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Unified cycle model of a class of internal combustion engines and their optimum performance characteristics

Shiyan ZHENG

《能源前沿（英文）》 2011年 第5卷 第4期   页码 367-375 doi: 10.1007/s11708-011-0170-x

摘要： The unified cycle model of a class of internal combustion engines is presented, in which the influence of the multi-irreversibilities mainly resulting from the adiabatic processes, finite-time processes and heat leak loss through the cylinder wall on the performance of the cycle are taken into account. Based on the thermodynamic analysis method, the mathematical expressions of the power output and efficiency of the cycle are calculated and some important characteristic curves are given. The influence of the various design parameters such as the high-low pressure ratio, the high-low temperature ratio, the compression and expansion isentropic efficiencies etc. on the performance of the cycle is analyzed. The optimum criteria of some important parameters such as the power output, efficiency and pressure ratio are derived. The results obtained from this unified cycle model are very general and useful, from which the optimal performance of the Atkinson, Otto, Diesel, Dual and Miller heat engines and some new heat engines can be directly derived.

关键词： internal combustion engine     irreversibility     power output     efficiency     optimization    

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Optimum design and preliminary experiments of a novel parallel end traction apparatus for upper-limb

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 726-746 doi: 10.1007/s11465-021-0651-5

摘要： Robot-assisted technology has been increasingly employed in the therapy of post stroke patients to deliver high-quality treatment and alleviate therapists’ burden. This paper introduces a novel parallel end traction apparatus (PETA) to supplement equipment selection. Considering the appearance and performance of the PETA, two types of special five-bar linkage mechanisms are selected as the potential configurations of the actuation execution unit because of their compact arrangement and parallel structure. Kinematic analysis of each mechanism, i.e., position solutions and Jacobian matrix, is carried out. Subsequently, a comparative study between the two mechanisms is conducted. In the established source of nondimensional parameter synthesis, the singularity, maximum continuous workspace, and performance variation trends are analyzed. Based on the evaluation results, the final scheme with determined configuration and corresponding near-optimized nondimensional parameters is obtained. Then, a prototype is constructed. By adding a lockable translational degree of freedom in the vertical direction, the PETA can provide 2D planar exercise and 3D spatial exercise. Finally, a control system is developed for passive exercise mode based on the derived inverse position solution, and preliminary experiments are performed to verify the applicability of the PETA.

关键词： parallel mechanism     upper-limb rehabilitation     singularity and workspace analyses     performance evaluation     optimum design    

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Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

R. LALITHA NARAYANA, V. RAMACHANDRA RAJU

《能源前沿（英文）》 2020年 第14卷 第1期   页码 105-113 doi: 10.1007/s11708-018-0536-4

摘要： This present work is aimed to examine the effect of mass flow rate on distillate output and performance of a solar still in active mode. Outdoor experiments were conducted at the coastal town, Kakinada (16° 93′N/83° 33′E), Andhra Pradesh, India. A solar still with a 30° of fixed cover inclination, 1m of effective basin area, and a flat-plate collector (FPC) with an effective area of 2 m were used. An attempt was also made earlier in passive mode to optimize the water depth for the same solar still for maximum yield and distillation efficiency. For the passive still, it is observed that the capacity of heat storage and heat drop are significant parameters that affect the still performance. For the selected still design, the study reveals that 0.04 m water depth is the optimum value for specific climatic conditions. In the active solar still, with the optimum water depth, different flow rates of 0.5, 1 and 1.5 L/min are considered through FPC. It is observed that both the mass flow rate and the variation of internal heat transfer coefficients with the mass flow rate have a significant effect on the yield and performance of the still. The experimental results show that the combination of 1.5 L/min mass flow rate and an optimum water depth of 0.04m leads to a maximum yield for the active solar still. The enhanced yield of the active solar still is 57.55%, compared with that of the passive solar still, due to increase in area of radiation collection and more heat absorption rate.

关键词： distillation efficiency     solar still     heat transfer coefficient     water depth     optimum and mass flow rate    

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Optimization and performance prediction of a new near-zero emission coal utilization system with combined

GUAN Jian, WANG Qinhui, LI Xiaomin, LUO Zhongyang, CEN Kefa

《能源前沿（英文）》 2007年 第1卷 第1期   页码 113-119 doi: 10.1007/s11708-007-0013-y

摘要： In accordance with the new near-zero emission coal utilization system with combined gasification and combustion, which is based on the CO acceptor gasification process, the product gas composition of the gasifier and the combustor was calculated by means of thermodynamic equilibrium calculation software FactSage 5.2. Based on these calculations, the whole system efficiency calculation method that complies with the mass and energy conservation principle was established. To enhance the system efficiency, the system pressure and the gasifier carbon conversion ratio were optimized. The results indicate that the system efficiency increases with increasing pressure and gasifier carbon conversion ratio. After taking into consideration the influence of the pressure and carbon conversion ratio on the performance of the system, the gasifier and the combustor were synthetically studied. The optimum system pressure and carbon conversion ratio were obtained as 2.5 MPa and 0.7, respectively. The system efficiency could reach around 62.1% when operated in these two optimum parameters. If the advanced ion transport membrane (ITM) air separation technology is used, there would be an increase of another 1.3%.

