Miniature Combustor with Liquid-Fuel Film

摘要CTS-0212163W。SirigNano和D.Dunn-Rankin，加州大学欧文分校标题：微型液体燃料薄膜燃烧器提出了一种新的概念，用于直接喷射式液体燃料燃烧器的小型化，其中燃料在壁膜中流动，减少热损失，优化汽化速率，并抑制猝灭。高表面/体积燃烧器的新替代方案是将液体燃料作为薄膜输送到燃烧器表面。这种输送同时冷却燃烧室壁，并暴露燃料以供汽化。一个简单的分析表明，如果燃烧室是微型发动机的一部分，那么燃烧室的体积从几百立方毫米到几立方厘米，燃料流速从大约每秒1毫克到每秒1克，功率级别从10瓦到10千瓦是可以实现的。液膜燃烧的概念不仅适用于紧凑型动力设备，还适用于任何要求或需要高表面积体积比的燃烧室。研究人员使用实验和计算方法分析了各种层流和湍流条件下的燃烧室。目标是最大限度地提高燃烧室的效率和稳定性，同时将尺寸和排放降至最低。尽管概念验证研究前景看好，但仍需要大量研究来推进薄膜燃烧策略。这包括与薄膜表面相互作用的旋流、在这些条件下的传热和汽化、燃烧室中的燃料/空气混合以及最小化反应时间等基本问题。还审查了一系列技术问题，包括燃料成膜方法(例如，多孔气瓶或壁面喷雾)、移至高压条件、火焰稳定性、点火策略以及对不同燃料类型的容忍。小型燃烧器对运行条件非常敏感，因此对系统的控制很可能是重要的。燃料和空气流量的控制、通过壁面冷却的热流控制和涡流控制是保持最佳燃烧器性能所需的潜在重要系统输入的示例。需要个人力量的想法的不断增长的市场范围从电子和电信设备(例如，蜂窝电话和笔记本电脑)到可以安全地探索潜在危险环境的小型移动侦察机器人。许多这样的轻量级设备需要几十瓦的功率，持续时间在几十个小时左右，从而推动电源考虑具有最高能量密度的设备。由于内燃机具有同时提供高功率密度和高能量密度的潜力，因此探索这种发电方法是很自然的。微型燃气轮机(燃烧室体积0.04cc)、微型(排气量0.078 cc)和微型(排气量0.0017 cc)旋转发动机、微型燃烧室(0.1cc燃烧室)和微型瑞士辊式燃烧器都是这种探索的例子。这些设备的效率还不足以与现有最好的电池竞争，但它们已经证明了内燃机作为个人电源的可行性。

AbstractCTS-0212163W. Sirignano and D. Dunn-Rankin, University of California-IrvineTitle: Miniature Combustor with Liquid-Fuel FilmA new concept is advanced for the miniaturization of direct-injection liquid-fueled combustors wherein the fuel is flowed in a wall film that reduces heat losses, optimizes vaporization rate, and inhibits quenching. The new alternative for high surface/volume combustors is the delivery of the liquid fuel as a film on the combustor surfaces. This delivery simultaneously cools the combustor walls and exposes the fuel for vaporization. A simple analysis indicates that if the combustor were part of a miniature engine, power levels from ten watts to ten kilowatts would be achievable with combustor volumes varying from a few hundred cubic millimeters to a few cubic centimeters and fuel flow rates varying from about a milligram per second to a gram per second. The liquid-film burning concept extends beyond compact power devices and applies to any combustor where high surface-to-volume ratio is imposed or desired. Studies analyze thecombustor over a range of laminar and turbulent conditions using both experimental and computational methods. The goals are to maximize the combustor efficiency and stability while minimizing size and emissions. Although proof-of-concept studies are promising, a substantial amount of research is needed to bring the film-combustion strategy forward. This includes fundamental issues regarding swirl flows interacting with filming surfaces, heat transfer and vaporization under these conditions, fuel/air mixing in the chamber, and minimizing reaction times. A range of technical issues are also examined, including fuel filming approaches (e.g., porous cylinders or wall sprays), moving to high pressure conditions, flame stability, ignition strategies, and tolerance of different fuel types. Small combustors are quite sensitive to operating conditions, so it is likely that control of the system will be important. Control of the fuel and air flow rates, heat flux control through wall cooling, and swirl control are examples of potentially important system inputs needed to maintain optimal combustor performance.The growing market of ideas that require personal power ranges from electronic and telecommunication equipment (e.g., cellular telephones and laptop computers) to small, mobile reconnaissance robots that can safely explore potentially hazardous environments. Many of these lightweight devices demand tens of watts of power for durations on the order of tens of hours, thereby driving the power source considerations towards those with highest energy density. Because internal combustion has the potential to simultaneously provide high power density and high energy density, it is natural to explore this method of power generation. The micro-gas turbine (combustor volume 0.04cc), the mini (0.078 cc displacement) and micro (0.0017 cc displacement) rotary engine , the microrocket (0.1 cc combustion chamber) , and the micro Swiss rollburner are examples of such exploration. These devices are not yet performing at efficiencies that make them competitive with the best available batteries, but they have demonstrated the plausibility of internal combustion as a personal power source.