自由活塞式热气机发电技术在世界上的发展

自由活塞式热气机是热气机的一个重要分支,也是一个非常活跃的研究领域。当前世界上已有数家公司正在研究和生产商品化的自由活塞式热气机,而目前发展较好的公司为美国的SunPower公司和Infinia公司。自由活塞式热气机可应用在太阳能发电系统、太空核动力发电系统、战场小型动力系统、士兵可佩带动力系统和家用的MCHP等领域,体现出良好的市场发展前景。     

自由活塞式发动机NOx排放的数值计算研究

以燃烧反应化学动力学程序SENKIN为基础,建立了预测发动机排放的计算模型,并针对自由活塞式发动机的特点进行了修正,并对修正后的模型进行了实验验证。利用该模型对自由活塞式发动机的排放进行了数值计算。计算结果揭示了该种发动机排放物的生成特点以及发动机转速、混合气燃空比对排放产物的影响规律。     

自由活塞式发动机NO_x排放的数值计算研究

以燃烧反应化学动力学程序 SENKIN为基础 ,建立了预测发动机排放的计算模型 ,并针对自由活塞式发动机的特点进行了修正 ,并对修正后的模型进行了实验验证。利用该模型对自由活塞式发动机的排放进行了数值计算。计算结果揭示了该种发动机排放物的生成特点以及发动机转速、混合气燃空比对排放产物的影响规律     

自由活塞式斯特林发动机的性能优化

以Simple分析法为基础,扩展针对自由活塞式斯特林发动机的分析软件,研究各项设计参数对自由活塞式斯特林发动机性能的影响,并对各项设计参数进行优化。结果表明:发动机性能随回热器孔隙率和相位角的变化有最佳值,而随系统平均压力和频率的增加而增加;当加热器和冷却器长径比(L/g)大于10时,环形间隙(g)越小,发动机输出功率与热效率越高;发动机输出功率随回热器长径比的增加而减小,热效率随回热器长径比的增加而增加;而发动机性能随加热器与冷却器长径比的变化有最佳值。     

组合式风力机／电换能装置

描述了组合式风力发电及加热装置、船舶风力助航和温差发电装置的概念设计。     

小型斯特林发动机不同外加热T况下运行的探索性实验

该文就其微型化可能产生的一系列问题,如:输出频率过高、产生转矩过小、冷热端差过小等进行了分析.提出自由活塞式斯特林发动机比热声式更具微型化的优势.并对一台长12cm、直径2.5cm的小型活塞式斯特林发动机进行了实验.实验中发动机热端温度范围64-626℃,通过测量其外壁面温度和声信号随时间的变化,得到发动机的稳定性和输出功率随外加热功率变化规律.该发动机的理论最高功率密度为102kW/m3.     

2008年世界主要发动机公司技术回顾

发电用发动机 Caterpillar Power Generation Systems（CPGS）推出16CM43发动机，发电功率14．4MW。由于提高了功率密度和可靠性，燃料选择灵活，16CM43可应用于主、辅机，分布式发电和峰值发电。     

小型斯特林发动机不同外加热工况下运行的探索性实验

该文就其微型化可能产生的一系列问题,如：输出频率过高、产生转矩过小、冷热端差过小等进行了分析。提出自由活塞式斯特林发动机比热声式更具微型化的优势。并对一台长12cm、直径2．5cm的小型活塞式斯特林发动机进行了实验。实验中发动机热端温度范围64～626℃,通过测量其外壁面温度和声信号随时问的变化,得到发动机的稳定性和输出功率随外加热功率变化规律。该发动机的理论最高功率密度为102kW／m^3。     

几种类型发电公司环境成本核算的分析研究

在自由的电力市场条件下，发电厂的环境成本将会被纳入发电成本，成为影响市场竞争力的重要因素。为了比较不同电源的环境成本对电价的影响程度，应用环境经济学理论分别对燃煤发电、天然气发电以及核能发电的环境成本进行了核算和比较。     

碟式斯特林发动机的研究进展

太阳能的利用和斯特林发动机的研发符合目前解决全球能源危机问题的需要。对斯特林热机的发展过程和循环工作原理进行了总结,综述了国内外对于碟式斯特林发电技术的应用现状,归纳了碟式斯特林发电系统中太阳光跟踪控制系统、接收器聚热技术、斯特林发动机功率控制技术和斯特林发动机密封技术等关键技术的研究成果和应用现状,总结并展望了碟式斯特林发电技术的发展重心,为进一步的研究工作提供参考。     

Dynamic analysis of a free piston Stirling engine working with closed and open thermodynamic cycles