关键词： influence     efficiency calculation     optimum     software FactSage     transport    

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旅客机环境控制系统优化研究

方林,王浚

《中国工程科学》 2006年 第8卷 第1期   页码 77-80

摘要：

为了选择经济高效的旅客机环境控制系统，对现役各种旅客机采用的环境控制系统方案进行了优化设计和比较，分别建立了二轮简单式低压除水系统、三轮升压式高压除水系统和四轮升压式高压除水系统（又称冷凝循环制冷系统）的优化设计数学模型，以起飞燃油质量代偿损失为目标函数，采用广义乘子法结合单纯形加速法求解，优化结果可作为设计研究旅客机环境控制系统的理论依据。

关键词： 旅客机     环境控制     优化设计    

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系统非优分析理论及方法

何平

《中国工程科学》 2003年 第5卷 第7期   页码 40-46

摘要：

对系统非优分析理论做了较为详细的论述。指出寻求不确定系统优化的主要问题，关键是缺少对系统的非优分析。在系统非优范畴的基础上建立了征兆群与经验分析，提出了系统非优度量以及从非优追踪到系统自组织等问题。

关键词： 系统非优范畴     非优征兆群     非优度量     系统自组织    

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Kinematic Model Building and Servo Parameter Identification of 3-HSS Parallel Mechanism

YANG Zhi-yong, WU Jiang, HUANG Tian, NI Yan-bing

《机械工程前沿（英文）》 2006年 第1卷 第1期   页码 60-66 doi: 10.1007/s11465-005-0019-2

摘要：

Aiming at a parallel mechanism with three degrees of freedom, a method for dynamic model building and the parameter identification of its servosystem is presented. First, the reverse solution models of position, velocity, and acceleration of parallelogram branch structure are deduced, and then, its dynamic model of a rigid body is set up by using the virtual work principle. Based on the above model, a method to identify the servo parameter of the parallel mechanism is put up. In this method, the triangle-shaped input with variable frequency is adopted to offset the disadvantages of pseudorandom number sequence in parameter identification, such as dramatically changing the vibration amplitude of the motor, easily impacting the motor that results in its velocity loop to easily open, and so on. Moreover, the rotary inertia can also be identified by the additive mass. The abovementioned data will lay a solid foundation for the optimum performance of the system in the whole workspace.

关键词： building     acceleration     additive     workspace     optimum performance    

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Determining the optimum economic insulation thickness of double pipes buried in the soil for district

Fating LI, Pengfei JIE, Zhou FANG, Zhimei WEN

《能源前沿（英文）》 2021年 第15卷 第1期   页码 170-185 doi: 10.1007/s11708-020-0680-5

摘要： The insulation thickness (IT) of double pipes buried in the soil (DPBIS) for district heating (DH) systems was optimized to minimize the annual total cost of DPBIS for DH systems. An optimization model to obtain the optimum insulation thickness (OIT) and minimum annual total cost (MATC) of DPBIS for DH systems was established. The zero point theorem and fsolve function were used to solve the optimization model. Three types of heat sources, four operating strategies, three kinds of insulation materials, three buried depth (BD) values, and seven nominal pipe size (NPS) values were considered in the calculation of the OIT and MATC of DPBIS for DH systems, respectively. The optimization results for the above factors were compared. The results show that the OIT and MATC of DPBIS for DH systems can be obtained by using the optimization model. Sensitivity analysis was conducted to investigate the impact of some economic parameters, i.e., unit heating cost, insulation material price, interest rate, and insulation material lifetime, on optimization results. It is found out that the impact of sensitivity factors on the OIT and MATC of DPBIS for DH systems is different.

关键词： double pipes     optimization model     optimum insulation thickness     minimum annual total cost    

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Estimation of optimum design of structural systems via machine learning

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1441-1452 doi: 10.1007/s11709-021-0774-0

摘要： Three different structural engineering designs were investigated to determine optimum design variables, and then to estimate design parameters and the main objective function of designs directly, speedily, and effectively. Two different optimization operations were carried out: One used the harmony search (HS) algorithm, combining different ranges of both HS parameters and iteration with population numbers. The other used an estimation application that was done via artificial neural networks (ANN) to find out the estimated values of parameters. To explore the estimation success of ANN models, different test cases were proposed for the three structural designs. Outcomes of the study suggest that ANN estimation for structures is an effective, successful, and speedy tool to forecast and determine the real optimum results for any design model.

