T91／P91钢的性能分析及焊接工艺

金属材料在火力发电厂的重要性是不言而喻的，它直接关系到机组的使用寿命和安全经济运行。介绍了T91／P91钢的化学成分和主要物理性能，分析了T91／P91钢的力学性能和抗氧化腐蚀性能，给出了T91／P91钢的焊接工艺和方法，指出了需要进一步研究的问题。     

Measured Field Performance and Computer Analysis of Large-Diameter Multiplate Steel Pipe Culvert Installed in Ohio

Between 2001 and 2002, a 6.4-m (21.0-ft) diameter corrugated steel pipe culvert was erected and buried under a 22.9-m (75.0-ft) highway embankment fill in Meigs County, Ohio. This steel pipe culvert was the first of its kind to be constructed in the southeastern region of Ohio. The culvert structure was selected by the Ohio Department of Transportation over an alternative of a 5 million conventional bridge structure, because it would cost about $3.4 million less. The field performance of the culvert was monitored by measuring the pressure distribution around the pipe, as well as the deflections of the pipe culvert during and after construction. The culvert study also included comparing measured field performance with numerical predictions given by the finite-element computer program CANDE-89. CANDE-89 with the slotted joint option had a limited ability to simulate the actual field behavior of the large-diameter multiplate culvert structure, especially in the earlier stages of construction.     

The effect of gas injection on the hydraulic transport of slurries in horizontal pipes

The hydraulic transport of solid particles in a horizontal pipe is a well known practice in chemical plants and mining industry. The injection of gas into the flowing slurry results in a variety of flow patterns that affect the pressure gradient of the three-phase mixture in comparison with solid-liquid slurry flow. Furthermore, it may reduce or increase the pressure gradient relative to the conventional hydraulic transport of solids. This study constitutes the first attempt to formulate one-dimensional hydrodynamic models for evaluating the pressure gradients for stationary and moving solid beds overlaid by three-phase slug flow and for fully suspended three-phase slug flow of non-settling suspensions. The models for slug flow over stationary and moving beds are formulated by coupling the solid-liquid two-layer models of Doron et al. [1987. Slurry flow in horizontal pipes—experimental and modeling. International Journal of Multiphase Flow 13, 535-547] with a three-phase slug flow model. The proposed model for fully suspended three-phase slug flow constitutes an extension of the simple model for gas-liquid slug flow in horizontal pipes of Orell [2005. Experimental validation of a simple model for gas-liquid slug flow in horizontal pipes. Chemical Engineering Science 60, 1371-1381]. The proposed models, that are applicable to Newtonian slurries, were tested against the experimental data available in the literature over a wide range of operating conditions. In general, a good agreement was obtained between the predicted and experimental results.     

Pitting corrosion on 316L pipes in terephthalic acid (TA) dryer

Grade 316L is a type of austenitic stainless steel with ultra‐low carbon content and it exhibits superior corrosion resistance. However, pitting is always observed in 316L steel when it is exposed to media containing halide ions. In the present study, we found that in the presence of acetate acid (HAc) containing chloride or bromide ions, pitting occurred on the surface of the rotary steam pipes with the matrix material of 316L steel in terephthalic acid (TA) dryer. In order to identify the causes of the failure, metallographic structures and chemical compositions of the matrix material were inspected by an optical microscope (OM) and a photoelectric direct reading spectrometer. Beside these, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) as well as ion chromatography (IC) were used to analyze the micromorphologies of the corrosion pits and the chemical compositions of the corrosion deposits within them. Analysis of the results revealed the sources of halide ions and the factors accelerating the corrosion rate. Beside these, detailed mechanisms of pitting were discussed and six out of all the seven theoretical morphologies of pitting features were obtained in practice.     

聚乙烯煤气管不开挖敷设技术

论述了三种不挖沟敷设聚乙烯管技术的施工、应用和优缺点。     

GDQR法用于输流曲管的流致振动研究

将广义微分求积法(GDQR)用于分析输流曲管的流致振动问题,这是一个新的尝试．基于输流曲管的面内振动微分方程,利用GDQR法使曲管系统在空间域上得以离散化,从而获得了输流曲管的动力学方程组．数值算例中,计算得到了输流曲管在几种典型边界条件下的固有频率以及曲管发生失稳的临界流速等,这些计算结果与前人的解析解结果吻合较好．此外,还给出了两端固定输流曲管典型的动力响应行为．研究表明,GDQR法极易处理输流曲管这一类动力学模型,精度令人满意,进一步的研究可望推广到输流管道的非线性振动分析中．     

中深层地热地埋管实际运行影响因素研究

为研究中深层地热地埋管运行的影响因素,分析西咸新区中深层地热地埋管供暖系统的长期运行结果,并结合关中地区地质数据,建立深度为2510 m的中深层地埋管换热器全尺寸模型,采用数值模拟法研究实际岩层分布下地埋管的运行、结构和材料因素对其取热能力的影响。结果表明,西咸新区某项目1号地埋管和2号地埋管两个地埋管,其平均取热功率均在310 kW以上,具有优良的取热能力。地埋管进水温度随季节变化明显,并引起用户侧负荷及热泵回水温度的波动。在结构方面,随内管径由63 mm增至125 mm,平均出口水温和换热功率分别降低1.9%和4.8%,但内管径过小将影响内管运行的安全性,综合安全和换热两方面因素,最佳内管径应选取ϕ110 × 10mm规格;随外管径由168.3 mm增至244.5 mm,平均出口水温和换热功率分别增加3.5%和9%,综合成本和换热两方面因素,最佳外管径应选取ϕ 177.8 × 19 mm规格;在运行方面,地埋管出口水温随着流量的增加而减小,换热功率随着流量增加而增加;出口水温随着进水温度的升高而上升,换热功率也随之减小。在材料方面,减小内管导热系数和增加固井材料导热系数均能增加地埋管出口水温和换热功率,考虑换热功率变化和成本因素,在工程中导热系数为0.42 W/（m∙K）的内管和导热系数为3 W/（m∙K）左右的固井材料。     

换热管试压胎具的设计

在换热设备制造过程中,一般要求对换热管进行逐根压力试验或抽验。本文讨论利用换热管端面进行密封的试压胎具的设计。     

Experimental validation of a simple model for gas-liquid slug flow in horizontal pipes

In this work, the simple submodel of Taitel and Barnea (Chem. Eng. Sci. 45 (1990) 1191) for horizontal gas-liquid slug flow has been reformulated. An additional source of pressure loss suggested by Cook and Behnia (Chem. Eng. Sci. 55 (2000) 4699) was incorporated in the model, thus improving its predictive accuracy. The proposed model was tested extensively against 12 pressure gradient and eight liquid holdup data sources for both air-water and air-oil slug flow in smooth and rough pipes over a wide range of operating conditions. The very good agreement between the predicted and experimental results substantiates the general validity of the model.     

钢结构方矩形钢管的市场与技术探讨

通过对钢结构承重梁柱所用的三种型材(H型钢、方矩形管和圆管)各种性能的对比和分析，认为方矩形钢管是钢结构中最佳的立柱材料。结合国内外现状，指出钢结构方矩形钢管在我国还有一定的发展空间。同时简单介绍了方矩形钢管的三种生产方法以及生产时可能存在的问题，并给出了解决办法。