In free piston Stirling engines the power generated by the engine is related to the length of the piston and displacer strokes. Length of strokes vary with respect to the hot end temperature, external load, charge pressure, rod diameter, stiffness of springs, masses of piston and displacer and static positions of the piston and displacer. When the length of displacer and piston strokes exceeds the estimated limits, some mechanical collisions occur between piston and displacer or displacer and cylinder. In this work, the dynamic model of a free piston Stirling engine working with closed and open thermodynamic cycles was derived and numerically solved for an optional pair of the piston and displacer masses. Safe ranges were investigated for the hot end temperature, charge pressure, damping coefficient of the piston motion, stiffness of the piston spring and area of the displacer rod. The stiffness of the displacer spring and static positions of the piston and displacer were optimized. Analysis indicated that, a free piston Stirling engine working with a closed thermodynamic cycle performs a stable operation within a small range of the hot end temperature and damping coefficient of the piston motion. By means of inverting the engine into an open-cycle engine, the limited range of the hot end temperature and the damping coefficient of the piston motion were partially enlarged.     

斯特林发动机V型传动系统激励力的计算分析研究

介绍了有关斯特林发动机传动系统激励力的计算分析研究。建立了斯特林发动机传动系统刚柔混合的多体动力学模型,计算了曲轴主轴承载荷和活塞侧推力等激励力。对比分析了有、无齿轮啮合力对主轴承载荷的影响,指出:计算斯特林发动机传动系统激励力时应考虑齿轮啮合冲击力的影响。对比分析了不同活塞间隙对活塞侧推力的影响,结果表明:活塞杆与缸套间隙在0.08~0.12 mm时,活塞侧推力的影响较小。     

Stirling based fuel cell hybrid systems: An alternative for molten carbonate fuel cells

This paper presents a new design for high temperature fuel cell and bottoming thermal engine hybrid systems. Now, instead of the commonly used gas turbine engine, an externally fired - Stirling - piston engine is used, showing outstanding performance when compared to previous designs.Firstly, a comparison between three thermal cycles potentially usable for recovering waste heat from the cell is presented, concluding the interest of the Stirling engine against other solutions used in the past.Secondly, the interest shown in the previous section is confirmed when the complete hybrid system is analyzed. Advantages are not only related to pure thermal and electrochemical parameters like specific power or overall efficiency. Additionally, further benefits can be obtained from the atmospheric operation of the fuel cell and the possibility to disconnect the bottoming engine from the cell to operate the latter on stand alone mode. This analysis includes on design and off design operation.     

Mobile hydraulic power supply: Liquid piston Stirling engine pump

Conventional mobile hydraulic power supplies involve numerous kinematic connections and are limited by the efficiency, noise, and emissions of internal combustion engines. The Stirling cycle possesses numerous benefits such as the ability to operate from any heat source, quiet operation, and high theoretical efficiency. The Stirling engine has seen limited success due to poor heat transfer in the working chambers, difficulty sealing low-molecular weight gases at high pressure, and non-ideal piston displacement profiles. As a solution to these limitations, a liquid piston Stirling engine pump is proposed. The liquid pistons conform to irregular volumes, allowing increased heat transfer through geometry features on the interior of the working chambers. Creating near-isothermal operation eliminates the costly external heat exchangers and increases the engine efficiency through decreasing the engine dead space. The liquid pistons provide a positive gas seal and thermal transport to the working chambers. Controlling the flow of the liquid pistons with valves enables matching the ideal Stirling cycle and creates a direct hydraulic power supply. Using liquid hydrogen as a fuel source allows cooling the compression side of the engine before expanded the fuel into a gas and combusting it to heat the expansion side of the engine. Cooling the compression side not only increases the engine power, but also significantly increases the potential thermal efficiency of the engine. A high efficiency Stirling engine makes energy regeneration through reversing the Stirling cycle practical. When used for regeneration, the captured energy can be stored in thermal batteries, such as a molten salt. The liquid piston Stirling engine pump requires further research in numerous areas such as understanding the behavior of the liquid pistons, modeling and optimization of a full engine pump, and careful selection of materials for the extreme operating temperatures. Addressing these obtainable research quandaries will enable a transformative Stirling engine pump with the potential to excel in numerous applications.     