关键词： optimization     metaheuristic algorithms     harmony search     structural designs     machine learning     artificial neural networks    

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Biological chip technology to quickly batch select optimum cryopreservation procedure

YU Lina, LIU Jing, ZHOU Yixin, HUA Zezhao

《能源前沿（英文）》 2007年 第1卷 第3期   页码 316-321 doi: 10.1007/s11708-007-0046-2

摘要： In the practices of cryobiology, selection of an optimum freeze/thawing program and an idealistic cryoprotective agent often requires rather tedious, time consuming and repetitive tests. Integrating the functions of sample preparation and viability detection, the concept of biochip technology was introduced to the field of cryopreservation, aiming at quickly finding an optimum freezing and thawing program. Prototype devices were fabricated and corresponding experimental tests were performed. It was shown that microflow-channel chip could not offer a high quality solution distribution. As an alternative, the spot-dropping chip proved to be an excellent way to load the sample quickly and reliably. Infrared thermal mapping on such a chip showed that it had a rather uniform heat transfer boundary. Applying the spot-dropping chip combined with the thermoelectric cooling device, the final output of cryopreservation of multiple samples was tested, and the optimal freeze/thawing program as well as the potentially best concentration of the cryoprotective agent was found by analyzing the results. Further, application of this technique to measure the thermo-physical properties of the cryo-protective agent was also investigated. The study demonstrated that a biochip with integrated automatic loading and inspection units opens the possibility of a massive optimization of the complex cryopreservation program in a quicker and more economical way.

关键词： idealistic cryoprotective     concentration     Prototype     technology     alternative    

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Implementation of an optimum algorithm for structural reliability analysis based on FEM

CHENG Ying, TU Hong-mao, FAN Hong-li

《机械工程前沿（英文）》 2006年 第1卷 第4期   页码 468-471 doi: 10.1007/s11465-006-0061-8

摘要： To analyze structural reliability by the stochastic FE (finite element) method rapidly and efficiently, a method combined with the FE method and gradient optimum algorithm based on ANSYS was presented when referring to the geometric interpretation of structural reliability index. ANSYS-based development was adopted to implement it. Results of an example demonstrate that the method requires fewer FE calculations compared with the design point method and Monte-Carlo simulation, and achieves satisfactory accuracy.

关键词： satisfactory     interpretation     algorithm     structural reliability     stochastic FE    

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Optimum nitrogen fertilization of

Wentao ZOU,Ruifeng JIA,Jinchang YANG,Rongsheng LI,Guangtian YIN

《农业科学与工程前沿（英文）》 2016年 第3卷 第4期   页码 368-374 doi: 10.15302/J-FASE-2016120

摘要： A greenhouse pot experiment was conducted to study the effects of nitrogen fertilization on seedlings grown with 0, 50, 100, 150, 200, 300, 400 and 600 mg N per seedling according to exponential functions. Seedling height, root collar diameter, leaf area and total biomass increased with increasing fertilization from 0 to 200 mg N per seedling and decreased with further increase in fertilization from 300 to 600 mg N per seedling. The net photosynthetic rate, stomatal conductance, intercellular CO concentration and transpiration rate of seedlings showed a unimodal parabolic trend, with peak values of 7.29 mmol·m ·s , 0.071 mol·m ·s , 220 mmol·mol and 1.34 mmol·m ·s , respectively, when the rate of fertilization was 200 mg N per seedling. Photosynthetic gas exchange parameters were significantly different among nitrogen treatments. Based on the critical values of leaf N and P concentration and N/P ratio, the optimum amount of nitrogen of seedlings was 200–400 mg per seedling for leaf N and P concentration, and 100–400 mg per seedling for N/P ratio. It was concluded that 200–400 mg N per seedling was the most suitable nitrogen range for seedlings.

关键词： Calophyllum inophyllum     growth     nitrogen fertilization     nutrient status     photosynthesis    

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Effectiveness analysis and optimum design of the rotary regenerator for thermophotovoltaic (TPV) system

Xi WU, Hong YE, Jianxiang WANG, Jie HE, Jian YANG

《能源前沿（英文）》 2012年 第6卷 第2期   页码 193-199 doi: 10.1007/s11708-012-0184-z

摘要： The influence of the period of rotation on the effectiveness of the thermophotovoltaic (TPV) rotary regenerator was theoretically and experimentally investigated. It was found that the deviations of the theoretical results from the experimental ones decrease with the increase of the period of rotation. To the TPV system of 10 kW combustion power, the deviation is 3.5% when the rotation period is 3 s; while the deviation decreases to 1.5% when the rotation period increases to 15 s. The deviation could be mainly attributed to the cold and hot fluids carryover loss which was not considered in the model. With a new model taking account of the carryover loss established, the predicted results were greatly improved. Based on the modified model, the influence of geometrical parameters of rotary regenerator on the effectiveness was analyzed for TPV systems of various combustion power. The results demonstrate that the effectiveness increases with the increase of the rotary regenerator diameter and height, while fluid carryover loss increases at the same time, which weakens the impact of geometrical parameters.

