Key Engineering Materials Vol. 561

Abstract: To a great extent，traffic accidents of liquefied gas tankers are caused by the defects inside the tankers themselves. Analyzing what causes the defects, and putting forward the corresponding prevention measures, to reduce accident risk, is of great significance. In this paper, the research object is a defective liquefied gas tanker in a propylene factory in Shandong. The defects in actual transportation process containing weld joints defects and anti-wave plates are analyzed, and the corresponding solutions are put forward on the basis of the literature analysis. The results show that the main causes of the defects are that the manufacture and processing did not correspond with design data. The defects repair of the liquefied gas tanker should be performed by qualified service units after specific repair plan and relevant formalities are put forward. The repaired liquefied gas tanker should be inspected qualified by the inspection organizations.

Abstract: The preliminary study of the three-channel size adjustable coaxial nozzle which was used in supercritical fluid particles preparation technology was given in this paper, what's more, we considered the influence of some experimental conditions on the preparation product, such as pressure, nozzle size. According to the problem of reunion of cefuroxime axetil particles appeared in the preparation process, this paper elaborates the mechanism of reunion, and adopted the method of adding surfactants to solve the reunion problems effectively.

Abstract: According to pipe racking system exist nonlinear characteristics and in order to get smooth velocity of the racking in moving process. This paper structures a new kind of fuzzy neural network PID which identifies the target model and also provides a non-linear relation model for dynamic programming. In addition, by adopting robust feedback controller, the stability of the closed-loop system and satisfactory control results in initial stage of fuzzy neural network learning are also guaranteed. And we analyze the error response curve of sine signal tracking, the experimental results show that the improved fuzzy neural network PID controller has a higher control performance. The control method has fast response speed, less overshoot and error, strong robust and can meet the requirements of the nonlinear system.

Abstract: According to the three-dimensional mathematical model and physical model of evacuated tube transportation(ETT) system, thermal-pressure coupling equations based on viscous fluid Navier-Stokes equation and k- ε turbulence model are established for the first time. The numerical simulation is carried out to investigate the inherent laws for different blockage ratios of ETT system. The simulation results show that: when the speed of the train and the pressure of the system are constants, in the temperature field, the aerodynamic heating is getting more as the blockage ratio increases, and its trend grows exponential. In the pressure field, with the increase of the blockage ratio, the stagnation pressure is gradually increased, but the growth is getting slower; vortex region pressure reduces gradually, and has accelerated the decreasing trend; the pressure difference between the head and the end of the train is linear increment.

Abstract: The objective of this paper is to study the characteristic of a circular tube with a built-in arc belt on fluid flow and heat transfer in uniform wall temperature flows. Numerical simulations for hydrodynamically laminar flow was direct ran at Re between 600 and 1800. Preliminary results on velocity and temperature statistics for uniform wall temperature show that, arc belt can swirl the pipe fluid, so that the fluid at the center of the tube and the fluid of the boundary layer of the wall can mix fully, and plays the role of enhanced heat transfer, but also significantly increases the resistance of the fluid and makes the resistance coefficient of the enhanced tube greater than smooth tube. The combination property PEC is all above 1.5.

Abstract: According to the relevant national standards, this paper produced Corecell ™ G foam sandwich structure and Nomex honeycomb sandwich structure composite materials specimens. These two materials were carried out tensile, compression, bending and shear experiment. Analyzing and comparing the pros and cons of the two materials in the mechanical properties of tensile strength, compressive strength, shear strength, flexural strength.

Abstract: Straight ducts capture some essential features of the motion of foam in porous media in petroleum industry. In this paper, Surface Evolver was employed to build the mathematical model to study the flow behavior of lamellas in the duct with different models. Numerical results show good agreement with experiments and some important features of lamella flow behavior in straight ducts are obtained. It is concluded that, the physical model with viscous force can adequately describe the flow characteristics of reality foam in the experiment. The actual pressure difference consists of the pressure difference caused by the curvature of the lamellas and the drag force on the boundary wall. Under the ideal condition of without drag force along the wall, the pressure drop for lamella flow in the duct is zero, and the shape and the velocity of the lamellas will maintain constant.

Abstract: In the testing of the oil temperature controlling of hydraulic pump performance test-system, the changing of oil temperature bring the testing accuracy decrease, so it can influence nicety and contrast of test-bed. A computer device of oil temperature real time control are designed. The result of control achieve B level accuracy of international and guild. The software of computer is minimum variance correcting by oneself.

Abstract: Air splicing technology is the key technology to realize high speed, high quality and automatic winding in modern textile industry. However the current research of splicing mechanism is still in qualitative analysis, theoretical and experimental exploration stage. By modern computational mechanics method, with the air flow analysis results in different structures and shapes of splicer chamber, the air flow patterns under high pressure are determined; and the optimized structural characteristics of the splicing chamber are obtained in this paper. The results provide theoretical support on the innovative splicer chamber design, promote the development of the new air splicing technology, create important practical value, and provide the feasible means and methods in the air splicer theory research and optimization design.

Abstract: According to the properties of carbon black, this paper considers that the better filter as the dust removal equipment for carbon black pneumatic conveying system is pulse bag filter, describes the structure and working principle of the pulse bag filter, puts forward the factors to be considered and technical parameters to be selected to make sure that the carbon black pneumatic conveying system can work long and stably.