Advanced Materials Research Vols. 557-559

Abstract: Large gear is widely used as a key component of heavy machineries. Gear shaping is the most commonly process of large gear manufacturing. For the design of large gear shaper, the determination of its main driving force depends on the empirical formula. However, its result has shown that the main driving force is much larger than what really needs, which produces a lot of waste. A novel analytical method is proposed in this paper. According to this method, the cutting area can be calculated precisely, and the design of main driving force will be more reasonably, it also provides the theoretical foundation for the design of large gear shaper.

Abstract: This paper is concerned about the scheduling problems in flexible production lines with no intermediate buffers. The optimization objective is to minimizing the makespan. The mathematical models are presented. Since the problem is NP-hard, a hybrid algorithm, based on genetic algorithm and tabu search, is put forward for solving the models. In this algorithm, the method of generating the initial population is proposed and the crossover and mutation operators, tabu list, and aspiration rule are newly designed. The performance of the hybrid algorithm is compared with that of the traditional genetic algorithm. The computational results show that satisfactory solutions can be obtained by the hybrid algorithm and it performs better than the genetic algorithm in terms of solution quality.

Abstract: The cold storage of nanofluids as the phase material in a two-dimensional enclosure was numerically simulated with Fluent software. The effect of copper particle concentration and Grashof number on cold storage properties was investigated. The results indicate that the cold storage properties exhibit little sensitivity to Grashof number, but the volume fraction of the nanoparticle is main effective factor on the cold storage properties. For a given initial Grashof number, as the solid particle volume fraction is raised the freezing time is lowered. Adding 1.0% Cu nanoparticles into pure water, the total freezing time can be saved by 16.3%. This is due to the enhanced thermal conductivity of the nanofluid in comparison to that of the base liquid. At the same time, due to lowering of the latent heat of fusion, less energy per unit mass of the nanofluid is needed for freezing the nanofluids. The observed higher heat release rate of the nanofluids is a clear indicator of its great potential for thermal energy storage applications.

Abstract: The effects of coupled internal pressure and external tension on corroded offshore pipe riser repaired with a designated laminate orientation of carbon/epoxy (C/E) and E-glass/epoxy (EG/E) fibre reinforced composite (FRC) was evaluated. The steel riser (API 5L X60) was characterised through Ramberg-Osgood model while input data of the composites were extracted from those used as benchmark for analysis in the first world-wide failure exercise (WWFE) [1, 2]. It was found that the C/E composite provides superiority over the EG/E and laminates with a dedicated orientation is capable of enhancing the performance of risers subjected to the coupled loadings.

Abstract: This paper deals with alkylation of benzene with propylene to produce cumene by Suspension Catalytic Distillation (SCD) which, as a new technology of process intensification, has been developed from traditional catalytic distillation. In this SCD process, the supported heteropolyacid catalysts are suspended inside the liquid phase on the column tray and flow with them, while in traditional catalytic distillation the catalyst pellets are generally fixed somewhere inside the column. SCD processes have been investigated for alkylation reaction of benzene with olefins in laboratorial scale. A pilot plant of SCD process for cumene synthesis had been run for several months. It has shown more advantageous characteristics for cumene synthesis compared with conventional process consisting of a reactor followed by distillation train. Based on experimental data and the reactive kinetic parameters of cumene synthesis using the supported heteropolyacid catalysts, numerical simulation of SCD process of the pilot plant was performed by an equilibrium stage model to study the effects of operation conditions on the process performance. The simulation results could agree, to a great extent, with the data acquired from the pilot plant experiment.

Abstract: A computational fluid dynamics (CFD) model was used to simulate unsteady fluid flow in a two-dimensional channel. The flow was computed for several different geometries and velocity. Calculations show different flow patterns of the cavity spacer, the submerged spacer and the zigzag spacer. Applications of two-dimensional CFD simulation give a visual method to determine the advantages of each spacer type.

Abstract: A pervaporation simulation was used to describe the fluid flow in a spacer filled channel for trichloroacetic acid (TCA) removal from water-TCA solution. The effects of spacers on enhancing fluid flow performance were examined. The CFD simulation results suggest that the presence of spacers causes velocity fluctuation, high shear stress and high pressure drop. This work also reports that the size, shape and location of spacers influence fluid flow performance remarkably.

Abstract: In the paper, flow status and solidification status of molten steel in inner-outer couple cooling mold in the filling process are simulated by using fluid dynamics software Flow-3d, and obtain distributing diagrams of flow field and temperature field and free-surface shape diagrams in the filling process. Influences of flow field and temperature field of filling process on solidification are analyzed in the slab continuous casting. It is indicated that inner cooler can improve molten steel flow status, which is favorable to inclusion in molten steel floating up, quicken the solidification rate of molten steel in the mold.

Abstract: Cooking fume(CF) with harmful pollutants and heat is paid more attention to by many peple. Physical and mathematical model are established on the basis of standard kitchen, and flow field characteristics(FFC) of the exhaust hood(EH) is simulated by CFD. Simulation of flow field of the EH indicates that, reasonable air exhaust rate(AER) is made for emissions of pollutants in kitchen; the effect of grille on flow field of the EH is obvious; the EH height selected correctly is beneficial to enhance the capture efficiency, and the exhaust effect will be strengthened. Air conditioning treatment should be applied in the kitchen and will be beneficial to decrease the indoor temperature of the kitchen and control pollutant concentration.

Abstract: As an important component of large-scale extruder system for polymer material, Die-plate can be regarded as the final determinant for pelletization quality. Flow fluctuation of extruder and die-hole blocking can be summarized as two uncertainties for pelletization quality problem. A Liquid-Solid-Liquid coupling FEM method is presented to simulate factors of temperature distribution, flow distribution and flow rate control. Based on the calculations and mechanism analysis, pelletization quality degree and assessment framework are designed and calculated to analyze the impact of operation uncertainties to final product. With the simulation and evaluation framework, control methods for pelletization quality are discussed for Die-plate design and operation condition settings.