关键词： thermophotovoltaic (TPV) system     rotary regenerator     effectiveness     carryover loss    

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Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1400-1414 doi: 10.1007/s11709-021-0779-8

摘要： Aggregates are the biggest contributor to concrete volume and are a crucial parameter in dictating its mechanical properties. As such, a detailed experimental investigation was carried out to evaluate the effect of sand-to-aggregate volume ratio (s/a) on the mechanical properties of concrete utilizing both destructive and non-destructive testing (employing UPV (ultrasonic pulse velocity) measurements). For investigation, standard cylindrical concrete samples were made with different s/a (0.36, 0.40, 0.44, 0.48, 0.52, and 0.56), cement content (340 and 450 kg/m3), water-to-cement ratio (0.45 and 0.50), and maximum aggregate size (12 and 19 mm). The effect of these design parameters on the 7, 14, and 28 d compressive strength, tensile strength, elastic modulus, and UPV of concrete were assessed. The careful analysis demonstrates that aggregate proportions and size need to be optimized for formulating mix designs; optimum ratios of s/a were found to be 0.40 and 0.44 for the maximum aggregate size of 12 and 19 mm, respectively, irrespective of the W/C (water-to-cement) and cement content.

关键词： aggregates     non-destructive testing     sand-to-aggregate volume ratio (s/a)     maximum aggregate size (MAS)    

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多径瑞利衰落信道下AQAM系统最佳信噪比门限值的研究

高欢芹,酆广增,朱琦

《中国工程科学》 2006年 第8卷 第1期   页码 67-71

摘要：

自适应调制根据瞬时信道信噪比选择适当的调制方式，能够改善系统的BER性能以及平均吞吐量性能。在常用于高速移动环境的六径瑞利衰落信道模型下，研究自适应调制系统的最佳信噪比门限值，使系统的平均吞吐量最大，同时保证了目标BER性能，得到的最佳门限值可以用于ITU-R M1225 Vehicular Test A模型的自适应调制系统。

关键词： 自适应调制     AQAM     最佳门限值    

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标题 作者 时间 类型 操作

Unified cycle model of a class of internal combustion engines and their optimum performance characteristics

Shiyan ZHENG

期刊论文

Optimum design and preliminary experiments of a novel parallel end traction apparatus for upper-limb

期刊论文

Experimental study on performance of passive and active solar stills in Indian coastal climatic condition

R. LALITHA NARAYANA, V. RAMACHANDRA RAJU

期刊论文

Optimization and performance prediction of a new near-zero emission coal utilization system with combined

GUAN Jian, WANG Qinhui, LI Xiaomin, LUO Zhongyang, CEN Kefa

期刊论文

旅客机环境控制系统优化研究

方林,王浚

期刊论文

系统非优分析理论及方法

何平

期刊论文

Kinematic Model Building and Servo Parameter Identification of 3-HSS Parallel Mechanism

YANG Zhi-yong, WU Jiang, HUANG Tian, NI Yan-bing

期刊论文

Determining the optimum economic insulation thickness of double pipes buried in the soil for district

Fating LI, Pengfei JIE, Zhou FANG, Zhimei WEN

期刊论文

Estimation of optimum design of structural systems via machine learning

期刊论文

Biological chip technology to quickly batch select optimum cryopreservation procedure

YU Lina, LIU Jing, ZHOU Yixin, HUA Zezhao

期刊论文

Implementation of an optimum algorithm for structural reliability analysis based on FEM

CHENG Ying, TU Hong-mao, FAN Hong-li

期刊论文

Optimum nitrogen fertilization of

Wentao ZOU,Ruifeng JIA,Jinchang YANG,Rongsheng LI,Guangtian YIN

期刊论文

Effectiveness analysis and optimum design of the rotary regenerator for thermophotovoltaic (TPV) system

Xi WU, Hong YE, Jianxiang WANG, Jie HE, Jian YANG

期刊论文

Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

期刊论文

多径瑞利衰落信道下AQAM系统最佳信噪比门限值的研究

高欢芹,酆广增,朱琦

期刊论文