核电站典型过流部件液滴冲蚀和流致振动的实验研究与数值模拟

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	核电站典型过流部件液滴冲蚀和流致振动的实验研究与数值模拟
	胡红祥
学位类型	博士
导师	郑玉贵
	2012
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	腐蚀科学与防护
关键词	波纹管涂层防护液滴冲蚀流致振动数值模拟 Bellow Coating Protection Liquid Droplet Erosion Flow-induced Vibration Simulation
摘要	"波纹管和蒸汽发生器（SG）传热管是核电站管路系统中的关键部件，现场发现其存在严重的液滴冲蚀和流致振动问题，威胁着核电站的安全运行。本文针对波纹管液滴冲蚀的问题提出了三种解决方案：材料替换、结构优化和涂层修复。采用空蚀和液固双相射流冲蚀来模拟冲蚀，采用计算流体力学方法来数值模拟波纹管的流速流态，从实验和数值模拟两个方面对解决方案的可行性进行验证。实验方面，通过模拟实验对比验证波纹管现役材料、替换材料和冷喷涂涂层及电火花涂层的抗液滴冲蚀性能的优劣，为材料替换和涂层修复方案的可行性提供切实可靠的实验数据支撑。数值模拟方面，对波纹管保护套的结构进行了优化设计，并研究了液滴大小及焊缝高度对液滴冲蚀的影响。此外，采用计算流体动力学技术，针对核电站SG传热管流致振动问题进行了初步探索。实验结果表明，Inconl625具有较高的抗空蚀性能和抗喷射冲蚀性能，可以作为波纹管现役材料Inconel 600的替换材料。而Ni-Al2O3冷喷涂涂层相比基体而言抗空蚀性能较差，但抗喷射冲蚀性能具有明显的优势。电火花沉积涂层结构为晶粒细化的枝晶组织，其硬度及抗空蚀性能均比各自基体有一定的提高。数值模拟结果显示，波纹管保护套经优化后可以起到很好的防护效果，其最佳尺寸为：弧形拐角内径70 mm，保护裙套距离环形挡板端部的垂直距离为16 mm。SG传热管流致振动的数值模拟结果表明，高Re下传热管管间距为2.5倍管径时在两管间及下游管后已出现涡街脱落现象，Re=5.5×105是圆管所受流体力及流体斯特劳哈数的临界值。关键词：波纹管，涂层防护，液滴冲蚀，流致振动，数值模拟"
其他摘要	"Bellows expansion joints and stream generator tubes are typical flow-handling components in nuclear power plants. Serious liquid droplet erosion (LDE) and flow-induced vibration (FIV) problems threaten the security of these components. As a result, in this paper, three stratagems were proposed to alleviate the LDE of the bellows: materials substitution, design optimization and coating repair. Cavitation erosion (CE) and jet impingement erosion (JIE) experiments were employed to test the materials resistance to LDE. CFD was used to simulate the flow field around the bellows. The feasibility of the three solutions was verified with both the experiments and simulation methods. In experiments, the LDE resistance of the candidate materials, cold-sprayed coatings and electron-spark deposited coating were tested, which provide the reliable data for material substitution and coating repair solutions. In simulation, the protecting cover was optimized in the view of reducing LDE, and the effect of the droplet size and weld seam on LDE were studied. In addition, the FIV of the tubes was also investigated by CFD technology. The results show that Inconel 625 has better resistance to CE and JIE than Inconel 600, which can substitute for Inconel 600. The JIE resistance of cold sprayed Ni-Al2O3 coating is superior to Inconel 600, but not the CE resistance due to the weak bond inside the coating. While the ESD coating behaved relative well to the substrate in resistance to CE because of its fine grains, high hardness and unique dendrite structure. In addition, the simulation results show that the optimized protecting cover well protects the bellows. The optimized geometry size is that the inner chamfer diameter is 70 mm and the distance is 16 mm from the top of the ring baffle to the protecting sleeve. Moreover, there is no vortex shedding in the wake of both upstream and downstream cylinders until the gap is 2.5D (D, the diameter of the cylinder.) between them. Re=5.5×105 is a critical value for the fluid forces and the Strouhal number. Keywords: bellows, coating protection, liquid droplet erosion, flow-induced vibration, simulation"
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64450
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	胡红祥. 核电站典型过流部件液滴冲蚀和流致振动的实验研究与数值模拟[D]. 北京. 中国科学院金属研究所,2012.