金属氢化物蓄热反应器内反应－传热过程的强化研究

Thermal energy storage using metal hydrides is a technology comes with a promising application prospect. However, a heat storage system incorporating this technology is prevented from further improvement because of the poor heat transfer performance of the reactor, the core component in the system. A composite compact, made of expanded graphite and metal hydride, is able to improve the heat transfer performance of metal hydride bed, offering a workable solution. Most of the researches focus on experiences however, falling short of quantitative regulation and design of process intensification from the perspective of internal reaction-heat transfer coupling properties of the reactor. The purposes are to explore, by means of experimental measurement, mechanism analysis, and numerical simulation, effects of structure evolvement of hydride particles on the particle-pore structure and the transport parameters during the absorption/desorption processes. The coupling mechanism between particle-pore structure and reaction-heat transfer is also explored. This study also intends to, while relying on “entranspy” dissipation extreme principle, determine the major resistance factors occurring in the reaction-heat transfer process in the reactor, afford an insight into the synergism between the distribution pattern of high heat-conductive materials and the reaction-heat transfer process, investigate design principles of the optimum distribution pattern of high heat-conductive materials, and find out the intensification behavior of the reaction-heat transfer coupling process in a metal hydride reactor. The research results will provide theoretical guidance for design and optimization of the metal hydride reactor for heat storage, which is very valuable and significant in the aspects of both the scientific research and engineering application.

金属氢化物蓄热技术具有良好的应用前景，但由于其核心部件——反应器的传热性能较差，限制了蓄热系统性能的提高。采用膨胀石墨与金属氢化物混合制成复合压块可以提高氢化物床层的传热性能，是较为有效的强化措施。但现有研究以经验总结为主，没有从反应器内部反应－传热耦合特性出发实现反应器过程强化的量化设计与调控。本项目拟通过实验测量、机理分析和数值模拟等方法，探索吸放氢反应过程中氢化物颗粒结构演化对床层孔隙结构及输运参数的影响，揭示反应器内颗粒－孔隙结构与反应－传热过程的相互影响机制。基于“火积”耗散理论辨识反应器内反应－传热过程中的主要阻力环节，揭示高导热材料在床层内分布与反应－传热特性之间的协同规律，探究高导热材料最优分布的理论设计原则。最终，提出金属氢化物反应器反应－传热过程的强化规律。研究成果将为金属氢化物蓄热反应器的设计和优化提供理论基础，具有重要的科学价值和工程意义。

金属氢化物蓄热技术具有良好的应用前景，但由于其核心部件——反应器的传热性能较差，限制了蓄热系统性能的提高。采用膨胀石墨与金属氢化物混合制成复合压块可以提高氢化物床层的传热性能，是较为有效的强化措施。但现有研究以经验总结为主，没有从反应器内部反应-传热耦合特性出发实现反应器的过程强化。本项目搭建了金属氢化物床层有效导热系数与渗透率测试装置，通过实验测量表征、原理分析和数值模拟等方法，开展了金属氢化物床层输运参数及微观结构表征研究，探索了反应床层微观结构与输运参数的相互影响规律。基于所建立的金属氢化物蓄热反应器多理场耦合模型分析了床层内的反应-传热耦合特性，建立了金属氢化物反应器的“火积”耗散函数表达式，并基于“火积”耗散极值原理确定了复合床层内膨胀石墨含量的最优分布，揭示了高导热材料分布与反应-传热过程的协同作用机制。最终，总结了金属氢化物蓄热反应器反应－传热过程的强化规律。上述研究成果为金属氢化物蓄热反应器的设计和优化提供了理论基础，也可以用于金属氢化物固态储氢反应器优化设计，具有重要的科学价值和工程意义。