1、斯特林发动机斯特林发动机是一种闭循环活塞式热机,闭循环的意思是工作燃气一直保存在气缸内,而开循环则如内燃机和一些蒸气机需要与大气交换气体。斯特林发动机一般被归为外燃机。切图以外的菱形驱动器测试配置斯特林发动机的设计：* 粉红-热筒壁* 深灰色-冷筒壁（与冷却进排气管在黄色）* 暗绿色-热绝缘分开的两个汽缸结束* 浅绿色-置换活塞* 深蓝色-功率活塞* 淡蓝色-曲柄连杆和飞轮 没有表明：热源和热汇。 在此设计了置换活塞构造没有专门建造的再生 。介绍斯特林发动机在热机中的效率目前是最高的，有时可以达到 80%。In the conversion of heat into mechanical wo
2、rk, the Stirling engine has the potential to achieve the highest efficiency of any heat engine. It can theoretically perform up to the full Carnot efficiency, although not yet in practice. The practical limitations include the non-ideal properties of the working gas, and material properties such as
3、friction, thermal conductivity, tensile strength, creep, rupture strength, and melting point. The Stirling engine can run on any heat source, including chemical, solar, geothermal and nuclear. There are many possible implementations of the Stirling engine. Most fall into the category of reciprocatin
4、g piston engine.In contrast to internal combustion engines, Stirling engines have the potential to use renewable heat sources more easily, to be quieter, and to be more reliable with lower maintenance. They are preferred for applications that value these unique advantages, particularly if the the co
5、st per unit energy generated ($/kWh) is more important than the capital cost per unit power ($/kW). On this basis, Stirling engines are cost competitive up to about 100 kW.3Compared to an internal combustion engine of the same power rating, Stirling engines currently have a higher capital cost and a
6、re usually larger and heavier. Their lower maintenance requirements make the overall energy cost comparable. The thermal efficiency is also comparable (for small engines), ranging from 15%-30%.3For applications such as micro-CHP, a Stirling engine is often preferable to an internal combustion engine
7、. Other applications include water pumping, space-based astronautics, and electrical generation from plentiful energy sources that are incompatible with the internal combustion engine, such as solar energy, and biomass such as agricultural waste and other waste such as domestic refuse. Stirlings hav
8、e also been used as a marine engine in Swedish Gotland class submarines. 4However Stirlings are generally not price-competitive as an automobile engine, due to high cost per unit power, low power density and high material costs.In recent years, the advantages of Stirling engines have become increasi
9、ngly significant, given the rise in liquid fuel prices and concerns such as peak oil and climate change. Stirling engines address these issues by being very compatible with all renewable energy and fuel sources. These growing interests in Stirling technology have fostered the ongoing research and de
10、velopment of Stirling devices, and R然而这还没有实现的理想仍然是一项巨大的工程挑战。然而，目前的设计，指出其效率高，操作安静和方便，他们可以利用什么否则将废热。斯特林发动机在目前激动人心的利益为核心的组成部分，国内热电联产（热电联产）单位，这可能产生重大影响全世界的能源消耗。 1 2 空军是一个许多可能的气体，可用于在一个斯特林发动机。所谓“热空气引擎”一般用来包含任何热空气引擎的工作液。热空气引擎可以使用任何一个几个不同的热力循环，包括布雷顿循环，爱立信斯特林循环或周期。 在斯特林发动机已用于小型低功耗应用了近两个世纪。斯特林发动机继续使用他们的能力提供机
11、械或电力，加热或冷却的应用，热源和散热片可用。斯特林发动机背景NameThough it had been suggested as early as 1884 that all closed cycle air engines should be generically called Stirling engines after the inventor of the first practical example, the idea found little favour and the various types on the market continued to be known b
12、y the name of their individual designer or manufacturer. Then, in the 1940s, the Philips company was searching for a suitable name for its version of the air engine which by that time had already been tested with other gases. Rejecting many suggestions, including hot gas engine (gas engine was alrea
13、dy in general use for internal combustion engines running on gaseous fuels) and external combustion engine (did not differentiate between open and closed cycles), Philips eventually settled on Stirling engine in April 1945. General acceptance of the term followed a few years later.8Early yearsIllust
14、ration to Robert Stirlings 1816 patent application of the air engine design which later came to be known as the Stirling Engine.The Stirling engine (or Stirlings air engine as it is was known at the time) was invented and patented by Reverend Dr. Robert Stirling in 1816.9 It followed earlier attempt
15、s at making an air engine but was probably the first to be put to practical use when in 1818 an engine built by Stirling was employed pumping water in a quarry.10 The main subject of Stirlings original patent was a heat exchanger which he called an “economiser“ for its enhancement of fuel economy in
16、 a variety of applications. The patent also described in detail the employment of one form of the economiser in his unique closed-cycle air engine design11 in which application it is now generally known as a regenerator. Subsequent development by Robert Stirling and his brother James, an engineer, r
17、esulted in patents for various improved configurations of the original engine. Their pressurisation enhancement had by 1843 sufficiently increased power output enough to drive all the machinery at a Dundee iron foundry.12As well as saving fuel, the inventors were motivated to create a safer alternat
