一种新型燃气机—涡旋式发动机的理论研究

涡旋式机械首先在压缩机领域，尤其是制冷压缩机领域获得了成功应用，并取得了成就，但涡旋式机械用于发动机才刚刚开始，许多基本方面有待深入研究，分析，本文介绍燃气循环涡旋式发动机的构成特点，对理论循环进行初步分析，并探讨实现燃气涡旋式发动机的一些技术措施。     

一种新型燃气机一涡旋式发动机的理论研究

涡旋式机械首先在压缩机领域，尤其是制冷压缩机领域获得了成功应用，并取得了成就，但涡旋式机械用于发动机才刚刚开始，许多基本方面有待深入研究、分析。本文介绍燃气循环涡旋式发动机的构成特点，对理论循环进行初步分析，并探讨实现燃气涡旋式发动机的一些技术措施。     

机油加注量对发动机性能影响的研究

发动机台架试验过程中，发现不同的机油液位对发动机的性能有较大影响，油底壳内过多的机油造成发动机功率降低，油耗增大，因此，有必要保证发动机机油加注量在合理的范围内。文章通过对发动机润滑油循环流量的需求进行了探讨，保证系统机油循环流量的合理性。由于’不同的机油加注量直接影响油底壳内机油液位，通过台架试验，得出不同液位的机油对发动机性能影响的程度，为发动机润滑系统设计人员提供参考。     

内燃机瞬态特性对整车循环工况动力性和经济性的影响

针对用发动机稳态万有特性计算整车循环工况性能所存在的不足,选用一款汽油机摩托车进行研究和验证。通过运用整车循环工况的试验数据,在发动机动态台架上模拟循环工况测定了发动机的瞬态特性。根据对发动机瞬态特性分析对原机进行了相应改进,使发动机瞬态时混合气形成和燃烧过程得到了改善,加快了发动机瞬态响应频率。最终试验测试结果显示,在发动机稳态特性变化很小的情况下,瞬态特性改进后不仅使整车变工况时动力性略有提升,而且明显降低了整车循环工况百公里油耗。     

布雷顿循环和兰金循环结合使燃气轮机性能优化_一种联合生产的方案

众所周知,布雷顿(Brayton)循环和兰金(Rankine)循环是广泛用于生产电力的循环。二种循环流体的结合是由国际动力技术公司提出的,并由艾莉森燃气轮机分部进行了试验。由排气余热产生的蒸汽在通过涡轮膨胀以前,先在燃气轮机燃烧室内与燃料和空气混合。在不变的涡轮温度下,可使现有发动机的热效率增加40％,输出功率增加60％。这种概念叫做双工质循环(DFC)。艾莉森公司在501-KB发动机上的试验结果已与发动机的计算机模型进行了比较,表明二者吻合很好。本文将表明,在选择的情况中,如何利用DFC在满足电力和蒸汽要求的同时,使热效率最高。与生产电力和蒸汽的其它方案进行了比较。     

基于首次着火循环的低温冷起动特性(Ⅱ)

在一台125cm^3单缸风冷电控喷射LPG发动机上,进行了单循环冷起动实验研究．通过分析发动机最初几个循环的瞬时转速、缸压以及HC排放,得到了发动机首次着火循环冷起动时的燃烧及排放情况．在对首次着火循环分析的基础上,研究了过量空气系数、环境温度、点火提前角和蓄电池电压对LPG发动机首次着火循环燃烧情况的影响．结果表明,蓄电池电压影响发动机冷起动首次着火循环的HC排放,同时对首次着火循环的起动转速也有影响;点火提前角对首次着火循环起动转速影响较大,但对单循环冷起动时的HC排放影响不大;LPG发动机首次循环可靠起动的最佳点火提前角为上止前10℃A．     