Free piston Stirling engines: A review

This paper presents a detailed review on free piston Stirling engines (FPSEs) technology. Generally, the Stirling engines can be categorized into two broad classes comprising kinematic and dynamic converters among which FPSEs are known as the dynamic type. Other well-known dynamic Stirling converters are Fluidyne and thermosacoustic engines among which the thermosacoustic ones are the most advanced Stirling converters recently presented. In this research, the dynamic Stirling engines are first introduced and reviewed. Then, the review work is directed toward the FPSEs, one of the most reliable dynamic Stirling converters utilized in different applications such as combined heat and power systems (CHPs). Subsequently, the working principles of different types of FPSEs and their performance are summarized. Next, several manufactured FPSEs, as well as their corresponding features and applications, are discussed. Finally, the article is conducted to analysis and modeling approaches of FPSEs. Accordingly, linear and nonlinear analytical techniques of FPSEs are introduced, and some comparative data are provided to verify the modeling schemes. Then, various design parameters affecting the engine performance are introduced and studied. The outcomes of this review work demonstrate the potential of FPSEs for different applications and reveal that the perturbation-based model is likely the most comprehensive nonlinear method for modeling and design of the FPSEs.     

有限速率过程对活塞式斯特林发动机性能的影响

本文讨论在给定热源温度和压缩比的情况下,过程进行的速率有限,并受热传导不可逆影响的内可逆活塞式斯特林发动机的最优性能,导出以理想气体或范德瓦尔斯气体为工质的斯特林发动机的最大输出功率与热效率的关系,以及最大热效率与输出功率的关系,并推出了一些新的有限时间热力学的性能界限。     

An analysis of beta type Stirling engine with rhombic drive mechanism

Stirling engine system is one of the options for electrifying a remote community not serviceable by the grid, which can operate on energy input in the form of heat. Major hurdle for the wide-spread usage of rhombic drive beta type Stirling engine is complexity of the drive and requirement of tight tolerances for its proper functioning. However, if the operating and geometrical constraints of the system are accounted for, different feasible design options can be identified. In the present work, various aspects that need to be considered at different decision making stages of the design and development of a Stirling engine are addressed. The proposed design methodology can generate and evaluate a range of possible design alternatives which can speed up the decision making process and also provide a clear understanding of the system design considerations. The present work is mainly about the design methodology for beta type Stirling engine and the optimization of phase angle, considering the effect of overlapping volume between compression and expansion spaces. It is also noticed that variation of compression space volume with phase angle remains sinusoidal for any phase difference. The aim of the present work is to find a feasible solution which should lead to a design of a single cylinder, beta type Stirling engine of 1.5 kW_e capacity for rural electrification.     

Simulation, construction and testing of a two-cylinder solar Stirling engine powered by a flat-plate solar collector without regenerator

In this research, a gamma-type, low-temperature differential (LTD) solar Stirling engine with two cylinders was modeled, constructed and primarily tested. A flat-plate solar collector was employed as an in-built heat source, thus the system design was based on a temperature difference of 80 °C. The principles of thermodynamics as well as Schmidt theory were adapted to use for modeling the engine. To simulate the system some computer programs were written to analyze the models and the optimized parameters of the engine design were determined. The optimized compression ratio was computed to be 12.5 for solar application according to the mean collector temperature of 100 °C and sink temperature of 20 °C. The corresponding theoretical efficiency of the engine for the mentioned designed parameters was calculated to be 0.012 for zero regenerator efficiency. Proposed engine dimensions are as follows: power piston stroke 0.044 m, power piston diameter 0.13 m, displacer stroke 0.055 m and the displacer diameter 0.41 m. Finally, the engine was tested. The results indicated that at mean collector temperature of 110 °C and sink temperature of 25 °C, the engine produced a maximum brake power of 0.27 W at 14 rpm. The mean engine speed was about 30 rpm at solar radiation intensity of 900 W/m² and without load. The indicated power was computed to be 1.2 W at 30 rpm.     

Power generation from a new air-based Marnoch heat engine

This paper examines the performance of a new Marnoch heat engine, which uses dry air and a pneumatic piston assembly to convert thermal energy to electricity. The system has unique capabilities of operating over temperature differentials less than 100 K. Unlike a common Stirling engine, the heat exchangers and piston assembly are not co-located, which is beneficial for positioning of heat exchangers in various configurations. This paper presents an operational laboratory-scale, proof-of-concept Marnoch heat engine (MHE), including its performance and power generation capabilities. It also presents a thermodynamic analysis of the system. Based on the MHE results, component modifications are made to improve its performance. The configuration has an efficiency of about thirty percent of a Carnot heat engine operating in the temperature range between 272 K and 372 K. Experimental data is acquired to provide verification of the predictive model, as well as demonstration of the MHE’s capabilities for efficient generation of electricity from waste heat sources.