Effects of structural parameters on water film properties of transpiring wall reactor

Corrosion and salt deposition problems severely restrict the industrialization of supercritical water oxidation. Transpiring wall reactor can effectively weaken these two problems by a protective water film. In this work, methanol was selected as organic matter, and the influences of vital structural parameters on water film properties and organic matter removal were studied via numerical simulation. The results indicate that higher than 99% of methanol conversion could be obtained and hardly affected by transpiration water layer, transpiring wall porosity and inner diameter. Increasing layer and porosity reduced reactor center temperature, but inner diameter's influence was lower relatively. Water film temperature reduced but coverage rate raised as layer, porosity, and inner diameter increased. Notably, the whole reactor was in supercritical state and coverage rate was only approximately 85% in the case of one layer. Increasing reactor length affected slightly the volume of the upper supercritical zone but enlarged the subcritical zone.     

Numerical modeling of hydrogen catalytic reactions over a circular bluff body

This paper was intended to delineate numerical research for hydrogen catalytic combustion over a circular cylinder. The wire/rod-type catalytic reactor is a simple geometry reactor with an economical design with less pressure loss. For the single rod in the reaction channel, the flow characteristic and the difference of conversion efficiency between non-gas-phase reaction and gas-phase reaction have been delineated in the present study. The flow field and the chemical reactions were numerically modeled using 2D Large Eddy Simulation combined with the gas-phase and surface reaction mechanisms. The results show that the current numerical simulation has been validated to precisely predict the vortex shedding and its frequency in the cold flows. Despite the variation trends being dominated by the upstream flow, the vortex shedding phenomena were affected by the flue gas generated from the rod surface. It can be seen from the linear relationship between the vortex shedding frequency of reacting flow and Reynolds Number. It is noted that the vortex shedding vanished if the gas-phase reaction was ignited in the reaction channel. In addition, the geometric modified conversion efficiency was proposed to delineate an indicator that could be potential for the optimization of rod-type catalytic reactor. In summary, the fundamental study of a rod in a 2D flow channel can provide information for optimizing the catalytic design or the rod array arrangement in the reactor. Moreover, the rod can also be a partial catalytic flame holder to ignite and stabilize the gas-phase reaction. The obtained results could be the potential for practical applications of rod-type catalytic combustion, catalytic gas turbine, hydrogen generation, partially catalytic reaction flame holder, and other catalytic reactions that can be appreciated.     

高耸桥墩保护性爆破拆除关键技术

为解决高耸钢砼桥墩上部倾斜导致的工程质量不合格问题,采用保护性控制爆破将上部倾斜部分钢砼桥墩予以拆除,同时保留下部未偏斜部分桥墩不受破坏。采用开设组合形状切口,预开定向窗、导向窗;设置组合高差卸荷槽,预伤钢筋弱化抗压抗拉能力为关键措施的控制爆破方案。方案实施取得了十分满意的效果,上部拟拆除部分桥墩顺利倾倒下坠,下部保留部分桥墩完好无损。采用保护性控制爆破技术能高效、安全地解决类似高耸钢砼桥墩(构筑物)部分拆除、部分保留利用的问题,并能取得可观的经济、社会效益。     

高强化柴油机冷却系统电控化设计仿真及试验研究

针对传统冷却系统与柴油机冷却需求不匹配的问题，进行了冷却系统电控化设计仿真研究。基于Simulink软件设计了电控冷却系统仿真模型，提出了电控冷却控制策略，并开展了变柴油机工况条件下电控冷却控制策略验证仿真。对传统冷却部件进行电控化改造（电控海水泵、电控淡水泵和电子节温器），搭建电控冷却系统试验台架，通过试验分析了电控冷却对柴油机耗油率和热平衡的影响，结果表明：相对于传统冷却系统，电控冷却系统在900 r/min、负荷率30%，1 200 r/min、负荷率60%，1 500 r/min、负荷率90%这3个工况点的耗油率分别降低9.4 g/（kW·h）、6.8 g/（kW·h）和3.9 g/（kW·h），燃油经济性和热量分配得到改善。     

