Due to the strong exothermic/endothermic effect during the H₂ absorption/desorption process, the design of metal hydride reactors has become a hot research topic to improve the rate of hydrogenation/dehydrogenation. Herein, based on bionic optimization and the constructal theory, a novel duplex helical elliptical tube reactor (DHER) is proposed for enhancing the heat transfer and reaction performances of metal hydride reactors. DHER displayed outstanding performances among 5 types of reactors, and the maximal temperature difference could be reduced by 5.1 K/5.6 K during the H₂ absorption/desorption. The parameters of DHER were designed and optimized with the spiral diameter (D_c) = 10 mm, elliptical major axis (A) = 4 mm, elliptical minor axis (B) = 2 mm, pitch (P_t) = 13 mm, tilt angle (α) = 45°, and installation angle (β) = 180°. The sensitivity analysis for DHER is investigated, and the sequential effects of the structural parameters on the reaction performance followed the order of D_c > A > B > P_t > α. Through a comparative analysis of geometrical characteristics of the structural parameters and the reaction performance of the reactor, the results indicated that the radial projected area of the heat exchange tube is the dominant factor in the reaction performance of DHER. Moreover, the surface was calculated based on the sensitivity analysis data and fitted by the quadratic response surface regression model to predict the reaction time under different structural parameters, which may provide guidance for the design of reactors. In addition, the hydriding and dehydriding cyclic processes without preheating and precooling stages were confirmed to have prominent and reliable performances for DHER, attaining only 1227 s under its optimal cycle conditions during absorption (0.8 MPa, 273.15 K) and desorption (0.1 MPa, 373.15 K).

中文翻译：

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双螺旋椭圆管金属氢化物反应器的设计优化，灵敏度分析和运行比较

由于在H ₂吸收/解吸过程中强烈的放热/吸热作用，金属氢化物反应器的设计已成为提高氢化/脱氢速率的热门研究课题。在此，基于仿生优化和构造理论，提出了一种新型的双螺旋椭圆管反应器（DHER），以提高金属氢化物反应器的传热和反应性能。DHER在5种类型的反应器中表现出出色的性能，在H ₂吸收/解吸过程中，最大温差可降低5.1 K / 5.6K 。设计并优化了DHER的参数，其螺旋直径（D _c）= 10 mm，椭圆长轴（A）= 4毫米，椭圆短轴（B）= 2毫米，螺距（P _t）= 13毫米，倾斜角（α）= 45°，安装角（β）= 180°。研究了DHER的敏感性分析，结构参数对反应性能的影响依次为D _c > A > B > P _t > α。通过对结构参数的几何特征和反应器的反应性能进行比较分析，结果表明，换热管的径向投影面积是DHER反应性能的主导因素。此外，基于敏感性分析数据计算表面，并通过二次响应表面回归模型进行拟合，以预测不同结构参数下的反应时间，这可为反应堆的设计提供指导。此外，没有预热和预冷阶段的氢化和脱水循环过程被证实具有出色的DHER性​​能，在最佳循环条件下吸收（0.8 MPa，273.15 K）和解吸（0.1 MPa，373.15）时仅达到1227 s。 K）。