镁/氢化镁储热系统放热过程优化分析  

Optimal analysis of the exothermic process of a Mg/MgH2 thermochemical heat storage system

作　　者：沈丹[1] 赵 长颖[1] 赵长颖[1] 

机构地区：[1]上海交通大学动力机械与工程教育部重点实验室,上海,200240

出　　处：《储能科学与技术》2014年第1期36-41,共6页Energy Storage Science and Technology

基　　金：国家重点基础研究发展计划(2013CB228303);国家自然科学基金项目(51176110)

摘　　要：基于镁/氢化镁热化学储热系统,建立了二维非稳态数学模型。对吸氢放热过程中的传热传质现象进行了数值模拟,主要研究了壁面温度和反应床当量导热系数对系统反应速率的影响。结果表明,放热过程中存在最佳的壁面温度使反应速率达到最快,过高或者过低的壁面温度都将使反应床的温度偏离理论上的最佳值,从而降低反应速率。针对不同当量导热系数的反应床,最佳壁面温度也不相同;反应床的当量导热系数并非越大越好,应该根据具体的边界温度以及氢气压力情况进行合理的选择以获得最佳的反应速率。A two-dimensional transient mathematical model was established for a magnesium/ magnesium hydride thermochemical heat storage system. The heat and mass transfer phenomena of the exothermic process of the system were simulated and the influences of wall temperature and bed effective thermal conductivity on the reaction rate were investigated. The results show that, during the exothermic process, there is an optimal wall temperature that gives the fastest reaction rate, both higher and lower wall temperatures make the bed temperature deviate from the theoretical optimal value, thereby decreasing the reaction rate. It is shown that the optimal wall temperature depends on the effective thermal conductivity. It is not always that the higher the effective thermal conductivity of the bed, the better the reaction rate. A number of factors including the specific wall temperature and hydrogen pressure have to be considered when making a choice of the effective thermal conductivity.

关 键 词：氢化镁 当量导热系数 壁面温度 放热过程 数值分析 

分 类 号：TK02[动力工程及工程热物理]