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61.
《International Journal of Hydrogen Energy》2019,44(54):29007-29016
The effect of carbon monoxide (CO) contained in H2 gas as an impurity on the hydrogen-accelerated fatigue crack growth of A333 pipe steel was studied in association with loading frequency dependency. The addition of CO to H2 gas inhibited the accelerated fatigue crack growth due to the hydrogen. The inhibitory effect was affected by the CO content in the H2 gas, loading frequency, and crack growth rate. Based on these results, it was revealed that the inhibitory effect of CO was governed by both competition between the rate of fresh surface creation by the crack growth and the rate of coverage of the surface by CO and time for hydrogen diffusion in the material to the crack tip with reduced hydrogen entry by CO. 相似文献
62.
An experimental study of two-phase flow in a 180° pipe bends with 0.016, 0.022 and 0.03 m and the curvature radii of 0.11, 0.154, 0.21 m, respectively have been carried out. The experiments were conducted under the input superficial phase velocity: air from 0.038 to 5.4 m s−1, water from 0.018 to 0.92 m s−1 and oil from 0.014 to 0.92 m s−1. The conducted research involved the observation of the forming flow patterns and determination of average volumetric in situ gas fraction. On the basis of the results of experimental flow map was created for gas–liquid flow and a method of calculating gas fractions was established. 相似文献
63.
Initial ovality is an inevitable problem in the process of pipe bends manufacturing which results in the stress redistribution of the pipe bends working at high temperature. In order to study the influence of ovality on creep life of pipe bends, full-size creep experiment of P92 pipe bend subjected to in-plane bending has been conducted. The creep strains and outside diameters of dangerous positions have been measured. The microstructures of three different positions of the pipe bend were compared through SEM and the results showed the number and size of the carbide precipitation were the largest at the flank of the pipe bend, which indicated that the creep damage developed fastest at the flank. The modified Kachanov–Robatnov constitutive equations were used to stimulate the creep of P92 pipe bends with FEA software. The representative stress, damage and multiaxiality distributions of the pipe bends have been discussed. The FEA results were consistent with the experimental results and the influence of initial ovality on creep life of P92 pipe bends were analyzed. The results showed that creep life of pipe bends reduced by the increase of ovality and their relationship coincided with the parabolic law. 相似文献
64.
本文介绍了煤炭的一种新兴的运输方式一管道输煤。并从管道输煤工艺系统入手,分析了其与单相流管道的区别、提出了管材特点及选择方法,并介绍了主泵选择注意点及主泵房的土建配套问题。 相似文献
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66.
本文结合云霄翔球广场一期工程静压PHC管桩施工实例,对2#楼主楼采用先引孔后压桩法施工技术和施工工艺,使桩端穿过砂层及卵石层进入持力层深度及有效桩长满足设计及规范要求,以保证施工质量和工期。 相似文献
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68.
Recently, a magnetostrictive patch transducer (MPT) by means of the highly magnetostrictive (such as nickel or iron–cobalt alloy) patch attached on the specimen has been applied in nondestructive ultrasonic testing in waveguides. In the study, we proposed a new MPTs array employing a multi-splitting meander coil (MSMC) for generating and receiving longitudinal guided waves in pipes. In the suggested configuration, the directions of the static magnetic field produced by the permanent magnets and the dynamic magnetic field produced by the MSMC are in the axial direction of the pipe. Two finite element models were established to simulate the distribution of the static and dynamic magnetic fields in the patch, respectively. The proposed MSMC was made of flexible printed circuit (FPC), so it could be easily installed on pipe surface. The performance of the proposed MPTs array was experimentally studied. Firstly, it was experimentally verified that the axisymmetric longitudinal guided wave mode, L(0,2), could be effectively generated and received in pipes with the developed MSMC-MPTs array. Secondly, the frequency response characteristics of the developed MSMC-MPTs array were related to D (the distance between adjacent belts of the MSMC). Thirdly, we demonstrated the ability of the developed MSMC-MPTs array for the identification and location of a crack defect in pipes. Finally, we compared the performances of the MSMC-MPTs array and conventional meander coil-MPTs and proved that the signals of the longitudinal guided wave mode could be enhanced by using the developed MSMC-MPTs array. 相似文献
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70.
针对现有钢结构真空管道梁造价高、运输条件受限且安装不便等问题,本文探讨了一种适用于未来长距离运输和车辆条件的组合材料管道梁结构,开展了三种常用跨度管道梁结构的试设计,分析了一联多跨方案对结构刚度和变形的影响.获得研究成果:①分层设计方案可充分发挥结构各自特点,降低施工和运输难度;②通过试设计获得了常用跨度管道梁的关键参... 相似文献