面向21世纪的动力系统——H型燃气轮机联合循环

引言四十多年来，GE公司的发电产品和技术始终处于领先地位，而其关键部件是燃气轮机，它决定了市场前进的步伐。由于GE公司的动力系统集团与飞机发动机集团密切合作和配合.使飞机发动机的先进技术和部件能够及时地移植到工业和发电用燃气轮机上，从而保证了其性能不断地提高。例如，八十年代后期，由于应用了飞机发动机上的先进冷却技术和材料，使透平的进气温度提高了167℃，性能也有了较大幅度的提高，形成了F系列燃气轮机。至1996年中期，F型机组的订货已达120台，点火运行时间已达50万小时。提高透平进气温度可以提高其效率，减少燃…     

重型M100甲醇发动机排放及燃烧热效率分布研究

甲醇作为重要的车用发动机替代燃料,其排放性能和燃烧热效率一直是行业内关注的热点。为研究法规工况下甲醇发动机的排放性能及燃烧热效率分布,通过在一台自主研发的重型M100甲醇发动机上进行了重型汽油机瞬态循环(GB 14762—2008)和ETC循环(GB 17691—2005)试验。研究结果表明:M100甲醇发动机的排放污染物值远低于现有法规限值;发动机燃烧热效率与同等排量的其它燃料发动机相当;重型汽油机瞬态循环下的排放性能优于ETC循环,而平均燃烧热效率稍差。     

喷油泵的标定对双燃料发动机燃烧循环变动及排放的影响

根据柴油／天然气双燃料发动机用喷油泵的工作特点，提出了一种新的控制小齿条位移时循环喷油量及各缸不均匀度的喷油泵标定方法，应用该方法进行了喷油泵的标定，并研究了该喷油泵对双燃料发动机燃烧循环变动及排放的影响。研究结果表明，采用新方法标定喷油泵后，双燃料发动机的燃烧循环变动大幅改善，NOx排放显著降低，工作稳定性提高。     

基于循环控制的LPG点燃式发动机冷起动首循环NO瞬态排放特性研究

从循环控制的角度，详细研究了LPG点燃式发动机冷起动首循环NO瞬态排放特性。实验在一台电控LPG进气道喷射单缸风冷四冲程125cm^3发动机上进行。通过高速采集系统记录发动机首循环瞬态NO排放、瞬时缸压和转速，从实验结果中分析发动机NO瞬态排放与其他参数之间的关系。研究表明：在稀燃工况下NO排放能更准确地反映着火的发生，可以作为首循环着火的判断依据；NO排放和循环缸压都随过量空气系数先增大后减小，最大缸内爆发压力发生在略浓的混合气浓度，而最大NO排放发生在较稀的混合气浓度；NO瞬态排放随循环缸压在稀燃、过渡和浓燃区呈现出不同的变化规律，首循环最佳过量空气系数应控制在过渡区域。     

Results of experimental investigations of the non‐throttling Granryd refrigerator

The operation of the non‐throttling Granryd refrigerator has been analysed. The experimental installation is presented. The measurement method and obtained results are presented and discussed. The mathematical model of the process was also built to analyse the influence of several design and operation parameters on the efficiency of the refrigerator. The importance of the internal thermal insulation of the expansion tank has been pointed out. Copyright © 1999 John Wiley & Sons, Ltd.     

Development of an alternative refrigeration cycle

The paper describes the experimental development of an alternative regenerative refrigeration cycle. The cycle attempts to overcome the inefficiencies caused by flash gas entering the evaporator by a novel use of the main compressor. The system incorporates an extra vessel in place of the traditional expansion valve. The vessel is filled with high temperature, high pressure refrigerant from the condenser. The compressor is then switched from the evaporator, thus reducing the pressure. As the pressure is lowered, it is hoped that the flash gas is removed. The cycle is compared, both theoretically and practically, with the standard vapour compression cycle. The problems encountered and their solutions are also presented were possible.     

