管道宽度

The elastic stress diagram design method is behind the times and cant meet the command in practice.In the paper the author collected and analyzed a large amount of data about the SLRCP on several typical domestic model experiments and the projects in practice. By summarizing and analyzing the data, the author set up a typical computing model and analyzed the model by the software ANSYS, by reading the output data of the stress and the crack from the program, combined with the experimental results, the author summarized the destroy procession of the stock. The paper also discussed the influence of other main factors to the crack and the stress besides the internal water pressure, such as the concrete material, the dimension of stock and the way of laid-out steel bars.

本文通过对大量实际工程中的坝后背管资料的收集、归纳和分析，选取了具有代表性的计算模型；用有限元软件ANSYS计算了典型坝后背管结构在实际内水压力作用下的应力分布和裂缝发展情况；以国内几个有代表性的模型试验和有限元计算的成果为依据，分析了在内水压力作用下钢衬钢筋混凝土压力管道管壁裂缝的特点，并尝试总结出此种管道的裂缝出现的原因及其发展规律，同时确定了坝后背管结构极限状态的新的定义方式——以坝后背管的裂缝宽度来定义。

On the basis of common theory about the probability-limited state for the structure, the author summarized the cracking law of this penstock and put forward a new definition of particular crack width to judge the structures limited state. This formula is simple and practicable, and it can be used for reference in engineering design.

文章从混凝土裂缝的基本理论出发，采用合理的计算模式，并结合压力管道结构的特殊性，推导出了在内水压力等因素的作用下钢衬钢筋混凝土压力管道最大裂缝宽度的计算公式，并和有限元软件ANSYS分析的结果进行了对比，两者的吻合程度较好。

1 Roving Creel Stand with tube feed system utilizing high-density polyethylene tubing, 18 X 14 mm, 48 strands spaced evenly over the product width, with 25 mm spacing or other as specified by the customer.

粗纱线轴架以管道供给的装置，利用高密度聚乙烯管道，18*14mm的48根平置于产品上方，和产品的宽度相当，其间空隙为25毫米或可按客户要求制作。

And the effect of water pressure on concrete crack width is mainly studied; concrete crack width of penstocks in Three Gorges Hydropower Station is predicted in the end.

并重点研究了水头的变化对压力管道混凝土最大裂缝宽度的影响，最后对三峡电站压力管道混凝土结构裂缝进行了预测。

Steel lined reinforced concrete penstocks are used in former Soviet Union and China. The concrete cracks are permitted in design of penstocks, but the crack widths are not permitted to exceed the limited value.

钢衬钢筋混凝土压力管道应用于大型水电站中，一般在设计时都允许混凝土出现裂缝，但对裂缝宽度进行了限制，而实际工程实测值往往超过计算值。

Aiming at the uncertainty problem of crack character and location of concrete outside the penstocks,the cracking area of concrete outside the penstocks of the Three Gorges Hydropower Station under designed load is obtained by using nonlinear 3D-FEM.

针对三峡压力管道外包混凝土裂缝性状和位置的不确定性问题，通过对三峡压力管道的三维非线性有限元分析，得出了在设计荷载作用下三峡压力管道外包混凝土开裂区域位置，并给出了管道混凝土可能的最大裂缝宽度值。

Aiming at the uncertainty problem of crack character and location of concrete outside the pen-stocks, the cracking area of concrete outside the penstocks of the Three Gorges Hydropower Station under designed load is obtained by using nonlinear 3D-FEM. And the likely maximum width of crack of penstock concrete is also worked out.

针对三峡压力管道外包混凝土裂缝性状和位置的不确定性问题，通过对三峡压力管道的三维非线性有限元分析，得出了在设计荷载作用下三峡压力管道外包混凝土开裂区域位置，并给出了管道混凝土可能的最大裂缝宽度值。

Using diamond wire saw, underwater cutting experiment of seabed oil steel tube was conducted.

搭建了金刚石串珠绳锯水下切割试验系统，设置了初始试验参数，分析了管道不同部位切割时，切割面积和切口宽度与绳锯进给速度的关系。

It was the first time that experimental studies of the flow characteristics and convective heat transfer in platelet regenerative cooling channels with high aspect ratio were conducted in China.

大高宽比再生冷却套在宽度上已属于微小通道，为考察其流动传热是否与常规尺度管道不同，本文理论分析采用经典N-S方程而未考虑微小尺度效应是否合理，研究流道高宽比等几何参数对其水力和对流换热特性的影响，分别搭建了挤压式水力实验台和泵压式对流换热实验台，设计了d〓=1.0~1.2mm，宽度为0.6~0.8mm，AR=3~15的5个不同高宽比矩形通道层板试验件，采用线切割加工槽道和扩散焊接盖板的制造工艺，得到了质量可靠的试验件，以水为工质，在国内首次对大高宽比层板再生冷却通道的流动和对流换热特性进行了实验研究。

Plunder melds and run with this jewel!

掠夺melds和运行与此宝石！

My dream is to be a crazy growing tree and extend at the edge between the city and the forest.

此刻，也许正是在通往天国的路上，我体验着这白色的晕旋。