抗压夹具在自动压力机上的误差分析

随着GB/T17671—1999标准的实施,国内陆续研制开发了一些全自动压力试验机,且以液压式应用最为广泛。与手动压力机相比,其加荷控制精度明显提高,使用操作方便。控制精度的提高对抗压夹具的应用标准要求也进一步提高。实践表明,抗压夹具的使用寿命与手动压力机相比缩短一半,强度     

ND钢热管寿命试验及与碳钢热管对比实验研究

ＮＤ钢管是一种新的耐酸腐蚀性能较好的材料，可以用于锅炉低温段空气预热器，而用作为热管的管材，其与工质的相容性，使用寿命等问题还没有见到报道．本实验研究了ＮＤ钢热管的寿命及相容性问题，并与普通碳钢热管的性能及寿命作了对比实验，为ＮＤ钢应用于热管积累了经验和第一手资料，为设计提供了依据．     

氧化铝陶瓷内衬不锈钢复合钢管的组织与性能

用自蔓延铝热－重力分离法制备了氧化铝陶瓷内初不锈钢复合钢管。测定了复合钢管的机械性能,并用金相显微镜、扫描电子显微镜、Ｘ射线衍射分析仪分析了复合钢管的组织结构,试验结果表明：外层钢管与层衬陶瓷间因形成ＦｅＯ·Ｃｒ２Ｏ３尖晶石相而产生反应润湿,陶瓷层由隐针状内层、柱状中间层和外层树枝晶组成。由于陶瓷与钢管结合模式的改变,复合钢管的压剪强度由普通碳钢复合管的１５．４ＭＰａ提高到不锈钢复合率的２６．５Ｍ     

输油专用超高分子量聚乙烯/钢复合管

根据原油输送的特点。结合输送原油对管道的要求，采用挤出成型制得超高分子量聚乙烯（UHMWPE）管材，并使之与钢管复合，得到UHMWPE/钢复合管。介绍了输油专用UHMWPE/钢复合管的优点。并与目前使用的几种输油管进行了对比。结果表明，UHMWPE/钢复合管的性能价格比优于目前使用的几种输油管。     

A NUMERICAL SOLUTION FOR THE ANOMALOUS SEDIMENTATION OF A SMALL BROWNIAN SPHERE IN A VERTICAL CYLINDER OF PERIODICALLY VARYING RADIUS

We consider the long-time asymptotic transport of a small Brownian sphere that is sedimenting through a viscous fluid within an infinite vertical cylinder whose radius changes periodically and abruptly between two values. Use of generalized Taylor dispersion theory gives rise to a set of steady-state differential equations that govern the long-time mean velocity. We prove that these equations possess a unique solution. Finite difference discretization of all governing equations and boundary conditions, except for the normalization condition, leads to a homogeneous system of equations that possesses an infinite number of solutions. Application of the normalization condition selects the particular solution of the set that satisfies all conditions. Despite the absence of classical wall effects, the long-time mean velocity of the particle through the pore is generally less than the Stokes sedimentation velocity that applies at every point within the fluid. This anomalous behavior could be used to enhance force-driven separation of Brownian particles that possess identical Stokes velocities but different diffusivities. Furthermore, this numerical approach may be applied to similar problems.     

A NUMERICAL SOLUTION FOR THE ANOMALOUS SEDIMENTATION OF A SMALL BROWNIAN SPHERE IN A VERTICAL CYLINDER OF PERIODICALLY VARYING RADIUS

We consider the long-time asymptotic transport of a small Brownian sphere that is sedimenting through a viscous fluid within an infinite vertical cylinder whose radius changes periodically and abruptly between two values. Use of generalized Taylor dispersion theory gives rise to a set of steady-state differential equations that govern the long-time mean velocity. We prove that these equations possess a unique solution. Finite difference discretization of all governing equations and boundary conditions, except for the normalization condition, leads to a homogeneous system of equations that possesses an infinite number of solutions. Application of the normalization condition selects the particular solution of the set that satisfies all conditions. Despite the absence of classical wall effects, the long-time mean velocity of the particle through the pore is generally less than the Stokes sedimentation velocity that applies at every point within the fluid. This anomalous behavior could be used to enhance force-driven separation of Brownian particles that possess identical Stokes velocities but different diffusivities. Furthermore, this numerical approach may be applied to similar problems.     

含环向缺陷不锈钢管道的承载能力

压力管道广泛应用于各工业领域，研究其承载能力，对保证生产的安全运行具有重要意义。通过对含环向缺陷不锈钢压力管道承载能力的试验研究方法，证实用于铁素体钢管的工程评定方法计算结果与不锈钢管试验结果有较好的可比性。     

含缺陷钢管复合材料修补抗内压疲劳性能研究

制备出带有壁厚减薄缺陷的钢管,研究了玻璃纤维复合材料环向补强对钢管抗内压性能的影响。结果表明,缺陷面积决定复合材料的补强面积,复合材料补强边界宽度超过缺陷轴向长度的80%时,补强效果较好,爆破时复合材料断裂,可充分发挥其性能;通过合理的设计,补强钢管的短时爆破压力大于30MPa,达到无缺陷钢筒爆破压力水平,同时疲劳次数大于15000次,补强效果优异。     

甲醇储罐小孔泄漏环境风险范围的确定

利用甲醇泄漏速率计算模型及相关计算参数,使用Risk System软件,通过对某30000m~3甲醇储罐小孔泄漏时环境风险范围的假设,确定了不同裂口面积、不同气象环境下,该事故对环境的影响距离及风险范围。     

高温异种钢管道焊缝开裂原因分析及解决措施

石化装置中,异种钢连接常见。在高温工况下,异种钢管道焊接焊缝质量要求高,管道强度及管道应力应满足高温工况条件,控制不好焊缝处易发生开裂。结合高温异种钢管道焊缝开裂的实际案例,分析开裂原因,并提出处理方案,即高温工况下,异种钢通过法兰连接,但应核算异种钢法兰密封面的膨胀量。     

圆管内含颗粒幂律流体的密相两相湍流

阐述了幂律流体控制方程的特点,研究了幂律流体的稠度系数和流动指数的变化对两相流动的影响.随着流动指数的增加,幂律流体在圆管中心附近的主流速度减小,同时颗粒相速度在圆管中心附近增大,而在管壁附近减小.随着稠度系数的增加,幂律流体和颗粒相的主流速度分布出现了与流动指数带来的影响相似的趋势.对带颗粒的幂律流体的两相流流动与液固两相流流动做了比较,幂律流体两相流的流体速度在管道中心附近的大部分区域比液固两相流的流体速度流动的速度大,而颗粒相的速度分布比较平坦.