The effects of curvature radius and cutting speed on the top kerf width of circumferential laser cutting of thin seamless steel pipes with a small diameter (outer diameter of pipe D <80mm and wall thickness t =2.5mm) were investigated experimentally .

Several key design variables may be changed, such as diameter of pipe and velocity of flow of gas. These cases have been considered, and their results have also been compared with each other.

By comparing the calculation of waterpower in fixing pipe with time-delay and self-closing valve and installing pipe with float-valve in flush tank,the water pressure of the indoor and outdoor main pipe is obtained, which is needed by the diameter of pipe with self-closing valve and of water meter at the range of set flowing speed,so the normal efficiency of self-closing valve is guaranteed.

The results show that the values of the kerf width on the upper surface, the half squareness, and the HAZ increase with the increase of spatial curvature radius except for the values of the cut surface roughness R z as the diameter of pipe remains unchanged and the pitch increases.

This paper deals with the successful research of industrialized single-screw extrusion line of ultra high molecular weight polyethylene pipe. The parameters include that the screw diameter is 65mm, the diameter of pipe is 110mm, the output is 20-40 kg/h, the molecular weight of UHMWPE resin is 2. 5～3 million,and UHMWPE pipe obtains the same continuous and stable extrusion process as that of common plastics pipe.

It is found that the best work conditions for the instrument is as following: The chromogenic agent's concentration is 0.01%, the inside diameter of pipe is 0.5mm, the length of pipe is 100cm, the sampling volume is 150ul, the pipe is knotted.

The Wei He Fertilizer Works uses water cycle cooling technology of Marley Company USA. The cycle water is about 900, 000 tons per day. Diameter of pipe is 1600- 1800 mm and underground depth is around 5m.

The basic steps for analysizing the system were checking the technical parameters of every equipment,the structure of pipe network and the diameter of pipe,determining the emergency discharge conditions for single equipment,the simultaneously discharge conditions for multiequipments and the maxium safety discharge of equipment,calculating the transfer capacity of discharge pipe network.

Some experiments were carried out by the method of flow injection analysis and the influence of chromogenic agent's concentration, the inside diameter of pipe, the length of pipe, the flow rate of carrier, the analysis rate, the sampling volume and the shape of pipe on the absorption were discussed.

Characteristics of local pressure drop caused by oil water emulsion flowing through horizontal inlet and vertical upward outlet 90° bent are studied. The inner diameter of pipe is 45? mm, the curvature radius of bent is 300?

Of theconfigurations tested, the stilling basin model M-24 with tworows of wedge-shaped baffle blocks in a basin length of sixtimes the diameter of pipe outlet (6d) performed better incomparison to USBR impact type VI stilling basin.

The most thermal stress is in inverse proportion to diameter of pipe and velocity of inlet air.

The computed results show that the large thermal stress exits in the SiC, and the stand pipe should be ellipse for the least thermal stress; the optimal ratio of thickness to diameter of pipe is 6, the velocity of inlet air is 25 m/s.

The structural and operational parameters of heat exchanger, the junction between standpipe and snake pipe, the diameter of snake pipe, ratio of thickness to diameter of pipe, velocity of inlet air were optimized for thermal stress.

Place to minimum 6 inch thickness around outside diameter of pipe.

In this paper, based on many experiments, an empirical correlation between the drag reduction onset wall shear stress Tw~* and the mote hydraulic volume of linear macromolecular polymer M[η] is presented. The accuracy of this formula is εatisfying, and the onset wall shear stress Tw~* derived from it is in accord with the experimental data obtained by other experimenters abroad.The concentration of polymer solutions, the diameter of pipes effect on onset wall shear stress Tw~* and the tendency of the flow...

In this paper, based on many experiments, an empirical correlation between the drag reduction onset wall shear stress Tw~* and the mote hydraulic volume of linear macromolecular polymer M[η] is presented. The accuracy of this formula is εatisfying, and the onset wall shear stress Tw~* derived from it is in accord with the experimental data obtained by other experimenters abroad.The concentration of polymer solutions, the diameter of pipes effect on onset wall shear stress Tw~* and the tendency of the flow curves after onset are analyzed.All the experiments were performed in two apparatuses consisting of smoothpipes. (Their inner diameters are d=0.587cm and D=2.3cm respectively.) Some polymers usually employed for drag reduction made in China——polyacrylamide, homopolymer and partially hydrolyzed (their molecular weight ranges from 3×10~6 to 10×10~6) were used.The factors which affect the condition at onset of drag reduction were observed and analyzed carefully.

In this paper the author on basis of theory of water hammer de- rives a famula of calculating the water hammer pressure in different diameters of pipes which might serve as a useful reference in enginee- ring designs.

本文根据水击基本理论,推导出异径管道水击压力计算公式,可供工程设计参考.

The turbulent flow of plastic fluids in smooth pipes has been studied by using the stochastic theory of turbulent flow, and the formulas have been presented for evaluating the time average velocity in the whole section of pipes, mean velocity and friction factor. The results obtained from the study have shown that the influence of the yeild stress of plastic fluids on turbulent flow is determined by τ_o/τ_w. The influence will be soon reduced as Re(z) increses or the diameter of pipe reduces. The influence...

The turbulent flow of plastic fluids in smooth pipes has been studied by using the stochastic theory of turbulent flow, and the formulas have been presented for evaluating the time average velocity in the whole section of pipes, mean velocity and friction factor. The results obtained from the study have shown that the influence of the yeild stress of plastic fluids on turbulent flow is determined by τ_o/τ_w. The influence will be soon reduced as Re(z) increses or the diameter of pipe reduces. The influence of the yeild stress on the dimensionless velocity profile is very small