A trapezoidal cycle with theoretical model based on organic Rankine cycle

Based on organic Rankine cycle (ORC), a trapezoidal cycle with theoretical model is proposed and built according to the trapezoidal configuration and the thermodynamic relation in T–s diagram. Simulations show that the relative deviation between trapezoidal cycle and ORC is lower than 5% within evaporation temperature of 5 °C lower than the critical temperature of the working fluids. Empirical equations to calculate the optimal evaporation temperature, the maximum net power output and the corresponding thermal efficiency are built, which relative deviations from ORC are lower than 4%. Trapezoidal cycle can break through the restrictions of the actual working fluids and the configuration of the ORC to extend the study of the ORC and investigate the general principle of the ORC (or the trapezoidal cycle). Trapezoidal cycle can develop to trilateral cycle or Carnot cycle, which are the boundary cycles of the trapezoidal cycle. Trapezoidal cycle can be used as a general cycle to investigate the relations and principles among the trilateral cycle, Carnot cycle and trapezoidal cycle (or ORC). The performance of these three cycles at maximum power and their relations are investigated in the same conditions of finite heat source. Results show that the maximum power and the corresponding thermal efficiency of the trapezoidal cycle are bounded between Carnot cycle and trilateral cycle. Copyright © 2016 John Wiley & Sons, Ltd.     

A preliminary study of the kalina power cycle in connection with a combined cycle system

Combined cycle systems have been recognized as efficient power systems in which exhaust gas from the topping cycle provides the available energy to the bottoming cycle. Since most heat sources available to the bottoming cycle are sensible-heat sources, there may be a better thermal match, and an increase thermodynamic efficiency, on reducing the entropy generation of the simple combined cycle. To increase the efficiency of the Rankine cycle working with sensible heat, two conventional methods have been proposed: one is to incorporate a multipressure boiler; the other is to implement a supercritical cycle. An alternative method is to use a multicomponent working fluid boiling at a variable temperature with a change in the liquid composition of the components, and yielding a better thermal match with the sensible-heat source than the constant temperature boiling process. The Kalina cycle is an implementation of this concept, where ammonia/water mixtures are used as the working fluid. The purpose of this study is to conduct a preliminary study of the Kalina power cycle system in connection with a combined cycle system, comparing the Kalina cycle and the Rankine cycle. This study is performed using new thermodynamic properties of ammonia/water mixtures developed by the authors.     

HAT循环的一种改型_CHAT循环

本文好ＨＡＴ循环的一种改型ＣＨＡＴ循环。该循环属于再热型的ＨＡＴ循环,并在文中对ＣＨＡＴ循环的特点进行了简要介绍。     

A novel power block for CSP systems

Concentrating Solar Thermal Power (CSP) and in particular parabolic trough, is a proven large-scale solar power technology. However, CSP cost is not yet competitive with conventional alternatives unless subsidized. Current CSP plants typically include a condensing steam cycle power block which was preferably designed for a continuous operation and higher operating conditions and therefore, limits the overall plant cost effectiveness and deployment. The drawbacks of this power block are as follows: (i) no power generation during low insolation periods (ii) expensive, large condenser (typically water cooled) due to the poor extracted steam properties (high specific volume, sub-atmospheric pressure) and (iii) high installation and operation costs.In the current study, a different power block scheme is proposed to eliminate these obstacles. This power block includes a top Rankine cycle with a back pressure steam turbine and a bottoming Kalina cycle comprising another back pressure turbine and using ammonia-water mixture as a working fluid. The bottoming (moderate temperature) cycle allows power production during low insolation periods. Because of the superior ammonia-water vapor properties, the condensing system requirements are much less demanding and the operation costs are lowered. Accordingly, air cooled condensers can be used with lower economical penalty. Another advantage is that back pressure steam turbines have a less complex design than condensing steam turbines which make their costs lower. All of these improvements could make the combined cycle unit more cost effective. This unit can be applicable in both parabolic trough and central receiver (solar tower) plants.The potential advantage of the new power block is illustrated by a detailed techno-economical analysis of two 50 MW parabolic trough power plants, comparing between the standard and the novel power block. The results indicate that the proposed plant suggests a 4-11% electricity cost saving.     

