Abstract Worldwide emphasis on fuel efficiency, low emissions, and use of low-quality fuels such as biogas continues to drive the development of combustors that operate over a wider range of fuel/air ratios and with higher burning velocities than their conventional counterparts. Enhancement of reaction rates is required to increase burning velocities and widen fuel/air operating ranges over values achievable in conventional combustors, and extensive research over the last few decades has shown that transferring heat in a reactor from hot combustion products to incoming reactants can accomplish this enhancement without external energy addition. These reactors, called heat recirculating reactors, use various geometries and flow strategies to optimize the heat transfer. In this paper, research on heat recirculating reactors is reviewed with an emphasis on the most important designs and applications. The basic characteristics of a heat recirculating reactor are encompassed in a simple configuration: a flame stabilized in a tube with high thermal conductivity. More complex designs that have evolved to further optimize heat transfer and recirculation are then described, including porous reactors with or without flame stabilization and channel reactors consisting of parallel tubes or slots. Advanced designs introduce additional means of heat transfer, such as transverse heat transfer from hot products through channel walls to incoming reactants, thereby leading to the counter-flow channel reactor. The flexibility of heat recirculating reactors to operate on a variety of fuels and over wide operating ranges has led to many applications including fuel reformers, radiant heaters and thermal oxidizers, and important work on these applications is reviewed. Finally, future research directions are discussed.

中文翻译：

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热循环反应器：基础研究和应用

摘要 世界范围内对燃料效率、低排放和使用低质量燃料（如沼气）的重视继续推动燃烧器的发展，这些燃烧器的燃料/空气比范围更广，燃烧速度比传统燃烧器更高。需要提高反应速率以增加燃烧速度并扩大燃料/空气操作范围，超过传统燃烧器可实现的值，过去几十年的广泛研究表明，将反应器中的热量从热燃烧产物转移到进入的反应物可以实现这一点无需外部能量添加即可增强。这些反应器称为热循环反应器，使用各种几何形状和流动策略来优化传热。在本文中，回顾了热循环反应器的研究，重点是最重要的设计和应用。热循环反应器的基本特性包含在一个简单的配置中：火焰稳定在具有高导热性的管中。然后描述了为进一步优化传热和再循环而发展的更复杂的设计，包括带有或不带有火焰稳定的多孔反应器和由平行管或槽组成的通道反应器。先进的设计引入了额外的传热方式，例如从热产品通过通道壁到进入反应物的横向传热，从而导致逆流通道反应器。热循环反应器在各种燃料和宽操作范围内运行的灵活性已导致许多应用，包括燃料重整器、辐射加热器和热氧化器，并且对这些应用的重要工作进行了回顾。最后，讨论了未来的研究方向。