【摘要】 为探究绝热型正仲氢转化反应器内部流动换热特性,采用CFD数值模拟方法,对多孔介质流动压降模型和基于组分输运的多孔介质催化剂表面反应模型进行了仿真计算,并结合低温超临界氢的实际运行工况及文献数据,将数值计算结果与实验值进行对比分析,以验证本文计算模型的可靠性。随后,以CSNS低温正仲氢转化反应器为研究对象,考察了20 K超临界氢在填充催化剂的通道内的正仲氢催化转化反应和流动换热性能,分析了反应器的流动阻力来源,并给出了出口仲氢浓度的预测。结果显示:在设计流量下,反应器的流动阻力符合预期,过滤器结构的流动阻力占比明显。当入口仲氢浓度为97%时,在1 L/s至2 L/s的流量范围内,出口仲氢浓度均达到了99%以上,能够满足中子物理实验对于仲氢浓度大于99%的要求。对于流量偏小的工况,传热情况会急剧恶化,容易对系统运行安全造成影响。根据仿真计算结果,获得了正仲氢转化仲氢浓度预测模型,该模型可依据质量空速精准预测转化器出口的仲氢浓度;另一方面,能按照仲氢浓度的要求,对催化剂填充量展开设计计算。更多还原

【Abstract】 A CFD method was employed to investigate the flow and heat transfer characteristics inside an adiabatic ortho-para hydrogen converter. Simulations were conducted by applying a porous media flow pressure drop model and a porous media catalyst surface reaction model based on component transport. Compared with the operating data of cryogenic supercritical hydrogen and literature data, the numerical results were analyzed with experimental values to validate the reliability of the computational model in this study. The CSNS cryogenic ortho-para hydrogen conversion reactor is analyzed, and the catalytic conversion reaction and flow-heat transfer performance of 20 K cryogenic supercritical hydrogen in the catalyst-filled porous channel were simulated. The flow resistance in the reactor was analyzed, and a prediction of the outlet para-hydrogen concentration was provided. The results show that, under the design flow rate, the flow resistance of the reactor met expectations, with the filter structure contributing significantly to the overall resist-/ance. When the inlet para-hydrogen concentration was 97%, within the flow range of 1 L s to/2 L s, the outlet para-hydrogen concentration consistently exceeded 99%, meeting the requirement of para-hydrogen concentration greater than 99% for neutron physics experiments. However,under lower flow conditions, heat transfer performance deteriorated sharply, leading to a rapid temperature rise inside the reactor. This will lead to a sharp increase in the pressure in the closed hydrogen loop, affecting the safety of system operation. Based on the simulation results, a prediction model for the para-hydrogen concentration in the ortho-para-hydrogen converter was developed. This model facilitates the accurate prediction of para hydrogen concentration at the converter outlet according to the mass space velocity in engineering applications. It also enables the design calculation of catalyst loading based on the required para-hydrogen concentration.更多还原