Thermodynamic Analysis and Comparison of Performances of Air Standard Atkinson,Otto, and Diesel Cycles with Heat Transfer Considerations

This paper focuses on the overall performances of Otto, Atkinson, and Diesel air standard cycles. This study compares performance of these cycles with regard to parameters such as variable specific heat ratio, heat transfer loss, frictional loss, and internal irreversibility based on finite‐time thermodynamics. The relationship between thermal efficiency and compression ratio, and between power output and compression ratio of these cycles are obtained by numerical examples. In this study, it is assumed that during the combustion process, the heat transfer occurs only through the cylinder wall. The heat transfer is affected by the average temperature of both the cylinder wall and the working fluid. The results show that for each cycle, with the increase of the compression ratio in the specific mean piston speed, power output and thermal efficiency first increase and after reaching their maximum value, start to decrease. The results also indicate that maximum power output and maximum thermal efficiency of an Atkinson cycle could be higher than the values of these parameters in Diesel cycle and Otto cycle in the same operating conditions. The maximum power output and the maximum thermal efficiency of the Otto cycle have the lowest value among studied cycles. By increasing the mean piston speed, power output and thermal efficiency of Atkinson, Diesel, and Otto cycles start to decrease. The results of this study provide guidance for the performance analysis and show the improvement areas of practical Otto, Atkinson, and Diesel engines.     

Experimental investigation of an improved version of the four-step magnesium-chlorine cycle

In this paper, an experimental study is undertaken to capture HCl in dry form in order to decrease the power consumption of the four-step Mg-Cl cycle using MgO as the capturing agent. A new experimental method is developed to capture HCl from its mixture with steam, and liberate HCl in a dry form. Several cases are studied to observe HCl capture performance, including testing of the resulting substances in detail using Thermogravimetric Analysis (TGA), and X-ray diffraction (XRD) tests. The results of these experiments show 30.8% HCl capture by solid MgO particles in a semi-batch packed bed reactor design with an uncertainty value of ±1.17%. The XRD results indicate that an optimum reactor temperature of ～275 °C is critical to prevent the process from side reactions and undesired products. The experimental results are adapted to the four-step Mg-Cl cycle to form a final design with HCl capture.     

变温热源内可逆中冷回热布雷顿循环功率密度分析

用有限时间热力学方法分析内可逆变温热源中冷回热布雷顿循环,导出了无因次功率密度的解析式,由数值计算给出了燃气轮机功率密度特性,分析了循环中各热力参数对功率密度的影响,并对最大功率工况与最大功率密度工况下的主要参数进行了比较,得出了最大功率密度设计的优点和不足。     

地热资源发电技术特点及发展方向

地热资源是一种清洁无污染、可再生的新型能源,对于发展低碳经济、实现可持续发展具有积极的作用.目前地热发电技术主要包括干蒸汽发电、扩容式蒸汽发电、双工质循环发电和卡琳娜循环发电等.其中干蒸汽发电系统工艺简单,技术成熟,安全可靠,循环效率可达20％以上,是高温地热田发电的主要形式;扩容式发电技术已在地热发电领域得到广泛应用,尤其是中高温地热田,二级扩容系统循环效率约为15％～20％;针对中低温地热资源,双工质循环发电技术是较为适用的,它由地热水系统和低沸点介质系统组成,循环效率较扩容式蒸汽发电技术可提高20％～30％;卡琳娜循环在低温地热资源应用领域中有其独特的优越性,通过调整氨和水的比例,可以适应低温地热水的发电特性,卡琳娜循环发电技术的循环效率比朗肯循环的效率高20％～50％.在低温地热资源的开发利用过程中,双工质循环和卡琳娜循环技术具有广阔的发展前景.作为一种新型地热资源,干热岩具有很高的开发利用价值.新型的联合循环发电技术是地热发电技术的发展方向.在浅层地热能得到大规模开发后,中深层地热资源和干热岩资源将成为地热发电技术新的资源,我国应注重中深层地热资源和干热岩资源的开发.