基于气液相变型尾气温差发电器的热质传递与热电输运耦合特性研究

Thermoelectric power generation technology can effectively recover engine waste heat for power generation, but with lower conversion efficiency at present. Optimizing the generator structure from the perspective of heat transfer is an important method to improve the efficiency. A gas-liquid phase change thermoelectric generator is proposed here, which uses the phase change of intermediate fluid to transfer the exhaust waste heat. Through the free combination of thermoelectric module and exhaust channel, high conversion efficiency can be achieved. The power generation performance of the new generator is the coupling of complex heat transfer, mass transfer and thermoelectric conversion. To achieve the high efficiency and compactness of generator, the coupled phase change heat transfer, thermoelectric transport mechanism and dynamic response characteristics closely related to the performance of new generator is studied here. (1) The coupled phase change heat transfer characteristics of boiling and condensation in enclosed space are to be studied. The heat and mass transfer mechanism under complex structure and heat transfer conditions are to be explored. (2) The effects of key parameters (such as cavity structure and fluid physical properties) on coupled phase change and thermoelectric conversion will be studied, and the heat-mass-electric multi-filed coupling mechanism of the system is to be revealed. (3) The dynamic model of gas-liquid phase change thermoelectric generator is to be conducted, and the influence of exhaust parameter on the dynamic characteristics of the system is to be discussed. This study will provide theoretical basis for the design and optimization of the new thermoelectric generator, and promote the industrialization process of exhaust thermoelectric generation technology.

利用温差发电技术能够有效回收内燃机尾气余热进行发电，但目前其热电转换效率较低，从传热角度优化发电器结构是提高热电转换效率的重要方法。本项目提出了一种气液相变型温差发电器，利用中间介质的气液相变传递尾气的热量，通过发电模块与尾气通道的自由组合，实现高效热电转换。新型发电器的发电性能是复杂传热传质与热电转换的耦合结果，为实现发电器的高效与紧凑，本项目重点围绕与新型发电器性能密切相关的耦合相变特性、热电输运机理以及动态响应规律开展如下研究：（1）研究封闭空间内沸腾与冷凝共存下的相变特性，探索复杂结构与传热条件下耦合相变热质传递机理；（2）研究腔体结构与流体物性等关键参数对耦合相变与热电转换的影响，揭示系统热-质-电多场耦合机理；（3）构建气液相变型温差发电器的动态模型，探讨尾气参数波动对系统动态特性的影响。本研究将为新型温差发电器的设计与优化提供理论依据，并推动尾气温差发电技术的产业化进程。

针对内燃气尾气余热温差发电效率低的问题，本项目提出了一种气液相变型温差发电器，并通过实验与数值模拟研究了新型发电器的热质传递与热电输运耦合特性。依据原定研究计划，主要研究内容与结果如下：（1）建立了封闭空间沸腾冷凝耦合相变传热实验系统，揭示了充液率、腔体高度以及冷凝面倾角对耦合相变传热特性的影响规律。（2）构建了气液相变型温差发电器的数学模型，全面解析了尾气参数、相变腔传热参数以及冷却流体参数对系统热电性能的定量关联，并实验验证了新型发电器具有高热电转换效率、低流阻以及电压分布更均匀等技术优势。（3）构建了尾气温差发电器的瞬态模型，验证了相变腔体可缓解尾气瞬变所带来的影响，并基于极限功率偏差最小法，完成多参数影响下新型发电器的结构优化。所得结果为构建高效尾气温差发电器建立了理论基础，有助于尾气温差发电器的产业化应用。在项目资助下本项目发表学术论文22篇，其中SCI期刊论文9篇，授权实用新型专利4项。