石墨慢化通道式熔盐堆有效缓发中子份额计算方法研究

有效缓发中子份额(βeff)是研究反应堆动力学特性的关键参数。在液态燃料熔盐堆(MSR)中，燃料流动引起缓发中子先驱核(DNP)在堆内的再分布，并使部分DNP在堆外回路衰变，从而导致βeff的计算方法与固态燃料反应堆不同。为评估石墨慢化通道式熔盐堆内燃料流动引起的反应性损失，研究缓发中子随燃料的流动行为，同时为堆设计和安全分析提供依据，分别基于解析方法和数值方法推导了计算βeff的数学模型，计算了熔盐实验堆(MSRE)在额定工况下的DNP损失份额和堆内DNP浓度分布，并分析了燃料在堆外流动时间和入口流量对βeff的影响。结果表明：两种方法均可对DNP行为提供合理描述；固定燃料在堆外流动时间，βeff随入口流量的增加而减小；固定入口流量，βeff随燃料在堆外流动时间的增加而减小，80 s后趋于稳定。     

气冷微堆燃料设计的中子学特性影响研究

为分析气冷微堆燃料设计的中子学特性影响，基于方形燃料组件模型，利用蒙特卡罗程序RMC研究了TRISO颗粒、燃料芯块在燃料设计中的主要参量对组件中子学特性的影响。研究结果表明，燃料颗粒体积占比和包覆层厚度不变时，组件寿期随燃料核芯直径的增大先显著增大，而后趋于平稳；燃料颗粒体积占比和燃料核芯直径不变时，组件寿期随包覆层厚度的增大而减小；燃料装载量不变时，芯块直径增大，组件寿期显著增大，而芯块高度影响较小；无燃料区厚度的增加对组件中子学特性有明显的负面影响，基体材料密度、基体杂质硼当量对组件中子学特性的影响较小。研究结果将为后续气冷微堆包覆颗粒弥散燃料的设计优化提供指导。     

固态热管反应堆模拟装置热工水力特性分析

热管反应堆具有小型化、结构简单、固有安全性高等优势，有着广泛的应用前景和研究意义。本文采用CFD方法对热管反应堆模拟装置进行了稳态工况下的热工水力特性分析，并与实验结果进行对比。结果表明，热管各测点温度相对误差不超过5.5%，温差发电器热端各测点温度相对误差不超过3.1%，证明了该模型方法的可行性和正确性。本研究为热管反应堆的数值模拟提供理论指导与方法支撑。     

基于简单开式布雷顿循环的热管反应堆系统功率质量比影响因素初步探索

基于简单开式布雷顿循环的热管反应堆系统具有结构简单、固有安全、放射性泄漏风险低等特点，是小型可移动反应堆的潜在优势技术选项，其功率质量比是评价总体方案先进性的重要指标。本文以5 MW热管反应堆为研究对象，建立包含热管反应堆与开式布雷顿发电装置的方案功率质量比评估模型，对多种关键参数对总体指标的影响规律进行了探索。研究表明功率质量比随热传导途径上温差增大而先提高后降低，最优值则与堆芯基体最高温度限值正相关。在给定温度限值条件下，热管反应堆电源系统内热量传输途径上温差设计是热管反应堆优化设计的关键因素。未来可进一步细化模型，对压气机、涡轮、热管等进行更详细建模，提高模型准确程度。      

高温钠热管传热性能试验研究

为获得高温钠热管传热性能，开展真空条件下钠热管启动性能和等温性能试验，获得了钠热管真空条件下启动速度与等温性能数据；开展强制冷却工况条件下传热性能试验，获得了钠热管声速限特性与试验工况下的最大传热功率。经试验验证，所研制高温钠热管在真空条件下，580 ℃时完全启动，启动用时20 min，轴向壁面温差低于11 ℃，等温性能良好；钠热管传热功率在工作温度为500～650 ℃时受声速极限限制，在650 ℃以上受携带极限限制；在750 ℃和850 ℃时，测得热管最大散热功率分别为4.78 kW与8.02 kW，对应的最大轴向热流密度分别为1.51 kW/cm²与2.53 kW/cm²。试验结果表明，所研制钠热管具有较强传热能力，可满足热管式核反应堆等工程应用需求。