【作者】 童亮；

【导师】 肖金生； 王志民；

【作者基本信息】 武汉理工大学 ， 车辆工程， 2012， 硕士

【摘要】 储氢技术是氢能实现规模化应用的瓶颈,也是燃料电池技术能否成功应用于交通运输领域的关键问题之一。活性炭和金属有机框架物(MOF: Metal-Organic Frameworks)以其高比表面积表现较好的储氢性能,而成为近几年储氢研究的热点。低温吸附储氢相对常温而言吸附量有大幅度提高,为实现车用储氢系统提供了可行途径。本文建立低温吸附储氢计算流体力学(CFD: Computational Fluid Dynamics)模型,接着对其进行低温吸附储氢充放气过程验证,并进行参数研究和优化,最后对大尺度储氢罐进行预测,为实际应用提供指导。首先,本文对吸附储氢CFD模型进行介绍,主要包括质量守恒方程、动量守恒方程、能量守恒方程和Dubinin-Astakov (D-A)等温吸附模型,并指出在低温条件下,需要通过线性驱动力(LDF:Linear Driving Force)模型考虑质量传递阻力的影响,利用动边界模型考虑外界环境温度的变化以及考虑低温下材料物性参数变化。其次,建立均匀吸附模型,利用FLUENT中UDF建立动边界模型,并结合均匀吸附模型予以验证,然后将动边界模型应用于D-A吸附模型和LDF模型,建立低温吸附储氢CFD模型,并考虑低温下材料物性变化的影响,对其进行低温吸附储氢充放气过程的实验验证。然后,以低温吸附储氢CFD模型为基础,对于低温吸附储氢主要从充气工况、换热边界条件和材料物性材料的研究等三个方面进行参数研究和优化。其中,充气工况主要包括充气速率和入口温度对低温吸附储氢的影响,换热边界条件主要包括环境温度、换热系数以及休眠阶段隔热对低温吸附储氢的影响,材料物性的参数研究主要包括热导率、比热和材料本身对低温吸附储氢的影响。最后,利用低温吸附储氢CFD模型,对低温条件下的大尺度储氢罐的充气过程进行预测。达到相同目标压力时,研究其充气时间、储氢量、温度分布和吸附储氢量分布,并进行对比分析,寻求增加储氢量和提高充气效率的方法,为实际应用提供指导。更多还原

【Abstract】 The hydrogen storage technology is one of the most difficult technical challenges for realizing the hydrogen power fuel cell vehicle scale application. In recent years, the activated carbon and metal-organic frameworks (MOF) with high surface area reveals a good capability in hydrogen storage, and becomes the central issue of the hydrogen storage research. In addition, the activated carbon adsorption can be significantly enhanced at cryogenic temperatures, and show a promising method for the vehicle hydrogen storage system. In article, cryo-adsorptive hydrogen storage Computational Fluid Dynamics (CFD) model is established and validated by the charge-discharge cycle experiment. Then we research and optimize the model and parameters, and finally predict the performance of large scale hydrogen storage tanks in order to provide guidance for practical application.Firstly, in this paper, based on mass conservation equation, momentum conservation equation, energy conservation equation and Dubinin-Astakov (D-A) isothermal adsorption model, the adsorption hydrogen storage CFD model is introduced. The article points out that we should take the influence of mass transfer resistance and the variation of environmental temperature into consideration by Linear Driving Force (LDF) model and dynamic boundary condition model at cryogenic temperatures respectively. And the variation of material physical parameters also should be taken in account.Secondly, we built an average rate of adsorption model and validate a dynamic boundary condition model which is established through the User Define Function (UDF) in FLUENT. Then the dynamic boundary condition model is applied to D-A adsorption model and the LDF model in order to establish cryo-adsorptive hydrogen storage CFD model. And this model is well validated by cryo-adsorption experiments.Then, based on the cryo-adsorptive hydrogen storage CFD model, we research and optimize the model and parameters from inlet conditions, boundary conditions and material properties. The researches of inlet conditions include the influence of mass flow rate and temperature of hydrogen at entrance. The researches of boundary conditions include the influence of environmental temperature, heat transfer coefficient, and heat insulation at dormancy. The researches of material properties include the influence of thermal conductivity, specific heat capacity and the material itself at cryogenic temperatures.Finally, based on the cryo-adsorptive hydrogen storage CFD model, we predict the performance of large scale hydrogen storage tanks. When the pressure reach to10MPa, we analysis the charging time, hydrogen storage amount, the temperature distribution and the adsorption distribution, sought to increase hydrogen storage amount and improve the charging efficiency, in order to provide guidance for practical application.更多还原