obtained. Compared with the traditional method proposed by the previous references, the new deformation and covariant equation could be used to describe the relation between the previous and the next thread tooth. By applying the new method on the sample of P-110S pipe threaded connection, the obtained results show that the load on thread tooth mainly concentrates on the four or five threads engaged and the middle teeth were not utilized well to bear the loads. The model offers a new way to calculate the loads carried on the thread teeth under tension load.

关键词： load distribution     calculation method     pipe threaded connections     tension load    

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Comparison of optimal capacitor placement methods in radial distribution system with load growth andZIP load model

Veera Venkata Satya Naryana MURTY, Ashwani KUMAR

《能源前沿（英文）》 2013年 第7卷 第2期   页码 197-213 doi: 10.1007/s11708-013-0249-7

摘要： In this paper, a combined power loss sensitivity (PLS) index-based approach is proposed to determine the optimal location of the capacitors in the radial distribution system (RDS) based on the real and reactive combined loss sensitivity index, as capacitor placement not only reduces real power loss with voltage profile improvement but also reduces reactive power loss due to the reactive power compensation in the network. The results have been obtained with the existing methods of power loss index (PLI) and index vector (IV) method for comparison. Besides, the optimal placement has been obtained with the proposed method as well as existing methods and the total kVar support has been obtained. In addition, the results of net cost savings for the 10-, 34-, and 69-bus systems are obtained for comparison. Moreover, the results have been obtained for a large system of 85 buses to validate the results with combined sensitivity based approach. Furthermore, the load growth factor has been considered in the study which is essential for the planning and expansion of the existing systems, whereas the impact of the realistic load model as ZIP load model has been considered for the study of all the systems.

关键词： load growth     load models     reactive power compensation     radial distribution system     power loss index (PLI)     power loss sensitivity (PLS)     index vector (IV)    

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标题 作者 时间 类型 操作

Improvement of part-load performance of gas turbine by adjusting compressor inlet air temperature and

期刊论文

Part-load, startup, and shutdown strategies of a solid oxide fuel cell-gas turbine hybrid system

Yang LI, Yiwu WENG, Shilie WENG

期刊论文

Heating energy performance and part load ratio characteristics of boiler staging in an office building

Da Young LEE, Byeong Mo SEO, Yeo Beom YOON, Sung Hyup HONG, Jong Min CHOI, Kwang Ho LEE

期刊论文

Heat prices for public buildings in Tianjin

Boyuan HAO,Zhe TIAN,Yan DING,Peng PENG

期刊论文

Residual stresses in coating-based systems, part I: Mechanisms and analytical modeling

ZHANG Xiancheng, WU Yixiong, XU Binshi, WANG Haidou

期刊论文

Process development for green part printing using binder jetting additive manufacturing

Hadi MIYANAJI, Morgan ORTH, Junaid Muhammad AKBAR, Li YANG

期刊论文

以东为鉴 秀丽晚成——西部风景园林开发浅议

孟兆祯

期刊论文

Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid

Nitin Kumar SAXENA,Ashwani Kumar SHARMA

期刊论文

Residual stresses in coating-based systems, part II: Optimal designing methodologies

ZHANG Xiancheng, WU Yixiong, XU Binshi, WANG Haidou

期刊论文

Current progress on internal medicine in China—2006 Part II

YAO Dingkang, ZHU Liang, YU Renqian, MEI Changlin

期刊论文

Current progress on internal medicine in China—2006 Part I

YAO Dingkang, ZHU Liang, ZHAO Xue, MEI Changlin

期刊论文

Reliability-based robust design optimization of vehicle components, Part I: Theory

Yimin ZHANG

期刊论文

Reliability-based robust design optimization of vehicle components, Part II: Case studies

Yimin ZHANG

期刊论文

Calculation method of load distribution on pipe threaded connections under tension load

Shoujun CHEN, Lianxin GAO, Qi AN

期刊论文

Comparison of optimal capacitor placement methods in radial distribution system with load growth andZIP load model

Veera Venkata Satya Naryana MURTY, Ashwani KUMAR

期刊论文