18、ive to the steam engines of the time,13 whose boilers frequently exploded causing many injuries and fatalities.1415 The need for Stirling engines to run at very high temperatures to maximize power and efficiency exposed limitations in the materials of the day and the few engines that were built in t
19、hose early years suffered unacceptably frequent failures (albeit with far less disastrous consequences than a boiler explosion16) - for example, the Dundee foundry engine was replaced by a steam engine after three hot cylinder failures in four years.17Later nineteenth century developmentsSubsequent
20、to the failure of the Dundee foundry engine there is no record of the Stirling brothers having any further involvement with air engine development and the Stirling engine never again competed with steam as an industrial scale power source (steam boilers were becoming safer18 and steam engines more e
21、fficient, thus presenting less of a target to rival prime movers). However, from about 1860 smaller engines of the Stirling/hot air type were produced in substantial numbers finding applications wherever a reliable source of low to medium power was required, such as raising water or providing air fo
22、r church organs.19 These generally operated at lower temperatures so as not to tax available materials, so were relatively inefficient. But their selling point was that, unlike a steam engine, they could be operated safely by anybody capable of managing a fire.20 Several types remained in production
23、 beyond the end of the century, but apart from a few minor mechanical improvements the design of the Stirling engine in general stagnated during this period.21Twentieth century revivalPhilips MP1002CA Stirling generator of 1951During the early part of the twentieth century the role of the Stirling e
24、ngine as a “domestic motor“22 was gradually usurped by the electric motor and small internal combustion engines until by the late 1930s it was largely forgotten, only produced for toys and a few small ventilating fans.23 At this time Philips was seeking to expand sales of its radios into areas where
25、 electricity was unavailable and the supply of batteries uncertain. Philips management decided that a low-power portable generator would facilitate such sales and tasked a group of engineers at the companys research lab (the Nat. Lab) in Eindhoven to evaluate alternatives.After a systematic comparis
26、on of various prime movers the Stirling engines quiet (both audibly and in terms of radio interference) operation and ability to run on a variety of heat sources (common lamp oil - “cheap and available everywhere“ - was favoured), the team picked Stirling.24 They were also aware that, unlike steam a
27、nd internal combustion engines, virtually no serious development work had been carried out on the Stirling engine for many years and asserted that modern materials and know-how should enable great improvements.25Encouraged by their first experimental engine, which produced 16 watts of shaft power fr
28、om a bore and stroke of 30x25mm,26 Phillips began a development program. This work continued throughout World War II and by the late 1940s handed over the Type 10 to Philips subsidiary Johan de Witt in Dordrecht to be productionised and incorporated into a generator set. The result, rated at 200 wat
29、ts from a bore and stroke of 55x27 mm, was designated MP1002CA (known as the Bungalow set). Production of an initial batch of 250 began in 1951, but it became clear that they could not be made at a competitive price and the advent of transistor radios with their much lower power requirements meant t
30、hat the original rationale for the set was disappearing. Approximately 150 of these sets were eventually produced.27 Some found their way into university and college engineering departments around the world28 giving generations of students a valuable introduction to the Stirling engine.Philips went
31、on to develop experimental Stirling engines for a wide variety of applications and continued to work in the field until the late 1970s, but only achieved commercial success with the reversed Stirling engine cryocooler. They did however take out a large number of patents and amass a wealth of informa
32、tion which they licensed to other companies and which formed the basis of much of the development work in the modern era.29在将热变成机械功的转换上，史特林引擎在真实的热机中可达最高的热效率，至多 80%，仅受工作气体和引擎材料的不理想性质限制，例如摩擦、热传导性、抗张强度、缓慢、熔点等。 此引擎理论上可用任何足量的热源运行，包括太阳能、化学能和核能。与内燃机相比，史特林引擎往往维修需求较低，更高效、更安静、而且更可靠。它们倾向被应用于某些特殊用途以发扬其独特优点。 特别是
33、首要目标非减低每单位功率的投资成本(金钱/千瓦) ，而是减低引擎产生每单位能量的成本( 金钱/度) 的时候。在额定功率下，史特林引擎的投资成本目前比内燃机引擎高，而且通常更大更重，因此这引擎科技很少单独以此作为竞争基准。 然而在一些用途上,适当的本益分析可令史特林引擎优于内燃机引擎。近年来，鉴于能源成本普遍上涨，能源短缺和气候变迁之类的环境问题，史特林引擎的优点愈来愈显著。 对史特林引擎科技提高兴趣促进了史特林装置的研发。其应用涵盖借由不相容于内燃机的丰富能源抽水、宇基太空航行、发电，像是太阳能、农业废料还有家庭垃圾。另一个史特林引擎的潜力是，若供应机械功，它可以作为一种热泵。已有实验利用风能
