扭断盖滚压封口机滚压封口设计

研究了扭断盖滚压封口机的滚压封口部分,参考了目前市场上使用的扭断盖滚压封口机,并提出了改进意见。     

双向旋转梯形槽干气密封流场的数值模拟

介绍一种用作抑制密封的新型泵用双向旋转梯形槽干气密封,并定义了该密封的主要几何结构参数.基于气体润滑理论,建立了梯形槽干气密封端面流场的数值计算模型.利用Fluent软件对流场进行数值模拟,获得了端面气膜压力分布、气流速度场、开启力及泄漏率等数据,并分析了端面槽深、槽宽比、吸入角和槽长坝长比对端面开启力、泄漏率这2个主要密封性能参数的影响规律,发现该密封的开启力与泄漏率均随槽深、槽宽比和槽长坝长比的增大而增大,随吸入角的增大而减小.研究结果为双向旋转梯形槽干气密封的设计和进一步研究提供了参考.     

混合刷式密封泄漏特性的数值研究

为分析某型号汽轮机改进的刷式密封结构的密封性能,采用non?Darcian多孔介质模型的Reynolds?averaged Navier?Stokes方程数值求解方法,对泄漏流动特性及转子表面、刷束自由高度和保护高度的压力、速度、湍流动能分布规律进行数值研究,并与迷宫密封进行相应的比较。结果表明：相同的间隙和压比下,混合刷式密封流场分布要比迷宫密封复杂,泄漏量明显小于迷宫密封;相同的结构和参数下,泄漏量随着压比的上升而增加;转子表面的轴向压力和湍流动能从进口到出口呈现阶梯状递减趋势,保护高度的径向压力基本趋于常数值;刷束径向速度和湍流动能随着压比的上升而增加,刷束下半部分和后挡板保护高度对泄漏特性影响比较大。研究结果为汽轮机刷式密封的结构设计,改善性能,提供了理论依据。     

灌缝胶应用现场评价指标及评价方法

良好的灌缝能减少沥青路面水损害,减缓路面病害的发生,延长沥青路面使用寿命.但目前沥青路面灌缝主要靠经验施工,对于灌缝后使用效果的评价研究较少.本文依托吉林省内多条高速公路沥青路面灌缝实际情况,建立了灌缝后使用情况评价指标及评价方法.     

气驱技术对油套管性能的新要求

为有效补充地层能量、大幅提高采收率,保持油田高效开发和持续稳产,国内外油田陆续开展了气驱试验。气驱技术在保持油田高效开发和持续稳产的同时,也延长了油田生命周期,但井筒完整性是制约气驱技术发展的关键因素之一。通过分析气驱井油套管失效情况,从全生命周期角度,提出了保证井筒完整性措施以及气驱工艺下油套管选材思路,并指出在注气井或采出井采用耐蚀合金连续油管和非金属连续油管,可兼顾防腐和气密封功能,将是气驱工艺的发展方向。     

Impact of graphene oxide nanoparticles and carbon black on the gamma radiation sensitization of acrylonitrile–butadiene rubber seal materials

Seals prepared from acrylonitrile–butadiene rubber (NBR) are primarily used in nuclear services. Nevertheless, at relatively high ionizing radiation doses, NBR seal materials may undergo radiation-induced degradation processes, leading to adverse effects on the sealing ability life. Herein, to strengthen the functional characteristics of NBR seals against radiation, graphene oxide (GO) nanoparticles were prepared and characterized by transmission electron microscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR), and ultraviolet/visible spectroscopies. Various NBR/GO composites fabricated with different ratios of GO nanoparticles and in the presence or absence of carbon black (CB) were investigated via cross-linking density, scanning electron microscopy, XRD, FTIR, and mechanical and thermal stability analyses. The synergistic effect of the simultaneous presence of GO and CB on the NBR seal sensitization to gamma radiation up to a dose of 1 MGy was studied. The physicomechanical properties were enhanced by adding GO nanosheets up to 3 phr and by incorporating 35 phr of a CB with GO until 5 phr. Further, the application of γ-irradiation resulted in an overall enhancement in the mechanical, physical, and thermal stability of the prepared composites up to 0.5 and 1 MGy with GO nanosheets in the absence or presence of CB particles, respectively. The mechanical measurements indicated significant increments by loading with GO nanosheets in the absence and presence of CB as well as by irradiation. The tensile strength elevated up to about 121%, 336%, and 366% by adding 3 phr GO, 3 GO:35 CB phr, and 5 GO:35 CB phr, respectively.     

封闭循环氢还原法制备纳米钨粉

通过对WO3氢还原过程的热力学分析,找到了制备均匀细颗粒W粉的热力学途径-彻底快速除去还原系统中的水分。通过系统内的特殊装置除水,降低了还原温度,以WO3为原料,用封闭循环氢还原法,在600℃下还原得到了W粉,其粒径在(20～60)nm之间熏纯度为99.76%。     

Studies on electric-discharge machining of non-contact seal face grooves

In this paper, the electric-discharge machining (EDM) of non-contact seal grooves was studied. Two types of material, namely: tungsten carbide and silicon carbide were tested by EDM due to their hard machining behaviors. The geometry of seal grooves is another reason why grinding or other precision machining processes cannot be applied. Four parameters of EDM processes were studied, namely: electrode material, pulse duration, discharge current, and polarity. According to experimental results, the optimal process parameters were obtained based on the specimen’s qualities, such as surface roughness and depth of cut. An industrial example was also studied in the final stage of the proposed paper.     

Analysis of failed nuclear plant components

Argonne National Laboratory has conducted analyses of failed components from nuclear power- gener-ating stations since 1974. The considerations involved in working with and analyzing radioactive compo-nents are reviewed here, and the decontamination of these components is discussed. Analyses of four failed components from nuclear plants are then described to illustrate the kinds of failures seen in serv-ice. The failures discussed are (1) intergranular stress- corrosion cracking of core spray injection piping in a boiling water reactor, (2) failure of canopy seal welds in adapter tube assemblies in the control rod drive head of a pressurized water reactor, (3) thermal fatigue of a recirculation pump shaft in a boiling water reactor, and (4) failure of pump seal wear rings by nickel leaching in a boiling water reactor. Work supported by Commonwealth Edison Company under ACK 85026.     

新型泵用机械密封的研究

本文研究了一种新型的自紧式机械密封装置，叙述了它的工作原理，结构型式，并与传统式的机械密封装置进行了分析对比。理论分析与试验结果表明，新型机械密封具有结构简单、轴向尺寸小及密封性好、可靠性高、安装维修方便等优点。