Applied Mechanics and Materials Vols. 249-250

Abstract: The International Thermal Experiment Reactor (ITER) is designed to operate for 20 years with high safety requirements. The magnets with their total weight being about 10,000t sit at the core of the ITER machine. In order to guarantee the safety of the ITER machine, the research of the manufacturing technology for ITER magnet supports (MS) is an indispensable working procedure before the MS are produced. The MS consist of toroidal field (TF) gravity supports (GS), poloidal field (PF) supports and correction coils (CC) supports. This paper summarizes that the preliminary research results for the manufacturing of the GS with thermal anchor, the reliable method to manufacture the U-shaped clamp with tapered slots for PF coil supports and the special devices for test of full-size fasteners used in all the MS.

Abstract: A numerical study for the simulation of melt in an injection-compression molding process by using moving grid is proposed in this paper. The fully three-dimensional Navier-Stokes equations are solved together with the front transport equation using a front capturing approach. Different from previous studies, the proposed model can take the movement of cavity through a moving grid approach. The melt filling of a disk is conducted to illustrate the applications of the proposed numerical model with several computations under different processing conditions. The numerically predicted results show the influence of compression time or compression speed in determining the molding pressure and the melt temperature.

Abstract: The performance of a proton exchange membrane fuel cell (PEMFC) under the fuel control system was investigated experimentally using dry hydrogen and oxygen gas. In this study, experiments have been carried out on the unit cell with the active area of 25cm2. Both sides of outflow lines were closed by valves. This investigation focuses on the low-power system which has a fuel flow control unit. The change of internal pressure in fuel cell and the checked system load were used as the control conditions for the solenoid valve. As the system loads were changed unexpectedly, the on/off control of fuel line was proposed as the way to supply hydrogen gas efficiently into the fuel cell. As a result, it was shown that the proposed procedures can display the load variation and increase the power request. Furthermore, this study could be beneficial for the fuel saving and the safety of fuel cell system.

Abstract: This paper focuses on drilling fault diagnosis with the technology of information fusion based on neural network and Dempster-Shafer evidence theory. Neural network is used to process the drilling engineering data monitored from drilling on-site. The primary diagnosis results of drilling faults can be obtained by comparing the outputs of the neural network. And also the outputs of neural network are utilized to construct a basic probability assignment function (mass function) to assign a value of mass function for each type of drilling faults. The final fault diagnosis results will be achieved by using Dempster-Shafer evidence theory on decision level through further reasoning primary diagnosis results of neural network. The proposed method can in time discover the engineering data whether abnormal so that can diagnose and classify them, and will improve the accuracy of the drilling fault diagnosis.

Abstract: Based on Fatemi-Socie model and Smith-Watson-Topper model, estimated fatigue lives were compared between conventional fatigue parameters method and three-parameter equation method. Predicted fatigue life of three different structural metal materials including 16MnR steel, 7075-T651 aluminium alloy and AZ31B magnesium alloy were checked. It is demonstrated that the three-parameter equation gives predicted results as well as conventional fatigue parameters method.

Abstract: Gas turbine cycles with after fogging where water is injected after compressor could offer enhanced efficiency compared to inlet fogging system due to higher water injection ratio. In this work the after fogging process is modeled based on the evaporation of droplets. Transient behaviors of the process are investigated with analytic expressions obtained by considering heat and mass transfer and thermodynamic relations. Effects of droplet size on the transient behaviors of important system variables are thoroughly investigated including diameter and mass of droplets, temperature and density of air, and mass flux and heat transfer from the droplets.

Abstract: Aimed at the structure and working condition analysis of the straight pad finger seal, an analysis model of the straight pad finger seal which contains three complete fingers is presented. And then the influence of heat effect to the seal structure body and fluid flow state is considered in the model. By using the thermal-fluid-solid interaction numerical calculation method, the working performance of the non-contacting finger seal and its change law with working condition is studied in the paper. The straight pad finger seal's leakage rate, gas film lift capacity and gas film flow field characteristics in different working conditions are analyzed. The results show that the gas film between finger foot and rotor has radial lift capacity, which can meet the requirement of reducing wear. And since the deformation of whole finger foot is relatively uniform, it is hard to have the appearance of circumferential warp. It is advantageous to adapt to the rotor radial runout and deflection. The performance of straight pad finger seal is influenced much more by the high-to low-pressure differential and the gas temperature of high pressure chamber. The work presented here provides helpful reference and theoretical basis to design the non-contacting finger seal with high performance.

Abstract: Planting requirement of Super Hybrid Rice is 2±1 seedlings per hill, so sowing seeds request seed quantity and position accuracy for super rice transplanting mechanization. Based on the physical characteristic of super rice seed’s surface that along its long axis the awns grow in all directions from glumes to the glumes tip, the rotation mechanism of rice seeds embryo to the same direction were researched. In consideration of the difference of rice seeds, the arc-shaped guided plate with high friction coefficient was proposed. Orthogonal method was used to analyze the influence of parameters on rice seeds arrangement and a set of parameters were got. Vibration seed metering device was fabricated, and its structure parameter could be adjusted conveniently. Experimental results showed that above 88% super rice seeds embryo were orienting ordered, and the seed metering device based on arc-shaped guided plate can be used in seeding pipeline.

Abstract: Centrifugal pump is widely used in plants as well as in common life. In many conditions, the centrifugal pumps do not operate in their optimal points for various reasons. In order to increase the efficiency, it is often used that the centrifugal pump rotates in different speed. In this paper, the 3D software UG is used to establish the model of pump. The simulation software FLUENT is used to analysis the flow field and pressure in the impeller. The numerical simulation shows that when the speed changed the flow field is similar in the impeller. The performance get from numerical simulation is compared with standard curve.

Abstract: In order to evaluate the efficacy of grooves on cooling performance of wet clutch, a numerical analysis based on the computational fluid dynamics (CFD) code FLUENT is presented in this study. This analysis is based on the numerical solution of the three-dimensional Navier-Stokes equation, coupled with the energy equation in the flow and the heat conduction equations in the friction material and the core disk. The turbulence characteristics were predicted using RNGk-ε model. The flow field and temperature distributions in radial grooves are obtained. It is shown that radial grooves possess the highest heat exchange performance at the entrance and is not linear distribution in the radial direction and cooling oil flow has a little effect on the highest temperature of friction plate. With the developed analysis method, it is possible to easily and quickly investigate the heat transfer behaviour of wet cluth with groove patterns.