34、驱动史特林热泵作为家用冷暖空调。斯特林发动机功能描述Engine operationSince the Stirling engine is a closed cycle, it contains a fixed mass of gas called the “working fluid“, most commonly air, hydrogen or helium. In normal operation, the engine is sealed and no gas enters or leaves the engine. No valves are required, unlike o
35、ther types of piston engines. The Stirling engine, like most heat-engines, cycles through four main processes: cooling, compression, heating and expansion. This is accomplished by moving the gas back and forth between hot and cold heat exchangers, often with a regenerator between the heater and cool
36、er. The hot heat exchanger is in thermal contact with an external heat source, such as a fuel burner, and the cold heat exchanger being in thermal contact with an external heat sink, such as air fins. A change in gas temperature will cause a corresponding change in gas pressure, while the motion of
37、the piston causes the gas to be alternately expanded and compressed.The gas follows the behavior described by the gas laws which describe how a gass pressure, temperature and volume are related. When the gas is heated, because it is in a sealed chamber, the pressure rises and this then acts on the p
38、ower piston to produce a power stroke. When the gas is cooled the pressure drops and this means that less work needs to be done by the piston to compress the gas on the return stroke, thus yielding a net power output.When one side of the piston is open to the atmosphere, the operation is slightly di
39、fferent. As the sealed volume of working gas comes in contact with the hot side, it expands, doing work on both the piston and on the atmosphere. When the working gas contacts the cold side, its pressure drops below atmospheric pressure and the atmosphere pushes on the piston and does work on the ga
40、s.To summarize, the Stirling engine uses the temperature difference between its hot end and cold end to establish a cycle of a fixed mass of gas, heated and expanded, and cooled and compressed, thus converting thermal energy into mechanical energy. The greater the temperature difference between the
41、hot and cold sources, the greater the thermal efficiency. The maximum theoretical efficiency is equivalent to the Carnot cycle, however the efficiency of real engines is only a fraction of this value, even in highly optimized engines.Sterling engine small clear.oggPlay videoVideo showing the compres
42、sor and displacer of a very small Stirling Engine in actionVery low-power engines have been built which will run on a temperature difference of as little as 7 C, for example between the palm of a hand and the surrounding air, or between room temperature and melting water ice.303132edit Pressurizatio
43、nIn most high power Stirling engines, both the minimum pressure and mean pressure of the working fluid are above atmospheric pressure. This initial engine pressurization can be realized by a pump, or by filling the engine from a compressed gas tank, or even just by sealing the engine when the mean t
44、emperature is lower than the mean operating temperature. All of these methods increase the mass of working fluid in the thermodynamic cycle. All of the heat exchangers must be sized appropriately to supply the necessary heat transfer rates. If the heat exchangers are well designed and can supply the
45、 heat flux needed for convective heat transfer, then the engine will produce power in proportion to the mean pressure, as predicted by the West number, and Beale number.3334 In practice, the maximum pressure is also limited to the safe pressure of the pressure vessel. Like most aspects of Stirling e
46、ngine design, optimization is multivariate, and often has conflicting requirements. 35edit Lubricants and frictionA Stirling engine and generator set with 55 kW electrical output, for combined heat and power applications.At high temperatures and pressures, the oxygen in air-pressurized crankcases, o
47、r in the working gas of hot air engines, can combine with the engines lubricating oil and explode. At least one person has died in such an explosion.36Lubricants can also clog heat exchangers, especially the regenerator. For these reasons, designers prefer non-lubricated, low-coefficient of friction
48、 materials (such as Rulon (plastic) or graphite), with low normal-forces on the moving parts, especially for sliding seals. Some designs avoid sliding surfaces altogether by using diaphragms for sealed pistons. These are some of the factors that allow Stirling engines to have lower maintenance requi
49、rements and longer life than internal-combustion engines.发动机运行由于斯特林发动机是一个封闭的循环，它包含一个固定的大规模的天然气被称为“工作流” ，最常见的空气，氢气或氦气。在正常运作，引擎是密封的，没有气体进入或离开发动机。无阀是必要的，不像其他类型的活塞式发动机。在斯特林发动机，最喜欢热引擎，通过 4 个周期的主要过程：冷却，压缩，加热和扩张。这是通过移动的气体之间来回热冷热交换器，往往与再生之间的加热器和冷却器。热换热器的热与外部的热源，如燃料燃烧器，和冷战式换热器是在接触热与外部散热片，如空气鱼翅。改变气体温度会引起相应的变化，气体压力，而运动的活塞造成的天然气将轮流扩大和压缩。 气体的行为如下描述了天然气的法律，说明气体的压力，温度和体积是有关系的。当气体被加热，因为它是在一个密封的房间，压力上升，这对当时行为的权力活塞产生动力中风。当冷却气体的压力下降，这意味着较少的工作需要做的活塞压缩气体返回中风，从而产生了净功率输出。 当一方活塞开放的气氛中，操作稍有不同。由于密封货量工作气体接触的热点方面，它的扩大，
